diff options
| author | akpm@osdl.org <akpm@osdl.org> | 2006-01-12 01:05:41 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-12 09:08:52 -0800 |
| commit | 07b047fc2466249aff7cdb23fa0b0955a7a00d48 (patch) | |
| tree | af22cc80470f8aff6d0c25276ef8fae2b3f537a7 /include | |
| parent | 06b425d80f56280e698b3e8487c372e0d39d9ba1 (diff) | |
| download | linux-07b047fc2466249aff7cdb23fa0b0955a7a00d48.tar.bz2 | |
[PATCH] i386: fix task_pt_regs()
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From: Al Viro <viro@ftp.linux.org.uk>
task_pt_regs() needs the same offset-by-8 to match copy_thread()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-i386/processor.h | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h index 13ecf66b098c..29ad87e9123f 100644 --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -561,10 +561,20 @@ unsigned long get_wchan(struct task_struct *p); (unsigned long)(&__ptr[THREAD_SIZE_LONGS]); \ }) +/* + * The below -8 is to reserve 8 bytes on top of the ring0 stack. + * This is necessary to guarantee that the entire "struct pt_regs" + * is accessable even if the CPU haven't stored the SS/ESP registers + * on the stack (interrupt gate does not save these registers + * when switching to the same priv ring). + * Therefore beware: accessing the xss/esp fields of the + * "struct pt_regs" is possible, but they may contain the + * completely wrong values. + */ #define task_pt_regs(task) \ ({ \ struct pt_regs *__regs__; \ - __regs__ = (struct pt_regs *)KSTK_TOP((task)->thread_info); \ + __regs__ = (struct pt_regs *)(KSTK_TOP((task)->thread_info)-8); \ __regs__ - 1; \ }) |