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| author |   Max Filippov <jcmvbkbc@gmail.com> | 2019-11-25 11:51:45 -0800 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2019-11-29 14:39:12 -0800 |
| commit | ba9c1d65991a8be2e160447dd06eb803cbb9ba61 (patch) | |
| tree | 4ab61ab6b7bbb68a128a7a2a83551e5e901e067b /arch/xtensa | |
| parent | xtensa: fix syscall_set_return_value (diff) | |
| download | linux-dev-ba9c1d65991a8be2e160447dd06eb803cbb9ba61.tar.xz linux-dev-ba9c1d65991a8be2e160447dd06eb803cbb9ba61.zip | |
xtensa: rearrange syscall tracing
system_call saves and restores syscall number across system call to make
clone and execv entry and exit tracing match. This complicates things
when syscall code may be changed by ptrace.
Preserve syscall code in copy_thread and start_thread directly instead of
doing tricks in system_call.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa')
| -rw-r--r-- | arch/xtensa/include/asm/processor.h | 3 | ||||
| -rw-r--r-- | arch/xtensa/kernel/entry.S | 6 | ||||
| -rw-r--r-- | arch/xtensa/kernel/process.c | 2 |
3 files changed, 4 insertions, 7 deletions
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index 7495520d7a3e..6fa903daf2a2 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -195,6 +195,7 @@ struct thread_struct { /* Clearing a0 terminates the backtrace. */ #define start_thread(regs, new_pc, new_sp) \ do { \ + unsigned long syscall = (regs)->syscall; \ memset((regs), 0, sizeof(*(regs))); \ (regs)->pc = (new_pc); \ (regs)->ps = USER_PS_VALUE; \ @@ -204,7 +205,7 @@ struct thread_struct { (regs)->depc = 0; \ (regs)->windowbase = 0; \ (regs)->windowstart = 1; \ - (regs)->syscall = NO_SYSCALL; \ + (regs)->syscall = syscall; \ } while (0) /* Forward declaration */ diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 2ca209e71565..59af494d9940 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1895,8 +1895,6 @@ ENTRY(system_call) l32i a7, a2, PT_SYSCALL 1: - s32i a7, a1, 4 - /* syscall = sys_call_table[syscall_nr] */ movi a4, sys_call_table @@ -1930,12 +1928,8 @@ ENTRY(system_call) abi_ret(4) 1: - l32i a4, a1, 4 - l32i a3, a2, PT_SYSCALL - s32i a4, a2, PT_SYSCALL mov a6, a2 call4 do_syscall_trace_leave - s32i a3, a2, PT_SYSCALL abi_ret(4) ENDPROC(system_call) diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index db278a9e80c7..9e1c49134c07 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -264,6 +264,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn, ®s->areg[XCHAL_NUM_AREGS - len/4], len); } + childregs->syscall = regs->syscall; + /* The thread pointer is passed in the '4th argument' (= a5) */ if (clone_flags & CLONE_SETTLS) childregs->threadptr = childregs->areg[5]; |