Commit 385910f2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

x86: be careful about tailcall breakage for sys_open[at] too

Came up through a quick grep for other cases similar to the ftruncate()
one in commit 0a489cb3

.

Also, add a comment, so that people who read the code understand why we
do what looks like a no-op.

(Again, this won't actually matter to any sane user, since libc will
save and restore the register gcc stomps on, but it's still wrong to
stomp on it)
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0a489cb3
......@@ -332,6 +332,7 @@ out:
asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
{
long ret = do_sys_ftruncate(fd, length, 1);
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
......@@ -346,6 +347,7 @@ asmlinkage long sys_truncate64(const char __user * path, loff_t length)
asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
{
long ret = do_sys_ftruncate(fd, length, 0);
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
......@@ -1097,20 +1099,30 @@ long do_sys_open(int dfd, const char __user *filename, int flags, int mode)
asmlinkage long sys_open(const char __user *filename, int flags, int mode)
{
long ret;
if (force_o_largefile())
flags |= O_LARGEFILE;
return do_sys_open(AT_FDCWD, filename, flags, mode);
ret = do_sys_open(AT_FDCWD, filename, flags, mode);
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
EXPORT_SYMBOL_GPL(sys_open);
asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,
int mode)
{
long ret;
if (force_o_largefile())
flags |= O_LARGEFILE;
return do_sys_open(dfd, filename, flags, mode);
ret = do_sys_open(dfd, filename, flags, mode);
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
EXPORT_SYMBOL_GPL(sys_openat);
......
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