In previous patch current_thread_info()->syscall is set with corresponding syscall number prior to further calls, thus there is no any need to pass 'scno'.
Also, add explicit comment why do we have to reread 'scno' local variable. Signed-off-by: Roman Pen <[email protected]> Cc: Russell King <[email protected]> Cc: Christoffer Dall <[email protected]> Cc: Stefano Stabellini <[email protected]> Cc: Sekhar Nori <[email protected]> Cc: Kees Cook <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Eric Paris <[email protected]> Cc: Will Deacon <[email protected]> Cc: [email protected] Cc: [email protected] --- arch/arm/kernel/entry-common.S | 1 - arch/arm/kernel/ptrace.c | 6 ++++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 89452ff..3d12eb5 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -228,7 +228,6 @@ ENDPROC(vector_swi) * context switches, and waiting for our parent to respond. */ __sys_trace: - mov r1, scno add r0, sp, #S_OFF bl syscall_trace_enter diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index ef9119f..1238787 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -928,9 +928,9 @@ static void tracehook_report_syscall(struct pt_regs *regs, regs->ARM_ip = ip; } -asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) +asmlinkage int syscall_trace_enter(struct pt_regs *regs) { - current_thread_info()->syscall = scno; + int scno = current_thread_info()->syscall; /* Do the secure computing check first; failures should be fast. */ #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER @@ -944,6 +944,8 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); + /* Syscall can be aborted (-1 can be set) or even changed + * by the tracer and subsequent PTRACE_SET_SYSCALL request */ scno = current_thread_info()->syscall; if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
