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 <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Reviewed-by: Andy Lutomirski <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
This commit is contained in:
H. Peter Anvin authored and H. Peter Anvin committed 2016-06-08 12:41:20 -07:00
1 parent 18fe58229d
commit ff3554b409
1 file changed
+12
+12
View File
@@ -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) \