From: James Morse <james.morse@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Will Deacon <will@kernel.org>,
Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: [PATCH 5/8] arm64: entry: convert el1_sync to C
Date: Thu, 3 Oct 2019 18:16:39 +0100 [thread overview]
Message-ID: <20191003171642.135652-6-james.morse@arm.com> (raw)
In-Reply-To: <20191003171642.135652-1-james.morse@arm.com>
From: Mark Rutland <mark.rutland@arm.com>
This patch converts the EL1 sync entry assembly logic to C code.
Doing this will allow us to make changes in a slightly more
readable way. A case in point is supporting kernel-first RAS.
do_sea() should be called on the CPU that took the fault.
Largely the assembly code is converted to C in a relatively
straightforward manner.
Since all sync sites share a common asm entry point, the ASM_BUG()
instances are no longer required for effective backtraces back to
assembly, and we don't need similar BUG() entries.
The ESR_ELx.EC codes for all (supported) debug exceptions are now
checked in the el1_sync_handler's switch statement, which renders the
check in el1_dbg redundant. This both simplifies the el1_dbg handler,
and makes the EL1 exception handling more robust to
currently-unallocated ESR_ELx.EC encodings.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[split out of a bigger series, added nokprobes, moved prototypes]
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
---
arch/arm64/include/asm/exception.h | 1 +
arch/arm64/kernel/Makefile | 6 +-
arch/arm64/kernel/entry-common.c | 98 ++++++++++++++++++++++++++++++
arch/arm64/kernel/entry.S | 69 +--------------------
4 files changed, 103 insertions(+), 71 deletions(-)
create mode 100644 arch/arm64/kernel/entry-common.c
diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index 8bb3fe2d71a8..e2f87b4ecbfc 100644
--- a/arch/arm64/include/asm/exception.h
+++ b/arch/arm64/include/asm/exception.h
@@ -9,6 +9,7 @@
#include <asm/esr.h>
#include <asm/kprobes.h>
+#include <asm/ptrace.h>
#include <linux/interrupt.h>
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 478491f07b4f..fc6488660f64 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -13,9 +13,9 @@ CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE)
# Object file lists.
obj-y := debug-monitors.o entry.o irq.o fpsimd.o \
- entry-fpsimd.o process.o ptrace.o setup.o signal.o \
- sys.o stacktrace.o time.o traps.o io.o vdso.o \
- hyp-stub.o psci.o cpu_ops.o insn.o \
+ entry-common.o entry-fpsimd.o process.o ptrace.o \
+ setup.o signal.o sys.o stacktrace.o time.o traps.o \
+ io.o vdso.o hyp-stub.o psci.o cpu_ops.o insn.o \
return_address.o cpuinfo.o cpu_errata.o \
cpufeature.o alternative.o cacheinfo.o \
smp.o smp_spin_table.o topology.o smccc-call.o \
diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
new file mode 100644
index 000000000000..e726d1f4b9e9
--- /dev/null
+++ b/arch/arm64/kernel/entry-common.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Exception handling code
+ *
+ * Copyright (C) 2019 ARM Ltd.
+ */
+
+#include <linux/context_tracking.h>
+#include <linux/ptrace.h>
+#include <linux/thread_info.h>
+
+#include <asm/cpufeature.h>
+#include <asm/daifflags.h>
+#include <asm/esr.h>
+#include <asm/exception.h>
+#include <asm/kprobes.h>
+#include <asm/sysreg.h>
+
+static void notrace el1_abort(struct pt_regs *regs, unsigned long esr)
+{
+ unsigned long far = read_sysreg(far_el1);
+
+ local_daif_inherit(regs);
+ far = untagged_addr(far);
+ do_mem_abort(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el1_abort);
+
+static void notrace el1_pc(struct pt_regs *regs, unsigned long esr)
+{
+ unsigned long far = read_sysreg(far_el1);
+
+ local_daif_inherit(regs);
+ do_sp_pc_abort(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el1_pc);
+
+static void el1_undef(struct pt_regs *regs)
+{
+ local_daif_inherit(regs);
+ do_undefinstr(regs);
+}
+NOKPROBE_SYMBOL(el1_undef);
+
+static void el1_inv(struct pt_regs *regs, unsigned long esr)
+{
+ local_daif_inherit(regs);
+ bad_mode(regs, 0, esr);
+}
+NOKPROBE_SYMBOL(el1_inv);
+
+static void notrace el1_dbg(struct pt_regs *regs, unsigned long esr)
+{
+ unsigned long far = read_sysreg(far_el1);
+
+ /*
+ * The CPU masked interrupts, and we are leaving them masked during
+ * do_debug_exception(). Update PMR as if we had called
+ * local_mask_daif().
+ */
+ if (system_uses_irq_prio_masking())
+ gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
+
+ do_debug_exception(far, esr, regs);
+}
+NOKPROBE_SYMBOL(el1_dbg);
+
+asmlinkage void notrace el1_sync_handler(struct pt_regs *regs)
+{
+ unsigned long esr = read_sysreg(esr_el1);
+
+ switch (ESR_ELx_EC(esr)) {
+ case ESR_ELx_EC_DABT_CUR:
+ case ESR_ELx_EC_IABT_CUR:
+ el1_abort(regs, esr);
+ break;
+ /*
+ * We don't handle ESR_ELx_EC_SP_ALIGN, since we will have hit a
+ * recursive exception when trying to push the initial pt_regs.
+ */
+ case ESR_ELx_EC_PC_ALIGN:
+ el1_pc(regs, esr);
+ break;
+ case ESR_ELx_EC_SYS64:
+ case ESR_ELx_EC_UNKNOWN:
+ el1_undef(regs);
+ break;
+ case ESR_ELx_EC_BREAKPT_CUR:
+ case ESR_ELx_EC_SOFTSTP_CUR:
+ case ESR_ELx_EC_WATCHPT_CUR:
+ case ESR_ELx_EC_BRK64:
+ el1_dbg(regs, esr);
+ break;
+ default:
+ el1_inv(regs, esr);
+ };
+}
+NOKPROBE_SYMBOL(el1_sync_handler);
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index e304fe04b098..5d7f42eb0e89 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -578,76 +578,9 @@ ENDPROC(el1_error_invalid)
.align 6
el1_sync:
kernel_entry 1
- mrs x1, esr_el1 // read the syndrome register
- lsr x24, x1, #ESR_ELx_EC_SHIFT // exception class
- cmp x24, #ESR_ELx_EC_DABT_CUR // data abort in EL1
- b.eq el1_da
- cmp x24, #ESR_ELx_EC_IABT_CUR // instruction abort in EL1
- b.eq el1_ia
- cmp x24, #ESR_ELx_EC_SYS64 // configurable trap
- b.eq el1_undef
- cmp x24, #ESR_ELx_EC_PC_ALIGN // pc alignment exception
- b.eq el1_pc
- cmp x24, #ESR_ELx_EC_UNKNOWN // unknown exception in EL1
- b.eq el1_undef
- cmp x24, #ESR_ELx_EC_BREAKPT_CUR // debug exception in EL1
- b.ge el1_dbg
- b el1_inv
-
-el1_ia:
- /*
- * Fall through to the Data abort case
- */
-el1_da:
- /*
- * Data abort handling
- */
- mrs x3, far_el1
- inherit_daif pstate=x23, tmp=x2
- clear_address_tag x0, x3
- mov x2, sp // struct pt_regs
- bl do_mem_abort
-
- kernel_exit 1
-el1_pc:
- /*
- * PC alignment exception handling. We don't handle SP alignment faults,
- * since we will have hit a recursive exception when trying to push the
- * initial pt_regs.
- */
- mrs x0, far_el1
- inherit_daif pstate=x23, tmp=x2
- mov x2, sp
- bl do_sp_pc_abort
- ASM_BUG()
-el1_undef:
- /*
- * Undefined instruction
- */
- inherit_daif pstate=x23, tmp=x2
mov x0, sp
- bl do_undefinstr
- kernel_exit 1
-el1_dbg:
- /*
- * Debug exception handling
- */
- cmp x24, #ESR_ELx_EC_BRK64 // if BRK64
- cinc x24, x24, eq // set bit '0'
- tbz x24, #0, el1_inv // EL1 only
- gic_prio_kentry_setup tmp=x3
- mrs x0, far_el1
- mov x2, sp // struct pt_regs
- bl do_debug_exception
+ bl el1_sync_handler
kernel_exit 1
-el1_inv:
- // TODO: add support for undefined instructions in kernel mode
- inherit_daif pstate=x23, tmp=x2
- mov x0, sp
- mov x2, x1
- mov x1, #BAD_SYNC
- bl bad_mode
- ASM_BUG()
ENDPROC(el1_sync)
.align 6
--
2.20.1
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next prev parent reply other threads:[~2019-10-03 17:18 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-03 17:16 [PATCH 0/8] arm64: Convert entry.S synchronous exception handling to C James Morse
2019-10-03 17:16 ` [PATCH 1/8] arm64: Fix incorrect irqflag restore for priority masking for compat James Morse
2019-10-03 17:16 ` [PATCH 2/8] arm64: remove __exception annotations James Morse
2019-10-04 10:17 ` Mark Rutland
2019-10-04 14:10 ` Masami Hiramatsu
2019-10-04 16:08 ` James Morse
2019-10-04 16:34 ` Mark Rutland
2019-10-04 13:03 ` Marc Gonzalez
2019-10-04 16:08 ` James Morse
2019-10-03 17:16 ` [PATCH 3/8] arm64: Add prototypes for functions called by entry.S James Morse
2019-10-04 10:22 ` Mark Rutland
2019-10-03 17:16 ` [PATCH 4/8] arm64: add local_daif_inherit() James Morse
2019-10-03 17:16 ` James Morse [this message]
2019-10-04 10:39 ` [PATCH 5/8] arm64: entry: convert el1_sync to C Mark Rutland
2019-10-03 17:16 ` [PATCH 6/8] arm64: entry: convert el0_sync " James Morse
2019-10-04 12:57 ` Mark Rutland
2019-10-04 16:09 ` James Morse
2019-10-04 16:37 ` Mark Rutland
2019-10-03 17:16 ` [PATCH 7/8] arm64: Remove asmlinkage from updated functions James Morse
2019-10-04 12:58 ` Mark Rutland
2019-10-03 17:16 ` [PATCH 8/8] arm64: entry-common: don't touch daif before bp-hardening James Morse
2019-10-04 13:31 ` Mark Rutland
2019-10-04 16:09 ` James Morse
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