x86, asm: use bool for bitops and other assembly outputs

The gcc people have confirmed that using "bool" when combined with
inline assembly always is treated as a byte-sized operand that can be
assumed to be 0 or 1, which is exactly what the SET instruction
emits.  Change the output types and intermediate variables of as many
operations as practical to "bool".

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-3-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>

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/x86/boot/bitops.h b/arch/x86/boot/bitops.h
index 878e4b9940d9..0d41d68131cc 100644
--- a/arch/x86/boot/bitops.h
+++ b/arch/x86/boot/bitops.h
@@ -16,14 +16,16 @@
 #define BOOT_BITOPS_H
 #define _LINUX_BITOPS_H         /* Inhibit inclusion of <linux/bitops.h> */
 
-static inline int constant_test_bit(int nr, const void *addr)
+#include <linux/types.h>
+
+static inline bool constant_test_bit(int nr, const void *addr)
 {
         const u32 *p = (const u32 *)addr;
         return ((1UL << (nr & 31)) & (p[nr >> 5])) != 0;
 }
-static inline int variable_test_bit(int nr, const void *addr)
+static inline bool variable_test_bit(int nr, const void *addr)
 {
-        u8 v;
+        bool v;
         const u32 *p = (const u32 *)addr;
 
         asm("btl %2,%1; setc %0" : "=qm" (v) : "m" (*p), "Ir" (nr));