On Thu, Mar 13, 2014 at 10:13:50AM +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/
Please note that we can't trace compat system calls here because AArch32 mode does not share the same syscall table with AArch64. Just define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS in order to avoid unexpected results (bogus syscalls reported or even hang-up).
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org
arch/arm64/Kconfig | 1 + arch/arm64/include/asm/ftrace.h | 20 ++++++++++++++++ arch/arm64/include/asm/syscall.h | 1 + arch/arm64/include/asm/unistd.h | 2 ++ arch/arm64/kernel/ptrace.c | 48 ++++++++++++++++++++++---------------- 5 files changed, 52 insertions(+), 20 deletions(-)
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/ftrace.h b/arch/arm64/include/asm/ftrace.h index c44c4b1..4ef06f1 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -44,6 +44,26 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) #define CALLER_ADDR4 ((unsigned long)return_address(4)) #define CALLER_ADDR5 ((unsigned long)return_address(5)) #define CALLER_ADDR6 ((unsigned long)return_address(6))
+#include <asm/compat.h>
+/*
- Because AArch32 mode does not share the same syscall table with AArch64,
- tracing compat syscalls may result in reporting bogus syscalls or even
- hang-up, so just do not trace them.
- See kernel/trace/trace_syscalls.c
- x86 code says:
- If the user realy wants these, then they should use the
- raw syscall tracepoints with filtering.
Fair enough.
- */
+#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS 1
You don't need the '1' here.
+static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) +{
if (is_compat_task())return true;return false;+}
return is_compat_task();
#endif /* ifndef __ASSEMBLY__ */ #endif /* __ASM_FTRACE_H */ 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 9993a8f..9c52b3e 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.
@@ -1062,29 +1065,31 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs) { unsigned long saved_reg;
- if (!test_thread_flag(TIF_SYSCALL_TRACE))
return regs->syscallno;
- if (test_thread_flag(TIF_SYSCALL_TRACE)) {
/** A scrach register (ip(r12) on AArch32, x7 on AArch64) is* used to denote syscall entry/exit:* 0 -> entry*/if (is_compat_task()) {
if (arch_trace_is_compat_syscall())
With those changes:
Acked-by: Will Deacon will.deacon@arm.com
Will