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Subject[PATCH v4 5/7] arm64: ftrace: Add system call tracepoint
Date
This patch allows system call entry or exit to be traced as ftrace events,
ie. sys_enter_*/sys_exit_*, if CONFIG_FTRACE_SYSCALLS is enabled.
Those events appear and can be controlled under
${sysfs}/tracing/events/syscalls/

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/syscall.h | 1 +
arch/arm64/include/asm/unistd.h | 2 ++
arch/arm64/kernel/ptrace.c | 9 +++++++++
4 files changed, 13 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6954959..b1dcdb4 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -43,6 +43,7 @@ config ARM64
select HAVE_MEMBLOCK
select HAVE_PATA_PLATFORM
select HAVE_PERF_EVENTS
+ select HAVE_SYSCALL_TRACEPOINTS
select IRQ_DOMAIN
select MODULES_USE_ELF_RELA
select NO_BOOTMEM
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index 70ba9d4..383771e 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -18,6 +18,7 @@

#include <linux/err.h>

+extern const void *sys_call_table[];

static inline int syscall_get_nr(struct task_struct *task,
struct pt_regs *regs)
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 82ce217..c335479 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -28,3 +28,5 @@
#endif
#define __ARCH_WANT_SYS_CLONE
#include <uapi/asm/unistd.h>
+
+#define NR_syscalls (__NR_syscalls)
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index c70133e..dc90f9f 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -41,6 +41,9 @@
#include <asm/traps.h>
#include <asm/system_misc.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
/*
* TODO: does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
@@ -1062,6 +1065,9 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs)
{
unsigned long saved_reg;

+ if (dir && unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
+ trace_sys_exit(regs, regs_return_value(regs));
+
if (test_thread_flag(TIF_SYSCALL_TRACE)) {
if (is_compat_task()) {
/* AArch32 uses ip (r12) for scratch */
@@ -1087,5 +1093,8 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs)
regs->regs[7] = saved_reg;
}

+ if (!dir && unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
+ trace_sys_enter(regs, regs->syscallno);
+
return regs->syscallno;
}
--
1.7.9.5


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