Re: [PATCH v3 5/6] arm64: ftrace: Add system call tracepoint

On Fri, Feb 07, 2014 at 10:18:55AM +0000, AKASHI Takahiro wrote:

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 | 5 +++++ 4 files changed, 9 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 43fce76..9bdaf5c 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -42,6 +42,7 @@ config ARM64 select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_MEMBLOCK 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 64ce39f..f4c3c4e 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.

@@ -1076,10 +1079,12 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs) } if (dir) {

• trace_sys_exit(regs, regs->syscallno);
  

  tracehook_report_syscall_exit(regs, 0); } else { if (tracehook_report_syscall_entry(regs)) regs->syscallno = ~0UL;

• trace_sys_enter(regs, regs->syscallno);
  

Shouldn't these calls be guarded by a TIF_SYSCALL_TRACEPOINT check?

Will