diff options
Diffstat (limited to 'libc')
| -rw-r--r-- | libc/sysdeps/linux/i386/__syscall_error.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/libc/sysdeps/linux/i386/__syscall_error.c b/libc/sysdeps/linux/i386/__syscall_error.c index de65a1f39..507cf2ab7 100644 --- a/libc/sysdeps/linux/i386/__syscall_error.c +++ b/libc/sysdeps/linux/i386/__syscall_error.c @@ -22,8 +22,24 @@ /* This routine is jumped to by all the syscall handlers, to stash * an error number into errno. */ -int attribute_hidden __syscall_error(int err_no) + +/* This version uses a lot of magic and relies heavily on x86 + * calling convention ... The advantage is that this is the same + * size as the previous __syscall_error() but all the .S functions + * need just one instruction. + * + * Local .S files have to set %eax to the negative errno value + * and then jump to this function. The neglected return to caller + * and return value of -1 is taken care of here so we don't have to + * worry about it in the .S functions. + * + * We have to stash the errno from %eax in a local stack var because + * __set_errno will prob call a function thus clobbering %eax on us. + */ +void attribute_hidden __syscall_error(void) { - __set_errno(err_no); - return -1; + register int eax asm("%eax"); + int stack = -eax; + __set_errno(stack); + eax = -1; } |