linux/kernel/uid16.c, branch v2.6.28

asmlinkage_protect replaces prevent_tail_call

2008-04-11T00:28:26Z

The prevent_tail_call() macro works around the problem of the compiler clobbering argument words on the stack, which for asmlinkage functions is the caller's (user's) struct pt_regs. The tail/sibling-call optimization is not the only way that the compiler can decide to use stack argument words as scratch space, which we have to prevent. Other optimizations can do it too. Until we have new compiler support to make "asmlinkage" binding on the compiler's own use of the stack argument frame, we have work around all the manifestations of this issue that crop up. More cases seem to be prevented by also keeping the incoming argument variables live at the end of the function. This makes their original stack slots attractive places to leave those variables, so the compiler tends not clobber them for something else. It's still no guarantee, but it handles some observed cases that prevent_tail_call() did not. Signed-off-by: Roland McGrath Signed-off-by: Linus Torvalds

header cleaning: don't include smp_lock.h when not used

2007-05-08T18:15:07Z

Remove includes of where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Add more prevent_tail_call()

2006-04-19T23:27:18Z

Those also break userland regs like following. 00000000 : 0: 0f b7 44 24 0c movzwl 0xc(%esp),%eax 5: 83 ca ff or $0xffffffff,%edx 8: 0f b7 4c 24 08 movzwl 0x8(%esp),%ecx d: 66 83 f8 ff cmp $0xffffffff,%ax 11: 0f 44 c2 cmove %edx,%eax 14: 66 83 f9 ff cmp $0xffffffff,%cx 18: 0f 45 d1 cmovne %ecx,%edx 1b: 89 44 24 0c mov %eax,0xc(%esp) 1f: 89 54 24 08 mov %edx,0x8(%esp) 23: e9 fc ff ff ff jmp 24 where the tailcall at the end overwrites the incoming stack-frame. Signed-off-by: OGAWA Hirofumi [ I would _really_ like to have a way to tell gcc about calling conventions. The "prevent_tail_call()" macro is pretty ugly ] Signed-off-by: Linus Torvalds

[PATCH] move capable() to capability.h

2006-01-12T02:42:13Z

- Move capable() from sched.h to capability.h; - Use where capable() is used (in include/, block/, ipc/, kernel/, a few drivers/, mm/, security/, & sound/; many more drivers/ to go) Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Linux-2.6.12-rc2

2005-04-16T22:20:36Z

Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!