From 117780eef7740729e803bdcc0d5f2f48137ea8e3 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Wed, 8 Jun 2016 12:38:38 -0700 Subject: 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 Link: http://lkml.kernel.org/r/1465414726-197858-3-git-send-email-hpa@linux.intel.com Reviewed-by: Andy Lutomirski Reviewed-by: Borislav Petkov Acked-by: Peter Zijlstra (Intel) --- arch/x86/boot/bitops.h | 8 +++++--- arch/x86/boot/boot.h | 8 ++++---- arch/x86/boot/string.c | 2 +- 3 files changed, 10 insertions(+), 8 deletions(-) (limited to 'arch/x86/boot') 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 */ -static inline int constant_test_bit(int nr, const void *addr) +#include + +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)); diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h index 9011a88353de..2edb2d53c3a2 100644 --- a/arch/x86/boot/boot.h +++ b/arch/x86/boot/boot.h @@ -176,16 +176,16 @@ static inline void wrgs32(u32 v, addr_t addr) } /* Note: these only return true/false, not a signed return value! */ -static inline int memcmp_fs(const void *s1, addr_t s2, size_t len) +static inline bool memcmp_fs(const void *s1, addr_t s2, size_t len) { - u8 diff; + bool diff; asm volatile("fs; repe; cmpsb; setnz %0" : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); return diff; } -static inline int memcmp_gs(const void *s1, addr_t s2, size_t len) +static inline bool memcmp_gs(const void *s1, addr_t s2, size_t len) { - u8 diff; + bool diff; asm volatile("gs; repe; cmpsb; setnz %0" : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); return diff; diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c index 318b8465d302..cc3bd583dce1 100644 --- a/arch/x86/boot/string.c +++ b/arch/x86/boot/string.c @@ -17,7 +17,7 @@ int memcmp(const void *s1, const void *s2, size_t len) { - u8 diff; + bool diff; asm("repe; cmpsb; setnz %0" : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); return diff; -- cgit v1.2.3 From 66928b4eb92dfb6d87c204238057b9278b36452b Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Wed, 8 Jun 2016 12:38:45 -0700 Subject: x86, asm, boot: Use CC_SET()/CC_OUT() in arch/x86/boot/boot.h Remove open-coded uses of set instructions to use CC_SET()/CC_OUT() in arch/x86/boot/boot.h. Signed-off-by: H. Peter Anvin Link: http://lkml.kernel.org/r/1465414726-197858-10-git-send-email-hpa@linux.intel.com Reviewed-by: Andy Lutomirski Reviewed-by: Borislav Petkov Acked-by: Peter Zijlstra (Intel) --- arch/x86/boot/boot.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'arch/x86/boot') diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h index 2edb2d53c3a2..7c1495f2b799 100644 --- a/arch/x86/boot/boot.h +++ b/arch/x86/boot/boot.h @@ -24,6 +24,7 @@ #include #include #include +#include #include "bitops.h" #include "ctype.h" #include "cpuflags.h" @@ -179,15 +180,15 @@ static inline void wrgs32(u32 v, addr_t addr) static inline bool memcmp_fs(const void *s1, addr_t s2, size_t len) { bool diff; - asm volatile("fs; repe; cmpsb; setnz %0" - : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); + asm volatile("fs; repe; cmpsb" CC_SET(nz) + : CC_OUT(nz) (diff), "+D" (s1), "+S" (s2), "+c" (len)); return diff; } static inline bool memcmp_gs(const void *s1, addr_t s2, size_t len) { bool diff; - asm volatile("gs; repe; cmpsb; setnz %0" - : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); + asm volatile("gs; repe; cmpsb" CC_SET(nz) + : CC_OUT(nz) (diff), "+D" (s1), "+S" (s2), "+c" (len)); return diff; } -- cgit v1.2.3