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Commit df340524 authored by Kees Cook's avatar Kees Cook Committed by Ingo Molnar
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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: default avatarKees 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: default avatarIngo Molnar <mingo@kernel.org>
parent 867ac9d7

arch/x86/include/asm/rmwcc.h

+24 −13
Original line number Diff line number Diff line 
#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 __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)

	__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 " %2, " arg0, var, cc, vcon (val))

	__GEN_RMWcc(op __BINARY_RMWcc_ARG arg0, var, cc,		\

		    __CLOBBERS_MEM, vcon (val))



#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */

#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 */