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Message-Id: <1494356483-81678-2-git-send-email-keescook@chromium.org>
Date: Tue, 9 May 2017 12:01:22 -0700
From: Kees Cook <keescook@...omium.org>
To: linux-kernel@...r.kernel.org
Cc: Kees Cook <keescook@...omium.org>,
Peter Zijlstra <peterz@...radead.org>,
Josh Poimboeuf <jpoimboe@...hat.com>,
PaX Team <pageexec@...email.hu>,
Jann Horn <jannh@...gle.com>,
Eric Biggers <ebiggers3@...il.com>,
Christoph Hellwig <hch@...radead.org>,
"axboe@...nel.dk" <axboe@...nel.dk>,
James Bottomley <James.Bottomley@...senpartnership.com>,
Elena Reshetova <elena.reshetova@...el.com>,
Hans Liljestrand <ishkamiel@...il.com>,
David Windsor <dwindsor@...il.com>,
"x86@...nel.org" <x86@...nel.org>,
Ingo Molnar <mingo@...nel.org>,
Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"David S. Miller" <davem@...emloft.net>,
Rik van Riel <riel@...hat.com>,
linux-arch <linux-arch@...r.kernel.org>,
kernel-hardening@...ts.openwall.com
Subject: [PATCH v4 1/2] 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.
Signed-off-by: Kees Cook <keescook@...omium.org>
---
arch/x86/include/asm/rmwcc.h | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h
index 661dd305694a..3e96f9a56b6d 100644
--- a/arch/x86/include/asm/rmwcc.h
+++ b/arch/x86/include/asm/rmwcc.h
@@ -8,18 +8,15 @@
#define __GEN_RMWcc(fullop, var, cc, ...) \
do { \
asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \
- : : "m" (var), ## __VA_ARGS__ \
+ : : [counter] "m" (var), ## __VA_ARGS__ \
: "memory" : 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) */
@@ -29,17 +26,26 @@ cc_label: \
do { \
bool c; \
asm volatile (fullop ";" CC_SET(cc) \
- : "+m" (var), CC_OUT(cc) (c) \
+ : [counter] "+m" (var), CC_OUT(cc) (c) \
: __VA_ARGS__ : "memory"); \
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)
+#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc) \
+ __GEN_RMWcc(op " " arg0 "\n\t" suffix, var, cc)
+
#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, 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, \
+ vcon (val))
#endif /* _ASM_X86_RMWcc */
--
2.7.4
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