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 | 52 ++++++++++++++++++++++---------------- 4 files changed, 34 insertions(+), 22 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/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 6a8928b..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. @@ -1062,31 +1065,36 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs) { unsigned long saved_reg;
- if (!test_thread_flag(TIF_SYSCALL_TRACE)) - return regs->syscallno; + 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 */ + saved_reg = regs->regs[12]; + regs->regs[12] = dir; + } else { + /* + * Save X7. X7 is used to denote syscall entry/exit: + * X7 = 0 -> entry, = 1 -> exit + */ + saved_reg = regs->regs[7]; + regs->regs[7] = dir; + }
- if (is_compat_task()) { - /* AArch32 uses ip (r12) for scratch */ - saved_reg = regs->regs[12]; - regs->regs[12] = dir; - } else { - /* - * Save X7. X7 is used to denote syscall entry/exit: - * X7 = 0 -> entry, = 1 -> exit - */ - saved_reg = regs->regs[7]; - regs->regs[7] = dir; - } + if (dir) + tracehook_report_syscall_exit(regs, 0); + else if (tracehook_report_syscall_entry(regs)) + regs->syscallno = ~0UL;
- if (dir) - tracehook_report_syscall_exit(regs, 0); - else if (tracehook_report_syscall_entry(regs)) - regs->syscallno = ~0UL; + if (is_compat_task()) + regs->regs[12] = saved_reg; + else + regs->regs[7] = saved_reg; + }
- if (is_compat_task()) - regs->regs[12] = saved_reg; - else - regs->regs[7] = saved_reg; + if (!dir && unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) + trace_sys_enter(regs, regs->syscallno);
return regs->syscallno; }