Messages in this thread Patch in this message | | | From | Sudeep Holla <> | Subject | [PATCH 3/6] x86: clean up _TIF_SYSCALL_EMU handling using ptrace_syscall_enter hook | Date | Thu, 28 Feb 2019 18:32:17 +0000 |
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Now that we have a new hook ptrace_syscall_enter that can be called from syscall entry code and it handles PTRACE_SYSEMU in generic code, we can do some cleanup using the same in syscall_trace_enter.
Further the extra logic to find single stepping PTRACE_SYSEMU_SINGLESTEP in syscall_slow_exit_work seems unnecessary. Let's remove the same.
Cc: Andy Lutomirski <luto@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> --- arch/x86/entry/common.c | 22 ++++------------------ 1 file changed, 4 insertions(+), 18 deletions(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 7bc105f47d21..36457c1f87d2 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -70,22 +70,16 @@ static long syscall_trace_enter(struct pt_regs *regs) struct thread_info *ti = current_thread_info(); unsigned long ret = 0; - bool emulated = false; u32 work; if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) BUG_ON(regs != task_pt_regs(current)); - work = READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY; - - if (unlikely(work & _TIF_SYSCALL_EMU)) - emulated = true; - - if ((emulated || (work & _TIF_SYSCALL_TRACE)) && - tracehook_report_syscall_entry(regs)) + if (unlikely(ptrace_syscall_enter(regs))) return -1L; - if (emulated) + work = READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY; + if ((work & _TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) return -1L; #ifdef CONFIG_SECCOMP @@ -227,15 +221,7 @@ static void syscall_slow_exit_work(struct pt_regs *regs, u32 cached_flags) if (cached_flags & _TIF_SYSCALL_TRACEPOINT) trace_sys_exit(regs, regs->ax); - /* - * If TIF_SYSCALL_EMU is set, we only get here because of - * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP). - * We already reported this syscall instruction in - * syscall_trace_enter(). - */ - step = unlikely( - (cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU)) - == _TIF_SINGLESTEP); + step = unlikely((cached_flags & _TIF_SINGLESTEP)); if (step || cached_flags & _TIF_SYSCALL_TRACE) tracehook_report_syscall_exit(regs, step); } -- 2.17.1
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