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path: root/arch/x86/lib/copy_user_nocache_64.S
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2008-07-30x86: wrong register was used in align macroVitaly Mayatskikh
New ALIGN_DESTINATION macro has sad typo: r8d register was used instead of ecx in fixup section. This can be considered as a regression. Register ecx was also wrongly loaded with value in r8d in copy_user_nocache routine. Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-10x86: fix compile error in current tip.gitJeremy Fitzhardinge
Gas 2.15 complains about 32-bit registers being used in lea. AS arch/x86/lib/copy_user_64.o /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S: Assembler messages: /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S:188: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S:257: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression AS arch/x86/lib/copy_user_nocache_64.o /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_nocache_64.S: Assembler messages: /local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_nocache_64.S:107: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Vitaly Mayatskikh <v.mayatskih@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09x86: fix copy_user on x86Vitaly Mayatskikh
Switch copy_user_generic_string(), copy_user_generic_unrolled() and __copy_user_nocache() from custom tail handlers to generic copy_user_tail_handle(). Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-17x86-64: Fix "bytes left to copy" return value for copy_from_user()Linus Torvalds
Most users by far do not care about the exact return value (they only really care about whether the copy succeeded in its entirety or not), but a few special core routines actually care deeply about exactly how many bytes were copied from user space. And the unrolled versions of the x86-64 user copy routines would sometimes report that it had copied more bytes than it actually had. Very few uses actually have partial copies to begin with, but to make this bug even harder to trigger, most x86 CPU's use the "rep string" instructions for normal user copies, and that version didn't have this issue. To make it even harder to hit, the one user of this that really cared about the return value (and used the uncached version of the copy that doesn't use the "rep string" instructions) was the generic write routine, which pre-populated its source, once more hiding the problem by avoiding the exception case that triggers the bug. In other words, very special thanks to Bron Gondwana who not only triggered this, but created a test-program to show it, and bisected the behavior down to commit 08291429cfa6258c4cd95d8833beb40f828b194e ("mm: fix pagecache write deadlocks") which changed the access pattern just enough that you can now trigger it with 'writev()' with multiple iovec's. That commit itself was not the cause of the bug, it just allowed all the stars to align just right that you could trigger the problem. [ Side note: this is just the minimal fix to make the copy routines (with __copy_from_user_inatomic_nocache as the particular version that was involved in showing this) have the right return values. We really should improve on the exceptional case further - to make the copy do a byte-accurate copy up to the exact page limit that causes it to fail. As it is, the callers have to do extra work to handle the limit case gracefully. ] Reported-by: Bron Gondwana <brong@fastmail.fm> Cc: Nick Piggin <npiggin@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (which didn't have this problem), and since most users that do the carethis was very hard to trigger, but
2007-10-12x86: fence oostores on 64-bitNick Piggin
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>
2007-10-11x86_64: move libThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>