Re: [PATCH] arm64: make a single hook to syscall_trace() for all syscall features

Currently syscall_trace() is called only for ptrace. With additional TIF_xx flags introduced, it is now called in all the cases of audit, ftrace and seccomp in addition to ptrace. Those features will be implemented later, but it's safe to include them now because they can not be turned on anyway. Signed-off-by: AKASHI Takahiro <takahiro.akashi(a)linaro.org&gt; --- arch/arm64/include/asm/thread_info.h | 13 +++++++++++++ arch/arm64/kernel/entry.S | 5 +++-- arch/arm64/kernel/ptrace.c | 11 +++++------ 3 files changed, 21 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 720e70b..c3df797 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h

+#define _TIF_WORK_SYSCALL (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ + _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)

#endif /* __KERNEL__ */ #endif /* __ASM_THREAD_INFO_H */ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 39ac630..c94b2ab 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -631,8 +631,9 @@ el0_svc_naked: // compat entry point enable_irq get_thread_info tsk - ldr x16, [tsk, #TI_FLAGS] // check for syscall tracing - tbnz x16, #TIF_SYSCALL_TRACE, __sys_trace // are we tracing syscalls? + ldr x16, [tsk, #TI_FLAGS] // check for syscall hooks + tst x16, #_TIF_WORK_SYSCALL + b.ne __sys_trace adr lr, ret_fast_syscall // return address cmp scno, sc_nr // check upper syscall limit b.hs ni_sys diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 6a8928b..64ce39f 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -1062,9 +1062,6 @@ 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 (is_compat_task()) { /* AArch32 uses ip (r12) for scratch */ saved_reg = regs->regs[12]; @@ -1078,10 +1075,12 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs) regs->regs[7] = dir; } - if (dir) + if (dir) { tracehook_report_syscall_exit(regs, 0); - else if (tracehook_report_syscall_entry(regs)) - regs->syscallno = ~0UL; + } else { + if (tracehook_report_syscall_entry(regs)) + regs->syscallno = ~0UL; + }