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| author | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2025-04-21 19:58:04 +0200 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2025-04-21 20:01:37 +0200 |
| commit | 0d9971468087c77e8727638123ae4aa60724e0ff (patch) | |
| tree | 9ccffed4968c4cefb5912bdabe63ac08aa5279ee | |
| parent | 0f2df19d9535d234b31c65f84a6c67ac2e0bd027 (diff) | |
| download | glibc-0d9971468087c77e8727638123ae4aa60724e0ff.zip glibc-0d9971468087c77e8727638123ae4aa60724e0ff.tar.gz glibc-0d9971468087c77e8727638123ae4aa60724e0ff.tar.bz2 | |
hurd: Clear FP exceptions before calling signal handler
This avoids SIGFPE handlers (or code longjmp-ed to) getting disturbed by the
exception that generated it.
Note: gcc's unwinding depends on the rpc_wait_trampoline/trampoline exact
code, so we here avoid breaking it.
| -rw-r--r-- | sysdeps/mach/hurd/x86/trampoline.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/sysdeps/mach/hurd/x86/trampoline.c b/sysdeps/mach/hurd/x86/trampoline.c index 02510b1..6f23c56 100644 --- a/sysdeps/mach/hurd/x86/trampoline.c +++ b/sysdeps/mach/hurd/x86/trampoline.c @@ -461,7 +461,10 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, const struct sigaction *action - in gdb: gdb/i386-gnu-tdep.c gnu_sigtramp_code. */ #ifdef __x86_64__ -asm ("rpc_wait_trampoline:\n" +asm ("trampoline:\n" + "fnclex\n" /* Clear any pending exception. */ + "jmp _trampoline\n" + "rpc_wait_trampoline:\n" /* This is the entry point when we have an RPC reply message to receive before running the handler. The MACH_MSG_SEND bit has already been cleared in the OPTION argument in our %rsi. The interrupted user @@ -480,7 +483,7 @@ asm ("rpc_wait_trampoline:\n" /* Switch to the signal stack. */ "movq %rbx, %rsp\n" - "trampoline:\n" + "_trampoline:\n" /* Entry point for running the handler normally. The arguments to the handler function are on the top of the stack, same as in the i386 version: @@ -506,7 +509,10 @@ asm ("rpc_wait_trampoline:\n" "movq 16(%rsp), %rdi\n" "ret"); #else -asm ("rpc_wait_trampoline:\n"); +asm ("trampoline:\n" + "fnclex\n" /* Clear any pending exception. */ + "jmp _trampoline\n" + "rpc_wait_trampoline:\n"); /* This is the entry point when we have an RPC reply message to receive before running the handler. The MACH_MSG_SEND bit has already been cleared in the OPTION argument on our stack. The interrupted user @@ -526,7 +532,7 @@ asm (/* Retry the interrupted mach_msg system call. */ /* Switch to the signal stack. */ "movl %ebx, %esp\n"); - asm ("trampoline:\n"); +asm ("_trampoline:\n"); /* Entry point for running the handler normally. The arguments to the handler function are already on the top of the stack: |