[PATCH v3 0/8] Add objtool and orc support for LoongArch

[PATCH v3 0/8] Add objtool and orc support for LoongArch

[Tiezhu Yang]

This version is based on the latest torvalds/linux.git (20231020)
which includes the commit 00c2ca84c680 ("LoongArch: Use SYM_CODE_*
to annotate exception handlers"), tested with the latest upstream
gcc and binutils (20231009).

v3:
  -- Use tab for indentation in special.h
  -- Replace BP/bp with FP/fp
  -- Modify jirl decoder to handle special case in hibernate_asm.o
  -- Remove the calling of bswap_if_needed() which always return false
  -- Remove OBJECT_FILES_NON_STANDARD_suspend_asm.o
  -- Remove check of assembler version in Makefile
  -- Remove UNWIND_HINT_EMPTY in kernel_entry
  -- Put unwind_init() after cpu_probe()
  -- Remove CONFIG_BPF_JIT_ALWAYS_ON in defconfig
  -- Rename title of patch #8 to "Add ORC stack unwinder support"
  -- Fix build error of scripts/sorttable.h reported by test robot
  -- Add exception_table[] to save exception handlers

Tiezhu Yang (8):
  objtool/LoongArch: Enable objtool to be built
  objtool/LoongArch: Implement instruction decoder
  objtool/x86: Separate arch-specific and generic parts
  objtool/LoongArch: Enable orc to be built
  objtool: Check local label about sibling call
  objtool: Check local label in add_dead_ends()
  objtool: Check local label in read_unwind_hints()
  LoongArch: Add ORC stack unwinder support

 arch/loongarch/Kconfig                             |   2 +
 arch/loongarch/Kconfig.debug                       |  11 +
 arch/loongarch/Makefile                            |  18 +
 arch/loongarch/include/asm/Kbuild                  |   1 +
 arch/loongarch/include/asm/bug.h                   |   1 +
 arch/loongarch/include/asm/exception.h             |   2 +
 arch/loongarch/include/asm/module.h                |   7 +
 arch/loongarch/include/asm/orc_header.h            |  19 +
 arch/loongarch/include/asm/orc_lookup.h            |  34 ++
 arch/loongarch/include/asm/orc_types.h             |  58 +++
 arch/loongarch/include/asm/stackframe.h            |   3 +
 arch/loongarch/include/asm/unwind.h                |  22 +-
 arch/loongarch/include/asm/unwind_hints.h          |  28 ++
 arch/loongarch/kernel/Makefile                     |   3 +
 arch/loongarch/kernel/entry.S                      |   5 +
 arch/loongarch/kernel/genex.S                      |   4 +
 arch/loongarch/kernel/module.c                     |  11 +-
 arch/loongarch/kernel/relocate_kernel.S            |   2 +
 arch/loongarch/kernel/setup.c                      |   2 +
 arch/loongarch/kernel/stacktrace.c                 |   1 +
 arch/loongarch/kernel/traps.c                      |  44 +-
 arch/loongarch/kernel/unwind_orc.c                 | 522 +++++++++++++++++++++
 arch/loongarch/kernel/vmlinux.lds.S                |   3 +
 arch/loongarch/lib/Makefile                        |   2 +
 arch/loongarch/mm/tlb.c                            |  27 +-
 arch/loongarch/mm/tlbex.S                          |   9 +
 arch/loongarch/vdso/Makefile                       |   1 +
 include/linux/compiler.h                           |   9 +
 scripts/Makefile                                   |   7 +-
 tools/arch/loongarch/include/asm/inst.h            | 161 +++++++
 tools/arch/loongarch/include/asm/orc_types.h       |  58 +++
 tools/include/linux/bitops.h                       |  11 +
 tools/objtool/Makefile                             |   4 +
 tools/objtool/arch/loongarch/Build                 |   3 +
 tools/objtool/arch/loongarch/decode.c              | 352 ++++++++++++++
 .../objtool/arch/loongarch/include/arch/cfi_regs.h |  22 +
 tools/objtool/arch/loongarch/include/arch/elf.h    |  30 ++
 .../objtool/arch/loongarch/include/arch/special.h  |  33 ++
 tools/objtool/arch/loongarch/orc.c                 | 171 +++++++
 tools/objtool/arch/loongarch/special.c             |  15 +
 tools/objtool/arch/x86/Build                       |   1 +
 tools/objtool/arch/x86/orc.c                       | 188 ++++++++
 tools/objtool/check.c                              | 118 +++--
 tools/objtool/include/objtool/orc.h                |  14 +
 tools/objtool/orc_dump.c                           |  69 +--
 tools/objtool/orc_gen.c                            | 113 +----
 46 files changed, 1964 insertions(+), 257 deletions(-)
 create mode 100644 arch/loongarch/include/asm/orc_header.h
 create mode 100644 arch/loongarch/include/asm/orc_lookup.h
 create mode 100644 arch/loongarch/include/asm/orc_types.h
 create mode 100644 arch/loongarch/include/asm/unwind_hints.h
 create mode 100644 arch/loongarch/kernel/unwind_orc.c
 create mode 100644 tools/arch/loongarch/include/asm/inst.h
 create mode 100644 tools/arch/loongarch/include/asm/orc_types.h
 create mode 100644 tools/objtool/arch/loongarch/Build
 create mode 100644 tools/objtool/arch/loongarch/decode.c
 create mode 100644 tools/objtool/arch/loongarch/include/arch/cfi_regs.h
 create mode 100644 tools/objtool/arch/loongarch/include/arch/elf.h
 create mode 100644 tools/objtool/arch/loongarch/include/arch/special.h
 create mode 100644 tools/objtool/arch/loongarch/orc.c
 create mode 100644 tools/objtool/arch/loongarch/special.c
 create mode 100644 tools/objtool/arch/x86/orc.c
 create mode 100644 tools/objtool/include/objtool/orc.h

-- 
2.1.0

[PATCH v3 1/8] objtool/LoongArch: Enable objtool to be built

[Tiezhu Yang]

Add the minimal changes to enable objtool build on LoongArch,
most of the functions are stubs to only fix the build errors
when make -C tools/objtool.

This is similar with commit e52ec98c5ab1 ("objtool/powerpc:
Enable objtool to be built on ppc").

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/objtool/arch/loongarch/Build                 |  2 +
 tools/objtool/arch/loongarch/decode.c              | 71 ++++++++++++++++++++++
 .../objtool/arch/loongarch/include/arch/cfi_regs.h | 22 +++++++
 tools/objtool/arch/loongarch/include/arch/elf.h    | 30 +++++++++
 .../objtool/arch/loongarch/include/arch/special.h  | 33 ++++++++++
 tools/objtool/arch/loongarch/special.c             | 15 +++++
 6 files changed, 173 insertions(+)
 create mode 100644 tools/objtool/arch/loongarch/Build
 create mode 100644 tools/objtool/arch/loongarch/decode.c
 create mode 100644 tools/objtool/arch/loongarch/include/arch/cfi_regs.h
 create mode 100644 tools/objtool/arch/loongarch/include/arch/elf.h
 create mode 100644 tools/objtool/arch/loongarch/include/arch/special.h
 create mode 100644 tools/objtool/arch/loongarch/special.c

diff --git a/tools/objtool/arch/loongarch/Build b/tools/objtool/arch/loongarch/Build
new file mode 100644
index 0000000..d24d563
--- /dev/null
+++ b/tools/objtool/arch/loongarch/Build
@@ -0,0 +1,2 @@
+objtool-y += decode.o
+objtool-y += special.o
diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
new file mode 100644
index 0000000..cc74ba4
--- /dev/null
+++ b/tools/objtool/arch/loongarch/decode.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+#include <objtool/check.h>
+
+int arch_ftrace_match(char *name)
+{
+	return !strcmp(name, "_mcount");
+}
+
+unsigned long arch_jump_destination(struct instruction *insn)
+{
+	return insn->offset + (insn->immediate << 2);
+}
+
+unsigned long arch_dest_reloc_offset(int addend)
+{
+	return addend;
+}
+
+bool arch_pc_relative_reloc(struct reloc *reloc)
+{
+	return false;
+}
+
+bool arch_callee_saved_reg(unsigned char reg)
+{
+	switch (reg) {
+	case CFI_RA:
+	case CFI_FP:
+	case CFI_S0 ... CFI_S8:
+		return true;
+	default:
+		return false;
+	}
+}
+
+int arch_decode_hint_reg(u8 sp_reg, int *base)
+{
+	return 0;
+}
+
+int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
+			    unsigned long offset, unsigned int maxlen,
+			    struct instruction *insn)
+{
+	return 0;
+}
+
+const char *arch_nop_insn(int len)
+{
+	return NULL;
+}
+
+const char *arch_ret_insn(int len)
+{
+	return NULL;
+}
+
+void arch_initial_func_cfi_state(struct cfi_init_state *state)
+{
+	int i;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		state->regs[i].base = CFI_UNDEFINED;
+		state->regs[i].offset = 0;
+	}
+
+	/* initial CFA (call frame address) */
+	state->cfa.base = CFI_SP;
+	state->cfa.offset = 0;
+}
diff --git a/tools/objtool/arch/loongarch/include/arch/cfi_regs.h b/tools/objtool/arch/loongarch/include/arch/cfi_regs.h
new file mode 100644
index 0000000..d183cc8
--- /dev/null
+++ b/tools/objtool/arch/loongarch/include/arch/cfi_regs.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_CFI_REGS_H
+#define _OBJTOOL_ARCH_CFI_REGS_H
+
+#define CFI_RA		1
+#define CFI_SP		3
+#define CFI_A0		4
+#define CFI_FP		22
+#define CFI_S0		23
+#define CFI_S1		24
+#define CFI_S2		25
+#define CFI_S3		26
+#define CFI_S4		27
+#define CFI_S5		28
+#define CFI_S6		29
+#define CFI_S7		30
+#define CFI_S8		31
+#define CFI_NUM_REGS	32
+
+#define CFI_BP		CFI_FP
+
+#endif /* _OBJTOOL_ARCH_CFI_REGS_H */
diff --git a/tools/objtool/arch/loongarch/include/arch/elf.h b/tools/objtool/arch/loongarch/include/arch/elf.h
new file mode 100644
index 0000000..9623d66
--- /dev/null
+++ b/tools/objtool/arch/loongarch/include/arch/elf.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_ELF_H
+#define _OBJTOOL_ARCH_ELF_H
+
+/*
+ * See the following link for more info about ELF Relocation types:
+ * https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_relocations
+ */
+#ifndef R_LARCH_NONE
+#define R_LARCH_NONE		0
+#endif
+#ifndef R_LARCH_32
+#define R_LARCH_32		1
+#endif
+#ifndef R_LARCH_64
+#define R_LARCH_64		2
+#endif
+#ifndef R_LARCH_32_PCREL
+#define R_LARCH_32_PCREL	99
+#endif
+
+#define R_NONE			R_LARCH_NONE
+#define R_ABS32			R_LARCH_32
+#define R_ABS64			R_LARCH_64
+#define R_DATA32		R_LARCH_32_PCREL
+#define R_DATA64		R_LARCH_32_PCREL
+#define R_TEXT32		R_LARCH_32_PCREL
+#define R_TEXT64		R_LARCH_32_PCREL
+
+#endif /* _OBJTOOL_ARCH_ELF_H */
diff --git a/tools/objtool/arch/loongarch/include/arch/special.h b/tools/objtool/arch/loongarch/include/arch/special.h
new file mode 100644
index 0000000..35fc979
--- /dev/null
+++ b/tools/objtool/arch/loongarch/include/arch/special.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_SPECIAL_H
+#define _OBJTOOL_ARCH_SPECIAL_H
+
+/*
+ * See more info about struct exception_table_entry
+ * in arch/loongarch/include/asm/extable.h
+ */
+#define EX_ENTRY_SIZE		12
+#define EX_ORIG_OFFSET		0
+#define EX_NEW_OFFSET		4
+
+/*
+ * See more info about struct jump_entry
+ * in include/linux/jump_label.h
+ */
+#define JUMP_ENTRY_SIZE		16
+#define JUMP_ORIG_OFFSET	0
+#define JUMP_NEW_OFFSET		4
+#define JUMP_KEY_OFFSET		8
+
+/*
+ * See more info about struct alt_instr
+ * in arch/loongarch/include/asm/alternative.h
+ */
+#define ALT_ENTRY_SIZE		12
+#define ALT_ORIG_OFFSET		0
+#define ALT_NEW_OFFSET		4
+#define ALT_FEATURE_OFFSET	8
+#define ALT_ORIG_LEN_OFFSET	10
+#define ALT_NEW_LEN_OFFSET	11
+
+#endif /* _OBJTOOL_ARCH_SPECIAL_H */
diff --git a/tools/objtool/arch/loongarch/special.c b/tools/objtool/arch/loongarch/special.c
new file mode 100644
index 0000000..9bba1e9
--- /dev/null
+++ b/tools/objtool/arch/loongarch/special.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <objtool/special.h>
+
+bool arch_support_alt_relocation(struct special_alt *special_alt,
+				 struct instruction *insn,
+				 struct reloc *reloc)
+{
+	return false;
+}
+
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				     struct instruction *insn)
+{
+	return NULL;
+}
-- 
2.1.0

[PATCH v3 2/8] objtool/LoongArch: Implement instruction decoder

[Tiezhu Yang]

Only copy the minimal definitions of instruction opcodes and formats
in inst.h from arch/loongarch to tools/arch/loongarch, and also copy
the definition of sign_extend64() to tools/include/linux/bitops.h to
decode the following kinds of instructions:

(1) stack pointer related instructions
addi.d, ld.d, st.d, ldptr.d and stptr.d

(2) branch and jump related instructions
beq, bne, blt, bge, bltu, bgeu, beqz, bnez, bceqz, bcnez, b, bl and jirl

(3) other instructions
break, nop and ertn

See more info about instructions in LoongArch Reference Manual:
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/arch/loongarch/include/asm/inst.h | 161 +++++++++++++++++++
 tools/include/linux/bitops.h            |  11 ++
 tools/objtool/arch/loongarch/decode.c   | 269 +++++++++++++++++++++++++++++++-
 3 files changed, 439 insertions(+), 2 deletions(-)
 create mode 100644 tools/arch/loongarch/include/asm/inst.h

diff --git a/tools/arch/loongarch/include/asm/inst.h b/tools/arch/loongarch/include/asm/inst.h
new file mode 100644
index 0000000..c25b585
--- /dev/null
+++ b/tools/arch/loongarch/include/asm/inst.h
@@ -0,0 +1,161 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_INST_H
+#define _ASM_INST_H
+
+#include <linux/bitops.h>
+
+#define LOONGARCH_INSN_NOP		0x03400000
+
+enum reg0i15_op {
+	break_op	= 0x54,
+};
+
+enum reg0i26_op {
+	b_op		= 0x14,
+	bl_op		= 0x15,
+};
+
+enum reg1i21_op {
+	beqz_op		= 0x10,
+	bnez_op		= 0x11,
+	bceqz_op	= 0x12, /* bits[9:8] = 0x00 */
+	bcnez_op	= 0x12, /* bits[9:8] = 0x01 */
+};
+
+enum reg2_op {
+	ertn_op		= 0x1920e,
+};
+
+enum reg2i12_op {
+	addid_op	= 0x0b,
+	andi_op		= 0x0d,
+	ldd_op		= 0xa3,
+	std_op		= 0xa7,
+};
+
+enum reg2i14_op {
+	ldptrd_op	= 0x26,
+	stptrd_op	= 0x27,
+};
+
+enum reg2i16_op {
+	jirl_op		= 0x13,
+	beq_op		= 0x16,
+	bne_op		= 0x17,
+	blt_op		= 0x18,
+	bge_op		= 0x19,
+	bltu_op		= 0x1a,
+	bgeu_op		= 0x1b,
+};
+
+struct reg0i15_format {
+	unsigned int immediate : 15;
+	unsigned int opcode : 17;
+};
+
+struct reg0i26_format {
+	unsigned int immediate_h : 10;
+	unsigned int immediate_l : 16;
+	unsigned int opcode : 6;
+};
+
+struct reg1i21_format {
+	unsigned int immediate_h  : 5;
+	unsigned int rj : 5;
+	unsigned int immediate_l : 16;
+	unsigned int opcode : 6;
+};
+
+struct reg2_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int opcode : 22;
+};
+
+struct reg2i12_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 12;
+	unsigned int opcode : 10;
+};
+
+struct reg2i14_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 14;
+	unsigned int opcode : 8;
+};
+
+struct reg2i16_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 16;
+	unsigned int opcode : 6;
+};
+
+union loongarch_instruction {
+	unsigned int word;
+	struct reg0i15_format	reg0i15_format;
+	struct reg0i26_format	reg0i26_format;
+	struct reg1i21_format	reg1i21_format;
+	struct reg2_format	reg2_format;
+	struct reg2i12_format	reg2i12_format;
+	struct reg2i14_format	reg2i14_format;
+	struct reg2i16_format	reg2i16_format;
+};
+
+#define LOONGARCH_INSN_SIZE	sizeof(union loongarch_instruction)
+
+enum loongarch_gpr {
+	LOONGARCH_GPR_ZERO = 0,
+	LOONGARCH_GPR_RA = 1,
+	LOONGARCH_GPR_TP = 2,
+	LOONGARCH_GPR_SP = 3,
+	LOONGARCH_GPR_A0 = 4,	/* Reused as V0 for return value */
+	LOONGARCH_GPR_A1,	/* Reused as V1 for return value */
+	LOONGARCH_GPR_A2,
+	LOONGARCH_GPR_A3,
+	LOONGARCH_GPR_A4,
+	LOONGARCH_GPR_A5,
+	LOONGARCH_GPR_A6,
+	LOONGARCH_GPR_A7,
+	LOONGARCH_GPR_T0 = 12,
+	LOONGARCH_GPR_T1,
+	LOONGARCH_GPR_T2,
+	LOONGARCH_GPR_T3,
+	LOONGARCH_GPR_T4,
+	LOONGARCH_GPR_T5,
+	LOONGARCH_GPR_T6,
+	LOONGARCH_GPR_T7,
+	LOONGARCH_GPR_T8,
+	LOONGARCH_GPR_FP = 22,
+	LOONGARCH_GPR_S0 = 23,
+	LOONGARCH_GPR_S1,
+	LOONGARCH_GPR_S2,
+	LOONGARCH_GPR_S3,
+	LOONGARCH_GPR_S4,
+	LOONGARCH_GPR_S5,
+	LOONGARCH_GPR_S6,
+	LOONGARCH_GPR_S7,
+	LOONGARCH_GPR_S8,
+	LOONGARCH_GPR_MAX
+};
+
+#define DEF_EMIT_REG2I16_FORMAT(NAME, OP)				\
+static inline void emit_##NAME(union loongarch_instruction *insn,	\
+			       enum loongarch_gpr rj,			\
+			       enum loongarch_gpr rd,			\
+			       int offset)				\
+{									\
+	insn->reg2i16_format.opcode = OP;				\
+	insn->reg2i16_format.immediate = offset;			\
+	insn->reg2i16_format.rj = rj;					\
+	insn->reg2i16_format.rd = rd;					\
+}
+
+DEF_EMIT_REG2I16_FORMAT(jirl, jirl_op)
+
+#endif /* _ASM_INST_H */
diff --git a/tools/include/linux/bitops.h b/tools/include/linux/bitops.h
index f18683b9..7319f6c 100644
--- a/tools/include/linux/bitops.h
+++ b/tools/include/linux/bitops.h
@@ -87,4 +87,15 @@ static inline __u32 rol32(__u32 word, unsigned int shift)
 	return (word << shift) | (word >> ((-shift) & 31));
 }
 
+/**
+ * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
+ * @value: value to sign extend
+ * @index: 0 based bit index (0<=index<64) to sign bit
+ */
+static __always_inline __s64 sign_extend64(__u64 value, int index)
+{
+	__u8 shift = 63 - index;
+	return (__s64)(value << shift) >> shift;
+}
+
 #endif
diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
index cc74ba4..0ee3333 100644
--- a/tools/objtool/arch/loongarch/decode.c
+++ b/tools/objtool/arch/loongarch/decode.c
@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 #include <string.h>
 #include <objtool/check.h>
+#include <objtool/warn.h>
+#include <asm/inst.h>
 
 int arch_ftrace_match(char *name)
 {
@@ -39,21 +41,284 @@ int arch_decode_hint_reg(u8 sp_reg, int *base)
 	return 0;
 }
 
+static bool is_loongarch(const struct elf *elf)
+{
+	if (elf->ehdr.e_machine == EM_LOONGARCH)
+		return true;
+
+	WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
+	return false;
+}
+
+#define ADD_OP(op) \
+	if (!(op = calloc(1, sizeof(*op)))) \
+		return -1; \
+	else for (*ops_list = op, ops_list = &op->next; op; op = NULL)
+
+static bool decode_insn_reg0i26_fomat(union loongarch_instruction inst,
+				      struct instruction *insn)
+{
+	switch (inst.reg0i26_format.opcode) {
+	case b_op:
+		insn->type = INSN_JUMP_UNCONDITIONAL;
+		insn->immediate = sign_extend64(inst.reg0i26_format.immediate_h << 16 |
+						inst.reg0i26_format.immediate_l, 25);
+		break;
+	case bl_op:
+		insn->type = INSN_CALL;
+		insn->immediate = sign_extend64(inst.reg0i26_format.immediate_h << 16 |
+						inst.reg0i26_format.immediate_l, 25);
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg1i21_fomat(union loongarch_instruction inst,
+				      struct instruction *insn)
+{
+	switch (inst.reg1i21_format.opcode) {
+	case beqz_op:
+	case bnez_op:
+	case bceqz_op:
+		insn->type = INSN_JUMP_CONDITIONAL;
+		insn->immediate = sign_extend64(inst.reg1i21_format.immediate_h << 16 |
+						inst.reg1i21_format.immediate_l, 20);
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg2i12_fomat(union loongarch_instruction inst,
+				      struct instruction *insn,
+				      struct stack_op **ops_list,
+				      struct stack_op *op)
+{
+	switch (inst.reg2i12_format.opcode) {
+	case addid_op:
+		if ((inst.reg2i12_format.rd == CFI_SP) || (inst.reg2i12_format.rj == CFI_SP)) {
+			/* addi.d sp,sp,si12 or addi.d fp,sp,si12 */
+			insn->immediate = sign_extend64(inst.reg2i12_format.immediate, 11);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = inst.reg2i12_format.rj;
+				op->src.offset = insn->immediate;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = inst.reg2i12_format.rd;
+			}
+		}
+		break;
+	case ldd_op:
+		if (inst.reg2i12_format.rj == CFI_SP) {
+			/* ld.d rd,sp,si12 */
+			insn->immediate = sign_extend64(inst.reg2i12_format.immediate, 11);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_SP;
+				op->src.offset = insn->immediate;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = inst.reg2i12_format.rd;
+			}
+		}
+		break;
+	case std_op:
+		if (inst.reg2i12_format.rj == CFI_SP) {
+			/* st.d rd,sp,si12 */
+			insn->immediate = sign_extend64(inst.reg2i12_format.immediate, 11);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = inst.reg2i12_format.rd;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_SP;
+				op->dest.offset = insn->immediate;
+			}
+		}
+		break;
+	case andi_op:
+		if (inst.reg2i12_format.rd == 0 &&
+		    inst.reg2i12_format.rj == 0 &&
+		    inst.reg2i12_format.immediate == 0)
+			/* andi r0,r0,0 */
+			insn->type = INSN_NOP;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg2i14_fomat(union loongarch_instruction inst,
+				      struct instruction *insn,
+				      struct stack_op **ops_list,
+				      struct stack_op *op)
+{
+	switch (inst.reg2i14_format.opcode) {
+	case ldptrd_op:
+		if (inst.reg2i14_format.rj == CFI_SP) {
+			/* ldptr.d rd,sp,si14 */
+			insn->immediate = sign_extend64(inst.reg2i14_format.immediate, 13);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_SP;
+				op->src.offset = insn->immediate;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = inst.reg2i14_format.rd;
+			}
+		}
+		break;
+	case stptrd_op:
+		if (inst.reg2i14_format.rj == CFI_SP) {
+			/* stptr.d ra,sp,0 */
+			if (inst.reg2i14_format.rd == LOONGARCH_GPR_RA &&
+			    inst.reg2i14_format.immediate == 0)
+				break;
+
+			/* stptr.d rd,sp,si14 */
+			insn->immediate = sign_extend64(inst.reg2i14_format.immediate, 13);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = inst.reg2i14_format.rd;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_SP;
+				op->dest.offset = insn->immediate;
+			}
+		}
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg2i16_fomat(union loongarch_instruction inst,
+				      struct instruction *insn)
+{
+	switch (inst.reg2i16_format.opcode) {
+	case jirl_op:
+		if (inst.reg2i16_format.rd == 0 &&
+		    inst.reg2i16_format.rj == CFI_RA &&
+		    inst.reg2i16_format.immediate == 0) {
+			/* jirl r0,ra,0 */
+			insn->type = INSN_RETURN;
+		} else if (inst.reg2i16_format.rd == CFI_RA) {
+			/* jirl ra,rj,offs16 */
+			insn->type = INSN_CALL_DYNAMIC;
+		} else if (inst.reg2i16_format.rd == CFI_A0 &&
+			   inst.reg2i16_format.immediate == 0) {
+			/*
+			 * jirl a0,t0,0
+			 * this is a special case in loongarch_suspend_enter,
+			 * just treat it as a call instruction.
+			 */
+			insn->type = INSN_CALL_DYNAMIC;
+		} else if (inst.reg2i16_format.rd == 0 &&
+			   inst.reg2i16_format.immediate == 0) {
+			/* jirl r0,rj,0 */
+			insn->type = INSN_JUMP_DYNAMIC;
+		} else if (inst.reg2i16_format.rd == 0 &&
+			   inst.reg2i16_format.immediate != 0) {
+			/*
+			 * jirl r0,t0,12
+			 * this is a rare case in JUMP_VIRT_ADDR,
+			 * just ignore it due to it is harmless for tracing.
+			 */
+			break;
+		} else {
+			/* jirl rd,rj,offs16 */
+			insn->type = INSN_JUMP_UNCONDITIONAL;
+			insn->immediate = sign_extend64(inst.reg2i16_format.immediate, 15);
+		}
+		break;
+	case beq_op:
+	case bne_op:
+	case blt_op:
+	case bge_op:
+	case bltu_op:
+	case bgeu_op:
+		insn->type = INSN_JUMP_CONDITIONAL;
+		insn->immediate = sign_extend64(inst.reg2i16_format.immediate, 15);
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
 int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
 			    unsigned long offset, unsigned int maxlen,
 			    struct instruction *insn)
 {
+	struct stack_op **ops_list = &insn->stack_ops;
+	const struct elf *elf = file->elf;
+	struct stack_op *op = NULL;
+	union loongarch_instruction inst;
+
+	if (!is_loongarch(elf))
+		return -1;
+
+	if (maxlen < LOONGARCH_INSN_SIZE)
+		return 0;
+
+	insn->len = LOONGARCH_INSN_SIZE;
+	insn->type = INSN_OTHER;
+	insn->immediate = 0;
+
+	inst = *(union loongarch_instruction *)(sec->data->d_buf + offset);
+
+	if (decode_insn_reg0i26_fomat(inst, insn))
+		return 0;
+	if (decode_insn_reg1i21_fomat(inst, insn))
+		return 0;
+	if (decode_insn_reg2i12_fomat(inst, insn, ops_list, op))
+		return 0;
+	if (decode_insn_reg2i14_fomat(inst, insn, ops_list, op))
+		return 0;
+	if (decode_insn_reg2i16_fomat(inst, insn))
+		return 0;
+
+	if (inst.word == 0)
+		insn->type = INSN_NOP;
+	else if (inst.reg0i15_format.opcode == break_op) {
+		/* break */
+		insn->type = INSN_BUG;
+	} else if (inst.reg2_format.opcode == ertn_op) {
+		/* ertn */
+		insn->type = INSN_RETURN;
+	}
+
 	return 0;
 }
 
 const char *arch_nop_insn(int len)
 {
-	return NULL;
+	static u32 nop;
+
+	if (len != LOONGARCH_INSN_SIZE)
+		WARN("invalid NOP size: %d\n", len);
+
+	nop = LOONGARCH_INSN_NOP;
+
+	return (const char *)&nop;
 }
 
 const char *arch_ret_insn(int len)
 {
-	return NULL;
+	static u32 ret;
+
+	if (len != LOONGARCH_INSN_SIZE)
+		WARN("invalid RET size: %d\n", len);
+
+	emit_jirl((union loongarch_instruction *)&ret, LOONGARCH_GPR_RA, LOONGARCH_GPR_ZERO, 0);
+
+	return (const char *)&ret;
 }
 
 void arch_initial_func_cfi_state(struct cfi_init_state *state)
-- 
2.1.0

[PATCH v3 3/8] objtool/x86: Separate arch-specific and generic parts

[Tiezhu Yang]

Move init_orc_entry(), write_orc_entry(), reg_name(), orc_type_name()
and print_reg() from generic orc_gen.c and orc_dump.c to arch-specific
orc.c, then introduce a new function orc_print_dump() to print info.

This is preparation for later patch, no functionality change.

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/objtool/arch/x86/Build        |   1 +
 tools/objtool/arch/x86/orc.c        | 188 ++++++++++++++++++++++++++++++++++++
 tools/objtool/include/objtool/orc.h |  14 +++
 tools/objtool/orc_dump.c            |  69 +------------
 tools/objtool/orc_gen.c             | 113 +---------------------
 5 files changed, 206 insertions(+), 179 deletions(-)
 create mode 100644 tools/objtool/arch/x86/orc.c
 create mode 100644 tools/objtool/include/objtool/orc.h

diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build
index 9f7869b..3dedb2f 100644
--- a/tools/objtool/arch/x86/Build
+++ b/tools/objtool/arch/x86/Build
@@ -1,5 +1,6 @@
 objtool-y += special.o
 objtool-y += decode.o
+objtool-y += orc.o
 
 inat_tables_script = ../arch/x86/tools/gen-insn-attr-x86.awk
 inat_tables_maps = ../arch/x86/lib/x86-opcode-map.txt
diff --git a/tools/objtool/arch/x86/orc.c b/tools/objtool/arch/x86/orc.c
new file mode 100644
index 0000000..b6cd943
--- /dev/null
+++ b/tools/objtool/arch/x86/orc.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/objtool_types.h>
+#include <asm/orc_types.h>
+
+#include <objtool/check.h>
+#include <objtool/orc.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
+{
+	struct cfi_reg *bp = &cfi->regs[CFI_BP];
+
+	memset(orc, 0, sizeof(*orc));
+
+	if (!cfi) {
+		/*
+		 * This is usually either unreachable nops/traps (which don't
+		 * trigger unreachable instruction warnings), or
+		 * STACK_FRAME_NON_STANDARD functions.
+		 */
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	}
+
+	switch (cfi->type) {
+	case UNWIND_HINT_TYPE_UNDEFINED:
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	case UNWIND_HINT_TYPE_END_OF_STACK:
+		orc->type = ORC_TYPE_END_OF_STACK;
+		return 0;
+	case UNWIND_HINT_TYPE_CALL:
+		orc->type = ORC_TYPE_CALL;
+		break;
+	case UNWIND_HINT_TYPE_REGS:
+		orc->type = ORC_TYPE_REGS;
+		break;
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		orc->type = ORC_TYPE_REGS_PARTIAL;
+		break;
+	default:
+		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
+		return -1;
+	}
+
+	orc->signal = cfi->signal;
+
+	switch (cfi->cfa.base) {
+	case CFI_SP:
+		orc->sp_reg = ORC_REG_SP;
+		break;
+	case CFI_SP_INDIRECT:
+		orc->sp_reg = ORC_REG_SP_INDIRECT;
+		break;
+	case CFI_BP:
+		orc->sp_reg = ORC_REG_BP;
+		break;
+	case CFI_BP_INDIRECT:
+		orc->sp_reg = ORC_REG_BP_INDIRECT;
+		break;
+	case CFI_R10:
+		orc->sp_reg = ORC_REG_R10;
+		break;
+	case CFI_R13:
+		orc->sp_reg = ORC_REG_R13;
+		break;
+	case CFI_DI:
+		orc->sp_reg = ORC_REG_DI;
+		break;
+	case CFI_DX:
+		orc->sp_reg = ORC_REG_DX;
+		break;
+	default:
+		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
+		return -1;
+	}
+
+	switch (bp->base) {
+	case CFI_UNDEFINED:
+		orc->bp_reg = ORC_REG_UNDEFINED;
+		break;
+	case CFI_CFA:
+		orc->bp_reg = ORC_REG_PREV_SP;
+		break;
+	case CFI_BP:
+		orc->bp_reg = ORC_REG_BP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown BP base reg %d", bp->base);
+		return -1;
+	}
+
+	orc->sp_offset = cfi->cfa.offset;
+	orc->bp_offset = bp->offset;
+
+	return 0;
+}
+
+int write_orc_entry(struct elf *elf, struct section *orc_sec,
+		    struct section *ip_sec, unsigned int idx,
+		    struct section *insn_sec, unsigned long insn_off,
+		    struct orc_entry *o)
+{
+	struct orc_entry *orc;
+
+	/* populate ORC data */
+	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
+	memcpy(orc, o, sizeof(*orc));
+	orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
+	orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
+
+	/* populate reloc for ip */
+	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
+				     insn_sec, insn_off))
+		return -1;
+
+	return 0;
+}
+
+static const char *reg_name(unsigned int reg)
+{
+	switch (reg) {
+	case ORC_REG_PREV_SP:
+		return "prevsp";
+	case ORC_REG_DX:
+		return "dx";
+	case ORC_REG_DI:
+		return "di";
+	case ORC_REG_BP:
+		return "bp";
+	case ORC_REG_SP:
+		return "sp";
+	case ORC_REG_R10:
+		return "r10";
+	case ORC_REG_R13:
+		return "r13";
+	case ORC_REG_BP_INDIRECT:
+		return "bp(ind)";
+	case ORC_REG_SP_INDIRECT:
+		return "sp(ind)";
+	default:
+		return "?";
+	}
+}
+
+static const char *orc_type_name(unsigned int type)
+{
+	switch (type) {
+	case ORC_TYPE_UNDEFINED:
+		return "(und)";
+	case ORC_TYPE_END_OF_STACK:
+		return "end";
+	case ORC_TYPE_CALL:
+		return "call";
+	case ORC_TYPE_REGS:
+		return "regs";
+	case ORC_TYPE_REGS_PARTIAL:
+		return "regs (partial)";
+	default:
+		return "?";
+	}
+}
+
+static void print_reg(unsigned int reg, int offset)
+{
+	if (reg == ORC_REG_BP_INDIRECT)
+		printf("(bp%+d)", offset);
+	else if (reg == ORC_REG_SP_INDIRECT)
+		printf("(sp)%+d", offset);
+	else if (reg == ORC_REG_UNDEFINED)
+		printf("(und)");
+	else
+		printf("%s%+d", reg_name(reg), offset);
+}
+
+void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i)
+{
+	printf("type:%s", orc_type_name(orc[i].type));
+
+	printf(" sp:");
+	print_reg(orc[i].sp_reg, bswap_if_needed(dummy_elf, orc[i].sp_offset));
+
+	printf(" bp:");
+	print_reg(orc[i].bp_reg, bswap_if_needed(dummy_elf, orc[i].bp_offset));
+
+	printf(" signal:%d\n", orc[i].signal);
+}
diff --git a/tools/objtool/include/objtool/orc.h b/tools/objtool/include/objtool/orc.h
new file mode 100644
index 0000000..15a32de
--- /dev/null
+++ b/tools/objtool/include/objtool/orc.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ORC_H
+#define _OBJTOOL_ORC_H
+
+#include <objtool/check.h>
+
+int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn);
+void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i);
+int write_orc_entry(struct elf *elf, struct section *orc_sec,
+		    struct section *ip_sec, unsigned int idx,
+		    struct section *insn_sec, unsigned long insn_off,
+		    struct orc_entry *o);
+
+#endif /* _OBJTOOL_ORC_H */
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index 0e183bb..a62247ef 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -6,65 +6,10 @@
 #include <unistd.h>
 #include <asm/orc_types.h>
 #include <objtool/objtool.h>
+#include <objtool/orc.h>
 #include <objtool/warn.h>
 #include <objtool/endianness.h>
 
-static const char *reg_name(unsigned int reg)
-{
-	switch (reg) {
-	case ORC_REG_PREV_SP:
-		return "prevsp";
-	case ORC_REG_DX:
-		return "dx";
-	case ORC_REG_DI:
-		return "di";
-	case ORC_REG_BP:
-		return "bp";
-	case ORC_REG_SP:
-		return "sp";
-	case ORC_REG_R10:
-		return "r10";
-	case ORC_REG_R13:
-		return "r13";
-	case ORC_REG_BP_INDIRECT:
-		return "bp(ind)";
-	case ORC_REG_SP_INDIRECT:
-		return "sp(ind)";
-	default:
-		return "?";
-	}
-}
-
-static const char *orc_type_name(unsigned int type)
-{
-	switch (type) {
-	case ORC_TYPE_UNDEFINED:
-		return "(und)";
-	case ORC_TYPE_END_OF_STACK:
-		return "end";
-	case ORC_TYPE_CALL:
-		return "call";
-	case ORC_TYPE_REGS:
-		return "regs";
-	case ORC_TYPE_REGS_PARTIAL:
-		return "regs (partial)";
-	default:
-		return "?";
-	}
-}
-
-static void print_reg(unsigned int reg, int offset)
-{
-	if (reg == ORC_REG_BP_INDIRECT)
-		printf("(bp%+d)", offset);
-	else if (reg == ORC_REG_SP_INDIRECT)
-		printf("(sp)%+d", offset);
-	else if (reg == ORC_REG_UNDEFINED)
-		printf("(und)");
-	else
-		printf("%s%+d", reg_name(reg), offset);
-}
-
 int orc_dump(const char *_objname)
 {
 	int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
@@ -205,17 +150,7 @@ int orc_dump(const char *_objname)
 			printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
 		}
 
-		printf("type:%s", orc_type_name(orc[i].type));
-
-		printf(" sp:");
-
-		print_reg(orc[i].sp_reg, bswap_if_needed(&dummy_elf, orc[i].sp_offset));
-
-		printf(" bp:");
-
-		print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));
-
-		printf(" signal:%d\n", orc[i].signal);
+		orc_print_dump(&dummy_elf, orc, i);
 	}
 
 	elf_end(elf);
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index bae3439..922e6aa 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -10,121 +10,10 @@
 #include <asm/orc_types.h>
 
 #include <objtool/check.h>
+#include <objtool/orc.h>
 #include <objtool/warn.h>
 #include <objtool/endianness.h>
 
-static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
-			  struct instruction *insn)
-{
-	struct cfi_reg *bp = &cfi->regs[CFI_BP];
-
-	memset(orc, 0, sizeof(*orc));
-
-	if (!cfi) {
-		/*
-		 * This is usually either unreachable nops/traps (which don't
-		 * trigger unreachable instruction warnings), or
-		 * STACK_FRAME_NON_STANDARD functions.
-		 */
-		orc->type = ORC_TYPE_UNDEFINED;
-		return 0;
-	}
-
-	switch (cfi->type) {
-	case UNWIND_HINT_TYPE_UNDEFINED:
-		orc->type = ORC_TYPE_UNDEFINED;
-		return 0;
-	case UNWIND_HINT_TYPE_END_OF_STACK:
-		orc->type = ORC_TYPE_END_OF_STACK;
-		return 0;
-	case UNWIND_HINT_TYPE_CALL:
-		orc->type = ORC_TYPE_CALL;
-		break;
-	case UNWIND_HINT_TYPE_REGS:
-		orc->type = ORC_TYPE_REGS;
-		break;
-	case UNWIND_HINT_TYPE_REGS_PARTIAL:
-		orc->type = ORC_TYPE_REGS_PARTIAL;
-		break;
-	default:
-		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
-		return -1;
-	}
-
-	orc->signal = cfi->signal;
-
-	switch (cfi->cfa.base) {
-	case CFI_SP:
-		orc->sp_reg = ORC_REG_SP;
-		break;
-	case CFI_SP_INDIRECT:
-		orc->sp_reg = ORC_REG_SP_INDIRECT;
-		break;
-	case CFI_BP:
-		orc->sp_reg = ORC_REG_BP;
-		break;
-	case CFI_BP_INDIRECT:
-		orc->sp_reg = ORC_REG_BP_INDIRECT;
-		break;
-	case CFI_R10:
-		orc->sp_reg = ORC_REG_R10;
-		break;
-	case CFI_R13:
-		orc->sp_reg = ORC_REG_R13;
-		break;
-	case CFI_DI:
-		orc->sp_reg = ORC_REG_DI;
-		break;
-	case CFI_DX:
-		orc->sp_reg = ORC_REG_DX;
-		break;
-	default:
-		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
-		return -1;
-	}
-
-	switch (bp->base) {
-	case CFI_UNDEFINED:
-		orc->bp_reg = ORC_REG_UNDEFINED;
-		break;
-	case CFI_CFA:
-		orc->bp_reg = ORC_REG_PREV_SP;
-		break;
-	case CFI_BP:
-		orc->bp_reg = ORC_REG_BP;
-		break;
-	default:
-		WARN_INSN(insn, "unknown BP base reg %d", bp->base);
-		return -1;
-	}
-
-	orc->sp_offset = cfi->cfa.offset;
-	orc->bp_offset = bp->offset;
-
-	return 0;
-}
-
-static int write_orc_entry(struct elf *elf, struct section *orc_sec,
-			   struct section *ip_sec, unsigned int idx,
-			   struct section *insn_sec, unsigned long insn_off,
-			   struct orc_entry *o)
-{
-	struct orc_entry *orc;
-
-	/* populate ORC data */
-	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
-	memcpy(orc, o, sizeof(*orc));
-	orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
-	orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
-
-	/* populate reloc for ip */
-	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
-				     insn_sec, insn_off))
-		return -1;
-
-	return 0;
-}
-
 struct orc_list_entry {
 	struct list_head list;
 	struct orc_entry orc;
-- 
2.1.0

[PATCH v3 4/8] objtool/LoongArch: Enable orc to be built

[Tiezhu Yang]

Implement arch-specific init_orc_entry(), write_orc_entry(), reg_name(),
orc_type_name(), print_reg() and orc_print_dump(), then set BUILD_ORC as
y to build the orc related files.

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/arch/loongarch/include/asm/orc_types.h |  58 +++++++++
 tools/objtool/Makefile                       |   4 +
 tools/objtool/arch/loongarch/Build           |   1 +
 tools/objtool/arch/loongarch/decode.c        |  16 +++
 tools/objtool/arch/loongarch/orc.c           | 171 +++++++++++++++++++++++++++
 5 files changed, 250 insertions(+)
 create mode 100644 tools/arch/loongarch/include/asm/orc_types.h
 create mode 100644 tools/objtool/arch/loongarch/orc.c

diff --git a/tools/arch/loongarch/include/asm/orc_types.h b/tools/arch/loongarch/include/asm/orc_types.h
new file mode 100644
index 0000000..caf1f71
--- /dev/null
+++ b/tools/arch/loongarch/include/asm/orc_types.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ORC_TYPES_H
+#define _ORC_TYPES_H
+
+#include <linux/types.h>
+
+/*
+ * The ORC_REG_* registers are base registers which are used to find other
+ * registers on the stack.
+ *
+ * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
+ * address of the previous frame: the caller's SP before it called the current
+ * function.
+ *
+ * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
+ * the current frame.
+ *
+ * The most commonly used base registers are SP and FP -- which the previous SP
+ * is usually based on -- and PREV_SP and UNDEFINED -- which the previous FP is
+ * usually based on.
+ *
+ * The rest of the base registers are needed for special cases like entry code
+ * and GCC realigned stacks.
+ */
+#define ORC_REG_UNDEFINED		0
+#define ORC_REG_PREV_SP			1
+#define ORC_REG_SP			2
+#define ORC_REG_FP			3
+#define ORC_REG_MAX			4
+
+#define ORC_TYPE_UNDEFINED		0
+#define ORC_TYPE_END_OF_STACK		1
+#define ORC_TYPE_CALL			2
+#define ORC_TYPE_REGS			3
+#define ORC_TYPE_REGS_PARTIAL		4
+
+#ifndef __ASSEMBLY__
+/*
+ * This struct is more or less a vastly simplified version of the DWARF Call
+ * Frame Information standard.  It contains only the necessary parts of DWARF
+ * CFI, simplified for ease of access by the in-kernel unwinder.  It tells the
+ * unwinder how to find the previous SP and FP (and sometimes entry regs) on
+ * the stack for a given code address.  Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+	s16		sp_offset;
+	s16		fp_offset;
+	s16		ra_offset;
+	unsigned int	sp_reg:4;
+	unsigned int	fp_reg:4;
+	unsigned int	ra_reg:4;
+	unsigned int	type:3;
+	unsigned int	signal:1;
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_TYPES_H */
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 83b100c..bf7f7f8 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -57,6 +57,10 @@ ifeq ($(SRCARCH),x86)
 	BUILD_ORC := y
 endif
 
+ifeq ($(SRCARCH),loongarch)
+	BUILD_ORC := y
+endif
+
 export BUILD_ORC
 export srctree OUTPUT CFLAGS SRCARCH AWK
 include $(srctree)/tools/build/Makefile.include
diff --git a/tools/objtool/arch/loongarch/Build b/tools/objtool/arch/loongarch/Build
index d24d563..1d4b784 100644
--- a/tools/objtool/arch/loongarch/Build
+++ b/tools/objtool/arch/loongarch/Build
@@ -1,2 +1,3 @@
 objtool-y += decode.o
 objtool-y += special.o
+objtool-y += orc.o
diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
index 0ee3333..555b6d0 100644
--- a/tools/objtool/arch/loongarch/decode.c
+++ b/tools/objtool/arch/loongarch/decode.c
@@ -3,6 +3,8 @@
 #include <objtool/check.h>
 #include <objtool/warn.h>
 #include <asm/inst.h>
+#include <asm/orc_types.h>
+#include <linux/objtool_types.h>
 
 int arch_ftrace_match(char *name)
 {
@@ -38,6 +40,20 @@ bool arch_callee_saved_reg(unsigned char reg)
 
 int arch_decode_hint_reg(u8 sp_reg, int *base)
 {
+	switch (sp_reg) {
+	case ORC_REG_UNDEFINED:
+		*base = CFI_UNDEFINED;
+		break;
+	case ORC_REG_SP:
+		*base = CFI_SP;
+		break;
+	case ORC_REG_FP:
+		*base = CFI_FP;
+		break;
+	default:
+		return -1;
+	}
+
 	return 0;
 }
 
diff --git a/tools/objtool/arch/loongarch/orc.c b/tools/objtool/arch/loongarch/orc.c
new file mode 100644
index 0000000..873536d
--- /dev/null
+++ b/tools/objtool/arch/loongarch/orc.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/objtool_types.h>
+#include <asm/orc_types.h>
+
+#include <objtool/check.h>
+#include <objtool/orc.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
+{
+	struct cfi_reg *fp = &cfi->regs[CFI_FP];
+	struct cfi_reg *ra = &cfi->regs[CFI_RA];
+
+	memset(orc, 0, sizeof(*orc));
+
+	if (!cfi) {
+		/*
+		 * This is usually either unreachable nops/traps (which don't
+		 * trigger unreachable instruction warnings), or
+		 * STACK_FRAME_NON_STANDARD functions.
+		 */
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	}
+
+	switch (cfi->type) {
+	case UNWIND_HINT_TYPE_UNDEFINED:
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	case UNWIND_HINT_TYPE_END_OF_STACK:
+		orc->type = ORC_TYPE_END_OF_STACK;
+		return 0;
+	case UNWIND_HINT_TYPE_CALL:
+		orc->type = ORC_TYPE_CALL;
+		break;
+	case UNWIND_HINT_TYPE_REGS:
+		orc->type = ORC_TYPE_REGS;
+		break;
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		orc->type = ORC_TYPE_REGS_PARTIAL;
+		break;
+	default:
+		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
+		return -1;
+	}
+
+	orc->signal = cfi->signal;
+
+	switch (cfi->cfa.base) {
+	case CFI_SP:
+		orc->sp_reg = ORC_REG_SP;
+		break;
+	case CFI_FP:
+		orc->sp_reg = ORC_REG_FP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
+		return -1;
+	}
+
+	switch (fp->base) {
+	case CFI_UNDEFINED:
+		orc->fp_reg = ORC_REG_UNDEFINED;
+		orc->fp_offset = 0;
+		break;
+	case CFI_CFA:
+		orc->fp_reg = ORC_REG_PREV_SP;
+		orc->fp_offset = fp->offset;
+		break;
+	case CFI_FP:
+		orc->fp_reg = ORC_REG_FP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown FP base reg %d", fp->base);
+		return -1;
+	}
+
+	switch (ra->base) {
+	case CFI_UNDEFINED:
+		orc->ra_reg = ORC_REG_UNDEFINED;
+		orc->ra_offset = 0;
+		break;
+	case CFI_CFA:
+		orc->ra_reg = ORC_REG_PREV_SP;
+		orc->ra_offset = ra->offset;
+		break;
+	case CFI_FP:
+		orc->ra_reg = ORC_REG_FP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown RA base reg %d", ra->base);
+		return -1;
+	}
+
+	orc->sp_offset = cfi->cfa.offset;
+
+	return 0;
+}
+
+int write_orc_entry(struct elf *elf, struct section *orc_sec,
+		    struct section *ip_sec, unsigned int idx,
+		    struct section *insn_sec, unsigned long insn_off,
+		    struct orc_entry *o)
+{
+	struct orc_entry *orc;
+
+	/* populate ORC data */
+	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
+	memcpy(orc, o, sizeof(*orc));
+
+	/* populate reloc for ip */
+	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
+				     insn_sec, insn_off))
+		return -1;
+
+	return 0;
+}
+
+static const char *reg_name(unsigned int reg)
+{
+	switch (reg) {
+	case ORC_REG_SP:
+		return "sp";
+	case ORC_REG_FP:
+		return "fp";
+	case ORC_REG_PREV_SP:
+		return "prevsp";
+	default:
+		return "?";
+	}
+}
+
+static const char *orc_type_name(unsigned int type)
+{
+	switch (type) {
+	case UNWIND_HINT_TYPE_CALL:
+		return "call";
+	case UNWIND_HINT_TYPE_REGS:
+		return "regs";
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		return "regs (partial)";
+	default:
+		return "?";
+	}
+}
+
+static void print_reg(unsigned int reg, int offset)
+{
+	if (reg == ORC_REG_UNDEFINED)
+		printf(" (und) ");
+	else
+		printf("%s + %3d", reg_name(reg), offset);
+
+}
+
+void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i)
+{
+	printf("type:%s", orc_type_name(orc[i].type));
+
+	printf(" sp:");
+	print_reg(orc[i].sp_reg, orc[i].sp_offset);
+
+	printf(" fp:");
+	print_reg(orc[i].fp_reg, orc[i].fp_offset);
+
+	printf(" ra:");
+	print_reg(orc[i].ra_reg, orc[i].ra_offset);
+
+	printf(" signal:%d\n", orc[i].signal);
+}
-- 
2.1.0

[PATCH v3 5/8] objtool: Check local label about sibling call

[Tiezhu Yang]

When update the latest upstream gcc and binutils which enables linker
relaxation by default, it generates more objtool warnings on LoongArch,
like this:

  init/version.o: warning: objtool: early_hostname+0x20: sibling call from callable instruction with modified stack frame

We can see that the branch and jump operation about local label ".L2"
is not sibling call, because a sibling call is a tail-call to another
symbol. In this case, make is_sibling_call() return false, set dest_sec
and dest_off to calculate jump_dest in add_jump_destinations().

Here are some detailed info:
[fedora@linux 6.6.test]$ gcc --version
gcc (GCC) 14.0.0 20231009 (experimental)
[fedora@linux 6.6.test]$ as --version
GNU assembler (GNU Binutils) 2.41.50.20231009
[fedora@linux 6.6.test]$ objdump -M no-aliases -D init/version.o | grep -A 21 "init.text"
Disassembly of section .init.text:

0000000000000000 <early_hostname>:
   0:	1a00000c 	pcalau12i   	$t0, 0
   4:	02ffc063 	addi.d      	$sp, $sp, -16
   8:	00150085 	or          	$a1, $a0, $zero
   c:	02810406 	addi.w      	$a2, $zero, 65
  10:	02c00184 	addi.d      	$a0, $t0, 0
  14:	29c02061 	st.d        	$ra, $sp, 8
  18:	54000000 	bl          	0	# 18 <early_hostname+0x18>
  1c:	0281000c 	addi.w      	$t0, $zero, 64
  20:	6c001584 	bgeu        	$t0, $a0, 20	# 34 <.L2>
  24:	1a000004 	pcalau12i   	$a0, 0
  28:	02810005 	addi.w      	$a1, $zero, 64
  2c:	02c00084 	addi.d      	$a0, $a0, 0
  30:	54000000 	bl          	0	# 30 <early_hostname+0x30>

0000000000000034 <.L2>:
  34:	28c02061 	ld.d        	$ra, $sp, 8
  38:	00150004 	or          	$a0, $zero, $zero
  3c:	02c04063 	addi.d      	$sp, $sp, 16
  40:	4c000020 	jirl        	$zero, $ra, 0

By the way, it need to move insn_reloc() before is_sibling_call()
to avoid implicit declaration build error.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
---
 tools/objtool/check.c | 69 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 41 insertions(+), 28 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e308d1b..a9cb224 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -161,12 +161,39 @@ static bool is_jump_table_jump(struct instruction *insn)
 	       insn_jump_table(alt_group->orig_group->first_insn);
 }
 
-static bool is_sibling_call(struct instruction *insn)
+static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn)
+{
+	struct reloc *reloc;
+
+	if (insn->no_reloc)
+		return NULL;
+
+	if (!file)
+		return NULL;
+
+	reloc = find_reloc_by_dest_range(file->elf, insn->sec,
+					 insn->offset, insn->len);
+	if (!reloc) {
+		insn->no_reloc = 1;
+		return NULL;
+	}
+
+	return reloc;
+}
+
+static bool is_sibling_call(struct objtool_file *file, struct instruction *insn)
 {
 	/*
 	 * Assume only STT_FUNC calls have jump-tables.
 	 */
 	if (insn_func(insn)) {
+		struct reloc *reloc = insn_reloc(file, insn);
+
+		/* Disallow sibling calls into STT_NOTYPE if it is local lable */
+		if (reloc && reloc->sym->type == STT_NOTYPE &&
+		    strncmp(reloc->sym->name, ".L", 2) == 0)
+			return false;
+
 		/* An indirect jump is either a sibling call or a jump to a table. */
 		if (insn->type == INSN_JUMP_DYNAMIC)
 			return !is_jump_table_jump(insn);
@@ -232,7 +259,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
 	 * of the sibling call returns.
 	 */
 	func_for_each_insn(file, func, insn) {
-		if (is_sibling_call(insn)) {
+		if (is_sibling_call(file, insn)) {
 			struct instruction *dest = insn->jump_dest;
 
 			if (!dest)
@@ -743,7 +770,7 @@ static int create_static_call_sections(struct objtool_file *file)
 		if (!elf_init_reloc_data_sym(file->elf, sec,
 					     idx * sizeof(*site) + 4,
 					     (idx * 2) + 1, key_sym,
-					     is_sibling_call(insn) * STATIC_CALL_SITE_TAIL))
+					     is_sibling_call(file, insn) * STATIC_CALL_SITE_TAIL))
 			return -1;
 
 		idx++;
@@ -1315,26 +1342,6 @@ __weak bool arch_is_embedded_insn(struct symbol *sym)
 	return false;
 }
 
-static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn)
-{
-	struct reloc *reloc;
-
-	if (insn->no_reloc)
-		return NULL;
-
-	if (!file)
-		return NULL;
-
-	reloc = find_reloc_by_dest_range(file->elf, insn->sec,
-					 insn->offset, insn->len);
-	if (!reloc) {
-		insn->no_reloc = 1;
-		return NULL;
-	}
-
-	return reloc;
-}
-
 static void remove_insn_ops(struct instruction *insn)
 {
 	struct stack_op *op, *next;
@@ -1577,8 +1584,14 @@ static int add_jump_destinations(struct objtool_file *file)
 			 * External sibling call or internal sibling call with
 			 * STT_FUNC reloc.
 			 */
-			add_call_dest(file, insn, reloc->sym, true);
-			continue;
+			if (reloc->sym->type == STT_NOTYPE &&
+			    strncmp(reloc->sym->name, ".L", 2) == 0) {
+				dest_sec = insn->sec;
+				dest_off = arch_jump_destination(insn);
+			} else {
+				add_call_dest(file, insn, reloc->sym, true);
+				continue;
+			}
 		} else if (reloc->sym->sec->idx) {
 			dest_sec = reloc->sym->sec;
 			dest_off = reloc->sym->sym.st_value +
@@ -3674,7 +3687,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 
 		case INSN_JUMP_CONDITIONAL:
 		case INSN_JUMP_UNCONDITIONAL:
-			if (is_sibling_call(insn)) {
+			if (is_sibling_call(file, insn)) {
 				ret = validate_sibling_call(file, insn, &state);
 				if (ret)
 					return ret;
@@ -3695,7 +3708,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 
 		case INSN_JUMP_DYNAMIC:
 		case INSN_JUMP_DYNAMIC_CONDITIONAL:
-			if (is_sibling_call(insn)) {
+			if (is_sibling_call(file, insn)) {
 				ret = validate_sibling_call(file, insn, &state);
 				if (ret)
 					return ret;
@@ -3859,7 +3872,7 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn)
 
 		case INSN_JUMP_UNCONDITIONAL:
 		case INSN_JUMP_CONDITIONAL:
-			if (!is_sibling_call(insn)) {
+			if (!is_sibling_call(file, insn)) {
 				if (!insn->jump_dest) {
 					WARN_INSN(insn, "unresolved jump target after linking?!?");
 					return -1;
-- 
2.1.0

[PATCH v3 6/8] objtool: Check local label in add_dead_ends()

[Tiezhu Yang]

When update the latest upstream gcc and binutils which enables linker
relaxation by default, it generates more objtool warnings on LoongArch,
like this:

  init/main.o: warning: objtool: unexpected relocation symbol type in .rela.discard.unreachable

We can see that the reloc sym name is local label instead of section
in relocation section '.rela.discard.unreachable', in this case, the
reloc sym type is STT_NOTYPE instead of STT_SECTION. Let us check it
to not return -1, then use reloc->sym->offset instead of reloc addend
which is 0 to find the corresponding instruction. At the same time,
replace the variable "addend" with "offset" to reflect the reality.

Here are some detailed info:
[fedora@linux 6.6.test]$ gcc --version
gcc (GCC) 14.0.0 20231009 (experimental)
[fedora@linux 6.6.test]$ as --version
GNU assembler (GNU Binutils) 2.41.50.20231009
[fedora@linux 6.6.test]$ readelf -r init/main.o | grep -A 2 "rela.discard.unreachable"
Relocation section '.rela.discard.unreachable' at offset 0x4b70 contains 1 entry:
  Offset          Info           Type           Sym. Value    Sym. Name + Addend
000000000000  00de00000063 R_LARCH_32_PCREL  0000000000000228 .L466^B1 + 0

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/objtool/check.c | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index a9cb224..eee5621 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -611,7 +611,7 @@ static int add_dead_ends(struct objtool_file *file)
 	struct section *rsec;
 	struct reloc *reloc;
 	struct instruction *insn;
-	s64 addend;
+	unsigned long offset;
 
 	/*
 	 * Check for manually annotated dead ends.
@@ -622,26 +622,29 @@ static int add_dead_ends(struct objtool_file *file)
 
 	for_each_reloc(rsec, reloc) {
 
-		if (reloc->sym->type != STT_SECTION) {
+		if (reloc->sym->type == STT_SECTION) {
+			offset = reloc_addend(reloc);
+		} else if ((reloc->sym->type == STT_NOTYPE) &&
+			    strncmp(reloc->sym->name, ".L", 2) == 0) {
+			offset = reloc->sym->offset;
+		} else {
 			WARN("unexpected relocation symbol type in %s", rsec->name);
 			return -1;
 		}
 
-		addend = reloc_addend(reloc);
-
-		insn = find_insn(file, reloc->sym->sec, addend);
+		insn = find_insn(file, reloc->sym->sec, offset);
 		if (insn)
 			insn = prev_insn_same_sec(file, insn);
-		else if (addend == reloc->sym->sec->sh.sh_size) {
+		else if (offset == reloc->sym->sec->sh.sh_size) {
 			insn = find_last_insn(file, reloc->sym->sec);
 			if (!insn) {
 				WARN("can't find unreachable insn at %s+0x%" PRIx64,
-				     reloc->sym->sec->name, addend);
+				     reloc->sym->sec->name, offset);
 				return -1;
 			}
 		} else {
 			WARN("can't find unreachable insn at %s+0x%" PRIx64,
-			     reloc->sym->sec->name, addend);
+			     reloc->sym->sec->name, offset);
 			return -1;
 		}
 
@@ -661,26 +664,29 @@ static int add_dead_ends(struct objtool_file *file)
 
 	for_each_reloc(rsec, reloc) {
 
-		if (reloc->sym->type != STT_SECTION) {
+		if (reloc->sym->type == STT_SECTION) {
+			offset = reloc_addend(reloc);
+		} else if ((reloc->sym->type == STT_NOTYPE) &&
+			    strncmp(reloc->sym->name, ".L", 2) == 0) {
+			offset = reloc->sym->offset;
+		} else {
 			WARN("unexpected relocation symbol type in %s", rsec->name);
 			return -1;
 		}
 
-		addend = reloc_addend(reloc);
-
-		insn = find_insn(file, reloc->sym->sec, addend);
+		insn = find_insn(file, reloc->sym->sec, offset);
 		if (insn)
 			insn = prev_insn_same_sec(file, insn);
-		else if (addend == reloc->sym->sec->sh.sh_size) {
+		else if (offset == reloc->sym->sec->sh.sh_size) {
 			insn = find_last_insn(file, reloc->sym->sec);
 			if (!insn) {
 				WARN("can't find reachable insn at %s+0x%" PRIx64,
-				     reloc->sym->sec->name, addend);
+				     reloc->sym->sec->name, offset);
 				return -1;
 			}
 		} else {
 			WARN("can't find reachable insn at %s+0x%" PRIx64,
-			     reloc->sym->sec->name, addend);
+			     reloc->sym->sec->name, offset);
 			return -1;
 		}
 
-- 
2.1.0

[PATCH v3 7/8] objtool: Check local label in read_unwind_hints()

[Tiezhu Yang]

When update the latest upstream gcc and binutils which enables linker
relaxation by default, it generates more objtool warnings on LoongArch.

We can see that the reloc sym name is local label instead of section
in relocation section '.rela.discard.unwind_hints', in this case, the
reloc sym type is STT_NOTYPE instead of STT_SECTION. Let us check it
to not return -1, then use reloc->sym->offset instead of reloc addend
which is 0 to find the corresponding instruction.

Here are some detailed info:
[fedora@linux 6.6.test]$ gcc --version
gcc (GCC) 14.0.0 20231009 (experimental)
[fedora@linux 6.6.test]$ as --version
GNU assembler (GNU Binutils) 2.41.50.20231009
[fedora@linux 6.6.test]$ readelf -r arch/loongarch/kernel/entry.o | grep -A 2 "rela.discard.unwind_hints"
Relocation section '.rela.discard.unwind_hints' at offset 0x458 contains 7 entries:
  Offset          Info           Type           Sym. Value    Sym. Name + Addend
000000000000  000800000063 R_LARCH_32_PCREL  000000000000001c .Lhere_1 + 0

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 tools/objtool/check.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index eee5621..607a745 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2227,6 +2227,7 @@ static int read_unwind_hints(struct objtool_file *file)
 	struct unwind_hint *hint;
 	struct instruction *insn;
 	struct reloc *reloc;
+	unsigned long offset;
 	int i;
 
 	sec = find_section_by_name(file->elf, ".discard.unwind_hints");
@@ -2254,7 +2255,17 @@ static int read_unwind_hints(struct objtool_file *file)
 			return -1;
 		}
 
-		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (reloc->sym->type == STT_SECTION) {
+			offset = reloc_addend(reloc);
+		} else if ((reloc->sym->type == STT_NOTYPE) &&
+			strncmp(reloc->sym->name, ".L", 2) == 0) {
+			offset = reloc->sym->offset;
+		} else {
+			WARN("unexpected relocation symbol type in %s", sec->rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, offset);
 		if (!insn) {
 			WARN("can't find insn for unwind_hints[%d]", i);
 			return -1;
-- 
2.1.0

[PATCH v3 8/8] LoongArch: Add ORC stack unwinder support

[Tiezhu Yang]

The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is
similar in concept to a DWARF unwinder. The difference is that the format
of the ORC data is much simpler than DWARF, which in turn allows the ORC
unwinder to be much simpler and faster.

The ORC data consists of unwind tables which are generated by objtool.
They contain out-of-band data which is used by the in-kernel ORC unwinder.
Objtool generates the ORC data by first doing compile-time stack metadata
validation (CONFIG_STACK_VALIDATION). After analyzing all the code paths
of a .o file, it determines information about the stack state at each
instruction address in the file and outputs that information to the
.orc_unwind and .orc_unwind_ip sections.

The per-object ORC sections are combined at link time and are sorted and
post-processed at boot time. The unwinder uses the resulting data to
correlate instruction addresses with their stack states at run time.

Most of the logic are similar with x86, in order to get ra info before ra
is saved into stack, add ra_reg and ra_offset into orc_entry. At the same
time, modify some arch-specific code to silence the objtool warnings.

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 arch/loongarch/Kconfig                    |   2 +
 arch/loongarch/Kconfig.debug              |  11 +
 arch/loongarch/Makefile                   |  18 ++
 arch/loongarch/include/asm/Kbuild         |   1 +
 arch/loongarch/include/asm/bug.h          |   1 +
 arch/loongarch/include/asm/exception.h    |   2 +
 arch/loongarch/include/asm/module.h       |   7 +
 arch/loongarch/include/asm/orc_header.h   |  19 ++
 arch/loongarch/include/asm/orc_lookup.h   |  34 ++
 arch/loongarch/include/asm/orc_types.h    |  58 ++++
 arch/loongarch/include/asm/stackframe.h   |   3 +
 arch/loongarch/include/asm/unwind.h       |  22 +-
 arch/loongarch/include/asm/unwind_hints.h |  28 ++
 arch/loongarch/kernel/Makefile            |   3 +
 arch/loongarch/kernel/entry.S             |   5 +
 arch/loongarch/kernel/genex.S             |   4 +
 arch/loongarch/kernel/module.c            |  11 +-
 arch/loongarch/kernel/relocate_kernel.S   |   2 +
 arch/loongarch/kernel/setup.c             |   2 +
 arch/loongarch/kernel/stacktrace.c        |   1 +
 arch/loongarch/kernel/traps.c             |  44 ++-
 arch/loongarch/kernel/unwind_orc.c        | 522 ++++++++++++++++++++++++++++++
 arch/loongarch/kernel/vmlinux.lds.S       |   3 +
 arch/loongarch/lib/Makefile               |   2 +
 arch/loongarch/mm/tlb.c                   |  27 +-
 arch/loongarch/mm/tlbex.S                 |   9 +
 arch/loongarch/vdso/Makefile              |   1 +
 include/linux/compiler.h                  |   9 +
 scripts/Makefile                          |   7 +-
 29 files changed, 824 insertions(+), 34 deletions(-)
 create mode 100644 arch/loongarch/include/asm/orc_header.h
 create mode 100644 arch/loongarch/include/asm/orc_lookup.h
 create mode 100644 arch/loongarch/include/asm/orc_types.h
 create mode 100644 arch/loongarch/include/asm/unwind_hints.h
 create mode 100644 arch/loongarch/kernel/unwind_orc.c

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index e14396a..21ef3bb 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -131,6 +131,7 @@ config LOONGARCH
 	select HAVE_KRETPROBES
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_NMI
+	select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS
 	select HAVE_PCI
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
@@ -141,6 +142,7 @@ config LOONGARCH
 	select HAVE_SAMPLE_FTRACE_DIRECT
 	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
 	select HAVE_SETUP_PER_CPU_AREA if NUMA
+	select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_TIF_NOHZ
diff --git a/arch/loongarch/Kconfig.debug b/arch/loongarch/Kconfig.debug
index 8d36aab..98d6063 100644
--- a/arch/loongarch/Kconfig.debug
+++ b/arch/loongarch/Kconfig.debug
@@ -26,4 +26,15 @@ config UNWINDER_PROLOGUE
 	  Some of the addresses it reports may be incorrect (but better than the
 	  Guess unwinder).
 
+config UNWINDER_ORC
+	bool "ORC unwinder"
+	select OBJTOOL
+	help
+	  This option enables the ORC (Oops Rewind Capability) unwinder for
+	  unwinding kernel stack traces.  It uses a custom data format which is
+	  a simplified version of the DWARF Call Frame Information standard.
+
+	  Enabling this option will increase the kernel's runtime memory usage
+	  by roughly 2-4MB, depending on your kernel config.
+
 endchoice
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index fb0fada..fab28f4 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -25,6 +25,24 @@ endif
 32bit-emul		= elf32loongarch
 64bit-emul		= elf64loongarch
 
+ifdef CONFIG_OBJTOOL
+KBUILD_AFLAGS	+= $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
+KBUILD_CFLAGS	+= $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
+KBUILD_CFLAGS	+= -fno-optimize-sibling-calls -fno-jump-tables -falign-functions=4
+endif
+
+ifdef CONFIG_UNWINDER_ORC
+orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
+orc_hash_sh := $(srctree)/scripts/orc_hash.sh
+targets += $(orc_hash_h)
+quiet_cmd_orc_hash = GEN     $@
+      cmd_orc_hash = mkdir -p $(dir $@); \
+		     $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
+$(orc_hash_h): $(srctree)/arch/loongarch/include/asm/orc_types.h $(orc_hash_sh) FORCE
+	$(call if_changed,orc_hash)
+archprepare: $(orc_hash_h)
+endif
+
 ifdef CONFIG_DYNAMIC_FTRACE
 KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
 CC_FLAGS_FTRACE := -fpatchable-function-entry=2
diff --git a/arch/loongarch/include/asm/Kbuild b/arch/loongarch/include/asm/Kbuild
index 93783fa..2bb285c 100644
--- a/arch/loongarch/include/asm/Kbuild
+++ b/arch/loongarch/include/asm/Kbuild
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+generated-y += orc_hash.h
 generic-y += dma-contiguous.h
 generic-y += mcs_spinlock.h
 generic-y += parport.h
diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
index d4ca3ba..0838887 100644
--- a/arch/loongarch/include/asm/bug.h
+++ b/arch/loongarch/include/asm/bug.h
@@ -44,6 +44,7 @@
 do {								\
 	instrumentation_begin();				\
 	__BUG_FLAGS(BUGFLAG_WARNING|(flags));			\
+	annotate_reachable();					\
 	instrumentation_end();					\
 } while (0)
 
diff --git a/arch/loongarch/include/asm/exception.h b/arch/loongarch/include/asm/exception.h
index af74a3f..0b3977c 100644
--- a/arch/loongarch/include/asm/exception.h
+++ b/arch/loongarch/include/asm/exception.h
@@ -42,4 +42,6 @@ asmlinkage void handle_reserved(void);
 asmlinkage void handle_vint(void);
 asmlinkage void noinstr handle_loongarch_irq(struct pt_regs *regs);
 
+extern void *exception_table[];
+
 #endif	/* __ASM_EXCEPTION_H */
diff --git a/arch/loongarch/include/asm/module.h b/arch/loongarch/include/asm/module.h
index 2ecd82b..96af0ba 100644
--- a/arch/loongarch/include/asm/module.h
+++ b/arch/loongarch/include/asm/module.h
@@ -6,6 +6,7 @@
 #define _ASM_MODULE_H
 
 #include <asm/inst.h>
+#include <asm/orc_types.h>
 #include <asm-generic/module.h>
 
 #define RELA_STACK_DEPTH 16
@@ -23,6 +24,12 @@ struct mod_arch_specific {
 
 	/* For CONFIG_DYNAMIC_FTRACE */
 	struct plt_entry *ftrace_trampolines;
+
+#ifdef CONFIG_UNWINDER_ORC
+	unsigned int num_orcs;
+	int *orc_unwind_ip;
+	struct orc_entry *orc_unwind;
+#endif
 };
 
 struct got_entry {
diff --git a/arch/loongarch/include/asm/orc_header.h b/arch/loongarch/include/asm/orc_header.h
new file mode 100644
index 0000000..07bacf3
--- /dev/null
+++ b/arch/loongarch/include/asm/orc_header.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (c) Meta Platforms, Inc. and affiliates. */
+
+#ifndef _ORC_HEADER_H
+#define _ORC_HEADER_H
+
+#include <linux/types.h>
+#include <linux/compiler.h>
+#include <asm/orc_hash.h>
+
+/*
+ * The header is currently a 20-byte hash of the ORC entry definition; see
+ * scripts/orc_hash.sh.
+ */
+#define ORC_HEADER					\
+	__used __section(".orc_header") __aligned(4)	\
+	static const u8 orc_header[] = { ORC_HASH }
+
+#endif /* _ORC_HEADER_H */
diff --git a/arch/loongarch/include/asm/orc_lookup.h b/arch/loongarch/include/asm/orc_lookup.h
new file mode 100644
index 0000000..2416312
--- /dev/null
+++ b/arch/loongarch/include/asm/orc_lookup.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+#ifndef _ORC_LOOKUP_H
+#define _ORC_LOOKUP_H
+
+/*
+ * This is a lookup table for speeding up access to the .orc_unwind table.
+ * Given an input address offset, the corresponding lookup table entry
+ * specifies a subset of the .orc_unwind table to search.
+ *
+ * Each block represents the end of the previous range and the start of the
+ * next range.  An extra block is added to give the last range an end.
+ *
+ * The block size should be a power of 2 to avoid a costly 'div' instruction.
+ *
+ * A block size of 256 was chosen because it roughly doubles unwinder
+ * performance while only adding ~5% to the ORC data footprint.
+ */
+#define LOOKUP_BLOCK_ORDER	8
+#define LOOKUP_BLOCK_SIZE	(1 << LOOKUP_BLOCK_ORDER)
+
+#ifndef LINKER_SCRIPT
+
+extern unsigned int orc_lookup[];
+extern unsigned int orc_lookup_end[];
+
+#define LOOKUP_START_IP		(unsigned long)_stext
+#define LOOKUP_STOP_IP		(unsigned long)_etext
+
+#endif /* LINKER_SCRIPT */
+
+#endif /* _ORC_LOOKUP_H */
diff --git a/arch/loongarch/include/asm/orc_types.h b/arch/loongarch/include/asm/orc_types.h
new file mode 100644
index 0000000..caf1f71
--- /dev/null
+++ b/arch/loongarch/include/asm/orc_types.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ORC_TYPES_H
+#define _ORC_TYPES_H
+
+#include <linux/types.h>
+
+/*
+ * The ORC_REG_* registers are base registers which are used to find other
+ * registers on the stack.
+ *
+ * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
+ * address of the previous frame: the caller's SP before it called the current
+ * function.
+ *
+ * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
+ * the current frame.
+ *
+ * The most commonly used base registers are SP and FP -- which the previous SP
+ * is usually based on -- and PREV_SP and UNDEFINED -- which the previous FP is
+ * usually based on.
+ *
+ * The rest of the base registers are needed for special cases like entry code
+ * and GCC realigned stacks.
+ */
+#define ORC_REG_UNDEFINED		0
+#define ORC_REG_PREV_SP			1
+#define ORC_REG_SP			2
+#define ORC_REG_FP			3
+#define ORC_REG_MAX			4
+
+#define ORC_TYPE_UNDEFINED		0
+#define ORC_TYPE_END_OF_STACK		1
+#define ORC_TYPE_CALL			2
+#define ORC_TYPE_REGS			3
+#define ORC_TYPE_REGS_PARTIAL		4
+
+#ifndef __ASSEMBLY__
+/*
+ * This struct is more or less a vastly simplified version of the DWARF Call
+ * Frame Information standard.  It contains only the necessary parts of DWARF
+ * CFI, simplified for ease of access by the in-kernel unwinder.  It tells the
+ * unwinder how to find the previous SP and FP (and sometimes entry regs) on
+ * the stack for a given code address.  Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+	s16		sp_offset;
+	s16		fp_offset;
+	s16		ra_offset;
+	unsigned int	sp_reg:4;
+	unsigned int	fp_reg:4;
+	unsigned int	ra_reg:4;
+	unsigned int	type:3;
+	unsigned int	signal:1;
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_TYPES_H */
diff --git a/arch/loongarch/include/asm/stackframe.h b/arch/loongarch/include/asm/stackframe.h
index 4fb1e64..45b507a 100644
--- a/arch/loongarch/include/asm/stackframe.h
+++ b/arch/loongarch/include/asm/stackframe.h
@@ -13,6 +13,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/loongarch.h>
 #include <asm/thread_info.h>
+#include <asm/unwind_hints.h>
 
 /* Make the addition of cfi info a little easier. */
 	.macro cfi_rel_offset reg offset=0 docfi=0
@@ -162,6 +163,7 @@
 	li.w	t0, CSR_CRMD_WE
 	csrxchg	t0, t0, LOONGARCH_CSR_CRMD
 #endif
+	UNWIND_HINT_REGS
 	.endm
 
 	.macro	SAVE_ALL docfi=0
@@ -219,6 +221,7 @@
 
 	.macro	RESTORE_SP_AND_RET docfi=0
 	cfi_ld	sp, PT_R3, \docfi
+	UNWIND_HINT_FUNC
 	ertn
 	.endm
 
diff --git a/arch/loongarch/include/asm/unwind.h b/arch/loongarch/include/asm/unwind.h
index b9dce87..d36e04e 100644
--- a/arch/loongarch/include/asm/unwind.h
+++ b/arch/loongarch/include/asm/unwind.h
@@ -16,6 +16,7 @@
 enum unwinder_type {
 	UNWINDER_GUESS,
 	UNWINDER_PROLOGUE,
+	UNWINDER_ORC,
 };
 
 struct unwind_state {
@@ -24,7 +25,7 @@ struct unwind_state {
 	struct task_struct *task;
 	bool first, error, reset;
 	int graph_idx;
-	unsigned long sp, pc, ra;
+	unsigned long sp, pc, ra, fp;
 };
 
 bool default_next_frame(struct unwind_state *state);
@@ -34,6 +35,17 @@ void unwind_start(struct unwind_state *state,
 bool unwind_next_frame(struct unwind_state *state);
 unsigned long unwind_get_return_address(struct unwind_state *state);
 
+#ifdef CONFIG_UNWINDER_ORC
+void unwind_init(void);
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+			void *orc, size_t orc_size);
+#else
+static inline void unwind_init(void) {}
+static inline
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+			void *orc, size_t orc_size) {}
+#endif
+
 static inline bool unwind_done(struct unwind_state *state)
 {
 	return state->stack_info.type == STACK_TYPE_UNKNOWN;
@@ -61,14 +73,17 @@ static __always_inline void __unwind_start(struct unwind_state *state,
 		state->sp = regs->regs[3];
 		state->pc = regs->csr_era;
 		state->ra = regs->regs[1];
+		state->fp = regs->regs[22];
 	} else if (task && task != current) {
 		state->sp = thread_saved_fp(task);
 		state->pc = thread_saved_ra(task);
 		state->ra = 0;
+		state->fp = 0;
 	} else {
 		state->sp = (unsigned long)__builtin_frame_address(0);
 		state->pc = (unsigned long)__builtin_return_address(0);
 		state->ra = 0;
+		state->fp = 0;
 	}
 	state->task = task;
 	get_stack_info(state->sp, state->task, &state->stack_info);
@@ -77,6 +92,9 @@ static __always_inline void __unwind_start(struct unwind_state *state,
 
 static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
 {
-	return unwind_done(state) ? 0 : state->pc;
+	if (unwind_done(state))
+		return 0;
+
+	return __kernel_text_address(state->pc) ? state->pc : 0;
 }
 #endif /* _ASM_UNWIND_H */
diff --git a/arch/loongarch/include/asm/unwind_hints.h b/arch/loongarch/include/asm/unwind_hints.h
new file mode 100644
index 0000000..82443fe
--- /dev/null
+++ b/arch/loongarch/include/asm/unwind_hints.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_LOONGARCH_UNWIND_HINTS_H
+#define _ASM_LOONGARCH_UNWIND_HINTS_H
+
+#include <linux/objtool.h>
+#include <asm/orc_types.h>
+
+#ifdef __ASSEMBLY__
+
+.macro UNWIND_HINT_UNDEFINED
+	UNWIND_HINT type=UNWIND_HINT_TYPE_UNDEFINED
+.endm
+
+.macro UNWIND_HINT_EMPTY
+	UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL
+.endm
+
+.macro UNWIND_HINT_REGS
+	UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_REGS
+.endm
+
+.macro UNWIND_HINT_FUNC
+	UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_CALL
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_LOONGARCH_UNWIND_HINTS_H */
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 4fcc168..a89428c 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -3,6 +3,8 @@
 # Makefile for the Linux/LoongArch kernel.
 #
 
+OBJECT_FILES_NON_STANDARD_head.o := y
+
 extra-y		:= vmlinux.lds
 
 obj-y		+= head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
@@ -62,6 +64,7 @@ obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 
 obj-$(CONFIG_UNWINDER_GUESS)	+= unwind_guess.o
 obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
+obj-$(CONFIG_UNWINDER_ORC)	+= unwind_orc.o
 
 obj-$(CONFIG_PERF_EVENTS)	+= perf_event.o perf_regs.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S
index 1ec8e4c..e43115f 100644
--- a/arch/loongarch/kernel/entry.S
+++ b/arch/loongarch/kernel/entry.S
@@ -14,11 +14,13 @@
 #include <asm/regdef.h>
 #include <asm/stackframe.h>
 #include <asm/thread_info.h>
+#include <asm/unwind_hints.h>
 
 	.text
 	.cfi_sections	.debug_frame
 	.align	5
 SYM_CODE_START(handle_syscall)
+	UNWIND_HINT_UNDEFINED
 	csrrd		t0, PERCPU_BASE_KS
 	la.pcrel	t1, kernelsp
 	add.d		t1, t1, t0
@@ -56,6 +58,7 @@ SYM_CODE_START(handle_syscall)
 	cfi_st		u0, PT_R21
 	cfi_st		fp, PT_R22
 
+	UNWIND_HINT_REGS
 	SAVE_STATIC
 
 #ifdef CONFIG_KGDB
@@ -75,6 +78,7 @@ SYM_CODE_END(handle_syscall)
 _ASM_NOKPROBE(handle_syscall)
 
 SYM_CODE_START(ret_from_fork)
+	UNWIND_HINT_REGS
 	bl		schedule_tail		# a0 = struct task_struct *prev
 	move		a0, sp
 	bl 		syscall_exit_to_user_mode
@@ -84,6 +88,7 @@ SYM_CODE_START(ret_from_fork)
 SYM_CODE_END(ret_from_fork)
 
 SYM_CODE_START(ret_from_kernel_thread)
+	UNWIND_HINT_REGS
 	bl		schedule_tail		# a0 = struct task_struct *prev
 	move		a0, s1
 	jirl		ra, s0, 0
diff --git a/arch/loongarch/kernel/genex.S b/arch/loongarch/kernel/genex.S
index 2bb3aa2..3f18e3b 100644
--- a/arch/loongarch/kernel/genex.S
+++ b/arch/loongarch/kernel/genex.S
@@ -32,6 +32,7 @@ SYM_FUNC_START(__arch_cpu_idle)
 SYM_FUNC_END(__arch_cpu_idle)
 
 SYM_CODE_START(handle_vint)
+	UNWIND_HINT_UNDEFINED
 	BACKUP_T0T1
 	SAVE_ALL
 	la_abs	t1, __arch_cpu_idle
@@ -49,6 +50,7 @@ SYM_CODE_START(handle_vint)
 SYM_CODE_END(handle_vint)
 
 SYM_CODE_START(except_vec_cex)
+	UNWIND_HINT_UNDEFINED
 	b	cache_parity_error
 SYM_CODE_END(except_vec_cex)
 
@@ -67,6 +69,7 @@ SYM_CODE_END(except_vec_cex)
 	.macro	BUILD_HANDLER exception handler prep
 	.align	5
 	SYM_CODE_START(handle_\exception)
+	UNWIND_HINT_UNDEFINED
 	666:
 	BACKUP_T0T1
 	SAVE_ALL
@@ -94,6 +97,7 @@ SYM_CODE_END(except_vec_cex)
 	BUILD_HANDLER reserved reserved none	/* others */
 
 SYM_CODE_START(handle_sys)
+	UNWIND_HINT_UNDEFINED
 	la_abs	t0, handle_syscall
 	jr	t0
 SYM_CODE_END(handle_sys)
diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index b13b285..83db7e5 100644
--- a/arch/loongarch/kernel/module.c
+++ b/arch/loongarch/kernel/module.c
@@ -20,6 +20,7 @@
 #include <linux/kernel.h>
 #include <asm/alternative.h>
 #include <asm/inst.h>
+#include <asm/unwind.h>
 
 static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
 {
@@ -515,7 +516,7 @@ static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
 int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs, struct module *mod)
 {
-	const Elf_Shdr *s, *se;
+	const Elf_Shdr *s, *se, *orc = NULL, *orc_ip = NULL;
 	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 
 	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
@@ -523,7 +524,15 @@ int module_finalize(const Elf_Ehdr *hdr,
 			apply_alternatives((void *)s->sh_addr, (void *)s->sh_addr + s->sh_size);
 		if (!strcmp(".ftrace_trampoline", secstrs + s->sh_name))
 			module_init_ftrace_plt(hdr, s, mod);
+		if (!strcmp(".orc_unwind", secstrs + s->sh_name))
+			orc = s;
+		if (!strcmp(".orc_unwind_ip", secstrs + s->sh_name))
+			orc_ip = s;
 	}
 
+	if (orc && orc_ip)
+		unwind_module_init(mod, (void *)orc_ip->sh_addr, orc_ip->sh_size,
+				       (void *)orc->sh_addr, orc->sh_size);
+
 	return 0;
 }
diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S
index f49f6b0..bcc191d 100644
--- a/arch/loongarch/kernel/relocate_kernel.S
+++ b/arch/loongarch/kernel/relocate_kernel.S
@@ -15,6 +15,7 @@
 #include <asm/addrspace.h>
 
 SYM_CODE_START(relocate_new_kernel)
+	UNWIND_HINT_UNDEFINED
 	/*
 	 * a0: EFI boot flag for the new kernel
 	 * a1: Command line pointer for the new kernel
@@ -90,6 +91,7 @@ SYM_CODE_END(relocate_new_kernel)
  * then start at the entry point from LOONGARCH_IOCSR_MBUF0.
  */
 SYM_CODE_START(kexec_smp_wait)
+	UNWIND_HINT_UNDEFINED
 1:	li.w		t0, 0x100			/* wait for init loop */
 2:	addi.w		t0, t0, -1			/* limit mailbox access */
 	bnez		t0, 2b
diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index aed65915..613f04d 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -48,6 +48,7 @@
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/time.h>
+#include <asm/unwind.h>
 
 #define SMBIOS_BIOSSIZE_OFFSET		0x09
 #define SMBIOS_BIOSEXTERN_OFFSET	0x13
@@ -606,6 +607,7 @@ static void __init prefill_possible_map(void)
 void __init setup_arch(char **cmdline_p)
 {
 	cpu_probe();
+	unwind_init();
 
 	init_environ();
 	efi_init();
diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
index 92270f1..9848d42 100644
--- a/arch/loongarch/kernel/stacktrace.c
+++ b/arch/loongarch/kernel/stacktrace.c
@@ -29,6 +29,7 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 			regs->csr_era = thread_saved_ra(task);
 		}
 		regs->regs[1] = 0;
+		regs->regs[22] = 0;
 	}
 
 	for (unwind_start(&state, task, regs);
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index aebfc37..5103fb1 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -53,6 +53,32 @@
 
 #include "access-helper.h"
 
+void *exception_table[EXCCODE_INT_START] = {
+	[0 ... EXCCODE_INT_START - 1] = handle_reserved,
+
+	[EXCCODE_TLBI]		= handle_tlb_load,
+	[EXCCODE_TLBL]		= handle_tlb_load,
+	[EXCCODE_TLBS]		= handle_tlb_store,
+	[EXCCODE_TLBM]		= handle_tlb_modify,
+	[EXCCODE_TLBNR]		= handle_tlb_protect,
+	[EXCCODE_TLBNX]		= handle_tlb_protect,
+	[EXCCODE_TLBPE]		= handle_tlb_protect,
+	[EXCCODE_ADE]		= handle_ade,
+	[EXCCODE_ALE]		= handle_ale,
+	[EXCCODE_BCE]		= handle_bce,
+	[EXCCODE_SYS]		= handle_sys,
+	[EXCCODE_BP]		= handle_bp,
+	[EXCCODE_INE]		= handle_ri,
+	[EXCCODE_IPE]		= handle_ri,
+	[EXCCODE_FPDIS]		= handle_fpu,
+	[EXCCODE_LSXDIS]	= handle_lsx,
+	[EXCCODE_LASXDIS]	= handle_lasx,
+	[EXCCODE_FPE]		= handle_fpe,
+	[EXCCODE_WATCH]		= handle_watch,
+	[EXCCODE_BTDIS]		= handle_lbt,
+};
+EXPORT_SYMBOL_GPL(exception_table);
+
 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
 			   const char *loglvl, bool user)
 {
@@ -1146,24 +1172,14 @@ void __init trap_init(void)
 {
 	long i;
 
+	/* Set instruction exception handler */
+	for (i = EXCCODE_ADE; i <= EXCCODE_BTDIS; i++)
+		set_handler(i * VECSIZE, exception_table[i], VECSIZE);
+
 	/* Set interrupt vector handler */
 	for (i = EXCCODE_INT_START; i <= EXCCODE_INT_END; i++)
 		set_handler(i * VECSIZE, handle_vint, VECSIZE);
 
-	set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
-	set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
-	set_handler(EXCCODE_BCE * VECSIZE, handle_bce, VECSIZE);
-	set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
-	set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
-	set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
-	set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
-	set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
-	set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
-	set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
-	set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
-	set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
-	set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
-
 	cache_error_setup();
 
 	local_flush_icache_range(eentry, eentry + 0x400);
diff --git a/arch/loongarch/kernel/unwind_orc.c b/arch/loongarch/kernel/unwind_orc.c
new file mode 100644
index 0000000..6570bb7
--- /dev/null
+++ b/arch/loongarch/kernel/unwind_orc.c
@@ -0,0 +1,522 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/objtool.h>
+#include <linux/module.h>
+#include <linux/sort.h>
+#include <asm/exception.h>
+#include <asm/orc_types.h>
+#include <asm/orc_lookup.h>
+#include <asm/orc_header.h>
+#include <asm/ptrace.h>
+#include <asm/setup.h>
+#include <asm/stacktrace.h>
+#include <asm/tlb.h>
+#include <asm/unwind.h>
+
+ORC_HEADER;
+
+#define orc_warn(fmt, ...) \
+	printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__)
+
+extern int __start_orc_unwind_ip[];
+extern int __stop_orc_unwind_ip[];
+extern struct orc_entry __start_orc_unwind[];
+extern struct orc_entry __stop_orc_unwind[];
+
+static bool orc_init __ro_after_init;
+static unsigned int lookup_num_blocks __ro_after_init;
+
+/* Fake frame pointer entry -- used as a fallback for generated code */
+static struct orc_entry orc_fp_entry = {
+	.type		= UNWIND_HINT_TYPE_CALL,
+	.sp_reg		= ORC_REG_FP,
+	.sp_offset	= 16,
+	.fp_reg		= ORC_REG_PREV_SP,
+	.fp_offset	= -16,
+	.ra_reg		= ORC_REG_PREV_SP,
+	.ra_offset	= -8,
+};
+
+static inline unsigned long orc_ip(const int *ip)
+{
+	return (unsigned long)ip + *ip;
+}
+
+static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
+				    unsigned int num_entries, unsigned long ip)
+{
+	int *first = ip_table;
+	int *last = ip_table + num_entries - 1;
+	int *mid = first, *found = first;
+
+	if (!num_entries)
+		return NULL;
+
+	/*
+	 * Do a binary range search to find the rightmost duplicate of a given
+	 * starting address.  Some entries are section terminators which are
+	 * "weak" entries for ensuring there are no gaps.  They should be
+	 * ignored when they conflict with a real entry.
+	 */
+	while (first <= last) {
+		mid = first + ((last - first) / 2);
+
+		if (orc_ip(mid) <= ip) {
+			found = mid;
+			first = mid + 1;
+		} else
+			last = mid - 1;
+	}
+
+	return u_table + (found - ip_table);
+}
+
+#ifdef CONFIG_MODULES
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+	struct module *mod;
+
+	mod = __module_address(ip);
+	if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
+		return NULL;
+	return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind,
+			  mod->arch.num_orcs, ip);
+}
+#else
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+	return NULL;
+}
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static struct orc_entry *orc_find(unsigned long ip);
+
+/*
+ * Ftrace dynamic trampolines do not have orc entries of their own.
+ * But they are copies of the ftrace entries that are static and
+ * defined in ftrace_*.S, which do have orc entries.
+ *
+ * If the unwinder comes across a ftrace trampoline, then find the
+ * ftrace function that was used to create it, and use that ftrace
+ * function's orc entry, as the placement of the return code in
+ * the stack will be identical.
+ */
+static struct orc_entry *orc_ftrace_find(unsigned long ip)
+{
+	struct ftrace_ops *ops;
+	unsigned long tramp_addr, offset;
+
+	ops = ftrace_ops_trampoline(ip);
+	if (!ops)
+		return NULL;
+
+	/* Set tramp_addr to the start of the code copied by the trampoline */
+	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
+		tramp_addr = (unsigned long)ftrace_regs_caller;
+	else
+		tramp_addr = (unsigned long)ftrace_caller;
+
+	/* Now place tramp_addr to the location within the trampoline ip is at */
+	offset = ip - ops->trampoline;
+	tramp_addr += offset;
+
+	/* Prevent unlikely recursion */
+	if (ip == tramp_addr)
+		return NULL;
+
+	return orc_find(tramp_addr);
+}
+#else
+static struct orc_entry *orc_ftrace_find(unsigned long ip)
+{
+	return NULL;
+}
+#endif
+
+/*
+ * If we crash with IP==0, the last successfully executed instruction
+ * was probably an indirect function call with a NULL function pointer,
+ * and we don't have unwind information for NULL.
+ * This hardcoded ORC entry for IP==0 allows us to unwind from a NULL function
+ * pointer into its parent and then continue normally from there.
+ */
+static struct orc_entry null_orc_entry = {
+	.sp_offset = sizeof(long),
+	.sp_reg = ORC_REG_SP,
+	.fp_reg = ORC_REG_UNDEFINED,
+	.type = ORC_TYPE_CALL
+};
+
+static struct orc_entry *orc_find(unsigned long ip)
+{
+	static struct orc_entry *orc;
+
+	if (ip == 0)
+		return &null_orc_entry;
+
+	/* For non-init vmlinux addresses, use the fast lookup table: */
+	if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
+		unsigned int idx, start, stop;
+
+		idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
+
+		if (unlikely((idx >= lookup_num_blocks-1))) {
+			orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%pB\n",
+				 idx, lookup_num_blocks, (void *)ip);
+			return NULL;
+		}
+
+		start = orc_lookup[idx];
+		stop = orc_lookup[idx + 1] + 1;
+
+		if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
+			     (__start_orc_unwind + stop > __stop_orc_unwind))) {
+			orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%pB\n",
+				 idx, lookup_num_blocks, start, stop, (void *)ip);
+			return NULL;
+		}
+
+		return __orc_find(__start_orc_unwind_ip + start,
+				  __start_orc_unwind + start, stop - start, ip);
+	}
+
+	/* vmlinux .init slow lookup: */
+	if (is_kernel_inittext(ip))
+		return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+				  __stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
+
+	/* Module lookup: */
+	orc = orc_module_find(ip);
+	if (orc)
+		return orc;
+
+	return orc_ftrace_find(ip);
+}
+
+#ifdef CONFIG_MODULES
+
+static DEFINE_MUTEX(sort_mutex);
+static int *cur_orc_ip_table = __start_orc_unwind_ip;
+static struct orc_entry *cur_orc_table = __start_orc_unwind;
+
+static void orc_sort_swap(void *_a, void *_b, int size)
+{
+	struct orc_entry *orc_a, *orc_b;
+	int *a = _a, *b = _b, tmp;
+	int delta = _b - _a;
+
+	/* Swap the .orc_unwind_ip entries: */
+	tmp = *a;
+	*a = *b + delta;
+	*b = tmp - delta;
+
+	/* Swap the corresponding .orc_unwind entries: */
+	orc_a = cur_orc_table + (a - cur_orc_ip_table);
+	orc_b = cur_orc_table + (b - cur_orc_ip_table);
+	swap(*orc_a, *orc_b);
+}
+
+static int orc_sort_cmp(const void *_a, const void *_b)
+{
+	struct orc_entry *orc_a;
+	const int *a = _a, *b = _b;
+	unsigned long a_val = orc_ip(a);
+	unsigned long b_val = orc_ip(b);
+
+	if (a_val > b_val)
+		return 1;
+	if (a_val < b_val)
+		return -1;
+
+	/*
+	 * The "weak" section terminator entries need to always be first
+	 * to ensure the lookup code skips them in favor of real entries.
+	 * These terminator entries exist to handle any gaps created by
+	 * whitelisted .o files which didn't get objtool generation.
+	 */
+	orc_a = cur_orc_table + (a - cur_orc_ip_table);
+	return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1;
+}
+
+void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
+			void *_orc, size_t orc_size)
+{
+	int *orc_ip = _orc_ip;
+	struct orc_entry *orc = _orc;
+	unsigned int num_entries = orc_ip_size / sizeof(int);
+
+	WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
+		     orc_size % sizeof(*orc) != 0 ||
+		     num_entries != orc_size / sizeof(*orc));
+
+	/*
+	 * The 'cur_orc_*' globals allow the orc_sort_swap() callback to
+	 * associate an .orc_unwind_ip table entry with its corresponding
+	 * .orc_unwind entry so they can both be swapped.
+	 */
+	mutex_lock(&sort_mutex);
+	cur_orc_ip_table = orc_ip;
+	cur_orc_table = orc;
+	sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
+	mutex_unlock(&sort_mutex);
+
+	mod->arch.orc_unwind_ip = orc_ip;
+	mod->arch.orc_unwind = orc;
+	mod->arch.num_orcs = num_entries;
+}
+#endif
+
+void __init unwind_init(void)
+{
+	size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
+	size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
+	size_t num_entries = orc_ip_size / sizeof(int);
+	struct orc_entry *orc;
+	int i;
+
+	if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
+	    orc_size % sizeof(struct orc_entry) != 0 ||
+	    num_entries != orc_size / sizeof(struct orc_entry)) {
+		orc_warn("WARNING: Bad or missing .orc_unwind table.  Disabling unwinder.\n");
+		return;
+	}
+
+	/*
+	 * Note, the orc_unwind and orc_unwind_ip tables were already
+	 * sorted at build time via the 'sorttable' tool.
+	 * It's ready for binary search straight away, no need to sort it.
+	 */
+
+	/* Initialize the fast lookup table: */
+	lookup_num_blocks = orc_lookup_end - orc_lookup;
+	for (i = 0; i < lookup_num_blocks-1; i++) {
+		orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+				 num_entries,
+				 LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
+		if (!orc) {
+			orc_warn("WARNING: Corrupt .orc_unwind table.  Disabling unwinder.\n");
+			return;
+		}
+
+		orc_lookup[i] = orc - __start_orc_unwind;
+	}
+
+	/* Initialize the ending block: */
+	orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries,
+			 LOOKUP_STOP_IP);
+	if (!orc) {
+		orc_warn("WARNING: Corrupt .orc_unwind table.  Disabling unwinder.\n");
+		return;
+	}
+	orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
+
+	orc_init = true;
+}
+
+static inline bool on_stack(struct stack_info *info, unsigned long addr, size_t len)
+{
+	unsigned long begin = info->begin;
+	unsigned long end   = info->end;
+
+	return (info->type != STACK_TYPE_UNKNOWN &&
+		addr >= begin && addr < end &&
+		addr + len > begin && addr + len <= end);
+}
+
+static bool stack_access_ok(struct unwind_state *state, unsigned long addr,
+			    size_t len)
+{
+	struct stack_info *info = &state->stack_info;
+
+	if (on_stack(info, addr, len))
+		return true;
+
+	return !get_stack_info(addr, state->task, info) &&
+		on_stack(info, addr, len);
+}
+
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+	return __unwind_get_return_address(state);
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+void unwind_start(struct unwind_state *state, struct task_struct *task,
+		    struct pt_regs *regs)
+{
+	__unwind_start(state, task, regs);
+	if (!unwind_done(state) && !__kernel_text_address(state->pc))
+		unwind_next_frame(state);
+}
+EXPORT_SYMBOL_GPL(unwind_start);
+
+static bool is_entry_func(unsigned long addr)
+{
+	extern u32 kernel_entry;
+	extern u32 kernel_entry_end;
+
+	return addr >= (unsigned long)&kernel_entry &&
+		addr < (unsigned long)&kernel_entry_end;
+}
+
+static inline unsigned long bt_address(unsigned long ra)
+{
+	extern unsigned long eentry;
+
+	if (__kernel_text_address(ra))
+		return ra;
+
+	/* We are in preempt_disable() here */
+	if (__module_text_address(ra))
+		return ra;
+
+	if (ra >= eentry && ra < eentry +  EXCCODE_INT_END * VECSIZE) {
+		unsigned long type = (ra - eentry) / VECSIZE;
+		unsigned long offset = (ra - eentry) % VECSIZE;
+		unsigned long func;
+
+		switch (type) {
+		case 0 ... EXCCODE_INT_START-1:
+			func = (unsigned long)exception_table[type];
+			break;
+		case EXCCODE_INT_START ... EXCCODE_INT_END:
+			func = (unsigned long)handle_vint;
+			break;
+		default:
+			func = (unsigned long)handle_reserved;
+			break;
+		}
+
+		return func + offset;
+	}
+
+	return ra;
+}
+
+bool unwind_next_frame(struct unwind_state *state)
+{
+	struct stack_info *info = &state->stack_info;
+	struct orc_entry *orc;
+	struct pt_regs *regs;
+	unsigned long *p, pc;
+
+	if (unwind_done(state))
+		return false;
+
+	/* Don't let modules unload while we're reading their ORC data. */
+	preempt_disable();
+
+	if (is_entry_func(state->pc))
+		goto end;
+
+	orc = orc_find(state->pc);
+	if (!orc) {
+		orc = &orc_fp_entry;
+		state->error = true;
+	}
+
+	switch (orc->sp_reg) {
+	case ORC_REG_SP:
+		state->sp = state->sp + orc->sp_offset;
+		break;
+	case ORC_REG_FP:
+		state->sp = state->fp;
+		break;
+	default:
+		orc_warn("unknown SP base reg %d at %pB\n",
+			orc->sp_reg, (void *)state->pc);
+		goto err;
+	}
+
+	switch (orc->fp_reg) {
+	case ORC_REG_PREV_SP:
+		p = (unsigned long *)(state->sp + orc->fp_offset);
+		if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
+			goto err;
+
+		state->fp = *p;
+		break;
+	case ORC_REG_UNDEFINED:
+		/* Nothing. */
+		break;
+	default:
+		orc_warn("unknown FP base reg %d at %pB\n",
+			orc->fp_reg, (void *)state->pc);
+		goto err;
+	}
+
+	switch (orc->type) {
+	case UNWIND_HINT_TYPE_CALL:
+		if (orc->ra_reg == ORC_REG_PREV_SP) {
+			p = (unsigned long *)(state->sp + orc->ra_offset);
+			if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
+				goto err;
+
+			pc = unwind_graph_addr(state, *p, state->sp);
+			pc -= LOONGARCH_INSN_SIZE;
+		} else if (orc->ra_reg == ORC_REG_UNDEFINED) {
+			if (!state->ra || state->ra == state->pc)
+				goto err;
+
+			pc = unwind_graph_addr(state, state->ra, state->sp);
+			pc -=  LOONGARCH_INSN_SIZE;
+			state->ra = 0;
+		} else {
+			orc_warn("unknown ra base reg %d at %pB\n",
+				orc->ra_reg, (void *)state->pc);
+			goto err;
+		}
+		break;
+	case UNWIND_HINT_TYPE_REGS:
+		if (state->stack_info.type == STACK_TYPE_IRQ && state->sp == info->end)
+			regs = (struct pt_regs *)info->next_sp;
+		else
+			regs = (struct pt_regs *)state->sp;
+
+		if (!stack_access_ok(state, (unsigned long)regs, sizeof(*regs)))
+			goto err;
+
+		if ((info->end == (unsigned long)regs + sizeof(*regs)) &&
+		    !regs->regs[3] && !regs->regs[1])
+			goto end;
+
+		if (user_mode(regs))
+			goto end;
+
+		pc = regs->csr_era;
+		if (!__kernel_text_address(pc))
+			goto err;
+
+		state->sp = regs->regs[3];
+		state->ra = regs->regs[1];
+		state->fp = regs->regs[22];
+		get_stack_info(state->sp, state->task, info);
+
+		break;
+	default:
+		orc_warn("unknown .orc_unwind entry type %d at %pB\n",
+			 orc->type, (void *)state->pc);
+		goto err;
+	}
+
+	state->pc = bt_address(pc);
+	if (!state->pc) {
+		pr_err("cannot find unwind pc at %pK\n", (void *)pc);
+		goto err;
+	}
+
+	if (!__kernel_text_address(state->pc))
+		goto err;
+
+	preempt_enable();
+	return true;
+
+err:
+	state->error = true;
+
+end:
+	preempt_enable();
+	state->stack_info.type = STACK_TYPE_UNKNOWN;
+	return false;
+}
+EXPORT_SYMBOL_GPL(unwind_next_frame);
diff --git a/arch/loongarch/kernel/vmlinux.lds.S b/arch/loongarch/kernel/vmlinux.lds.S
index bb2ec86..09fd4eb 100644
--- a/arch/loongarch/kernel/vmlinux.lds.S
+++ b/arch/loongarch/kernel/vmlinux.lds.S
@@ -2,6 +2,7 @@
 #include <linux/sizes.h>
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
+#include <asm/orc_lookup.h>
 
 #define PAGE_SIZE _PAGE_SIZE
 #define RO_EXCEPTION_TABLE_ALIGN	4
@@ -99,6 +100,8 @@ SECTIONS
 	_sdata = .;
 	RO_DATA(4096)
 
+	ORC_UNWIND_TABLE
+
 	.got : ALIGN(16) { *(.got) }
 	.plt : ALIGN(16) { *(.plt) }
 	.got.plt : ALIGN(16) { *(.got.plt) }
diff --git a/arch/loongarch/lib/Makefile b/arch/loongarch/lib/Makefile
index a77bf160..e3023d9 100644
--- a/arch/loongarch/lib/Makefile
+++ b/arch/loongarch/lib/Makefile
@@ -3,6 +3,8 @@
 # Makefile for LoongArch-specific library files.
 #
 
+OBJECT_FILES_NON_STANDARD := y
+
 lib-y	+= delay.o memset.o memcpy.o memmove.o \
 	   clear_user.o copy_user.o csum.o dump_tlb.o unaligned.o
 
diff --git a/arch/loongarch/mm/tlb.c b/arch/loongarch/mm/tlb.c
index 2c0a411..f01172a 100644
--- a/arch/loongarch/mm/tlb.c
+++ b/arch/loongarch/mm/tlb.c
@@ -9,8 +9,9 @@
 #include <linux/hugetlb.h>
 #include <linux/export.h>
 
-#include <asm/cpu.h>
 #include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/exception.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 #include <asm/tlb.h>
@@ -266,24 +267,20 @@ static void setup_tlb_handler(int cpu)
 	setup_ptwalker();
 	local_flush_tlb_all();
 
+	if (cpu_has_ptw) {
+		exception_table[EXCCODE_TLBI] = handle_tlb_load_ptw;
+		exception_table[EXCCODE_TLBL] = handle_tlb_load_ptw;
+		exception_table[EXCCODE_TLBS] = handle_tlb_store_ptw;
+		exception_table[EXCCODE_TLBM] = handle_tlb_modify_ptw;
+	}
+
 	/* The tlb handlers are generated only once */
 	if (cpu == 0) {
 		memcpy((void *)tlbrentry, handle_tlb_refill, 0x80);
 		local_flush_icache_range(tlbrentry, tlbrentry + 0x80);
-		if (!cpu_has_ptw) {
-			set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load, VECSIZE);
-			set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load, VECSIZE);
-			set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store, VECSIZE);
-			set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify, VECSIZE);
-		} else {
-			set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load_ptw, VECSIZE);
-			set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load_ptw, VECSIZE);
-			set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store_ptw, VECSIZE);
-			set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify_ptw, VECSIZE);
-		}
-		set_handler(EXCCODE_TLBNR * VECSIZE, handle_tlb_protect, VECSIZE);
-		set_handler(EXCCODE_TLBNX * VECSIZE, handle_tlb_protect, VECSIZE);
-		set_handler(EXCCODE_TLBPE * VECSIZE, handle_tlb_protect, VECSIZE);
+
+		for (int i = EXCCODE_TLBL; i <= EXCCODE_TLBPE; i++)
+			set_handler(i * VECSIZE, exception_table[i], VECSIZE);
 	}
 #ifdef CONFIG_NUMA
 	else {
diff --git a/arch/loongarch/mm/tlbex.S b/arch/loongarch/mm/tlbex.S
index d5d682f..a44387b 100644
--- a/arch/loongarch/mm/tlbex.S
+++ b/arch/loongarch/mm/tlbex.S
@@ -18,6 +18,7 @@
 
 	.macro tlb_do_page_fault, write
 	SYM_CODE_START(tlb_do_page_fault_\write)
+	UNWIND_HINT_UNDEFINED
 	SAVE_ALL
 	csrrd		a2, LOONGARCH_CSR_BADV
 	move		a0, sp
@@ -32,6 +33,7 @@
 	tlb_do_page_fault 1
 
 SYM_CODE_START(handle_tlb_protect)
+	UNWIND_HINT_UNDEFINED
 	BACKUP_T0T1
 	SAVE_ALL
 	move		a0, sp
@@ -44,6 +46,7 @@ SYM_CODE_START(handle_tlb_protect)
 SYM_CODE_END(handle_tlb_protect)
 
 SYM_CODE_START(handle_tlb_load)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, EXCEPTION_KS0
 	csrwr		t1, EXCEPTION_KS1
 	csrwr		ra, EXCEPTION_KS2
@@ -190,6 +193,7 @@ nopage_tlb_load:
 SYM_CODE_END(handle_tlb_load)
 
 SYM_CODE_START(handle_tlb_load_ptw)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_KS0
 	csrwr		t1, LOONGARCH_CSR_KS1
 	la_abs		t0, tlb_do_page_fault_0
@@ -197,6 +201,7 @@ SYM_CODE_START(handle_tlb_load_ptw)
 SYM_CODE_END(handle_tlb_load_ptw)
 
 SYM_CODE_START(handle_tlb_store)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, EXCEPTION_KS0
 	csrwr		t1, EXCEPTION_KS1
 	csrwr		ra, EXCEPTION_KS2
@@ -346,6 +351,7 @@ nopage_tlb_store:
 SYM_CODE_END(handle_tlb_store)
 
 SYM_CODE_START(handle_tlb_store_ptw)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_KS0
 	csrwr		t1, LOONGARCH_CSR_KS1
 	la_abs		t0, tlb_do_page_fault_1
@@ -353,6 +359,7 @@ SYM_CODE_START(handle_tlb_store_ptw)
 SYM_CODE_END(handle_tlb_store_ptw)
 
 SYM_CODE_START(handle_tlb_modify)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, EXCEPTION_KS0
 	csrwr		t1, EXCEPTION_KS1
 	csrwr		ra, EXCEPTION_KS2
@@ -500,6 +507,7 @@ nopage_tlb_modify:
 SYM_CODE_END(handle_tlb_modify)
 
 SYM_CODE_START(handle_tlb_modify_ptw)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_KS0
 	csrwr		t1, LOONGARCH_CSR_KS1
 	la_abs		t0, tlb_do_page_fault_1
@@ -507,6 +515,7 @@ SYM_CODE_START(handle_tlb_modify_ptw)
 SYM_CODE_END(handle_tlb_modify_ptw)
 
 SYM_CODE_START(handle_tlb_refill)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_TLBRSAVE
 	csrrd		t0, LOONGARCH_CSR_PGD
 	lddir		t0, t0, 3
diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile
index 5c97d1463..997f41c 100644
--- a/arch/loongarch/vdso/Makefile
+++ b/arch/loongarch/vdso/Makefile
@@ -3,6 +3,7 @@
 
 KASAN_SANITIZE := n
 KCOV_INSTRUMENT := n
+OBJECT_FILES_NON_STANDARD := y
 
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index d7779a1..df29ddb 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -116,6 +116,14 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
  */
 #define __stringify_label(n) #n
 
+#define __annotate_reachable(c) ({					\
+	asm volatile(__stringify_label(c) ":\n\t"			\
+			".pushsection .discard.reachable\n\t"		\
+			".long " __stringify_label(c) "b - .\n\t"	\
+			".popsection\n\t");				\
+})
+#define annotate_reachable() __annotate_reachable(__COUNTER__)
+
 #define __annotate_unreachable(c) ({					\
 	asm volatile(__stringify_label(c) ":\n\t"			\
 		     ".pushsection .discard.unreachable\n\t"		\
@@ -128,6 +136,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #define __annotate_jump_table __section(".rodata..c_jump_table")
 
 #else /* !CONFIG_OBJTOOL */
+#define annotate_reachable()
 #define annotate_unreachable()
 #define __annotate_jump_table
 #endif /* CONFIG_OBJTOOL */
diff --git a/scripts/Makefile b/scripts/Makefile
index 576cf64..e4cca53 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -31,9 +31,12 @@ HOSTLDLIBS_sign-file = $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null |
 
 ifdef CONFIG_UNWINDER_ORC
 ifeq ($(ARCH),x86_64)
-ARCH := x86
+SRCARCH := x86
 endif
-HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/x86/include
+ifeq ($(ARCH),loongarch)
+SRCARCH := loongarch
+endif
+HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/$(SRCARCH)/include
 HOSTCFLAGS_sorttable.o += -DUNWINDER_ORC_ENABLED
 endif
 
-- 
2.1.0

Re: [PATCH v3 0/8] Add objtool and orc support for LoongArch

[Huacai Chen]

Cross compiling on X86 for LoongArch fails:

  CALL    scripts/checksyscalls.sh
  DESCEND objtool
make[5]: *** No rule to make target
'/usr/lib/gcc/x86_64-redhat-linux/8/include/stdbool.h', needed by
'/home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/exec-cmd.o'.
Stop.
make[4]: *** [Makefile:80:
/home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd-in.o]
Error 2
make[3]: *** [Makefile:82:
/home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd.a]
Error 2
make[2]: *** [Makefile:73: objtool] Error 2
make[1]: *** [/home/chenhuacai/linux-official.git/Makefile:1355:
tools/objtool] Error 2
make: *** [Makefile:234: __sub-make] Error 2

Huacai

On Fri, Oct 20, 2023 at 10:27 AM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
> This version is based on the latest torvalds/linux.git (20231020)
> which includes the commit 00c2ca84c680 ("LoongArch: Use SYM_CODE_*
> to annotate exception handlers"), tested with the latest upstream
> gcc and binutils (20231009).
>
> v3:
>   -- Use tab for indentation in special.h
>   -- Replace BP/bp with FP/fp
>   -- Modify jirl decoder to handle special case in hibernate_asm.o
>   -- Remove the calling of bswap_if_needed() which always return false
>   -- Remove OBJECT_FILES_NON_STANDARD_suspend_asm.o
>   -- Remove check of assembler version in Makefile
>   -- Remove UNWIND_HINT_EMPTY in kernel_entry
>   -- Put unwind_init() after cpu_probe()
>   -- Remove CONFIG_BPF_JIT_ALWAYS_ON in defconfig
>   -- Rename title of patch #8 to "Add ORC stack unwinder support"
>   -- Fix build error of scripts/sorttable.h reported by test robot
>   -- Add exception_table[] to save exception handlers
>
> Tiezhu Yang (8):
>   objtool/LoongArch: Enable objtool to be built
>   objtool/LoongArch: Implement instruction decoder
>   objtool/x86: Separate arch-specific and generic parts
>   objtool/LoongArch: Enable orc to be built
>   objtool: Check local label about sibling call
>   objtool: Check local label in add_dead_ends()
>   objtool: Check local label in read_unwind_hints()
>   LoongArch: Add ORC stack unwinder support
>
>  arch/loongarch/Kconfig                             |   2 +
>  arch/loongarch/Kconfig.debug                       |  11 +
>  arch/loongarch/Makefile                            |  18 +
>  arch/loongarch/include/asm/Kbuild                  |   1 +
>  arch/loongarch/include/asm/bug.h                   |   1 +
>  arch/loongarch/include/asm/exception.h             |   2 +
>  arch/loongarch/include/asm/module.h                |   7 +
>  arch/loongarch/include/asm/orc_header.h            |  19 +
>  arch/loongarch/include/asm/orc_lookup.h            |  34 ++
>  arch/loongarch/include/asm/orc_types.h             |  58 +++
>  arch/loongarch/include/asm/stackframe.h            |   3 +
>  arch/loongarch/include/asm/unwind.h                |  22 +-
>  arch/loongarch/include/asm/unwind_hints.h          |  28 ++
>  arch/loongarch/kernel/Makefile                     |   3 +
>  arch/loongarch/kernel/entry.S                      |   5 +
>  arch/loongarch/kernel/genex.S                      |   4 +
>  arch/loongarch/kernel/module.c                     |  11 +-
>  arch/loongarch/kernel/relocate_kernel.S            |   2 +
>  arch/loongarch/kernel/setup.c                      |   2 +
>  arch/loongarch/kernel/stacktrace.c                 |   1 +
>  arch/loongarch/kernel/traps.c                      |  44 +-
>  arch/loongarch/kernel/unwind_orc.c                 | 522 +++++++++++++++++++++
>  arch/loongarch/kernel/vmlinux.lds.S                |   3 +
>  arch/loongarch/lib/Makefile                        |   2 +
>  arch/loongarch/mm/tlb.c                            |  27 +-
>  arch/loongarch/mm/tlbex.S                          |   9 +
>  arch/loongarch/vdso/Makefile                       |   1 +
>  include/linux/compiler.h                           |   9 +
>  scripts/Makefile                                   |   7 +-
>  tools/arch/loongarch/include/asm/inst.h            | 161 +++++++
>  tools/arch/loongarch/include/asm/orc_types.h       |  58 +++
>  tools/include/linux/bitops.h                       |  11 +
>  tools/objtool/Makefile                             |   4 +
>  tools/objtool/arch/loongarch/Build                 |   3 +
>  tools/objtool/arch/loongarch/decode.c              | 352 ++++++++++++++
>  .../objtool/arch/loongarch/include/arch/cfi_regs.h |  22 +
>  tools/objtool/arch/loongarch/include/arch/elf.h    |  30 ++
>  .../objtool/arch/loongarch/include/arch/special.h  |  33 ++
>  tools/objtool/arch/loongarch/orc.c                 | 171 +++++++
>  tools/objtool/arch/loongarch/special.c             |  15 +
>  tools/objtool/arch/x86/Build                       |   1 +
>  tools/objtool/arch/x86/orc.c                       | 188 ++++++++
>  tools/objtool/check.c                              | 118 +++--
>  tools/objtool/include/objtool/orc.h                |  14 +
>  tools/objtool/orc_dump.c                           |  69 +--
>  tools/objtool/orc_gen.c                            | 113 +----
>  46 files changed, 1964 insertions(+), 257 deletions(-)
>  create mode 100644 arch/loongarch/include/asm/orc_header.h
>  create mode 100644 arch/loongarch/include/asm/orc_lookup.h
>  create mode 100644 arch/loongarch/include/asm/orc_types.h
>  create mode 100644 arch/loongarch/include/asm/unwind_hints.h
>  create mode 100644 arch/loongarch/kernel/unwind_orc.c
>  create mode 100644 tools/arch/loongarch/include/asm/inst.h
>  create mode 100644 tools/arch/loongarch/include/asm/orc_types.h
>  create mode 100644 tools/objtool/arch/loongarch/Build
>  create mode 100644 tools/objtool/arch/loongarch/decode.c
>  create mode 100644 tools/objtool/arch/loongarch/include/arch/cfi_regs.h
>  create mode 100644 tools/objtool/arch/loongarch/include/arch/elf.h
>  create mode 100644 tools/objtool/arch/loongarch/include/arch/special.h
>  create mode 100644 tools/objtool/arch/loongarch/orc.c
>  create mode 100644 tools/objtool/arch/loongarch/special.c
>  create mode 100644 tools/objtool/arch/x86/orc.c
>  create mode 100644 tools/objtool/include/objtool/orc.h
>
> --
> 2.1.0
>

Re: [PATCH v3 5/8] objtool: Check local label about sibling call

[Peter Zijlstra]

On Fri, Oct 20, 2023 at 10:26:58AM +0800, Tiezhu Yang wrote:

> +		if (reloc && reloc->sym->type == STT_NOTYPE &&
> +		    strncmp(reloc->sym->name, ".L", 2) == 0)

> +			if (reloc->sym->type == STT_NOTYPE &&
> +			    strncmp(reloc->sym->name, ".L", 2) == 0) {

Would not something like the below be better?

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e308d1ba664e..a57d293c834d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2506,6 +2506,9 @@ static int classify_symbols(struct objtool_file *file)
 	struct symbol *func;
 
 	for_each_sym(file, func) {
+		if (func->type == STT_NOTYPE && strstarts(func->name, ".L"))
+			func->local_label = true;
+
 		if (func->bind != STB_GLOBAL)
 			continue;
 
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 9f71e988eca4..2b8a69de4db8 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -67,6 +67,7 @@ struct symbol {
 	u8 profiling_func    : 1;
 	u8 warned	     : 1;
 	u8 embedded_insn     : 1;
+	u8 local_label       : 1;
 	struct list_head pv_target;
 	struct reloc *relocs;
 };

Re: [PATCH v3 0/8] Add objtool and orc support for LoongArch

[Tiezhu Yang]

On 10/20/2023 04:51 PM, Huacai Chen wrote:
> Cross compiling on X86 for LoongArch fails:
>
>   CALL    scripts/checksyscalls.sh
>   DESCEND objtool
> make[5]: *** No rule to make target
> '/usr/lib/gcc/x86_64-redhat-linux/8/include/stdbool.h', needed by
> '/home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/exec-cmd.o'.
> Stop.
> make[4]: *** [Makefile:80:
> /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd-in.o]
> Error 2
> make[3]: *** [Makefile:82:
> /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd.a]
> Error 2
> make[2]: *** [Makefile:73: objtool] Error 2
> make[1]: *** [/home/chenhuacai/linux-official.git/Makefile:1355:
> tools/objtool] Error 2
> make: *** [Makefile:234: __sub-make] Error 2

It seems that there is no stdbool.h in your cross compile environment.

It works well with the following steps, you can try it.

wget 
https://github.com/loongson/build-tools/releases/download/2023.08.08/x86_64-cross-tools-loongarch64-gcc-libc.tar.xz
tar xf x86_64-cross-tools-loongarch64-gcc-libc.tar.xz -C /opt
export PATH=/opt/cross-tools/bin/:$PATH
export 
LD_LIBRARY_PATH=/opt/cross-tools/loongarch64-unknown-linux-gnu/lib:$LD_LIBRARY_PATH
export LD_LIBRARY_PATH=/opt/cross-tools/lib:$LD_LIBRARY_PATH
export CROSS_COMPILE=loongarch64-unknown-linux-gnu-
export ARCH=loongarch

find /opt -name stdbool.h
/opt/cross-tools/lib/gcc/loongarch64-unknown-linux-gnu/14.0.0/include/stdbool.h
/opt/cross-tools/loongarch64-unknown-linux-gnu/include/c++/14.0.0/tr1/stdbool.h

cd linux.git
make loongson3_defconfig
make menuconfig   # select CONFIG_UNWINDER_ORC
make -j4

Thanks,
Tiezhu

Re: [PATCH v3 0/8] Add objtool and orc support for LoongArch

[Xi Ruoyao]

On Fri, 2023-10-20 at 18:28 +0800, Tiezhu Yang wrote:
> On 10/20/2023 04:51 PM, Huacai Chen wrote:
> > Cross compiling on X86 for LoongArch fails:
> > 
> >    CALL    scripts/checksyscalls.sh
> >    DESCEND objtool
> > make[5]: *** No rule to make target
> > '/usr/lib/gcc/x86_64-redhat-linux/8/include/stdbool.h', needed by
> > '/home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/exec-cmd.o'.
> > Stop.
> > make[4]: *** [Makefile:80:
> > /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd-in.o]
> > Error 2
> > make[3]: *** [Makefile:82:
> > /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd.a]
> > Error 2
> > make[2]: *** [Makefile:73: objtool] Error 2
> > make[1]: *** [/home/chenhuacai/linux-official.git/Makefile:1355:
> > tools/objtool] Error 2
> > make: *** [Makefile:234: __sub-make] Error 2
> 
> It seems that there is no stdbool.h in your cross compile environment.
> 
> It works well with the following steps, you can try it.

/* snip */

> find /opt -name stdbool.h
> /opt/cross-tools/lib/gcc/loongarch64-unknown-linux-gnu/14.0.0/include/stdbool.h
> /opt/cross-tools/loongarch64-unknown-linux-gnu/include/c++/14.0.0/tr1/stdbool.h

The problem is HOSTCC cannot find stdbool.h, not (target) CC.  So these
two files are not relevant.

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University

Re: [PATCH v3 0/8] Add objtool and orc support for LoongArch

[Tiezhu Yang]

On 10/20/2023 06:45 PM, Xi Ruoyao wrote:
> On Fri, 2023-10-20 at 18:28 +0800, Tiezhu Yang wrote:
>> On 10/20/2023 04:51 PM, Huacai Chen wrote:
>>> Cross compiling on X86 for LoongArch fails:
>>>
>>>    CALL    scripts/checksyscalls.sh
>>>    DESCEND objtool
>>> make[5]: *** No rule to make target
>>> '/usr/lib/gcc/x86_64-redhat-linux/8/include/stdbool.h', needed by
>>> '/home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/exec-cmd.o'.
>>> Stop.
>>> make[4]: *** [Makefile:80:
>>> /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd-in.o]
>>> Error 2
>>> make[3]: *** [Makefile:82:
>>> /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd.a]
>>> Error 2
>>> make[2]: *** [Makefile:73: objtool] Error 2
>>> make[1]: *** [/home/chenhuacai/linux-official.git/Makefile:1355:
>>> tools/objtool] Error 2
>>> make: *** [Makefile:234: __sub-make] Error 2
>>
>> It seems that there is no stdbool.h in your cross compile environment.
>>
>> It works well with the following steps, you can try it.
>
> /* snip */
>
>> find /opt -name stdbool.h
>> /opt/cross-tools/lib/gcc/loongarch64-unknown-linux-gnu/14.0.0/include/stdbool.h
>> /opt/cross-tools/loongarch64-unknown-linux-gnu/include/c++/14.0.0/tr1/stdbool.h
>
> The problem is HOSTCC cannot find stdbool.h, not (target) CC.  So these
> two files are not relevant.
>

Oh, thank you for pointing out the real reason of this issue.

By the way, my test system is Fedora 38 x86_64, it works well.

Thanks,
Tiezhu

Re: [PATCH v3 5/8] objtool: Check local label about sibling call

[Tiezhu Yang]

On 10/20/2023 05:30 PM, Peter Zijlstra wrote:
> On Fri, Oct 20, 2023 at 10:26:58AM +0800, Tiezhu Yang wrote:
>
>> +		if (reloc && reloc->sym->type == STT_NOTYPE &&
>> +		    strncmp(reloc->sym->name, ".L", 2) == 0)
>
>> +			if (reloc->sym->type == STT_NOTYPE &&
>> +			    strncmp(reloc->sym->name, ".L", 2) == 0) {
>
> Would not something like the below be better?
>
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index e308d1ba664e..a57d293c834d 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -2506,6 +2506,9 @@ static int classify_symbols(struct objtool_file *file)
>  	struct symbol *func;
>
>  	for_each_sym(file, func) {
> +		if (func->type == STT_NOTYPE && strstarts(func->name, ".L"))
> +			func->local_label = true;
> +
>  		if (func->bind != STB_GLOBAL)
>  			continue;
>
> diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
> index 9f71e988eca4..2b8a69de4db8 100644
> --- a/tools/objtool/include/objtool/elf.h
> +++ b/tools/objtool/include/objtool/elf.h
> @@ -67,6 +67,7 @@ struct symbol {
>  	u8 profiling_func    : 1;
>  	u8 warned	     : 1;
>  	u8 embedded_insn     : 1;
> +	u8 local_label       : 1;
>  	struct list_head pv_target;
>  	struct reloc *relocs;
>  };
>

Yes, this looks much better, thank you very much.
I will update the related code of patch #5, #6 and #7.

Thanks,
Tiezhu

Re: [PATCH v3 4/8] objtool/LoongArch: Enable orc to be built

[Huacai Chen]

Hi, Tiezhu,

On Fri, Oct 20, 2023 at 10:27 AM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
> Implement arch-specific init_orc_entry(), write_orc_entry(), reg_name(),
> orc_type_name(), print_reg() and orc_print_dump(), then set BUILD_ORC as
> y to build the orc related files.
>
> Co-developed-by: Jinyang He <hejinyang@loongson.cn>
> Signed-off-by: Jinyang He <hejinyang@loongson.cn>
> Co-developed-by: Youling Tang <tangyouling@loongson.cn>
> Signed-off-by: Youling Tang <tangyouling@loongson.cn>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  tools/arch/loongarch/include/asm/orc_types.h |  58 +++++++++
>  tools/objtool/Makefile                       |   4 +
>  tools/objtool/arch/loongarch/Build           |   1 +
>  tools/objtool/arch/loongarch/decode.c        |  16 +++
>  tools/objtool/arch/loongarch/orc.c           | 171 +++++++++++++++++++++++++++
>  5 files changed, 250 insertions(+)
>  create mode 100644 tools/arch/loongarch/include/asm/orc_types.h
>  create mode 100644 tools/objtool/arch/loongarch/orc.c
>
> diff --git a/tools/arch/loongarch/include/asm/orc_types.h b/tools/arch/loongarch/include/asm/orc_types.h
> new file mode 100644
> index 0000000..caf1f71
> --- /dev/null
> +++ b/tools/arch/loongarch/include/asm/orc_types.h
> @@ -0,0 +1,58 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +#ifndef _ORC_TYPES_H
> +#define _ORC_TYPES_H
> +
> +#include <linux/types.h>
> +
> +/*
> + * The ORC_REG_* registers are base registers which are used to find other
> + * registers on the stack.
> + *
> + * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
> + * address of the previous frame: the caller's SP before it called the current
> + * function.
> + *
> + * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
> + * the current frame.
> + *
> + * The most commonly used base registers are SP and FP -- which the previous SP
> + * is usually based on -- and PREV_SP and UNDEFINED -- which the previous FP is
> + * usually based on.
> + *
> + * The rest of the base registers are needed for special cases like entry code
> + * and GCC realigned stacks.
> + */
> +#define ORC_REG_UNDEFINED              0
> +#define ORC_REG_PREV_SP                        1
> +#define ORC_REG_SP                     2
> +#define ORC_REG_FP                     3
> +#define ORC_REG_MAX                    4
> +
> +#define ORC_TYPE_UNDEFINED             0
> +#define ORC_TYPE_END_OF_STACK          1
> +#define ORC_TYPE_CALL                  2
> +#define ORC_TYPE_REGS                  3
> +#define ORC_TYPE_REGS_PARTIAL          4
> +
> +#ifndef __ASSEMBLY__
> +/*
> + * This struct is more or less a vastly simplified version of the DWARF Call
> + * Frame Information standard.  It contains only the necessary parts of DWARF
> + * CFI, simplified for ease of access by the in-kernel unwinder.  It tells the
> + * unwinder how to find the previous SP and FP (and sometimes entry regs) on
> + * the stack for a given code address.  Each instance of the struct corresponds
> + * to one or more code locations.
> + */
> +struct orc_entry {
> +       s16             sp_offset;
> +       s16             fp_offset;
> +       s16             ra_offset;
> +       unsigned int    sp_reg:4;
> +       unsigned int    fp_reg:4;
> +       unsigned int    ra_reg:4;
> +       unsigned int    type:3;
> +       unsigned int    signal:1;
> +};
> +#endif /* __ASSEMBLY__ */
> +
> +#endif /* _ORC_TYPES_H */
> diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
> index 83b100c..bf7f7f8 100644
> --- a/tools/objtool/Makefile
> +++ b/tools/objtool/Makefile
> @@ -57,6 +57,10 @@ ifeq ($(SRCARCH),x86)
>         BUILD_ORC := y
>  endif
>
> +ifeq ($(SRCARCH),loongarch)
> +       BUILD_ORC := y
> +endif
> +
>  export BUILD_ORC
>  export srctree OUTPUT CFLAGS SRCARCH AWK
>  include $(srctree)/tools/build/Makefile.include
> diff --git a/tools/objtool/arch/loongarch/Build b/tools/objtool/arch/loongarch/Build
> index d24d563..1d4b784 100644
> --- a/tools/objtool/arch/loongarch/Build
> +++ b/tools/objtool/arch/loongarch/Build
> @@ -1,2 +1,3 @@
>  objtool-y += decode.o
>  objtool-y += special.o
> +objtool-y += orc.o
> diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
> index 0ee3333..555b6d0 100644
> --- a/tools/objtool/arch/loongarch/decode.c
> +++ b/tools/objtool/arch/loongarch/decode.c
> @@ -3,6 +3,8 @@
>  #include <objtool/check.h>
>  #include <objtool/warn.h>
>  #include <asm/inst.h>
> +#include <asm/orc_types.h>
> +#include <linux/objtool_types.h>
>

We should add lines here to avoid cross-compile errors:

+#ifndef EM_LOONGARCH
+#define EM_LOONGARCH   258
+#endif



Huacai

>  int arch_ftrace_match(char *name)
>  {
> @@ -38,6 +40,20 @@ bool arch_callee_saved_reg(unsigned char reg)
>
>  int arch_decode_hint_reg(u8 sp_reg, int *base)
>  {
> +       switch (sp_reg) {
> +       case ORC_REG_UNDEFINED:
> +               *base = CFI_UNDEFINED;
> +               break;
> +       case ORC_REG_SP:
> +               *base = CFI_SP;
> +               break;
> +       case ORC_REG_FP:
> +               *base = CFI_FP;
> +               break;
> +       default:
> +               return -1;
> +       }
> +
>         return 0;
>  }
>
> diff --git a/tools/objtool/arch/loongarch/orc.c b/tools/objtool/arch/loongarch/orc.c
> new file mode 100644
> index 0000000..873536d
> --- /dev/null
> +++ b/tools/objtool/arch/loongarch/orc.c
> @@ -0,0 +1,171 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +#include <linux/objtool_types.h>
> +#include <asm/orc_types.h>
> +
> +#include <objtool/check.h>
> +#include <objtool/orc.h>
> +#include <objtool/warn.h>
> +#include <objtool/endianness.h>
> +
> +int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
> +{
> +       struct cfi_reg *fp = &cfi->regs[CFI_FP];
> +       struct cfi_reg *ra = &cfi->regs[CFI_RA];
> +
> +       memset(orc, 0, sizeof(*orc));
> +
> +       if (!cfi) {
> +               /*
> +                * This is usually either unreachable nops/traps (which don't
> +                * trigger unreachable instruction warnings), or
> +                * STACK_FRAME_NON_STANDARD functions.
> +                */
> +               orc->type = ORC_TYPE_UNDEFINED;
> +               return 0;
> +       }
> +
> +       switch (cfi->type) {
> +       case UNWIND_HINT_TYPE_UNDEFINED:
> +               orc->type = ORC_TYPE_UNDEFINED;
> +               return 0;
> +       case UNWIND_HINT_TYPE_END_OF_STACK:
> +               orc->type = ORC_TYPE_END_OF_STACK;
> +               return 0;
> +       case UNWIND_HINT_TYPE_CALL:
> +               orc->type = ORC_TYPE_CALL;
> +               break;
> +       case UNWIND_HINT_TYPE_REGS:
> +               orc->type = ORC_TYPE_REGS;
> +               break;
> +       case UNWIND_HINT_TYPE_REGS_PARTIAL:
> +               orc->type = ORC_TYPE_REGS_PARTIAL;
> +               break;
> +       default:
> +               WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
> +               return -1;
> +       }
> +
> +       orc->signal = cfi->signal;
> +
> +       switch (cfi->cfa.base) {
> +       case CFI_SP:
> +               orc->sp_reg = ORC_REG_SP;
> +               break;
> +       case CFI_FP:
> +               orc->sp_reg = ORC_REG_FP;
> +               break;
> +       default:
> +               WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
> +               return -1;
> +       }
> +
> +       switch (fp->base) {
> +       case CFI_UNDEFINED:
> +               orc->fp_reg = ORC_REG_UNDEFINED;
> +               orc->fp_offset = 0;
> +               break;
> +       case CFI_CFA:
> +               orc->fp_reg = ORC_REG_PREV_SP;
> +               orc->fp_offset = fp->offset;
> +               break;
> +       case CFI_FP:
> +               orc->fp_reg = ORC_REG_FP;
> +               break;
> +       default:
> +               WARN_INSN(insn, "unknown FP base reg %d", fp->base);
> +               return -1;
> +       }
> +
> +       switch (ra->base) {
> +       case CFI_UNDEFINED:
> +               orc->ra_reg = ORC_REG_UNDEFINED;
> +               orc->ra_offset = 0;
> +               break;
> +       case CFI_CFA:
> +               orc->ra_reg = ORC_REG_PREV_SP;
> +               orc->ra_offset = ra->offset;
> +               break;
> +       case CFI_FP:
> +               orc->ra_reg = ORC_REG_FP;
> +               break;
> +       default:
> +               WARN_INSN(insn, "unknown RA base reg %d", ra->base);
> +               return -1;
> +       }
> +
> +       orc->sp_offset = cfi->cfa.offset;
> +
> +       return 0;
> +}
> +
> +int write_orc_entry(struct elf *elf, struct section *orc_sec,
> +                   struct section *ip_sec, unsigned int idx,
> +                   struct section *insn_sec, unsigned long insn_off,
> +                   struct orc_entry *o)
> +{
> +       struct orc_entry *orc;
> +
> +       /* populate ORC data */
> +       orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
> +       memcpy(orc, o, sizeof(*orc));
> +
> +       /* populate reloc for ip */
> +       if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
> +                                    insn_sec, insn_off))
> +               return -1;
> +
> +       return 0;
> +}
> +
> +static const char *reg_name(unsigned int reg)
> +{
> +       switch (reg) {
> +       case ORC_REG_SP:
> +               return "sp";
> +       case ORC_REG_FP:
> +               return "fp";
> +       case ORC_REG_PREV_SP:
> +               return "prevsp";
> +       default:
> +               return "?";
> +       }
> +}
> +
> +static const char *orc_type_name(unsigned int type)
> +{
> +       switch (type) {
> +       case UNWIND_HINT_TYPE_CALL:
> +               return "call";
> +       case UNWIND_HINT_TYPE_REGS:
> +               return "regs";
> +       case UNWIND_HINT_TYPE_REGS_PARTIAL:
> +               return "regs (partial)";
> +       default:
> +               return "?";
> +       }
> +}
> +
> +static void print_reg(unsigned int reg, int offset)
> +{
> +       if (reg == ORC_REG_UNDEFINED)
> +               printf(" (und) ");
> +       else
> +               printf("%s + %3d", reg_name(reg), offset);
> +
> +}
> +
> +void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i)
> +{
> +       printf("type:%s", orc_type_name(orc[i].type));
> +
> +       printf(" sp:");
> +       print_reg(orc[i].sp_reg, orc[i].sp_offset);
> +
> +       printf(" fp:");
> +       print_reg(orc[i].fp_reg, orc[i].fp_offset);
> +
> +       printf(" ra:");
> +       print_reg(orc[i].ra_reg, orc[i].ra_offset);
> +
> +       printf(" signal:%d\n", orc[i].signal);
> +}
> --
> 2.1.0
>

Re: [PATCH v3 8/8] LoongArch: Add ORC stack unwinder support

[Huacai Chen]

Hi, Tiezhu,

On Fri, Oct 20, 2023 at 10:27 AM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
> The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is
> similar in concept to a DWARF unwinder. The difference is that the format
> of the ORC data is much simpler than DWARF, which in turn allows the ORC
> unwinder to be much simpler and faster.
>
> The ORC data consists of unwind tables which are generated by objtool.
> They contain out-of-band data which is used by the in-kernel ORC unwinder.
> Objtool generates the ORC data by first doing compile-time stack metadata
> validation (CONFIG_STACK_VALIDATION). After analyzing all the code paths
> of a .o file, it determines information about the stack state at each
> instruction address in the file and outputs that information to the
> .orc_unwind and .orc_unwind_ip sections.
>
> The per-object ORC sections are combined at link time and are sorted and
> post-processed at boot time. The unwinder uses the resulting data to
> correlate instruction addresses with their stack states at run time.
>
> Most of the logic are similar with x86, in order to get ra info before ra
> is saved into stack, add ra_reg and ra_offset into orc_entry. At the same
> time, modify some arch-specific code to silence the objtool warnings.
>
> Co-developed-by: Jinyang He <hejinyang@loongson.cn>
> Signed-off-by: Jinyang He <hejinyang@loongson.cn>
> Co-developed-by: Youling Tang <tangyouling@loongson.cn>
> Signed-off-by: Youling Tang <tangyouling@loongson.cn>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  arch/loongarch/Kconfig                    |   2 +
>  arch/loongarch/Kconfig.debug              |  11 +
>  arch/loongarch/Makefile                   |  18 ++
>  arch/loongarch/include/asm/Kbuild         |   1 +
>  arch/loongarch/include/asm/bug.h          |   1 +
>  arch/loongarch/include/asm/exception.h    |   2 +
>  arch/loongarch/include/asm/module.h       |   7 +
>  arch/loongarch/include/asm/orc_header.h   |  19 ++
>  arch/loongarch/include/asm/orc_lookup.h   |  34 ++
>  arch/loongarch/include/asm/orc_types.h    |  58 ++++
>  arch/loongarch/include/asm/stackframe.h   |   3 +
>  arch/loongarch/include/asm/unwind.h       |  22 +-
>  arch/loongarch/include/asm/unwind_hints.h |  28 ++
>  arch/loongarch/kernel/Makefile            |   3 +
>  arch/loongarch/kernel/entry.S             |   5 +
>  arch/loongarch/kernel/genex.S             |   4 +
>  arch/loongarch/kernel/module.c            |  11 +-
>  arch/loongarch/kernel/relocate_kernel.S   |   2 +
>  arch/loongarch/kernel/setup.c             |   2 +
>  arch/loongarch/kernel/stacktrace.c        |   1 +
>  arch/loongarch/kernel/traps.c             |  44 ++-
>  arch/loongarch/kernel/unwind_orc.c        | 522 ++++++++++++++++++++++++++++++
>  arch/loongarch/kernel/vmlinux.lds.S       |   3 +
>  arch/loongarch/lib/Makefile               |   2 +
>  arch/loongarch/mm/tlb.c                   |  27 +-
>  arch/loongarch/mm/tlbex.S                 |   9 +
>  arch/loongarch/vdso/Makefile              |   1 +
>  include/linux/compiler.h                  |   9 +
>  scripts/Makefile                          |   7 +-
>  29 files changed, 824 insertions(+), 34 deletions(-)
>  create mode 100644 arch/loongarch/include/asm/orc_header.h
>  create mode 100644 arch/loongarch/include/asm/orc_lookup.h
>  create mode 100644 arch/loongarch/include/asm/orc_types.h
>  create mode 100644 arch/loongarch/include/asm/unwind_hints.h
>  create mode 100644 arch/loongarch/kernel/unwind_orc.c
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index e14396a..21ef3bb 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -131,6 +131,7 @@ config LOONGARCH
>         select HAVE_KRETPROBES
>         select HAVE_MOD_ARCH_SPECIFIC
>         select HAVE_NMI
> +       select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS
>         select HAVE_PCI
>         select HAVE_PERF_EVENTS
>         select HAVE_PERF_REGS
> @@ -141,6 +142,7 @@ config LOONGARCH
>         select HAVE_SAMPLE_FTRACE_DIRECT
>         select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
>         select HAVE_SETUP_PER_CPU_AREA if NUMA
> +       select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
>         select HAVE_STACKPROTECTOR
>         select HAVE_SYSCALL_TRACEPOINTS
>         select HAVE_TIF_NOHZ
> diff --git a/arch/loongarch/Kconfig.debug b/arch/loongarch/Kconfig.debug
> index 8d36aab..98d6063 100644
> --- a/arch/loongarch/Kconfig.debug
> +++ b/arch/loongarch/Kconfig.debug
> @@ -26,4 +26,15 @@ config UNWINDER_PROLOGUE
>           Some of the addresses it reports may be incorrect (but better than the
>           Guess unwinder).
>
> +config UNWINDER_ORC
> +       bool "ORC unwinder"
> +       select OBJTOOL
> +       help
> +         This option enables the ORC (Oops Rewind Capability) unwinder for
> +         unwinding kernel stack traces.  It uses a custom data format which is
> +         a simplified version of the DWARF Call Frame Information standard.
> +
> +         Enabling this option will increase the kernel's runtime memory usage
> +         by roughly 2-4MB, depending on your kernel config.
> +
>  endchoice
> diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
> index fb0fada..fab28f4 100644
> --- a/arch/loongarch/Makefile
> +++ b/arch/loongarch/Makefile
> @@ -25,6 +25,24 @@ endif
>  32bit-emul             = elf32loongarch
>  64bit-emul             = elf64loongarch
>
> +ifdef CONFIG_OBJTOOL
> +KBUILD_AFLAGS  += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
> +KBUILD_CFLAGS  += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
> +KBUILD_CFLAGS  += -fno-optimize-sibling-calls -fno-jump-tables -falign-functions=4
> +endif
> +
> +ifdef CONFIG_UNWINDER_ORC
> +orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
> +orc_hash_sh := $(srctree)/scripts/orc_hash.sh
> +targets += $(orc_hash_h)
> +quiet_cmd_orc_hash = GEN     $@
> +      cmd_orc_hash = mkdir -p $(dir $@); \
> +                    $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
> +$(orc_hash_h): $(srctree)/arch/loongarch/include/asm/orc_types.h $(orc_hash_sh) FORCE
> +       $(call if_changed,orc_hash)
> +archprepare: $(orc_hash_h)
> +endif
> +
>  ifdef CONFIG_DYNAMIC_FTRACE
>  KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
>  CC_FLAGS_FTRACE := -fpatchable-function-entry=2
> diff --git a/arch/loongarch/include/asm/Kbuild b/arch/loongarch/include/asm/Kbuild
> index 93783fa..2bb285c 100644
> --- a/arch/loongarch/include/asm/Kbuild
> +++ b/arch/loongarch/include/asm/Kbuild
> @@ -1,4 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0
> +generated-y += orc_hash.h
>  generic-y += dma-contiguous.h
>  generic-y += mcs_spinlock.h
>  generic-y += parport.h
> diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
> index d4ca3ba..0838887 100644
> --- a/arch/loongarch/include/asm/bug.h
> +++ b/arch/loongarch/include/asm/bug.h
> @@ -44,6 +44,7 @@
>  do {                                                           \
>         instrumentation_begin();                                \
>         __BUG_FLAGS(BUGFLAG_WARNING|(flags));                   \
> +       annotate_reachable();                                   \
>         instrumentation_end();                                  \
>  } while (0)
>
> diff --git a/arch/loongarch/include/asm/exception.h b/arch/loongarch/include/asm/exception.h
> index af74a3f..0b3977c 100644
> --- a/arch/loongarch/include/asm/exception.h
> +++ b/arch/loongarch/include/asm/exception.h
> @@ -42,4 +42,6 @@ asmlinkage void handle_reserved(void);
>  asmlinkage void handle_vint(void);
>  asmlinkage void noinstr handle_loongarch_irq(struct pt_regs *regs);
>
> +extern void *exception_table[];
> +
>  #endif /* __ASM_EXCEPTION_H */
> diff --git a/arch/loongarch/include/asm/module.h b/arch/loongarch/include/asm/module.h
> index 2ecd82b..96af0ba 100644
> --- a/arch/loongarch/include/asm/module.h
> +++ b/arch/loongarch/include/asm/module.h
> @@ -6,6 +6,7 @@
>  #define _ASM_MODULE_H
>
>  #include <asm/inst.h>
> +#include <asm/orc_types.h>
>  #include <asm-generic/module.h>
>
>  #define RELA_STACK_DEPTH 16
> @@ -23,6 +24,12 @@ struct mod_arch_specific {
>
>         /* For CONFIG_DYNAMIC_FTRACE */
>         struct plt_entry *ftrace_trampolines;
> +
> +#ifdef CONFIG_UNWINDER_ORC
> +       unsigned int num_orcs;
> +       int *orc_unwind_ip;
> +       struct orc_entry *orc_unwind;
> +#endif
>  };
>
>  struct got_entry {
> diff --git a/arch/loongarch/include/asm/orc_header.h b/arch/loongarch/include/asm/orc_header.h
> new file mode 100644
> index 0000000..07bacf3
> --- /dev/null
> +++ b/arch/loongarch/include/asm/orc_header.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright (c) Meta Platforms, Inc. and affiliates. */
> +
> +#ifndef _ORC_HEADER_H
> +#define _ORC_HEADER_H
> +
> +#include <linux/types.h>
> +#include <linux/compiler.h>
> +#include <asm/orc_hash.h>
> +
> +/*
> + * The header is currently a 20-byte hash of the ORC entry definition; see
> + * scripts/orc_hash.sh.
> + */
> +#define ORC_HEADER                                     \
> +       __used __section(".orc_header") __aligned(4)    \
> +       static const u8 orc_header[] = { ORC_HASH }
> +
> +#endif /* _ORC_HEADER_H */
> diff --git a/arch/loongarch/include/asm/orc_lookup.h b/arch/loongarch/include/asm/orc_lookup.h
> new file mode 100644
> index 0000000..2416312
> --- /dev/null
> +++ b/arch/loongarch/include/asm/orc_lookup.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
> + */
> +#ifndef _ORC_LOOKUP_H
> +#define _ORC_LOOKUP_H
> +
> +/*
> + * This is a lookup table for speeding up access to the .orc_unwind table.
> + * Given an input address offset, the corresponding lookup table entry
> + * specifies a subset of the .orc_unwind table to search.
> + *
> + * Each block represents the end of the previous range and the start of the
> + * next range.  An extra block is added to give the last range an end.
> + *
> + * The block size should be a power of 2 to avoid a costly 'div' instruction.
> + *
> + * A block size of 256 was chosen because it roughly doubles unwinder
> + * performance while only adding ~5% to the ORC data footprint.
> + */
> +#define LOOKUP_BLOCK_ORDER     8
> +#define LOOKUP_BLOCK_SIZE      (1 << LOOKUP_BLOCK_ORDER)
> +
> +#ifndef LINKER_SCRIPT
> +
> +extern unsigned int orc_lookup[];
> +extern unsigned int orc_lookup_end[];
> +
> +#define LOOKUP_START_IP                (unsigned long)_stext
> +#define LOOKUP_STOP_IP         (unsigned long)_etext
> +
> +#endif /* LINKER_SCRIPT */
> +
> +#endif /* _ORC_LOOKUP_H */
> diff --git a/arch/loongarch/include/asm/orc_types.h b/arch/loongarch/include/asm/orc_types.h
> new file mode 100644
> index 0000000..caf1f71
> --- /dev/null
> +++ b/arch/loongarch/include/asm/orc_types.h
> @@ -0,0 +1,58 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +#ifndef _ORC_TYPES_H
> +#define _ORC_TYPES_H
> +
> +#include <linux/types.h>
> +
> +/*
> + * The ORC_REG_* registers are base registers which are used to find other
> + * registers on the stack.
> + *
> + * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
> + * address of the previous frame: the caller's SP before it called the current
> + * function.
> + *
> + * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
> + * the current frame.
> + *
> + * The most commonly used base registers are SP and FP -- which the previous SP
> + * is usually based on -- and PREV_SP and UNDEFINED -- which the previous FP is
> + * usually based on.
> + *
> + * The rest of the base registers are needed for special cases like entry code
> + * and GCC realigned stacks.
> + */
> +#define ORC_REG_UNDEFINED              0
> +#define ORC_REG_PREV_SP                        1
> +#define ORC_REG_SP                     2
> +#define ORC_REG_FP                     3
> +#define ORC_REG_MAX                    4
> +
> +#define ORC_TYPE_UNDEFINED             0
> +#define ORC_TYPE_END_OF_STACK          1
> +#define ORC_TYPE_CALL                  2
> +#define ORC_TYPE_REGS                  3
> +#define ORC_TYPE_REGS_PARTIAL          4
> +
> +#ifndef __ASSEMBLY__
> +/*
> + * This struct is more or less a vastly simplified version of the DWARF Call
> + * Frame Information standard.  It contains only the necessary parts of DWARF
> + * CFI, simplified for ease of access by the in-kernel unwinder.  It tells the
> + * unwinder how to find the previous SP and FP (and sometimes entry regs) on
> + * the stack for a given code address.  Each instance of the struct corresponds
> + * to one or more code locations.
> + */
> +struct orc_entry {
> +       s16             sp_offset;
> +       s16             fp_offset;
> +       s16             ra_offset;
> +       unsigned int    sp_reg:4;
> +       unsigned int    fp_reg:4;
> +       unsigned int    ra_reg:4;
> +       unsigned int    type:3;
> +       unsigned int    signal:1;
> +};
> +#endif /* __ASSEMBLY__ */
> +
> +#endif /* _ORC_TYPES_H */
> diff --git a/arch/loongarch/include/asm/stackframe.h b/arch/loongarch/include/asm/stackframe.h
> index 4fb1e64..45b507a 100644
> --- a/arch/loongarch/include/asm/stackframe.h
> +++ b/arch/loongarch/include/asm/stackframe.h
> @@ -13,6 +13,7 @@
>  #include <asm/asm-offsets.h>
>  #include <asm/loongarch.h>
>  #include <asm/thread_info.h>
> +#include <asm/unwind_hints.h>
>
>  /* Make the addition of cfi info a little easier. */
>         .macro cfi_rel_offset reg offset=0 docfi=0
> @@ -162,6 +163,7 @@
>         li.w    t0, CSR_CRMD_WE
>         csrxchg t0, t0, LOONGARCH_CSR_CRMD
>  #endif
> +       UNWIND_HINT_REGS
>         .endm
>
>         .macro  SAVE_ALL docfi=0
> @@ -219,6 +221,7 @@
>
>         .macro  RESTORE_SP_AND_RET docfi=0
>         cfi_ld  sp, PT_R3, \docfi
> +       UNWIND_HINT_FUNC
>         ertn
>         .endm
>
> diff --git a/arch/loongarch/include/asm/unwind.h b/arch/loongarch/include/asm/unwind.h
> index b9dce87..d36e04e 100644
> --- a/arch/loongarch/include/asm/unwind.h
> +++ b/arch/loongarch/include/asm/unwind.h
> @@ -16,6 +16,7 @@
>  enum unwinder_type {
>         UNWINDER_GUESS,
>         UNWINDER_PROLOGUE,
> +       UNWINDER_ORC,
>  };
>
>  struct unwind_state {
> @@ -24,7 +25,7 @@ struct unwind_state {
>         struct task_struct *task;
>         bool first, error, reset;
>         int graph_idx;
> -       unsigned long sp, pc, ra;
> +       unsigned long sp, pc, ra, fp;
>  };
>
>  bool default_next_frame(struct unwind_state *state);
> @@ -34,6 +35,17 @@ void unwind_start(struct unwind_state *state,
>  bool unwind_next_frame(struct unwind_state *state);
>  unsigned long unwind_get_return_address(struct unwind_state *state);
>
> +#ifdef CONFIG_UNWINDER_ORC
> +void unwind_init(void);
> +void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
> +                       void *orc, size_t orc_size);
> +#else
> +static inline void unwind_init(void) {}
> +static inline
> +void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
> +                       void *orc, size_t orc_size) {}
> +#endif
> +
>  static inline bool unwind_done(struct unwind_state *state)
>  {
>         return state->stack_info.type == STACK_TYPE_UNKNOWN;
> @@ -61,14 +73,17 @@ static __always_inline void __unwind_start(struct unwind_state *state,
>                 state->sp = regs->regs[3];
>                 state->pc = regs->csr_era;
>                 state->ra = regs->regs[1];
> +               state->fp = regs->regs[22];
>         } else if (task && task != current) {
>                 state->sp = thread_saved_fp(task);
>                 state->pc = thread_saved_ra(task);
>                 state->ra = 0;
> +               state->fp = 0;
>         } else {
>                 state->sp = (unsigned long)__builtin_frame_address(0);
>                 state->pc = (unsigned long)__builtin_return_address(0);
>                 state->ra = 0;
> +               state->fp = 0;
>         }
>         state->task = task;
>         get_stack_info(state->sp, state->task, &state->stack_info);
> @@ -77,6 +92,9 @@ static __always_inline void __unwind_start(struct unwind_state *state,
>
>  static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
>  {
> -       return unwind_done(state) ? 0 : state->pc;
> +       if (unwind_done(state))
> +               return 0;
> +
> +       return __kernel_text_address(state->pc) ? state->pc : 0;
>  }
>  #endif /* _ASM_UNWIND_H */
> diff --git a/arch/loongarch/include/asm/unwind_hints.h b/arch/loongarch/include/asm/unwind_hints.h
> new file mode 100644
> index 0000000..82443fe
> --- /dev/null
> +++ b/arch/loongarch/include/asm/unwind_hints.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_LOONGARCH_UNWIND_HINTS_H
> +#define _ASM_LOONGARCH_UNWIND_HINTS_H
> +
> +#include <linux/objtool.h>
> +#include <asm/orc_types.h>
> +
> +#ifdef __ASSEMBLY__
> +
> +.macro UNWIND_HINT_UNDEFINED
> +       UNWIND_HINT type=UNWIND_HINT_TYPE_UNDEFINED
> +.endm
> +
> +.macro UNWIND_HINT_EMPTY
> +       UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL
> +.endm
> +
> +.macro UNWIND_HINT_REGS
> +       UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_REGS
> +.endm
> +
> +.macro UNWIND_HINT_FUNC
> +       UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_CALL
> +.endm
> +
> +#endif /* __ASSEMBLY__ */
> +
> +#endif /* _ASM_LOONGARCH_UNWIND_HINTS_H */
> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
> index 4fcc168..a89428c 100644
> --- a/arch/loongarch/kernel/Makefile
> +++ b/arch/loongarch/kernel/Makefile
> @@ -3,6 +3,8 @@
>  # Makefile for the Linux/LoongArch kernel.
>  #
>
> +OBJECT_FILES_NON_STANDARD_head.o := y
> +
>  extra-y                := vmlinux.lds
>
>  obj-y          += head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
> @@ -62,6 +64,7 @@ obj-$(CONFIG_CRASH_DUMP)      += crash_dump.o
>
>  obj-$(CONFIG_UNWINDER_GUESS)   += unwind_guess.o
>  obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
> +obj-$(CONFIG_UNWINDER_ORC)     += unwind_orc.o
>
>  obj-$(CONFIG_PERF_EVENTS)      += perf_event.o perf_regs.o
>  obj-$(CONFIG_HAVE_HW_BREAKPOINT)       += hw_breakpoint.o
> diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S
> index 1ec8e4c..e43115f 100644
> --- a/arch/loongarch/kernel/entry.S
> +++ b/arch/loongarch/kernel/entry.S
> @@ -14,11 +14,13 @@
>  #include <asm/regdef.h>
>  #include <asm/stackframe.h>
>  #include <asm/thread_info.h>
> +#include <asm/unwind_hints.h>
>
>         .text
>         .cfi_sections   .debug_frame
>         .align  5
>  SYM_CODE_START(handle_syscall)
> +       UNWIND_HINT_UNDEFINED
>         csrrd           t0, PERCPU_BASE_KS
>         la.pcrel        t1, kernelsp
>         add.d           t1, t1, t0
> @@ -56,6 +58,7 @@ SYM_CODE_START(handle_syscall)
>         cfi_st          u0, PT_R21
>         cfi_st          fp, PT_R22
>
> +       UNWIND_HINT_REGS
>         SAVE_STATIC
>
>  #ifdef CONFIG_KGDB
> @@ -75,6 +78,7 @@ SYM_CODE_END(handle_syscall)
>  _ASM_NOKPROBE(handle_syscall)
>
>  SYM_CODE_START(ret_from_fork)
> +       UNWIND_HINT_REGS
>         bl              schedule_tail           # a0 = struct task_struct *prev
>         move            a0, sp
>         bl              syscall_exit_to_user_mode
> @@ -84,6 +88,7 @@ SYM_CODE_START(ret_from_fork)
>  SYM_CODE_END(ret_from_fork)
>
>  SYM_CODE_START(ret_from_kernel_thread)
> +       UNWIND_HINT_REGS
>         bl              schedule_tail           # a0 = struct task_struct *prev
>         move            a0, s1
>         jirl            ra, s0, 0
> diff --git a/arch/loongarch/kernel/genex.S b/arch/loongarch/kernel/genex.S
> index 2bb3aa2..3f18e3b 100644
> --- a/arch/loongarch/kernel/genex.S
> +++ b/arch/loongarch/kernel/genex.S
> @@ -32,6 +32,7 @@ SYM_FUNC_START(__arch_cpu_idle)
>  SYM_FUNC_END(__arch_cpu_idle)
>
>  SYM_CODE_START(handle_vint)
> +       UNWIND_HINT_UNDEFINED
>         BACKUP_T0T1
>         SAVE_ALL
>         la_abs  t1, __arch_cpu_idle
> @@ -49,6 +50,7 @@ SYM_CODE_START(handle_vint)
>  SYM_CODE_END(handle_vint)
>
>  SYM_CODE_START(except_vec_cex)
> +       UNWIND_HINT_UNDEFINED
>         b       cache_parity_error
>  SYM_CODE_END(except_vec_cex)
>
> @@ -67,6 +69,7 @@ SYM_CODE_END(except_vec_cex)
>         .macro  BUILD_HANDLER exception handler prep
>         .align  5
>         SYM_CODE_START(handle_\exception)
> +       UNWIND_HINT_UNDEFINED
>         666:
>         BACKUP_T0T1
>         SAVE_ALL
> @@ -94,6 +97,7 @@ SYM_CODE_END(except_vec_cex)
>         BUILD_HANDLER reserved reserved none    /* others */
>
>  SYM_CODE_START(handle_sys)
> +       UNWIND_HINT_UNDEFINED
>         la_abs  t0, handle_syscall
>         jr      t0
>  SYM_CODE_END(handle_sys)
> diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
> index b13b285..83db7e5 100644
> --- a/arch/loongarch/kernel/module.c
> +++ b/arch/loongarch/kernel/module.c
> @@ -20,6 +20,7 @@
>  #include <linux/kernel.h>
>  #include <asm/alternative.h>
>  #include <asm/inst.h>
> +#include <asm/unwind.h>
>
>  static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
>  {
> @@ -515,7 +516,7 @@ static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
>  int module_finalize(const Elf_Ehdr *hdr,
>                     const Elf_Shdr *sechdrs, struct module *mod)
>  {
> -       const Elf_Shdr *s, *se;
> +       const Elf_Shdr *s, *se, *orc = NULL, *orc_ip = NULL;
>         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
>
>         for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
> @@ -523,7 +524,15 @@ int module_finalize(const Elf_Ehdr *hdr,
>                         apply_alternatives((void *)s->sh_addr, (void *)s->sh_addr + s->sh_size);
>                 if (!strcmp(".ftrace_trampoline", secstrs + s->sh_name))
>                         module_init_ftrace_plt(hdr, s, mod);
> +               if (!strcmp(".orc_unwind", secstrs + s->sh_name))
> +                       orc = s;
> +               if (!strcmp(".orc_unwind_ip", secstrs + s->sh_name))
> +                       orc_ip = s;
>         }
>
> +       if (orc && orc_ip)
> +               unwind_module_init(mod, (void *)orc_ip->sh_addr, orc_ip->sh_size,
> +                                      (void *)orc->sh_addr, orc->sh_size);
> +
>         return 0;
>  }
> diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S
> index f49f6b0..bcc191d 100644
> --- a/arch/loongarch/kernel/relocate_kernel.S
> +++ b/arch/loongarch/kernel/relocate_kernel.S
> @@ -15,6 +15,7 @@
>  #include <asm/addrspace.h>
>
>  SYM_CODE_START(relocate_new_kernel)
> +       UNWIND_HINT_UNDEFINED
>         /*
>          * a0: EFI boot flag for the new kernel
>          * a1: Command line pointer for the new kernel
> @@ -90,6 +91,7 @@ SYM_CODE_END(relocate_new_kernel)
>   * then start at the entry point from LOONGARCH_IOCSR_MBUF0.
>   */
>  SYM_CODE_START(kexec_smp_wait)
> +       UNWIND_HINT_UNDEFINED
>  1:     li.w            t0, 0x100                       /* wait for init loop */
>  2:     addi.w          t0, t0, -1                      /* limit mailbox access */
>         bnez            t0, 2b
> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
> index aed65915..613f04d 100644
> --- a/arch/loongarch/kernel/setup.c
> +++ b/arch/loongarch/kernel/setup.c
> @@ -48,6 +48,7 @@
>  #include <asm/sections.h>
>  #include <asm/setup.h>
>  #include <asm/time.h>
> +#include <asm/unwind.h>
>
>  #define SMBIOS_BIOSSIZE_OFFSET         0x09
>  #define SMBIOS_BIOSEXTERN_OFFSET       0x13
> @@ -606,6 +607,7 @@ static void __init prefill_possible_map(void)
>  void __init setup_arch(char **cmdline_p)
>  {
>         cpu_probe();
> +       unwind_init();
>
>         init_environ();
>         efi_init();
> diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
> index 92270f1..9848d42 100644
> --- a/arch/loongarch/kernel/stacktrace.c
> +++ b/arch/loongarch/kernel/stacktrace.c
> @@ -29,6 +29,7 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
>                         regs->csr_era = thread_saved_ra(task);
>                 }
>                 regs->regs[1] = 0;
> +               regs->regs[22] = 0;
>         }
>
>         for (unwind_start(&state, task, regs);
> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
> index aebfc37..5103fb1 100644
> --- a/arch/loongarch/kernel/traps.c
> +++ b/arch/loongarch/kernel/traps.c
> @@ -53,6 +53,32 @@
>
>  #include "access-helper.h"
>
> +void *exception_table[EXCCODE_INT_START] = {
> +       [0 ... EXCCODE_INT_START - 1] = handle_reserved,
> +
> +       [EXCCODE_TLBI]          = handle_tlb_load,
> +       [EXCCODE_TLBL]          = handle_tlb_load,
> +       [EXCCODE_TLBS]          = handle_tlb_store,
> +       [EXCCODE_TLBM]          = handle_tlb_modify,
> +       [EXCCODE_TLBNR]         = handle_tlb_protect,
> +       [EXCCODE_TLBNX]         = handle_tlb_protect,
> +       [EXCCODE_TLBPE]         = handle_tlb_protect,
> +       [EXCCODE_ADE]           = handle_ade,
> +       [EXCCODE_ALE]           = handle_ale,
> +       [EXCCODE_BCE]           = handle_bce,
> +       [EXCCODE_SYS]           = handle_sys,
> +       [EXCCODE_BP]            = handle_bp,
> +       [EXCCODE_INE]           = handle_ri,
> +       [EXCCODE_IPE]           = handle_ri,
> +       [EXCCODE_FPDIS]         = handle_fpu,
> +       [EXCCODE_LSXDIS]        = handle_lsx,
> +       [EXCCODE_LASXDIS]       = handle_lasx,
> +       [EXCCODE_FPE]           = handle_fpe,
> +       [EXCCODE_WATCH]         = handle_watch,
> +       [EXCCODE_BTDIS]         = handle_lbt,
> +};
> +EXPORT_SYMBOL_GPL(exception_table);
> +
>  static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
>                            const char *loglvl, bool user)
>  {
> @@ -1146,24 +1172,14 @@ void __init trap_init(void)
>  {
>         long i;
>
> +       /* Set instruction exception handler */
> +       for (i = EXCCODE_ADE; i <= EXCCODE_BTDIS; i++)
> +               set_handler(i * VECSIZE, exception_table[i], VECSIZE);
> +
>         /* Set interrupt vector handler */
>         for (i = EXCCODE_INT_START; i <= EXCCODE_INT_END; i++)
>                 set_handler(i * VECSIZE, handle_vint, VECSIZE);
>
> -       set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
> -       set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
> -       set_handler(EXCCODE_BCE * VECSIZE, handle_bce, VECSIZE);
> -       set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
> -       set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
> -       set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
> -       set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
> -       set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
> -       set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
> -       set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
> -       set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
> -       set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
> -       set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
> -
>         cache_error_setup();
>
>         local_flush_icache_range(eentry, eentry + 0x400);
> diff --git a/arch/loongarch/kernel/unwind_orc.c b/arch/loongarch/kernel/unwind_orc.c
> new file mode 100644
> index 0000000..6570bb7
> --- /dev/null
> +++ b/arch/loongarch/kernel/unwind_orc.c
> @@ -0,0 +1,522 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include <linux/objtool.h>
> +#include <linux/module.h>
> +#include <linux/sort.h>
> +#include <asm/exception.h>
> +#include <asm/orc_types.h>
> +#include <asm/orc_lookup.h>
> +#include <asm/orc_header.h>
> +#include <asm/ptrace.h>
> +#include <asm/setup.h>
> +#include <asm/stacktrace.h>
> +#include <asm/tlb.h>
> +#include <asm/unwind.h>
> +
> +ORC_HEADER;
> +
> +#define orc_warn(fmt, ...) \
> +       printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__)
> +
> +extern int __start_orc_unwind_ip[];
> +extern int __stop_orc_unwind_ip[];
> +extern struct orc_entry __start_orc_unwind[];
> +extern struct orc_entry __stop_orc_unwind[];
> +
> +static bool orc_init __ro_after_init;
> +static unsigned int lookup_num_blocks __ro_after_init;
> +
> +/* Fake frame pointer entry -- used as a fallback for generated code */
> +static struct orc_entry orc_fp_entry = {
> +       .type           = UNWIND_HINT_TYPE_CALL,
This should be ORC_TYPE_CALL, though their value are the same.

> +       .sp_reg         = ORC_REG_FP,
> +       .sp_offset      = 16,
> +       .fp_reg         = ORC_REG_PREV_SP,
> +       .fp_offset      = -16,
> +       .ra_reg         = ORC_REG_PREV_SP,
> +       .ra_offset      = -8,
> +};
> +
> +static inline unsigned long orc_ip(const int *ip)
> +{
> +       return (unsigned long)ip + *ip;
> +}
> +
> +static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
> +                                   unsigned int num_entries, unsigned long ip)
> +{
> +       int *first = ip_table;
> +       int *last = ip_table + num_entries - 1;
> +       int *mid = first, *found = first;
> +
> +       if (!num_entries)
> +               return NULL;
> +
> +       /*
> +        * Do a binary range search to find the rightmost duplicate of a given
> +        * starting address.  Some entries are section terminators which are
> +        * "weak" entries for ensuring there are no gaps.  They should be
> +        * ignored when they conflict with a real entry.
> +        */
> +       while (first <= last) {
> +               mid = first + ((last - first) / 2);
> +
> +               if (orc_ip(mid) <= ip) {
> +                       found = mid;
> +                       first = mid + 1;
> +               } else
> +                       last = mid - 1;
> +       }
> +
> +       return u_table + (found - ip_table);
> +}
> +
> +#ifdef CONFIG_MODULES
> +static struct orc_entry *orc_module_find(unsigned long ip)
> +{
> +       struct module *mod;
> +
> +       mod = __module_address(ip);
> +       if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
> +               return NULL;
> +       return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind,
> +                         mod->arch.num_orcs, ip);
> +}
> +#else
> +static struct orc_entry *orc_module_find(unsigned long ip)
> +{
> +       return NULL;
> +}
> +#endif
> +
> +#ifdef CONFIG_DYNAMIC_FTRACE
> +static struct orc_entry *orc_find(unsigned long ip);
> +
> +/*
> + * Ftrace dynamic trampolines do not have orc entries of their own.
> + * But they are copies of the ftrace entries that are static and
> + * defined in ftrace_*.S, which do have orc entries.
> + *
> + * If the unwinder comes across a ftrace trampoline, then find the
> + * ftrace function that was used to create it, and use that ftrace
> + * function's orc entry, as the placement of the return code in
> + * the stack will be identical.
> + */
> +static struct orc_entry *orc_ftrace_find(unsigned long ip)
> +{
> +       struct ftrace_ops *ops;
> +       unsigned long tramp_addr, offset;
> +
> +       ops = ftrace_ops_trampoline(ip);
> +       if (!ops)
> +               return NULL;
> +
> +       /* Set tramp_addr to the start of the code copied by the trampoline */
> +       if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
> +               tramp_addr = (unsigned long)ftrace_regs_caller;
> +       else
> +               tramp_addr = (unsigned long)ftrace_caller;
> +
> +       /* Now place tramp_addr to the location within the trampoline ip is at */
> +       offset = ip - ops->trampoline;
> +       tramp_addr += offset;
> +
> +       /* Prevent unlikely recursion */
> +       if (ip == tramp_addr)
> +               return NULL;
> +
> +       return orc_find(tramp_addr);
> +}
> +#else
> +static struct orc_entry *orc_ftrace_find(unsigned long ip)
> +{
> +       return NULL;
> +}
> +#endif
> +
> +/*
> + * If we crash with IP==0, the last successfully executed instruction
> + * was probably an indirect function call with a NULL function pointer,
> + * and we don't have unwind information for NULL.
> + * This hardcoded ORC entry for IP==0 allows us to unwind from a NULL function
> + * pointer into its parent and then continue normally from there.
> + */
> +static struct orc_entry null_orc_entry = {
> +       .sp_offset = sizeof(long),
> +       .sp_reg = ORC_REG_SP,
> +       .fp_reg = ORC_REG_UNDEFINED,
> +       .type = ORC_TYPE_CALL
> +};
> +
> +static struct orc_entry *orc_find(unsigned long ip)
> +{
> +       static struct orc_entry *orc;
> +
> +       if (ip == 0)
> +               return &null_orc_entry;
> +
> +       /* For non-init vmlinux addresses, use the fast lookup table: */
> +       if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
> +               unsigned int idx, start, stop;
> +
> +               idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
> +
> +               if (unlikely((idx >= lookup_num_blocks-1))) {
> +                       orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%pB\n",
> +                                idx, lookup_num_blocks, (void *)ip);
> +                       return NULL;
> +               }
> +
> +               start = orc_lookup[idx];
> +               stop = orc_lookup[idx + 1] + 1;
> +
> +               if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
> +                            (__start_orc_unwind + stop > __stop_orc_unwind))) {
> +                       orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%pB\n",
> +                                idx, lookup_num_blocks, start, stop, (void *)ip);
> +                       return NULL;
> +               }
> +
> +               return __orc_find(__start_orc_unwind_ip + start,
> +                                 __start_orc_unwind + start, stop - start, ip);
> +       }
> +
> +       /* vmlinux .init slow lookup: */
> +       if (is_kernel_inittext(ip))
> +               return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
> +                                 __stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
> +
> +       /* Module lookup: */
> +       orc = orc_module_find(ip);
> +       if (orc)
> +               return orc;
> +
> +       return orc_ftrace_find(ip);
> +}
> +
> +#ifdef CONFIG_MODULES
> +
> +static DEFINE_MUTEX(sort_mutex);
> +static int *cur_orc_ip_table = __start_orc_unwind_ip;
> +static struct orc_entry *cur_orc_table = __start_orc_unwind;
> +
> +static void orc_sort_swap(void *_a, void *_b, int size)
> +{
> +       struct orc_entry *orc_a, *orc_b;
> +       int *a = _a, *b = _b, tmp;
> +       int delta = _b - _a;
> +
> +       /* Swap the .orc_unwind_ip entries: */
> +       tmp = *a;
> +       *a = *b + delta;
> +       *b = tmp - delta;
> +
> +       /* Swap the corresponding .orc_unwind entries: */
> +       orc_a = cur_orc_table + (a - cur_orc_ip_table);
> +       orc_b = cur_orc_table + (b - cur_orc_ip_table);
> +       swap(*orc_a, *orc_b);
> +}
> +
> +static int orc_sort_cmp(const void *_a, const void *_b)
> +{
> +       struct orc_entry *orc_a;
> +       const int *a = _a, *b = _b;
> +       unsigned long a_val = orc_ip(a);
> +       unsigned long b_val = orc_ip(b);
> +
> +       if (a_val > b_val)
> +               return 1;
> +       if (a_val < b_val)
> +               return -1;
> +
> +       /*
> +        * The "weak" section terminator entries need to always be first
> +        * to ensure the lookup code skips them in favor of real entries.
> +        * These terminator entries exist to handle any gaps created by
> +        * whitelisted .o files which didn't get objtool generation.
> +        */
> +       orc_a = cur_orc_table + (a - cur_orc_ip_table);
> +       return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1;
> +}
> +
> +void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
> +                       void *_orc, size_t orc_size)
> +{
> +       int *orc_ip = _orc_ip;
> +       struct orc_entry *orc = _orc;
> +       unsigned int num_entries = orc_ip_size / sizeof(int);
> +
> +       WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
> +                    orc_size % sizeof(*orc) != 0 ||
> +                    num_entries != orc_size / sizeof(*orc));
> +
> +       /*
> +        * The 'cur_orc_*' globals allow the orc_sort_swap() callback to
> +        * associate an .orc_unwind_ip table entry with its corresponding
> +        * .orc_unwind entry so they can both be swapped.
> +        */
> +       mutex_lock(&sort_mutex);
> +       cur_orc_ip_table = orc_ip;
> +       cur_orc_table = orc;
> +       sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
> +       mutex_unlock(&sort_mutex);
> +
> +       mod->arch.orc_unwind_ip = orc_ip;
> +       mod->arch.orc_unwind = orc;
> +       mod->arch.num_orcs = num_entries;
> +}
> +#endif
> +
> +void __init unwind_init(void)
> +{
> +       size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
> +       size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
> +       size_t num_entries = orc_ip_size / sizeof(int);
> +       struct orc_entry *orc;
> +       int i;
> +
> +       if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
> +           orc_size % sizeof(struct orc_entry) != 0 ||
> +           num_entries != orc_size / sizeof(struct orc_entry)) {
> +               orc_warn("WARNING: Bad or missing .orc_unwind table.  Disabling unwinder.\n");
> +               return;
> +       }
> +
> +       /*
> +        * Note, the orc_unwind and orc_unwind_ip tables were already
> +        * sorted at build time via the 'sorttable' tool.
> +        * It's ready for binary search straight away, no need to sort it.
> +        */
> +
> +       /* Initialize the fast lookup table: */
> +       lookup_num_blocks = orc_lookup_end - orc_lookup;
> +       for (i = 0; i < lookup_num_blocks-1; i++) {
> +               orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
> +                                num_entries,
> +                                LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
> +               if (!orc) {
> +                       orc_warn("WARNING: Corrupt .orc_unwind table.  Disabling unwinder.\n");
> +                       return;
> +               }
> +
> +               orc_lookup[i] = orc - __start_orc_unwind;
> +       }
> +
> +       /* Initialize the ending block: */
> +       orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries,
> +                        LOOKUP_STOP_IP);
> +       if (!orc) {
> +               orc_warn("WARNING: Corrupt .orc_unwind table.  Disabling unwinder.\n");
> +               return;
> +       }
> +       orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
> +
> +       orc_init = true;
> +}
> +
> +static inline bool on_stack(struct stack_info *info, unsigned long addr, size_t len)
> +{
> +       unsigned long begin = info->begin;
> +       unsigned long end   = info->end;
> +
> +       return (info->type != STACK_TYPE_UNKNOWN &&
> +               addr >= begin && addr < end &&
> +               addr + len > begin && addr + len <= end);
> +}
> +
> +static bool stack_access_ok(struct unwind_state *state, unsigned long addr,
> +                           size_t len)
> +{
> +       struct stack_info *info = &state->stack_info;
> +
> +       if (on_stack(info, addr, len))
> +               return true;
> +
> +       return !get_stack_info(addr, state->task, info) &&
> +               on_stack(info, addr, len);
I believe it should be "return (get_stack_info(addr, state->task,
info) == 0)" here.

> +}
> +
> +unsigned long unwind_get_return_address(struct unwind_state *state)
> +{
> +       return __unwind_get_return_address(state);
> +}
> +EXPORT_SYMBOL_GPL(unwind_get_return_address);
> +
> +void unwind_start(struct unwind_state *state, struct task_struct *task,
> +                   struct pt_regs *regs)
> +{
> +       __unwind_start(state, task, regs);
I believe you should add "state->type = UNWINDER_ORC" here.

> +       if (!unwind_done(state) && !__kernel_text_address(state->pc))
> +               unwind_next_frame(state);
> +}
> +EXPORT_SYMBOL_GPL(unwind_start);
> +
> +static bool is_entry_func(unsigned long addr)
> +{
> +       extern u32 kernel_entry;
> +       extern u32 kernel_entry_end;
> +
> +       return addr >= (unsigned long)&kernel_entry &&
> +               addr < (unsigned long)&kernel_entry_end;
> +}
> +
> +static inline unsigned long bt_address(unsigned long ra)
> +{
> +       extern unsigned long eentry;
> +
> +       if (__kernel_text_address(ra))
> +               return ra;
> +
> +       /* We are in preempt_disable() here */
> +       if (__module_text_address(ra))
> +               return ra;
> +
> +       if (ra >= eentry && ra < eentry +  EXCCODE_INT_END * VECSIZE) {
> +               unsigned long type = (ra - eentry) / VECSIZE;
> +               unsigned long offset = (ra - eentry) % VECSIZE;
> +               unsigned long func;
> +
> +               switch (type) {
> +               case 0 ... EXCCODE_INT_START-1:
> +                       func = (unsigned long)exception_table[type];
> +                       break;
> +               case EXCCODE_INT_START ... EXCCODE_INT_END:
> +                       func = (unsigned long)handle_vint;
> +                       break;
> +               default:
> +                       func = (unsigned long)handle_reserved;
> +                       break;
> +               }
> +
> +               return func + offset;
> +       }
> +
> +       return ra;
> +}
> +
> +bool unwind_next_frame(struct unwind_state *state)
> +{
> +       struct stack_info *info = &state->stack_info;
> +       struct orc_entry *orc;
> +       struct pt_regs *regs;
> +       unsigned long *p, pc;
> +
> +       if (unwind_done(state))
> +               return false;
> +
> +       /* Don't let modules unload while we're reading their ORC data. */
> +       preempt_disable();
> +
> +       if (is_entry_func(state->pc))
> +               goto end;
> +
> +       orc = orc_find(state->pc);
> +       if (!orc) {
> +               orc = &orc_fp_entry;
> +               state->error = true;
> +       }
> +
> +       switch (orc->sp_reg) {
> +       case ORC_REG_SP:
> +               state->sp = state->sp + orc->sp_offset;
> +               break;
> +       case ORC_REG_FP:
> +               state->sp = state->fp;
> +               break;
> +       default:
> +               orc_warn("unknown SP base reg %d at %pB\n",
> +                       orc->sp_reg, (void *)state->pc);
> +               goto err;
> +       }
> +
> +       switch (orc->fp_reg) {
> +       case ORC_REG_PREV_SP:
> +               p = (unsigned long *)(state->sp + orc->fp_offset);
> +               if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
> +                       goto err;
> +
> +               state->fp = *p;
> +               break;
> +       case ORC_REG_UNDEFINED:
> +               /* Nothing. */
> +               break;
> +       default:
> +               orc_warn("unknown FP base reg %d at %pB\n",
> +                       orc->fp_reg, (void *)state->pc);
> +               goto err;
> +       }
> +
> +       switch (orc->type) {
> +       case UNWIND_HINT_TYPE_CALL:
Use ORC_TYPE_CALL here.

> +               if (orc->ra_reg == ORC_REG_PREV_SP) {
> +                       p = (unsigned long *)(state->sp + orc->ra_offset);
> +                       if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
> +                               goto err;
> +
> +                       pc = unwind_graph_addr(state, *p, state->sp);
> +                       pc -= LOONGARCH_INSN_SIZE;
> +               } else if (orc->ra_reg == ORC_REG_UNDEFINED) {
> +                       if (!state->ra || state->ra == state->pc)
> +                               goto err;
> +
> +                       pc = unwind_graph_addr(state, state->ra, state->sp);
> +                       pc -=  LOONGARCH_INSN_SIZE;
> +                       state->ra = 0;
> +               } else {
> +                       orc_warn("unknown ra base reg %d at %pB\n",
> +                               orc->ra_reg, (void *)state->pc);
> +                       goto err;
> +               }
> +               break;
> +       case UNWIND_HINT_TYPE_REGS:
Use ORC_TYPE_REGS here.


Huacai

> +               if (state->stack_info.type == STACK_TYPE_IRQ && state->sp == info->end)
> +                       regs = (struct pt_regs *)info->next_sp;
> +               else
> +                       regs = (struct pt_regs *)state->sp;
> +
> +               if (!stack_access_ok(state, (unsigned long)regs, sizeof(*regs)))
> +                       goto err;
> +
> +               if ((info->end == (unsigned long)regs + sizeof(*regs)) &&
> +                   !regs->regs[3] && !regs->regs[1])
> +                       goto end;
> +
> +               if (user_mode(regs))
> +                       goto end;
> +
> +               pc = regs->csr_era;
> +               if (!__kernel_text_address(pc))
> +                       goto err;
> +
> +               state->sp = regs->regs[3];
> +               state->ra = regs->regs[1];
> +               state->fp = regs->regs[22];
> +               get_stack_info(state->sp, state->task, info);
> +
> +               break;
> +       default:
> +               orc_warn("unknown .orc_unwind entry type %d at %pB\n",
> +                        orc->type, (void *)state->pc);
> +               goto err;
> +       }
> +
> +       state->pc = bt_address(pc);
> +       if (!state->pc) {
> +               pr_err("cannot find unwind pc at %pK\n", (void *)pc);
> +               goto err;
> +       }
> +
> +       if (!__kernel_text_address(state->pc))
> +               goto err;
> +
> +       preempt_enable();
> +       return true;
> +
> +err:
> +       state->error = true;
> +
> +end:
> +       preempt_enable();
> +       state->stack_info.type = STACK_TYPE_UNKNOWN;
> +       return false;
> +}
> +EXPORT_SYMBOL_GPL(unwind_next_frame);
> diff --git a/arch/loongarch/kernel/vmlinux.lds.S b/arch/loongarch/kernel/vmlinux.lds.S
> index bb2ec86..09fd4eb 100644
> --- a/arch/loongarch/kernel/vmlinux.lds.S
> +++ b/arch/loongarch/kernel/vmlinux.lds.S
> @@ -2,6 +2,7 @@
>  #include <linux/sizes.h>
>  #include <asm/asm-offsets.h>
>  #include <asm/thread_info.h>
> +#include <asm/orc_lookup.h>
>
>  #define PAGE_SIZE _PAGE_SIZE
>  #define RO_EXCEPTION_TABLE_ALIGN       4
> @@ -99,6 +100,8 @@ SECTIONS
>         _sdata = .;
>         RO_DATA(4096)
>
> +       ORC_UNWIND_TABLE
> +
>         .got : ALIGN(16) { *(.got) }
>         .plt : ALIGN(16) { *(.plt) }
>         .got.plt : ALIGN(16) { *(.got.plt) }
> diff --git a/arch/loongarch/lib/Makefile b/arch/loongarch/lib/Makefile
> index a77bf160..e3023d9 100644
> --- a/arch/loongarch/lib/Makefile
> +++ b/arch/loongarch/lib/Makefile
> @@ -3,6 +3,8 @@
>  # Makefile for LoongArch-specific library files.
>  #
>
> +OBJECT_FILES_NON_STANDARD := y
> +
>  lib-y  += delay.o memset.o memcpy.o memmove.o \
>            clear_user.o copy_user.o csum.o dump_tlb.o unaligned.o
>
> diff --git a/arch/loongarch/mm/tlb.c b/arch/loongarch/mm/tlb.c
> index 2c0a411..f01172a 100644
> --- a/arch/loongarch/mm/tlb.c
> +++ b/arch/loongarch/mm/tlb.c
> @@ -9,8 +9,9 @@
>  #include <linux/hugetlb.h>
>  #include <linux/export.h>
>
> -#include <asm/cpu.h>
>  #include <asm/bootinfo.h>
> +#include <asm/cpu.h>
> +#include <asm/exception.h>
>  #include <asm/mmu_context.h>
>  #include <asm/pgtable.h>
>  #include <asm/tlb.h>
> @@ -266,24 +267,20 @@ static void setup_tlb_handler(int cpu)
>         setup_ptwalker();
>         local_flush_tlb_all();
>
> +       if (cpu_has_ptw) {
> +               exception_table[EXCCODE_TLBI] = handle_tlb_load_ptw;
> +               exception_table[EXCCODE_TLBL] = handle_tlb_load_ptw;
> +               exception_table[EXCCODE_TLBS] = handle_tlb_store_ptw;
> +               exception_table[EXCCODE_TLBM] = handle_tlb_modify_ptw;
> +       }
> +
>         /* The tlb handlers are generated only once */
>         if (cpu == 0) {
>                 memcpy((void *)tlbrentry, handle_tlb_refill, 0x80);
>                 local_flush_icache_range(tlbrentry, tlbrentry + 0x80);
> -               if (!cpu_has_ptw) {
> -                       set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load, VECSIZE);
> -                       set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load, VECSIZE);
> -                       set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store, VECSIZE);
> -                       set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify, VECSIZE);
> -               } else {
> -                       set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load_ptw, VECSIZE);
> -                       set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load_ptw, VECSIZE);
> -                       set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store_ptw, VECSIZE);
> -                       set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify_ptw, VECSIZE);
> -               }
> -               set_handler(EXCCODE_TLBNR * VECSIZE, handle_tlb_protect, VECSIZE);
> -               set_handler(EXCCODE_TLBNX * VECSIZE, handle_tlb_protect, VECSIZE);
> -               set_handler(EXCCODE_TLBPE * VECSIZE, handle_tlb_protect, VECSIZE);
> +
> +               for (int i = EXCCODE_TLBL; i <= EXCCODE_TLBPE; i++)
> +                       set_handler(i * VECSIZE, exception_table[i], VECSIZE);
>         }
>  #ifdef CONFIG_NUMA
>         else {
> diff --git a/arch/loongarch/mm/tlbex.S b/arch/loongarch/mm/tlbex.S
> index d5d682f..a44387b 100644
> --- a/arch/loongarch/mm/tlbex.S
> +++ b/arch/loongarch/mm/tlbex.S
> @@ -18,6 +18,7 @@
>
>         .macro tlb_do_page_fault, write
>         SYM_CODE_START(tlb_do_page_fault_\write)
> +       UNWIND_HINT_UNDEFINED
>         SAVE_ALL
>         csrrd           a2, LOONGARCH_CSR_BADV
>         move            a0, sp
> @@ -32,6 +33,7 @@
>         tlb_do_page_fault 1
>
>  SYM_CODE_START(handle_tlb_protect)
> +       UNWIND_HINT_UNDEFINED
>         BACKUP_T0T1
>         SAVE_ALL
>         move            a0, sp
> @@ -44,6 +46,7 @@ SYM_CODE_START(handle_tlb_protect)
>  SYM_CODE_END(handle_tlb_protect)
>
>  SYM_CODE_START(handle_tlb_load)
> +       UNWIND_HINT_UNDEFINED
>         csrwr           t0, EXCEPTION_KS0
>         csrwr           t1, EXCEPTION_KS1
>         csrwr           ra, EXCEPTION_KS2
> @@ -190,6 +193,7 @@ nopage_tlb_load:
>  SYM_CODE_END(handle_tlb_load)
>
>  SYM_CODE_START(handle_tlb_load_ptw)
> +       UNWIND_HINT_UNDEFINED
>         csrwr           t0, LOONGARCH_CSR_KS0
>         csrwr           t1, LOONGARCH_CSR_KS1
>         la_abs          t0, tlb_do_page_fault_0
> @@ -197,6 +201,7 @@ SYM_CODE_START(handle_tlb_load_ptw)
>  SYM_CODE_END(handle_tlb_load_ptw)
>
>  SYM_CODE_START(handle_tlb_store)
> +       UNWIND_HINT_UNDEFINED
>         csrwr           t0, EXCEPTION_KS0
>         csrwr           t1, EXCEPTION_KS1
>         csrwr           ra, EXCEPTION_KS2
> @@ -346,6 +351,7 @@ nopage_tlb_store:
>  SYM_CODE_END(handle_tlb_store)
>
>  SYM_CODE_START(handle_tlb_store_ptw)
> +       UNWIND_HINT_UNDEFINED
>         csrwr           t0, LOONGARCH_CSR_KS0
>         csrwr           t1, LOONGARCH_CSR_KS1
>         la_abs          t0, tlb_do_page_fault_1
> @@ -353,6 +359,7 @@ SYM_CODE_START(handle_tlb_store_ptw)
>  SYM_CODE_END(handle_tlb_store_ptw)
>
>  SYM_CODE_START(handle_tlb_modify)
> +       UNWIND_HINT_UNDEFINED
>         csrwr           t0, EXCEPTION_KS0
>         csrwr           t1, EXCEPTION_KS1
>         csrwr           ra, EXCEPTION_KS2
> @@ -500,6 +507,7 @@ nopage_tlb_modify:
>  SYM_CODE_END(handle_tlb_modify)
>
>  SYM_CODE_START(handle_tlb_modify_ptw)
> +       UNWIND_HINT_UNDEFINED
>         csrwr           t0, LOONGARCH_CSR_KS0
>         csrwr           t1, LOONGARCH_CSR_KS1
>         la_abs          t0, tlb_do_page_fault_1
> @@ -507,6 +515,7 @@ SYM_CODE_START(handle_tlb_modify_ptw)
>  SYM_CODE_END(handle_tlb_modify_ptw)
>
>  SYM_CODE_START(handle_tlb_refill)
> +       UNWIND_HINT_UNDEFINED
>         csrwr           t0, LOONGARCH_CSR_TLBRSAVE
>         csrrd           t0, LOONGARCH_CSR_PGD
>         lddir           t0, t0, 3
> diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile
> index 5c97d1463..997f41c 100644
> --- a/arch/loongarch/vdso/Makefile
> +++ b/arch/loongarch/vdso/Makefile
> @@ -3,6 +3,7 @@
>
>  KASAN_SANITIZE := n
>  KCOV_INSTRUMENT := n
> +OBJECT_FILES_NON_STANDARD := y
>
>  # Include the generic Makefile to check the built vdso.
>  include $(srctree)/lib/vdso/Makefile
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index d7779a1..df29ddb 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -116,6 +116,14 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
>   */
>  #define __stringify_label(n) #n
>
> +#define __annotate_reachable(c) ({                                     \
> +       asm volatile(__stringify_label(c) ":\n\t"                       \
> +                       ".pushsection .discard.reachable\n\t"           \
> +                       ".long " __stringify_label(c) "b - .\n\t"       \
> +                       ".popsection\n\t");                             \
> +})
> +#define annotate_reachable() __annotate_reachable(__COUNTER__)
> +
>  #define __annotate_unreachable(c) ({                                   \
>         asm volatile(__stringify_label(c) ":\n\t"                       \
>                      ".pushsection .discard.unreachable\n\t"            \
> @@ -128,6 +136,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
>  #define __annotate_jump_table __section(".rodata..c_jump_table")
>
>  #else /* !CONFIG_OBJTOOL */
> +#define annotate_reachable()
>  #define annotate_unreachable()
>  #define __annotate_jump_table
>  #endif /* CONFIG_OBJTOOL */
> diff --git a/scripts/Makefile b/scripts/Makefile
> index 576cf64..e4cca53 100644
> --- a/scripts/Makefile
> +++ b/scripts/Makefile
> @@ -31,9 +31,12 @@ HOSTLDLIBS_sign-file = $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null |
>
>  ifdef CONFIG_UNWINDER_ORC
>  ifeq ($(ARCH),x86_64)
> -ARCH := x86
> +SRCARCH := x86
>  endif
> -HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/x86/include
> +ifeq ($(ARCH),loongarch)
> +SRCARCH := loongarch
> +endif
> +HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/$(SRCARCH)/include
>  HOSTCFLAGS_sorttable.o += -DUNWINDER_ORC_ENABLED
>  endif
>
> --
> 2.1.0
>

Re: [PATCH v3 0/8] Add objtool and orc support for LoongArch

[Huacai Chen]

Hi, Tiezhu,

On Fri, Oct 20, 2023 at 6:55 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
>
>
> On 10/20/2023 06:45 PM, Xi Ruoyao wrote:
> > On Fri, 2023-10-20 at 18:28 +0800, Tiezhu Yang wrote:
> >> On 10/20/2023 04:51 PM, Huacai Chen wrote:
> >>> Cross compiling on X86 for LoongArch fails:
> >>>
> >>>    CALL    scripts/checksyscalls.sh
> >>>    DESCEND objtool
> >>> make[5]: *** No rule to make target
> >>> '/usr/lib/gcc/x86_64-redhat-linux/8/include/stdbool.h', needed by
> >>> '/home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/exec-cmd.o'.
> >>> Stop.
> >>> make[4]: *** [Makefile:80:
> >>> /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd-in.o]
> >>> Error 2
> >>> make[3]: *** [Makefile:82:
> >>> /home/chenhuacai/linux-official.git/tools/objtool/libsubcmd/libsubcmd.a]
> >>> Error 2
> >>> make[2]: *** [Makefile:73: objtool] Error 2
> >>> make[1]: *** [/home/chenhuacai/linux-official.git/Makefile:1355:
> >>> tools/objtool] Error 2
> >>> make: *** [Makefile:234: __sub-make] Error 2
> >>
> >> It seems that there is no stdbool.h in your cross compile environment.
> >>
> >> It works well with the following steps, you can try it.
> >
> > /* snip */
> >
> >> find /opt -name stdbool.h
> >> /opt/cross-tools/lib/gcc/loongarch64-unknown-linux-gnu/14.0.0/include/stdbool.h
> >> /opt/cross-tools/loongarch64-unknown-linux-gnu/include/c++/14.0.0/tr1/stdbool.h
> >
> > The problem is HOSTCC cannot find stdbool.h, not (target) CC.  So these
> > two files are not relevant.
> >
>
> Oh, thank you for pointing out the real reason of this issue.
>
> By the way, my test system is Fedora 38 x86_64, it works well.
I can also cross compile now.

And I have fixed some issues I comments in this series, then I have pushed here:
https://github.com/chenhuacai/linux/commits/master

To save time, you can do additional modifications (e.g. Peter's
suggestions) on top of my version.

And there are still some problems that need some more effort.
1, Build warnings:
  AS      arch/loongarch/kernel/fpu.o
arch/loongarch/kernel/fpu.o: warning: objtool: _restore_fp+0xb0:
unreachable instruction
arch/loongarch/kernel/fpu.o: warning: objtool: _restore_lsx+0xf4:
unreachable instruction
arch/loongarch/kernel/fpu.o: warning: objtool: _restore_lasx+0xf4:
unreachable instruction
  CC      arch/loongarch/kernel/kfpu.o
  AS      arch/loongarch/kernel/lbt.o
arch/loongarch/kernel/lbt.o: warning: objtool:
_restore_ftop_context+0x18: unreachable instruction

2, Partial call stack:
[10589.180597] [<9000000002e435e0>] show_stack+0x34/0x14c
[10589.188124] [<9000000003f0bd7c>] dump_stack_lvl+0x5c/0x88
[10589.193487] [<9000000003f0bdb8>] dump_stack+0x10/0x20
[10589.198505] [<9000000002e43704>] show_regs+0xc/0x1c
[10589.203350] [<9000000003edb174>] nmi_cpu_backtrace+0x154/0x15c
[10589.209146] [<9000000002e43acc>] handle_backtrace+0xc/0x40
[10589.214597] [<9000000002f165d8>] __flush_smp_call_function_queue+0xe4/0x2bc
[10589.221518] [<9000000002f17538>]
generic_smp_call_function_single_interrupt+0xc/0x1c
[10589.229217] [<9000000002e4e6a0>] loongson_ipi_interrupt+0x7c/0xc0
[10589.235274] [<9000000002ecf1c4>] __handle_irq_event_percpu+0x50/0x130
[10589.241675] [<9000000002ecf2b8>] handle_irq_event_percpu+0x14/0x70
[10589.247818] [<9000000002ed5aa4>] handle_percpu_irq+0x50/0x78
[10589.253443] [<9000000002ece3c0>] generic_handle_domain_irq+0x24/0x40
[10589.259758] [<900000000369be68>] handle_cpu_irq+0x68/0xa4
[10589.265122] [<9000000003f0c128>] handle_loongarch_irq+0x2c/0x4c
[10589.271004] [<9000000003f0c1cc>] do_vint+0x84/0xbc

3, Runtime warnings:
[   51.891244] [<9000000002b935e0>] show_stack+0x34/0x14c
[   51.898777] [<9000000003c5bd7c>] dump_stack_lvl+0x5c/0x88
[   51.904144] [<9000000003c5bdb8>] dump_stack+0x10/0x20
[   51.909161] [<9000000003c2b158>] nmi_cpu_backtrace+0x138/0x15c
[   51.914960] [<9000000003c2b324>] nmi_trigger_cpumask_backtrace+0x1a8/0x1e4
[   51.921794] [<9000000002b944ec>] arch_trigger_cpumask_backtrace+0x10/0x20
[   51.928541] [<9000000003508bd0>] sysrq_handle_showallcpus+0x14/0x24
[   51.934772] [<90000000035095b8>] __handle_sysrq+0x184/0x1e0
[   51.940310] [<9000000003509cf8>] write_sysrq_trigger+0x94/0x9c
[   51.946107] [<9000000002e98a6c>] proc_reg_write+0xb4/0xf0
[   51.951472] [<9000000002e07c4c>] vfs_write+0x108/0x3d8
[   51.956580] [<9000000002e080d0>] ksys_write+0x74/0x124
[   51.961686] [<9000000002e0818c>] sys_write+0xc/0x1c
[   51.966533] [<9000000003c5d0b8>] do_syscall+0x78/0x98
[   51.971552] [<9000000002b91198>] handle_syscall+0xb8/0x158
[   51.977002] WARNING: unknown SP base reg 0 at handle_syscall+0xb8/0x158

Huacai

>
> Thanks,
> Tiezhu
>
>