[PATCH 00/13] Update csky subsystem for linux-5.9-rc1

[PATCH 00/13] Update csky subsystem for linux-5.9-rc1

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

Here are the patchess for the next linux version. Add features
(seccomp-filter, err-injection, top-down&random mmap-layout, irq_work,
show_ipi, context-tracking), and fixup (kprobe_on_ftrace, ...),
Optimize (fault print, ...).

I think we'll finish most of features for arch/csky this year :) 

Guo Ren (12):
  csky: Add SECCOMP_FILTER supported
  csky: Add cpu feature register hint for smp
  csky: Fixup duplicated restore sp in RESTORE_REGS_FTRACE
  csky: Fixup kprobes handler couldn't change pc
  csky: Add support for function error injection
  csky: Optimize the trap processing flow
  csky: Use top-down mmap layout
  csky: Set CONFIG_NR_CPU 4 as default
  csky: Fixup warning by EXPORT_SYMBOL(kmap)
  csky: Add irq_work support
  csky: Add arch_show_interrupts for IPI interrupts
  csky: Add context tracking support

Tobias Klauser (1):
  csky: remove unusued thread_saved_pc and *_segments functions/macros

 arch/csky/Kconfig                             |  29 +++-
 arch/csky/abiv2/inc/abi/entry.h               |   3 -
 arch/csky/abiv2/mcount.S                      |   4 +-
 arch/csky/include/asm/Kbuild                  |   1 +
 arch/csky/include/asm/bug.h                   |   3 +-
 arch/csky/include/asm/irq_work.h              |  11 ++
 arch/csky/include/asm/processor.h             |   6 -
 arch/csky/include/asm/ptrace.h                |   7 +
 arch/csky/include/asm/thread_info.h           |   2 +-
 arch/csky/kernel/entry.S                      |  26 +++
 arch/csky/kernel/process.c                    |  10 --
 arch/csky/kernel/ptrace.c                     |  37 +----
 arch/csky/kernel/smp.c                        |  62 ++++++-
 arch/csky/kernel/traps.c                      | 223 +++++++++++++++++---------
 arch/csky/lib/Makefile                        |   1 +
 arch/csky/lib/error-inject.c                  |  10 ++
 arch/csky/mm/fault.c                          |  10 +-
 arch/csky/mm/highmem.c                        |   2 -
 tools/testing/selftests/seccomp/seccomp_bpf.c |  13 +-
 19 files changed, 317 insertions(+), 143 deletions(-)
 create mode 100644 arch/csky/include/asm/irq_work.h
 create mode 100644 arch/csky/lib/error-inject.c

-- 
2.7.4

[PATCH 01/13] csky: remove unusued thread_saved_pc and *_segments functions/macros

[guoren]

From: Tobias Klauser <tklauser@distanz.ch>

These are used nowhere in the tree (except for some architectures which
define them for their own use) and were already removed for other
architectures in:

commit 6474924e2b5d ("arch: remove unused macro/function thread_saved_pc()")
commit c17c02040bf0 ("arch: remove unused *_segments() macros/functions")

Remove them from arch/csky as well.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
---
 arch/csky/include/asm/processor.h |  6 ------
 arch/csky/kernel/process.c        | 10 ----------
 2 files changed, 16 deletions(-)

diff --git a/arch/csky/include/asm/processor.h b/arch/csky/include/asm/processor.h
index 24442d8..4800f65 100644
--- a/arch/csky/include/asm/processor.h
+++ b/arch/csky/include/asm/processor.h
@@ -82,12 +82,6 @@ static inline void release_thread(struct task_struct *dead_task)
 
 extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 
-#define copy_segments(tsk, mm)		do { } while (0)
-#define release_segments(mm)		do { } while (0)
-#define forget_segments()		do { } while (0)
-
-extern unsigned long thread_saved_pc(struct task_struct *tsk);
-
 unsigned long get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk)		(task_pt_regs(tsk)->pc)
diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c
index 8b3fad0..3da63cf 100644
--- a/arch/csky/kernel/process.c
+++ b/arch/csky/kernel/process.c
@@ -30,16 +30,6 @@ asmlinkage void ret_from_kernel_thread(void);
  */
 void flush_thread(void){}
 
-/*
- * Return saved PC from a blocked thread
- */
-unsigned long thread_saved_pc(struct task_struct *tsk)
-{
-	struct switch_stack *sw = (struct switch_stack *)tsk->thread.sp;
-
-	return sw->r15;
-}
-
 int copy_thread_tls(unsigned long clone_flags,
 		unsigned long usp,
 		unsigned long kthread_arg,
-- 
2.7.4

[PATCH 02/13] csky: Add SECCOMP_FILTER supported

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

secure_computing() is called first in syscall_trace_enter() so that
a system call will be aborted quickly without doing succeeding syscall
tracing if seccomp rules want to deny that system call.

TODO:
 - Update https://github.com/seccomp/libseccomp csky support

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/Kconfig                             | 14 ++++++++++++++
 arch/csky/include/asm/Kbuild                  |  1 +
 arch/csky/include/asm/thread_info.h           |  2 +-
 arch/csky/kernel/entry.S                      |  3 +++
 arch/csky/kernel/ptrace.c                     |  8 ++++++--
 tools/testing/selftests/seccomp/seccomp_bpf.c | 13 ++++++++++++-
 6 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index bd31ab1..822362d 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -38,6 +38,7 @@ config CSKY
 	select GX6605S_TIMER if CPU_CK610
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_AUDITSYSCALL
+	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_COPY_THREAD_TLS
 	select HAVE_DEBUG_BUGVERBOSE
 	select HAVE_DYNAMIC_FTRACE
@@ -296,3 +297,16 @@ endmenu
 source "arch/csky/Kconfig.platforms"
 
 source "kernel/Kconfig.hz"
+
+config SECCOMP
+	bool "Enable seccomp to safely compute untrusted bytecode"
+	help
+	  This kernel feature is useful for number crunching applications
+	  that may need to compute untrusted bytecode during their
+	  execution. By using pipes or other transports made available to
+	  the process as file descriptors supporting the read/write
+	  syscalls, it's possible to isolate those applications in
+	  their own address space using seccomp. Once seccomp is
+	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
+	  and the task is only allowed to execute a few safe syscalls
+	  defined by each seccomp mode.
diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 9337225..64876e59 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -4,5 +4,6 @@ generic-y += gpio.h
 generic-y += kvm_para.h
 generic-y += local64.h
 generic-y += qrwlock.h
+generic-y += seccomp.h
 generic-y += user.h
 generic-y += vmlinux.lds.h
diff --git a/arch/csky/include/asm/thread_info.h b/arch/csky/include/asm/thread_info.h
index 8980e4e..68e7a12 100644
--- a/arch/csky/include/asm/thread_info.h
+++ b/arch/csky/include/asm/thread_info.h
@@ -85,6 +85,6 @@ static inline struct thread_info *current_thread_info(void)
 				 _TIF_NOTIFY_RESUME | _TIF_UPROBE)
 
 #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
-				 _TIF_SYSCALL_TRACEPOINT)
+				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
 
 #endif	/* _ASM_CSKY_THREAD_INFO_H */
diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index f138003..efd2e69 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -168,6 +168,8 @@ ENTRY(csky_systemcall)
 csky_syscall_trace:
 	mov	a0, sp                  /* sp = pt_regs pointer */
 	jbsr	syscall_trace_enter
+	cmpnei	a0, 0
+	bt	1f
 	/* Prepare args before do system call */
 	ldw	a0, (sp, LSAVE_A0)
 	ldw	a1, (sp, LSAVE_A1)
@@ -188,6 +190,7 @@ csky_syscall_trace:
 #endif
 	stw	a0, (sp, LSAVE_A0)	/* Save return value */
 
+1:
 #ifdef CONFIG_DEBUG_RSEQ
 	mov	a0, sp
 	jbsr	rseq_syscall
diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c
index 944ca2f..0de10f7 100644
--- a/arch/csky/kernel/ptrace.c
+++ b/arch/csky/kernel/ptrace.c
@@ -320,16 +320,20 @@ long arch_ptrace(struct task_struct *child, long request,
 	return ret;
 }
 
-asmlinkage void syscall_trace_enter(struct pt_regs *regs)
+asmlinkage int syscall_trace_enter(struct pt_regs *regs)
 {
 	if (test_thread_flag(TIF_SYSCALL_TRACE))
 		if (tracehook_report_syscall_entry(regs))
-			syscall_set_nr(current, regs, -1);
+			return -1;
+
+	if (secure_computing() == -1)
+		return -1;
 
 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 		trace_sys_enter(regs, syscall_get_nr(current, regs));
 
 	audit_syscall_entry(regs_syscallid(regs), regs->a0, regs->a1, regs->a2, regs->a3);
+	return 0;
 }
 
 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 252140a..8d18a0d 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -116,6 +116,8 @@ struct seccomp_data {
 #  define __NR_seccomp 277
 # elif defined(__riscv)
 #  define __NR_seccomp 277
+# elif defined(__csky__)
+#  define __NR_seccomp 277
 # elif defined(__hppa__)
 #  define __NR_seccomp 338
 # elif defined(__powerpc__)
@@ -1603,6 +1605,14 @@ TEST_F(TRACE_poke, getpid_runs_normally)
 # define ARCH_REGS	struct user_regs_struct
 # define SYSCALL_NUM	a7
 # define SYSCALL_RET	a0
+#elif defined(__csky__)
+# define ARCH_REGS	struct pt_regs
+#if defined(__CSKYABIV2__)
+# define SYSCALL_NUM	regs[3]
+#else
+# define SYSCALL_NUM	regs[9]
+#endif
+# define SYSCALL_RET	a0
 #elif defined(__hppa__)
 # define ARCH_REGS	struct user_regs_struct
 # define SYSCALL_NUM	gr[20]
@@ -1693,7 +1703,8 @@ void change_syscall(struct __test_metadata *_metadata,
 	EXPECT_EQ(0, ret) {}
 
 #if defined(__x86_64__) || defined(__i386__) || defined(__powerpc__) || \
-	defined(__s390__) || defined(__hppa__) || defined(__riscv)
+	defined(__s390__) || defined(__hppa__) || defined(__riscv) || \
+	defined(__csky__)
 	{
 		regs.SYSCALL_NUM = syscall;
 	}
-- 
2.7.4

[PATCH 03/13] csky: Add cpu feature register hint for smp

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

CPU features registers are setup by customers' bootloader, but
Linux must help transfer them from the primary to secondary cores.
This patch add hint2 CPU feature register supported.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/kernel/smp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index b5c5bc3..1945fb2 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -156,6 +156,7 @@ void __init setup_smp(void)
 extern void _start_smp_secondary(void);
 
 volatile unsigned int secondary_hint;
+volatile unsigned int secondary_hint2;
 volatile unsigned int secondary_ccr;
 volatile unsigned int secondary_stack;
 
@@ -168,6 +169,7 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 	secondary_stack =
 		(unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8;
 	secondary_hint = mfcr("cr31");
+	secondary_hint2 = mfcr("cr<21, 1>");
 	secondary_ccr  = mfcr("cr18");
 	secondary_msa1 = read_mmu_msa1();
 
@@ -209,6 +211,7 @@ void csky_start_secondary(void)
 	unsigned int cpu = smp_processor_id();
 
 	mtcr("cr31", secondary_hint);
+	mtcr("cr<21, 1>", secondary_hint2);
 	mtcr("cr18", secondary_ccr);
 
 	mtcr("vbr", vec_base);
-- 
2.7.4

[PATCH 04/13] csky: Fixup duplicated restore sp in RESTORE_REGS_FTRACE

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

There is no user return for RESTORE_REGS_FTRACE, so it's no need to
save sp into ss0 as RESTORE_REGS_ALL.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/abiv2/inc/abi/entry.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/csky/abiv2/inc/abi/entry.h b/arch/csky/abiv2/inc/abi/entry.h
index 4fdd6c1..bedcc6f 100644
--- a/arch/csky/abiv2/inc/abi/entry.h
+++ b/arch/csky/abiv2/inc/abi/entry.h
@@ -136,8 +136,6 @@
 
 .macro	RESTORE_REGS_FTRACE
 	ldw	tls, (sp, 0)
-	ldw	a0, (sp, 16)
-	mtcr	a0, ss0
 
 #ifdef CONFIG_CPU_HAS_HILO
 	ldw	a0, (sp, 140)
@@ -158,7 +156,6 @@
 	addi    sp, 40
 	ldm     r16-r30, (sp)
 	addi    sp, 72
-	mfcr	sp, ss0
 .endm
 
 .macro SAVE_SWITCH_STACK
-- 
2.7.4

[PATCH 05/13] csky: Fixup kprobes handler couldn't change pc

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

The "Changing Execution Path" section in the Documentation/kprobes.txt
said:

Since kprobes can probe into a running kernel code, it can change the
register set, including instruction pointer.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/abiv2/mcount.S | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/csky/abiv2/mcount.S b/arch/csky/abiv2/mcount.S
index 911512b..d745e10 100644
--- a/arch/csky/abiv2/mcount.S
+++ b/arch/csky/abiv2/mcount.S
@@ -55,7 +55,9 @@
 
 .macro mcount_exit_regs
 	RESTORE_REGS_FTRACE
-	ldw	t1, (sp, 0)
+	subi	sp, 152
+	ldw	t1, (sp, 4)
+	addi	sp, 152
 	ldw	r8, (sp, 4)
 	ldw	lr, (sp, 8)
 	addi	sp, 12
-- 
2.7.4

[PATCH 06/13] csky: Add support for function error injection

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

Inspired by the commit 42d038c4fb00 ("arm64: Add support for function
error injection"), this patch supports function error injection for
csky.

This patch mainly support two functions: one is regs_set_return_value()
which is used to overwrite the return value; the another function is
override_function_with_return() which is to override the probed
function returning and jump to its caller.

Test log:

 cd /sys/kernel/debug/fail_function/
 echo sys_clone > inject
 echo 100 > probability
 echo 1 > interval
 ls /
[  108.644163] FAULT_INJECTION: forcing a failure.
[  108.644163] name fail_function, interval 1, probability 100, space 0, times 1
[  108.647799] CPU: 0 PID: 104 Comm: sh Not tainted 5.8.0-rc5+ #46
[  108.648384] Call Trace:
[  108.649339] [<8005eed4>] walk_stackframe+0x0/0xf0
[  108.649679] [<8005f16a>] show_stack+0x32/0x5c
[  108.649927] [<8040f9d2>] dump_stack+0x6e/0x9c
[  108.650271] [<80406f7e>] should_fail+0x15e/0x1ac
[  108.650720] [<80118ba8>] fei_kprobe_handler+0x28/0x5c
[  108.651519] [<80754110>] kprobe_breakpoint_handler+0x144/0x1cc
[  108.652289] [<8005d6da>] trap_c+0x8e/0x110
[  108.652816] [<8005ce8c>] csky_trap+0x5c/0x70
-sh: can't fork: Invalid argument

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/Kconfig              |  1 +
 arch/csky/include/asm/ptrace.h |  6 ++++++
 arch/csky/lib/Makefile         |  1 +
 arch/csky/lib/error-inject.c   | 10 ++++++++++
 4 files changed, 18 insertions(+)
 create mode 100644 arch/csky/lib/error-inject.c

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 822362d..c51f64c 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -45,6 +45,7 @@ config CSKY
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
+	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZO
diff --git a/arch/csky/include/asm/ptrace.h b/arch/csky/include/asm/ptrace.h
index bcfb707..82da5e0 100644
--- a/arch/csky/include/asm/ptrace.h
+++ b/arch/csky/include/asm/ptrace.h
@@ -52,6 +52,12 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
 	return regs->a0;
 }
 
+static inline void regs_set_return_value(struct pt_regs *regs,
+					 unsigned long val)
+{
+	regs->a0 = val;
+}
+
 /* Valid only for Kernel mode traps. */
 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 {
diff --git a/arch/csky/lib/Makefile b/arch/csky/lib/Makefile
index 078e2d5..7fbdbb2 100644
--- a/arch/csky/lib/Makefile
+++ b/arch/csky/lib/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 lib-y  := usercopy.o delay.o
+obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/csky/lib/error-inject.c b/arch/csky/lib/error-inject.c
new file mode 100644
index 00000000..c15fb36
--- /dev/null
+++ b/arch/csky/lib/error-inject.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/error-injection.h>
+#include <linux/kprobes.h>
+
+void override_function_with_return(struct pt_regs *regs)
+{
+	instruction_pointer_set(regs, regs->lr);
+}
+NOKPROBE_SYMBOL(override_function_with_return);
-- 
2.7.4

[PATCH 07/13] csky: Optimize the trap processing flow

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

 - Seperate different trap functions
 - Add trap_no()
 - Remove panic code print
 - Redesign die_if_kerenl to die with riscv's
 - Print exact trap info for app segment fault

[   17.389321] gzip[126]: unhandled signal 11 code 0x3 at 0x0007835a in busybox[8000+d4000]
[   17.393882]
[   17.393882] CURRENT PROCESS:
[   17.393882]
[   17.394309] COMM=gzip PID=126
[   17.394513] TEXT=00008000-000db2e4 DATA=000dcf14-000dd1ad BSS=000dd1ad-000ff000
[   17.395499] USER-STACK=7f888e50  KERNEL-STACK=bf130300
[   17.395499]
[   17.396801] PC: 0x0007835a (0x7835a)
[   17.397048] LR: 0x000058b4 (0x58b4)
[   17.397285] SP: 0xbe519f68
[   17.397555] orig_a0: 0x00002852
[   17.397886] PSR: 0x00020341
[   17.398356]  a0: 0x00002852   a1: 0x000f2f5a   a2: 0x0000d7ae   a3: 0x0000005d
[   17.399289]  r4: 0x000de150   r5: 0x00000002   r6: 0x00000102   r7: 0x00007efa
[   17.399800]  r8: 0x7f888bc4   r9: 0x00000001  r10: 0x000002eb  r11: 0x0000aac1
[   17.400166] r12: 0x00002ef2  r13: 0x00000007  r15: 0x000058b4
[   17.400531] r16: 0x0000004c  r17: 0x00000031  r18: 0x000f5816  r19: 0x000e8068
[   17.401006] r20: 0x000f5818  r21: 0x000e8068  r22: 0x000f5918  r23: 0x90000000
[   17.401721] r24: 0x00000031  r25: 0x000000c8  r26: 0x00000000  r27: 0x00000000
[   17.402199] r28: 0x2ac2a000  r29: 0x00000000  r30: 0x00000000  tls: 0x2aadbaa8
[   17.402686]  hi: 0x00120340   lo: 0x7f888bec
/etc/init.ci/ntfs3g_run: line 61:   126 Segmentation fault      gzip -c -9 /mnt/test.bin > /mnt/test_bin.gz

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/include/asm/bug.h    |   3 +-
 arch/csky/include/asm/ptrace.h |   1 +
 arch/csky/kernel/ptrace.c      |  29 +-----
 arch/csky/kernel/traps.c       | 223 +++++++++++++++++++++++++++--------------
 arch/csky/mm/fault.c           |  10 +-
 5 files changed, 157 insertions(+), 109 deletions(-)

diff --git a/arch/csky/include/asm/bug.h b/arch/csky/include/asm/bug.h
index bd7b323..33ebd16 100644
--- a/arch/csky/include/asm/bug.h
+++ b/arch/csky/include/asm/bug.h
@@ -20,7 +20,8 @@ do {					\
 
 struct pt_regs;
 
-void die_if_kernel(char *str, struct pt_regs *regs, int nr);
+void die(struct pt_regs *regs, const char *str);
 void show_regs(struct pt_regs *regs);
+void show_code(struct pt_regs *regs);
 
 #endif /* __ASM_CSKY_BUG_H */
diff --git a/arch/csky/include/asm/ptrace.h b/arch/csky/include/asm/ptrace.h
index 82da5e0..91ceb1b 100644
--- a/arch/csky/include/asm/ptrace.h
+++ b/arch/csky/include/asm/ptrace.h
@@ -24,6 +24,7 @@
 #define user_mode(regs) (!((regs)->sr & PS_S))
 #define instruction_pointer(regs) ((regs)->pc)
 #define profile_pc(regs) instruction_pointer(regs)
+#define trap_no(regs) ((regs->sr >> 16) & 0xff)
 
 static inline void instruction_pointer_set(struct pt_regs *regs,
 					   unsigned long val)
diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c
index 0de10f7..b06612c 100644
--- a/arch/csky/kernel/ptrace.c
+++ b/arch/csky/kernel/ptrace.c
@@ -347,13 +347,8 @@ asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 		trace_sys_exit(regs, syscall_get_return_value(current, regs));
 }
 
-extern void show_stack(struct task_struct *task, unsigned long *stack, const char *loglvl);
 void show_regs(struct pt_regs *fp)
 {
-	unsigned long   *sp;
-	unsigned char   *tp;
-	int	i;
-
 	pr_info("\nCURRENT PROCESS:\n\n");
 	pr_info("COMM=%s PID=%d\n", current->comm, current->pid);
 
@@ -400,29 +395,9 @@ void show_regs(struct pt_regs *fp)
 		fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
 	pr_info("r10: 0x%08lx  r11: 0x%08lx  r12: 0x%08lx  r13: 0x%08lx\n",
 		fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
-	pr_info("r14: 0x%08lx   r1: 0x%08lx  r15: 0x%08lx\n",
-		fp->regs[8], fp->regs[9], fp->lr);
+	pr_info("r14: 0x%08lx   r1: 0x%08lx\n",
+		fp->regs[8], fp->regs[9]);
 #endif
 
-	pr_info("\nCODE:");
-	tp = ((unsigned char *) fp->pc) - 0x20;
-	tp += ((int)tp % 4) ? 2 : 0;
-	for (sp = (unsigned long *) tp, i = 0; (i < 0x40);  i += 4) {
-		if ((i % 0x10) == 0)
-			pr_cont("\n%08x: ", (int) (tp + i));
-		pr_cont("%08x ", (int) *sp++);
-	}
-	pr_cont("\n");
-
-	pr_info("\nKERNEL STACK:");
-	tp = ((unsigned char *) fp) - 0x40;
-	for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) {
-		if ((i % 0x10) == 0)
-			pr_cont("\n%08x: ", (int) (tp + i));
-		pr_cont("%08x ", (int) *sp++);
-	}
-	pr_cont("\n");
-
-	show_stack(NULL, (unsigned long *)fp->regs[4], KERN_INFO);
 	return;
 }
diff --git a/arch/csky/kernel/traps.c b/arch/csky/kernel/traps.c
index fcc3a69..959a917 100644
--- a/arch/csky/kernel/traps.c
+++ b/arch/csky/kernel/traps.c
@@ -15,6 +15,8 @@
 #include <linux/rtc.h>
 #include <linux/uaccess.h>
 #include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/sched/debug.h>
 
 #include <asm/setup.h>
 #include <asm/traps.h>
@@ -27,6 +29,8 @@
 #include <abi/fpu.h>
 #endif
 
+int show_unhandled_signals = 1;
+
 /* Defined in entry.S */
 asmlinkage void csky_trap(void);
 
@@ -77,117 +81,184 @@ void __init trap_init(void)
 #endif
 }
 
-void die_if_kernel(char *str, struct pt_regs *regs, int nr)
+static DEFINE_SPINLOCK(die_lock);
+
+void die(struct pt_regs *regs, const char *str)
 {
-	if (user_mode(regs))
-		return;
+	static int die_counter;
+	int ret;
 
+	oops_enter();
+
+	spin_lock_irq(&die_lock);
 	console_verbose();
-	pr_err("%s: %08x\n", str, nr);
+	bust_spinlocks(1);
+
+	pr_emerg("%s [#%d]\n", str, ++die_counter);
+	print_modules();
 	show_regs(regs);
+	show_stack(current, (unsigned long *)regs->regs[4], KERN_INFO);
+
+	ret = notify_die(DIE_OOPS, str, regs, 0, trap_no(regs), SIGSEGV);
+
+	bust_spinlocks(0);
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-	do_exit(SIGSEGV);
+	spin_unlock_irq(&die_lock);
+	oops_exit();
+
+	if (in_interrupt())
+		panic("Fatal exception in interrupt");
+	if (panic_on_oops)
+		panic("Fatal exception");
+	if (ret != NOTIFY_STOP)
+		do_exit(SIGSEGV);
 }
 
-void buserr(struct pt_regs *regs)
+void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
 {
-#ifdef CONFIG_CPU_CK810
-	static unsigned long prev_pc;
+	struct task_struct *tsk = current;
 
-	if ((regs->pc == prev_pc) && prev_pc != 0) {
-		prev_pc = 0;
-	} else {
-		prev_pc = regs->pc;
-		return;
+	if (show_unhandled_signals && unhandled_signal(tsk, signo)
+	    && printk_ratelimit()) {
+		pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x%08lx",
+			tsk->comm, task_pid_nr(tsk), signo, code, addr);
+		print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
+		pr_cont("\n");
+		show_regs(regs);
 	}
-#endif
 
-	die_if_kernel("Kernel mode BUS error", regs, 0);
+	force_sig_fault(signo, code, (void __user *)addr);
+}
 
-	pr_err("User mode Bus Error\n");
-	show_regs(regs);
+static void do_trap_error(struct pt_regs *regs, int signo, int code,
+	unsigned long addr, const char *str)
+{
+	current->thread.trap_no = trap_no(regs);
 
-	force_sig_fault(SIGSEGV, 0, (void __user *)regs->pc);
+	if (user_mode(regs)) {
+		do_trap(regs, signo, code, addr);
+	} else {
+		if (!fixup_exception(regs))
+			die(regs, str);
+	}
 }
 
-asmlinkage void trap_c(struct pt_regs *regs)
-{
-	int sig;
-	unsigned long vector;
-	siginfo_t info;
-	struct task_struct *tsk = current;
+#define DO_ERROR_INFO(name, signo, code, str)				\
+asmlinkage __visible void name(struct pt_regs *regs)			\
+{									\
+	do_trap_error(regs, signo, code, regs->pc, "Oops - " str);	\
+}
 
-	vector = (regs->sr >> 16) & 0xff;
+DO_ERROR_INFO(do_trap_unknown,
+	SIGILL, ILL_ILLTRP, "unknown exception");
+DO_ERROR_INFO(do_trap_zdiv,
+	SIGFPE, FPE_INTDIV, "error zero div exception");
+DO_ERROR_INFO(do_trap_buserr,
+	SIGSEGV, ILL_ILLADR, "error bus error exception");
 
-	switch (vector) {
-	case VEC_ZERODIV:
-		die_if_kernel("Kernel mode ZERO DIV", regs, vector);
-		sig = SIGFPE;
-		break;
-	/* ptrace */
-	case VEC_TRACE:
+asmlinkage void do_trap_misaligned(struct pt_regs *regs)
+{
+#ifdef CONFIG_CPU_NEED_SOFTALIGN
+	csky_alignment(regs);
+#else
+	current->thread.trap_no = trap_no(regs);
+	do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->pc,
+		      "Oops - load/store address misaligned");
+#endif
+}
+
+asmlinkage void do_trap_bkpt(struct pt_regs *regs)
+{
 #ifdef CONFIG_KPROBES
-		if (kprobe_single_step_handler(regs))
-			return;
+	if (kprobe_single_step_handler(regs))
+		return;
 #endif
 #ifdef CONFIG_UPROBES
-		if (uprobe_single_step_handler(regs))
-			return;
+	if (uprobe_single_step_handler(regs))
+		return;
 #endif
-		info.si_code = TRAP_TRACE;
-		sig = SIGTRAP;
-		break;
-	case VEC_ILLEGAL:
-		tsk->thread.trap_no = vector;
+	if (user_mode(regs)) {
+		send_sig(SIGTRAP, current, 0);
+		return;
+	}
+
+	do_trap_error(regs, SIGILL, ILL_ILLTRP, regs->pc,
+		      "Oops - illegal trap exception");
+}
+
+asmlinkage void do_trap_illinsn(struct pt_regs *regs)
+{
+	current->thread.trap_no = trap_no(regs);
+
 #ifdef CONFIG_KPROBES
-		if (kprobe_breakpoint_handler(regs))
-			return;
+	if (kprobe_breakpoint_handler(regs))
+		return;
 #endif
 #ifdef CONFIG_UPROBES
-		if (uprobe_breakpoint_handler(regs))
-			return;
+	if (uprobe_breakpoint_handler(regs))
+		return;
 #endif
-		die_if_kernel("Kernel mode ILLEGAL", regs, vector);
 #ifndef CONFIG_CPU_NO_USER_BKPT
-		if (*(uint16_t *)instruction_pointer(regs) != USR_BKPT)
+	if (*(uint16_t *)instruction_pointer(regs) != USR_BKPT) {
+		send_sig(SIGTRAP, current, 0);
+		return;
+	}
 #endif
-		{
-			sig = SIGILL;
-			break;
-		}
-	/* gdbserver  breakpoint */
+
+	do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->pc,
+		      "Oops - illegal instruction exception");
+}
+
+asmlinkage void do_trap_fpe(struct pt_regs *regs)
+{
+#ifdef CONFIG_CPU_HAS_FP
+	return fpu_fpe(regs);
+#else
+	do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->pc,
+		      "Oops - fpu instruction exception");
+#endif
+}
+
+asmlinkage void do_trap_priv(struct pt_regs *regs)
+{
+#ifdef CONFIG_CPU_HAS_FP
+	if (user_mode(regs) && fpu_libc_helper(regs))
+		return;
+#endif
+	do_trap_error(regs, SIGILL, ILL_PRVOPC, regs->pc,
+		      "Oops - illegal privileged exception");
+}
+
+asmlinkage void trap_c(struct pt_regs *regs)
+{
+	switch (trap_no(regs)) {
+	case VEC_ZERODIV:
+		do_trap_zdiv(regs);
+		break;
+	case VEC_TRACE:
+		do_trap_bkpt(regs);
+		break;
+	case VEC_ILLEGAL:
+		do_trap_illinsn(regs);
+		break;
 	case VEC_TRAP1:
-	/* jtagserver breakpoint */
 	case VEC_BREAKPOINT:
-		die_if_kernel("Kernel mode BKPT", regs, vector);
-		info.si_code = TRAP_BRKPT;
-		sig = SIGTRAP;
+		do_trap_bkpt(regs);
 		break;
 	case VEC_ACCESS:
-		tsk->thread.trap_no = vector;
-		return buserr(regs);
-#ifdef CONFIG_CPU_NEED_SOFTALIGN
+		do_trap_buserr(regs);
+		break;
 	case VEC_ALIGN:
-		tsk->thread.trap_no = vector;
-		return csky_alignment(regs);
-#endif
-#ifdef CONFIG_CPU_HAS_FPU
+		do_trap_misaligned(regs);
+		break;
 	case VEC_FPE:
-		tsk->thread.trap_no = vector;
-		die_if_kernel("Kernel mode FPE", regs, vector);
-		return fpu_fpe(regs);
+		do_trap_fpe(regs);
+		break;
 	case VEC_PRIV:
-		tsk->thread.trap_no = vector;
-		die_if_kernel("Kernel mode PRIV", regs, vector);
-		if (fpu_libc_helper(regs))
-			return;
-#endif
+		do_trap_priv(regs);
+		break;
 	default:
-		sig = SIGSEGV;
+		do_trap_unknown(regs);
 		break;
 	}
-
-	tsk->thread.trap_no = vector;
-
-	send_sig(sig, current, 0);
 }
diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index 0b9cbf2..b1dce9f 100644
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -183,13 +183,13 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
 bad_area_nosemaphore:
 	/* User mode accesses just cause a SIGSEGV */
 	if (user_mode(regs)) {
-		tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+		tsk->thread.trap_no = trap_no(regs);
 		force_sig_fault(SIGSEGV, si_code, (void __user *)address);
 		return;
 	}
 
 no_context:
-	tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+	tsk->thread.trap_no = trap_no(regs);
 
 	/* Are we prepared to handle this kernel fault? */
 	if (fixup_exception(regs))
@@ -202,10 +202,10 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
 	bust_spinlocks(1);
 	pr_alert("Unable to handle kernel paging request at virtual "
 		 "address 0x%08lx, pc: 0x%08lx\n", address, regs->pc);
-	die_if_kernel("Oops", regs, write);
+	die(regs, "Oops");
 
 out_of_memory:
-	tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+	tsk->thread.trap_no = trap_no(regs);
 
 	/*
 	 * We ran out of memory, call the OOM killer, and return the userspace
@@ -215,7 +215,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
 	return;
 
 do_sigbus:
-	tsk->thread.trap_no = (regs->sr >> 16) & 0xff;
+	tsk->thread.trap_no = trap_no(regs);
 
 	mmap_read_unlock(mm);
 
-- 
2.7.4

[PATCH 08/13] csky: Use top-down mmap layout

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

Follow riscv mmap layout with commit "riscv: make mmap allocation
top-down by default (54c95a11cc1b)".

Before:
 cat /proc/self/maps
00008000-000dc000 r-xp 00000000 fe:00 17         /bin/busybox
000dc000-000dd000 r--p 000d3000 fe:00 17         /bin/busybox
000dd000-000de000 rw-p 000d4000 fe:00 17         /bin/busybox
2aaa8000-2aac6000 r-xp 00000000 fe:00 196        /lib/ld-2.28.9000.so
2aac6000-2aac7000 r-xp 00000000 00:00 0          [vdso]
2aac7000-2aac8000 r--p 0001e000 fe:00 196        /lib/ld-2.28.9000.so
2aac8000-2aac9000 rw-p 0001f000 fe:00 196        /lib/ld-2.28.9000.so
2aac9000-2aad9000 r-xp 00000000 fe:00 219        /lib/libresolv-2.28.9000.so
2aad9000-2aada000 r--p 0000f000 fe:00 219        /lib/libresolv-2.28.9000.so
2aada000-2aadb000 rw-p 00010000 fe:00 219        /lib/libresolv-2.28.9000.so
2aadb000-2aadd000 rw-p 00000000 00:00 0
2aadd000-2ac27000 r-xp 00000000 fe:00 203        /lib/libc-2.28.9000.so
2ac27000-2ac28000 ---p 0014a000 fe:00 203        /lib/libc-2.28.9000.so
2ac28000-2ac2a000 r--p 0014a000 fe:00 203        /lib/libc-2.28.9000.so
2ac2a000-2ac2b000 rw-p 0014c000 fe:00 203        /lib/libc-2.28.9000.so
2ac2b000-2ac2e000 rw-p 00000000 00:00 0
7fb99000-7fbba000 rwxp 00000000 00:00 0          [stack]

After:
 cat /proc/self/maps
00008000-000dc000 r-xp 00000000 fe:00 17         /bin/busybox
000dc000-000dd000 r--p 000d3000 fe:00 17         /bin/busybox
000dd000-000de000 rw-p 000d4000 fe:00 17         /bin/busybox
77e13000-77f5d000 r-xp 00000000 fe:00 203        /lib/libc-2.28.9000.so
77f5d000-77f5e000 ---p 0014a000 fe:00 203        /lib/libc-2.28.9000.so
77f5e000-77f60000 r--p 0014a000 fe:00 203        /lib/libc-2.28.9000.so
77f60000-77f61000 rw-p 0014c000 fe:00 203        /lib/libc-2.28.9000.so
77f61000-77f66000 rw-p 00000000 00:00 0
77f66000-77f76000 r-xp 00000000 fe:00 219        /lib/libresolv-2.28.9000.so
77f76000-77f77000 r--p 0000f000 fe:00 219        /lib/libresolv-2.28.9000.so
77f77000-77f78000 rw-p 00010000 fe:00 219        /lib/libresolv-2.28.9000.so
77f78000-77f96000 r-xp 00000000 fe:00 196        /lib/ld-2.28.9000.so
77f96000-77f97000 r-xp 00000000 00:00 0          [vdso]
77f97000-77f98000 r--p 0001e000 fe:00 196        /lib/ld-2.28.9000.so
77f98000-77f99000 rw-p 0001f000 fe:00 196        /lib/ld-2.28.9000.so
7fd7b000-7fd9c000 rwxp 00000000 00:00 0          [stack]

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/Kconfig | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index c51f64c..fd92d73 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -9,6 +9,7 @@ config CSKY
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_QUEUED_RWLOCKS if NR_CPUS>2
 	select ARCH_WANT_FRAME_POINTERS if !CPU_CK610
+	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
 	select COMMON_CLK
 	select CLKSRC_MMIO
 	select CSKY_MPINTC if CPU_CK860
@@ -38,6 +39,7 @@ config CSKY
 	select GX6605S_TIMER if CPU_CK610
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_AUDITSYSCALL
+	select HAVE_ARCH_MMAP_RND_BITS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_COPY_THREAD_TLS
 	select HAVE_DEBUG_BUGVERBOSE
@@ -151,6 +153,14 @@ config L1_CACHE_SHIFT
 	default "5"	if (CPU_CK807 || CPU_CK810)
 	default "6"	if (CPU_CK860)
 
+config ARCH_MMAP_RND_BITS_MIN
+	default 8
+
+# max bits determined by the following formula:
+#  VA_BITS - PAGE_SHIFT - 3
+config ARCH_MMAP_RND_BITS_MAX
+	default 17
+
 menu "Processor type and features"
 
 choice
-- 
2.7.4

[PATCH 09/13] csky: Set CONFIG_NR_CPU 4 as default

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

The C860 processors support 4 cores smp for maximum, so set NR_CPU
to 4 as default

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index fd92d73..ad98b93 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -279,7 +279,7 @@ config NR_CPUS
 	int "Maximum number of CPUs (2-32)"
 	range 2 32
 	depends on SMP
-	default "2"
+	default "4"
 
 config HIGHMEM
 	bool "High Memory Support"
-- 
2.7.4

[PATCH 10/13] csky: Fixup warning by EXPORT_SYMBOL(kmap)

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

This a wrong code, and no kmap symbol for export.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/mm/highmem.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/csky/mm/highmem.c b/arch/csky/mm/highmem.c
index 89ec32e..89c1080 100644
--- a/arch/csky/mm/highmem.c
+++ b/arch/csky/mm/highmem.c
@@ -19,8 +19,6 @@ void kmap_flush_tlb(unsigned long addr)
 }
 EXPORT_SYMBOL(kmap_flush_tlb);
 
-EXPORT_SYMBOL(kmap);
-
 void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 {
 	unsigned long vaddr;
-- 
2.7.4

[PATCH 11/13] csky: Add irq_work support

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

Running work in hardware interrupt context for csky. Implement:
 - arch_irq_work_raise()
 - arch_irq_work_has_interrupt()

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/include/asm/irq_work.h | 11 +++++++++++
 arch/csky/kernel/smp.c           | 12 ++++++++++++
 2 files changed, 23 insertions(+)
 create mode 100644 arch/csky/include/asm/irq_work.h

diff --git a/arch/csky/include/asm/irq_work.h b/arch/csky/include/asm/irq_work.h
new file mode 100644
index 00000000..33aaf39
--- /dev/null
+++ b/arch/csky/include/asm/irq_work.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_IRQ_WORK_H
+#define __ASM_CSKY_IRQ_WORK_H
+
+static inline bool arch_irq_work_has_interrupt(void)
+{
+	return true;
+}
+extern void arch_irq_work_raise(void);
+#endif /* __ASM_CSKY_IRQ_WORK_H */
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 1945fb2..60f2ab1 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -12,6 +12,7 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/irq.h>
+#include <linux/irq_work.h>
 #include <linux/irqdomain.h>
 #include <linux/of.h>
 #include <linux/sched/task_stack.h>
@@ -35,6 +36,7 @@ enum ipi_message_type {
 	IPI_EMPTY,
 	IPI_RESCHEDULE,
 	IPI_CALL_FUNC,
+	IPI_IRQ_WORK,
 	IPI_MAX
 };
 
@@ -53,6 +55,9 @@ static irqreturn_t handle_ipi(int irq, void *dev)
 		if (ops & (1 << IPI_CALL_FUNC))
 			generic_smp_call_function_interrupt();
 
+		if (ops & (1 << IPI_IRQ_WORK))
+			irq_work_run();
+
 		BUG_ON((ops >> IPI_MAX) != 0);
 	}
 
@@ -108,6 +113,13 @@ void smp_send_reschedule(int cpu)
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
 
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+	send_ipi_message(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
+}
+#endif
+
 void __init smp_prepare_boot_cpu(void)
 {
 }
-- 
2.7.4

[PATCH 12/13] csky: Add arch_show_interrupts for IPI interrupts

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

Here is the result:

 cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
 15:       1348       1299        952       1076  C-SKY SMP Intc  15  IPI Interrupt
 16:       1203       1825       1598       1307  C-SKY SMP Intc  16  csky_mp_timer
 43:        292          0          0          0  C-SKY SMP Intc  43  ttyS0
 57:        106          0          0          0  C-SKY SMP Intc  57  virtio0
IPI0:         0          0          0          0  Empty interrupts
IPI1:        19         41         45         27  Rescheduling interrupts
IPI2:      1330       1259        908       1050  Function call interrupts
IPI3:         0          0          0          0  Irq work interrupts

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/kernel/smp.c | 49 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 41 insertions(+), 8 deletions(-)

diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 60f2ab1..e7425e6 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -15,6 +15,7 @@
 #include <linux/irq_work.h>
 #include <linux/irqdomain.h>
 #include <linux/of.h>
+#include <linux/seq_file.h>
 #include <linux/sched/task_stack.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/hotplug.h>
@@ -27,11 +28,6 @@
 #include <abi/fpu.h>
 #endif
 
-struct ipi_data_struct {
-	unsigned long bits ____cacheline_aligned;
-};
-static DEFINE_PER_CPU(struct ipi_data_struct, ipi_data);
-
 enum ipi_message_type {
 	IPI_EMPTY,
 	IPI_RESCHEDULE,
@@ -40,8 +36,16 @@ enum ipi_message_type {
 	IPI_MAX
 };
 
+struct ipi_data_struct {
+	unsigned long bits ____cacheline_aligned;
+	unsigned long stats[IPI_MAX] ____cacheline_aligned;
+};
+static DEFINE_PER_CPU(struct ipi_data_struct, ipi_data);
+
 static irqreturn_t handle_ipi(int irq, void *dev)
 {
+	unsigned long *stats = this_cpu_ptr(&ipi_data)->stats;
+
 	while (true) {
 		unsigned long ops;
 
@@ -49,14 +53,20 @@ static irqreturn_t handle_ipi(int irq, void *dev)
 		if (ops == 0)
 			return IRQ_HANDLED;
 
-		if (ops & (1 << IPI_RESCHEDULE))
+		if (ops & (1 << IPI_RESCHEDULE)) {
+			stats[IPI_RESCHEDULE]++;
 			scheduler_ipi();
+		}
 
-		if (ops & (1 << IPI_CALL_FUNC))
+		if (ops & (1 << IPI_CALL_FUNC)) {
+			stats[IPI_CALL_FUNC]++;
 			generic_smp_call_function_interrupt();
+		}
 
-		if (ops & (1 << IPI_IRQ_WORK))
+		if (ops & (1 << IPI_IRQ_WORK)) {
+			stats[IPI_IRQ_WORK]++;
 			irq_work_run();
+		}
 
 		BUG_ON((ops >> IPI_MAX) != 0);
 	}
@@ -88,6 +98,29 @@ send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
 	send_arch_ipi(to_whom);
 }
 
+static const char * const ipi_names[] = {
+	[IPI_EMPTY]		= "Empty interrupts",
+	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
+	[IPI_CALL_FUNC]		= "Function call interrupts",
+	[IPI_IRQ_WORK]		= "Irq work interrupts",
+};
+
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	unsigned int cpu, i;
+
+	for (i = 0; i < IPI_MAX; i++) {
+		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
+			   prec >= 4 ? " " : "");
+		for_each_online_cpu(cpu)
+			seq_printf(p, "%10lu ",
+				per_cpu_ptr(&ipi_data, cpu)->stats[i]);
+		seq_printf(p, " %s\n", ipi_names[i]);
+	}
+
+	return 0;
+}
+
 void arch_send_call_function_ipi_mask(struct cpumask *mask)
 {
 	send_ipi_message(mask, IPI_CALL_FUNC);
-- 
2.7.4

[PATCH 13/13] csky: Add context tracking support

[guoren]

From: Guo Ren <guoren@linux.alibaba.com>

This patch support context tracking with no hz full.

Here is the test result with dynticks-testing (see tick_stop):

 cat /sys/kernel/debug/tracing/per_cpu/cpu0/trace
 tracer: nop

 entries-in-buffer/entries-written: 356/356   #P:1

                              _-----=> irqs-off
                             / _----=> need-resched
                            | / _---=> hardirq/softirq
                            || / _--=> preempt-depth
                            ||| /     delay
           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
              | |       |   ||||       |         |
...
          sleep-192   [000] d.h.   167.088270: hrtimer_expire_entry: hrtimer=(ptrval) function=tick_sched_timer now=166436355700
          sleep-192   [000] d.h.   167.092279: hrtimer_expire_entry: hrtimer=(ptrval) function=tick_sched_timer now=166440365700
         <idle>-0     [000] d.h2   167.096492: hrtimer_expire_entry: hrtimer=(ptrval) function=tick_sched_timer now=166444578400
         <idle>-0     [000] d..1   167.097876: tick_stop: success=1 dependency=NONE
                                               ^^^^^^^^^
         <idle>-0     [000] d.h1   168.818206: hrtimer_expire_entry: hrtimer=(ptrval) function=tick_sched_timer now=168166280900
   kworker/u2:0-7     [000] ....   168.821760: workqueue_execute_start: work struct (ptrval): function wb_workfn
   kworker/u2:0-7     [000] d.h1   168.824464: hrtimer_expire_entry: hrtimer=(ptrval) function=tick_sched_timer now=168172547100
    kworker/0:1-18    [000] ....   168.825053: workqueue_execute_start: work struct (ptrval): function vmstat_update
    kworker/0:1-18    [000] ....   168.825238: workqueue_execute_start: work struct (ptrval): function vmstat_shepherd
    kworker/0:1-18    [000] ....   168.825516: workqueue_execute_start: work struct (ptrval): function neigh_periodic_work
         <idle>-0     [000] d..1   168.826121: tick_stop: success=1 dependency=NONE
   kworker/u2:0-7     [000] ....   169.377327: workqueue_execute_start: work struct (ptrval): function flush_to_ldisc
         <idle>-0     [000] d..1   169.379832: tick_stop: success=1 dependency=NONE
   kworker/u2:0-7     [000] ....   169.607935: workqueue_execute_start: work struct (ptrval): function flush_to_ldisc
   kworker/u2:0-7     [000] d.h1   169.608148: hrtimer_expire_entry: hrtimer=(ptrval) function=tick_sched_timer now=168956235500
         <idle>-0     [000] d..1   169.608654: tick_stop: success=1 dependency=NONE

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Greentime Hu <greentime.hu@sifive.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/csky/Kconfig        |  2 ++
 arch/csky/kernel/entry.S | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index ad98b93..af23873 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -42,6 +42,8 @@ config CSKY
 	select HAVE_ARCH_MMAP_RND_BITS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_COPY_THREAD_TLS
+	select HAVE_CONTEXT_TRACKING
+	select HAVE_VIRT_CPU_ACCOUNTING_GEN
 	select HAVE_DEBUG_BUGVERBOSE
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index efd2e69..5936391 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -23,6 +23,22 @@
 #endif
 .endm
 
+.macro	context_tracking
+	mfcr	a0, epsr
+	btsti	a0, 31
+	bt	1f
+	jbsr	context_tracking_user_exit
+	ldw	a0, (sp, LSAVE_A0)
+	ldw	a1, (sp, LSAVE_A1)
+	ldw	a2, (sp, LSAVE_A2)
+	ldw	a3, (sp, LSAVE_A3)
+#if defined(__CSKYABIV1__)
+	ldw	r6, (sp, LSAVE_A4)
+	ldw	r7, (sp, LSAVE_A5)
+#endif
+1:
+.endm
+
 .macro tlbop_begin name, val0, val1, val2
 ENTRY(csky_\name)
 	mtcr    a3, ss2
@@ -103,6 +119,7 @@ ENTRY(csky_\name)
 .endm
 .macro tlbop_end is_write
 	zero_fp
+	context_tracking
 	RD_MEH	a2
 	psrset  ee, ie
 	mov     a0, sp
@@ -128,6 +145,7 @@ tlbop_end 1
 ENTRY(csky_systemcall)
 	SAVE_ALL TRAP0_SIZE
 	zero_fp
+	context_tracking
 	psrset  ee, ie
 
 	lrw     r9, __NR_syscalls
@@ -237,6 +255,9 @@ ret_from_exception:
 	and	r10, r9
 	cmpnei	r10, 0
 	bt	exit_work
+#ifdef CONFIG_CONTEXT_TRACKING
+	jbsr	context_tracking_user_enter
+#endif
 1:
 #ifdef CONFIG_PREEMPTION
 	mov	r9, sp
@@ -277,6 +298,7 @@ work_resched:
 ENTRY(csky_trap)
 	SAVE_ALL 0
 	zero_fp
+	context_tracking
 	psrset	ee
 	mov	a0, sp                 /* Push Stack pointer arg */
 	jbsr	trap_c                 /* Call C-level trap handler */
@@ -311,6 +333,7 @@ ENTRY(csky_get_tls)
 ENTRY(csky_irq)
 	SAVE_ALL 0
 	zero_fp
+	context_tracking
 	psrset	ee
 
 #ifdef CONFIG_TRACE_IRQFLAGS
-- 
2.7.4