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x86/asm: Add suffix macro for GEN_*_RMWcc() 

The coming x86 refcount protection needs to be able to add trailing
instructions to the GEN_*_RMWcc() operations. This extracts the
difference between the goto/non-goto cases so the helper macros
can be defined outside the #ifdef cases. Additionally adds argument
naming to the resulting asm for referencing from suffixed
instructions, and adds clobbers for "cc", and "cx" to let suffixes
use _ASM_CX, and retain any set flags.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Jann Horn <jannh@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arozansk@redhat.com
Cc: axboe@kernel.dk
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/1500921349-10803-2-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kees Cook 2017-07-24 11:35:47 -07:00 committed by Ingo Molnar
parent 867ac9d737
commit df3405245a
1 changed files with 26 additions and 15 deletions
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41
arch/x86/include/asm/rmwcc.h
View File

@ -1,45 +1,56 @@
#ifndef _ASM_X86_RMWcc
#define _ASM_X86_RMWcc
#define __CLOBBERS_MEM "memory"
#define __CLOBBERS_MEM_CC_CX "memory", "cc", "cx"
#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO)
/* Use asm goto */
#define __GEN_RMWcc(fullop, var, cc, ...) \
#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
do { \
asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \
: : "m" (var), ## __VA_ARGS__ \
: "memory" : cc_label); \
: : [counter] "m" (var), ## __VA_ARGS__ \
: clobbers : cc_label); \
return 0; \
cc_label: \
return 1; \
} while (0)
#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
__GEN_RMWcc(op " " arg0, var, cc)
#define __BINARY_RMWcc_ARG " %1, "
#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
__GEN_RMWcc(op " %1, " arg0, var, cc, vcon (val))
#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
/* Use flags output or a set instruction */
#define __GEN_RMWcc(fullop, var, cc, ...) \
#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
do { \
bool c; \
asm volatile (fullop ";" CC_SET(cc) \
: "+m" (var), CC_OUT(cc) (c) \
: __VA_ARGS__ : "memory"); \
: [counter] "+m" (var), CC_OUT(cc) (c) \
: __VA_ARGS__ : clobbers); \
return c; \
} while (0)
#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
__GEN_RMWcc(op " " arg0, var, cc)
#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
__GEN_RMWcc(op " %2, " arg0, var, cc, vcon (val))
#define __BINARY_RMWcc_ARG " %2, "
#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
__GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM)
#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc) \
__GEN_RMWcc(op " " arg0 "\n\t" suffix, var, cc, \
__CLOBBERS_MEM_CC_CX)
#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
__GEN_RMWcc(op __BINARY_RMWcc_ARG arg0, var, cc, \
__CLOBBERS_MEM, vcon (val))
#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, vcon, val, arg0, cc) \
__GEN_RMWcc(op __BINARY_RMWcc_ARG arg0 "\n\t" suffix, var, cc, \
__CLOBBERS_MEM_CC_CX, vcon (val))
#endif /* _ASM_X86_RMWcc */