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| author | Max Filippov <jcmvbkbc@gmail.com> | 2019-11-29 14:54:06 -0800 |
|---|---|---|
| committer | Max Filippov <jcmvbkbc@gmail.com> | 2019-11-29 15:47:54 -0800 |
| commit | 02ce94c229251555ac726ecfebe3458ef5905fa9 (patch) | |
| tree | 19e5ae21b866a950e0b42c5bc8655f5d8d1b0ef5 /arch/xtensa | |
| parent | ba9c1d65991a8be2e160447dd06eb803cbb9ba61 (diff) | |
| download | linux-02ce94c229251555ac726ecfebe3458ef5905fa9.tar.bz2 | |
xtensa: fix system_call interaction with ptrace
Don't overwrite return value if system call was cancelled at entry by
ptrace. Return status code from do_syscall_trace_enter so that
pt_regs::syscall doesn't need to be changed to skip syscall.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa')
| -rw-r--r-- | arch/xtensa/kernel/entry.S | 4 | ||||
| -rw-r--r-- | arch/xtensa/kernel/ptrace.c | 18 |
2 files changed, 18 insertions, 4 deletions
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 59af494d9940..138469e26560 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1892,6 +1892,7 @@ ENTRY(system_call) mov a6, a2 call4 do_syscall_trace_enter + beqz a6, .Lsyscall_exit l32i a7, a2, PT_SYSCALL 1: @@ -1904,8 +1905,6 @@ ENTRY(system_call) addx4 a4, a7, a4 l32i a4, a4, 0 - movi a5, sys_ni_syscall; - beq a4, a5, 1f /* Load args: arg0 - arg5 are passed via regs. */ @@ -1925,6 +1924,7 @@ ENTRY(system_call) s32i a6, a2, PT_AREG2 bnez a3, 1f +.Lsyscall_exit: abi_ret(4) 1: diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c index b964f0b2d886..145742d70a9f 100644 --- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -542,14 +542,28 @@ long arch_ptrace(struct task_struct *child, long request, return ret; } -void do_syscall_trace_enter(struct pt_regs *regs) +void do_syscall_trace_leave(struct pt_regs *regs); +int do_syscall_trace_enter(struct pt_regs *regs) { + if (regs->syscall == NO_SYSCALL) + regs->areg[2] = -ENOSYS; + if (test_thread_flag(TIF_SYSCALL_TRACE) && - tracehook_report_syscall_entry(regs)) + tracehook_report_syscall_entry(regs)) { + regs->areg[2] = -ENOSYS; regs->syscall = NO_SYSCALL; + return 0; + } + + if (regs->syscall == NO_SYSCALL) { + do_syscall_trace_leave(regs); + return 0; + } if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_enter(regs, syscall_get_nr(current, regs)); + + return 1; } void do_syscall_trace_leave(struct pt_regs *regs) |