diff options
| author | Nick Piggin <npiggin@suse.de> | 2007-10-12 21:06:00 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-12 21:41:21 -0400 |
| commit | df1bdc0667eb3132fe60b3562347ca9133694ee0 (patch) | |
| tree | 5d044be900ccc9f13662e1aeae7df6ed108ee43a /arch/x86 | |
| parent | 2b9e0aae1d50e880c58d46788e5e3ebd89d75d62 (diff) | |
x86: fence oostores on 64-bit
movnt* instructions are not strongly ordered with respect to other stores,
so if we are to assume stores are strongly ordered in the rest of the 64
bit code, we must fence these off (see similar examples in 32 bit code).
[ The AMD memory ordering document seems to say that nontemporal stores can
also pass earlier regular stores, so maybe we need sfences _before_
movnt* everywhere too? ]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/lib/copy_user_nocache_64.S | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/lib/copy_user_nocache_64.S b/arch/x86/lib/copy_user_nocache_64.S index 4620efb12f13..5196762b3b0e 100644 --- a/arch/x86/lib/copy_user_nocache_64.S +++ b/arch/x86/lib/copy_user_nocache_64.S | |||
| @@ -117,6 +117,7 @@ ENTRY(__copy_user_nocache) | |||
| 117 | popq %rbx | 117 | popq %rbx |
| 118 | CFI_ADJUST_CFA_OFFSET -8 | 118 | CFI_ADJUST_CFA_OFFSET -8 |
| 119 | CFI_RESTORE rbx | 119 | CFI_RESTORE rbx |
| 120 | sfence | ||
| 120 | ret | 121 | ret |
| 121 | CFI_RESTORE_STATE | 122 | CFI_RESTORE_STATE |
| 122 | 123 | ||