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authorH. Peter Anvin <hpa@zytor.com>2016-06-08 22:38:40 +0300
committerH. Peter Anvin <hpa@linux.intel.com>2016-06-08 22:41:20 +0300
commitff3554b409b82d349f71e9d7082648b7b0a1a5bb (patch)
treebf0166f5e2be0455efb82ba62c1532baa6e41555 /arch/x86/include/asm/asm.h
parent18fe58229d80c7f4f138a07e84ba608e1ebd232b (diff)
downloadlinux-ff3554b409b82d349f71e9d7082648b7b0a1a5bb.tar.xz
x86, asm: define CC_SET() and CC_OUT() macros
The CC_SET() and CC_OUT() macros can be used together to take advantage of the new __GCC_ASM_FLAG_OUTPUTS__ feature in gcc 6+ while remaining backwards compatible. CC_SET() generates a SET instruction on older compilers; CC_OUT() makes sure the output is received in the correct variable. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Link: http://lkml.kernel.org/r/1465414726-197858-5-git-send-email-hpa@linux.intel.com Reviewed-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'arch/x86/include/asm/asm.h')
-rw-r--r--arch/x86/include/asm/asm.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index f5063b6659eb..7acb51c49fec 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -42,6 +42,18 @@
#define _ASM_SI __ASM_REG(si)
#define _ASM_DI __ASM_REG(di)
+/*
+ * Macros to generate condition code outputs from inline assembly,
+ * The output operand must be type "bool".
+ */
+#ifdef __GCC_ASM_FLAG_OUTPUTS__
+# define CC_SET(c) "\n\t/* output condition code " #c "*/\n"
+# define CC_OUT(c) "=@cc" #c
+#else
+# define CC_SET(c) "\n\tset" #c " %[_cc_" #c "]\n"
+# define CC_OUT(c) [_cc_ ## c] "=qm"
+#endif
+
/* Exception table entry */
#ifdef __ASSEMBLY__
# define _ASM_EXTABLE_HANDLE(from, to, handler) \