diff options
| author | mirabilos <tg@mirbsd.org> | 2015-07-25 18:51:26 +0200 |
|---|---|---|
| committer | Waldemar Brodkorb <wbx@uclibc-ng.org> | 2015-08-02 10:44:27 +0200 |
| commit | f5fa14e19c3dcd5f9648a8caaba63bc430f536da (patch) | |
| tree | 9540a8a5819ae4ee80ff33c383ae0ba76d472e82 /libc/sysdeps/linux | |
| parent | cdfebe7629971fc671a10c9b419f33f9ff928cbd (diff) | |
fix inline asm changing the stack pointer leading to segfaults problem
Diffstat (limited to 'libc/sysdeps/linux')
| -rw-r--r-- | libc/sysdeps/linux/i386/brk.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/libc/sysdeps/linux/i386/brk.c b/libc/sysdeps/linux/i386/brk.c index c2c93271e..a513886e3 100644 --- a/libc/sysdeps/linux/i386/brk.c +++ b/libc/sysdeps/linux/i386/brk.c @@ -1,6 +1,7 @@ /* brk system call for Linux/i386. Copyright (C) 1995, 1996, 2000 Free Software Foundation, Inc. - This file is part of the GNU C Library. + Copyright (c) 2015 mirabilos <tg@mirbsd.org> + This file is part of uclibc-ng, derived from the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public @@ -27,15 +28,18 @@ int brk(void *addr) { void *newbrk; - /* %ebx is used in PIC code, need to save/restore it manually. - * gcc won't do it for us if we will request it in constraints + /* + * EBC is used in PIC code, we need to save/restore it manually. + * Unfortunately, GCC won't do that for us even if we use con- + * straints, and we cannot push it either as ESP clobbers are + * silently ignored, but EDX is preserved, so it's scratch space. */ - __asm__("pushl %%ebx\n" - "movl %2, %%ebx\n" - "int $0x80\n" - "popl %%ebx\n" + __asm__("xchgl %%edx,%%ebx" + "\n int $0x80" + "\n xchgl %%edx,%%ebx" : "=a" (newbrk) - : "0" (__NR_brk), "g" (addr) + : "0" (__NR_brk), "d" (addr) + : "cc" ); __curbrk = newbrk; |