Checkin b3ac891b67bd4b1fc728d1c784cad1212dea433d:
x86: Add support for lock prefix in alternatives
... did not define LOCK_PREFIX_HERE in the case of a uniprocessor
build. As a result, it would cause any of the usages of this macro to
fail on a uniprocessor build. Fix this by defining LOCK_PREFIX_HERE
as a null string.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-2-git-send-email-luca@luca-barbieri.com>
The current lock prefix UP/SMP alternative code doesn't allow
LOCK_PREFIX to be used in alternatives code.
This patch solves the problem by adding a new LOCK_PREFIX_ALTERNATIVE_PATCH
macro that only records the lock prefix location but does not emit
the prefix.
The user of this macro can then start any alternative sequence with
"lock" and have it UP/SMP patched.
To make this work, the UP/SMP alternative code is changed to do the
lock/DS prefix switching only if the byte actually contains a lock or
DS prefix.
Thus, if an alternative without the "lock" is selected, it will now do
nothing instead of clobbering the code.
Changes in v2:
- Naming change
- Change label to not conflict with alternatives
Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
LKML-Reference: <1267005265-27958-2-git-send-email-luca@luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
In order to avoid unnecessary chains of branches, rather than
implementing copy_user_generic() as a function consisting of
just a single (possibly patched) branch, instead properly deal
with patching call instructions in the alternative instructions
framework, and move the patching into the callers.
As a follow-on, one could also introduce something like
__EXPORT_SYMBOL_ALT() to avoid patching call sites in modules.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB8180200007800026AE7@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Having run into the run-(boot-)time check a couple of times lately,
I finally took time to find a build-time check so that one doesn't
need to analyze the register/stack dump and resolve this (through
manual lookup in vmlinux) to the offending construct.
The assembler will emit a message like "Error: value of <num> too
large for field of 1 bytes at <offset>", which while not pointing
out the source location still makes analysis quite a bit easier.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <4B0FF8AA0200007800022703@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Some of the NOPs tables aren't used on 64-bits, quite some code and
data is needed post-init for module loading only, and a couple of
functions aren't used outside that file (i.e. can be static, and don't
need to be exported).
The change to __INITDATA/__INITRODATA is needed to avoid an assembler
warning.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <4A8BC8A00200007800010823@vpn.id2.novell.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Alternative header duplicates assembly that could be merged in
one single macro. Merging this into this macro also allows to
directly declare ALTERNATIVE() statements within assembly code.
Uses a __stringify() of the feature bits rather than passing a
"i" operand. Leave the old %0 operand as-is (set to 0), unused
to stay compatible with API.
(v2: tab alignment fixes)
[ Impact: cleanup ]
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
LKML-Reference: <20090428151346.GA31212@Krystal>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:
a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
H. Peter Anvin