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/include/asm/bitops.h | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) (limited to 'arch/x86/include/asm/bitops.h') diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h index b2b797d1f49a..8cbb7f495546 100644 --- a/arch/x86/include/asm/bitops.h +++ b/arch/x86/include/asm/bitops.h @@ -201,7 +201,7 @@ static __always_inline void change_bit(long nr, volatile unsigned long *addr) * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ -static __always_inline int test_and_set_bit(long nr, volatile unsigned long *addr) +static __always_inline bool test_and_set_bit(long nr, volatile unsigned long *addr) { GEN_BINARY_RMWcc(LOCK_PREFIX "bts", *addr, "Ir", nr, "%0", "c"); } @@ -213,7 +213,7 @@ static __always_inline int test_and_set_bit(long nr, volatile unsigned long *add * * This is the same as test_and_set_bit on x86. */ -static __always_inline int +static __always_inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr) { return test_and_set_bit(nr, addr); @@ -228,9 +228,9 @@ test_and_set_bit_lock(long nr, volatile unsigned long *addr) * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ -static __always_inline int __test_and_set_bit(long nr, volatile unsigned long *addr) +static __always_inline bool __test_and_set_bit(long nr, volatile unsigned long *addr) { - unsigned char oldbit; + bool oldbit; asm("bts %2,%1\n\t" "setc %0" @@ -247,7 +247,7 @@ static __always_inline int __test_and_set_bit(long nr, volatile unsigned long *a * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ -static __always_inline int test_and_clear_bit(long nr, volatile unsigned long *addr) +static __always_inline bool test_and_clear_bit(long nr, volatile unsigned long *addr) { GEN_BINARY_RMWcc(LOCK_PREFIX "btr", *addr, "Ir", nr, "%0", "c"); } @@ -268,9 +268,9 @@ static __always_inline int test_and_clear_bit(long nr, volatile unsigned long *a * accessed from a hypervisor on the same CPU if running in a VM: don't change * this without also updating arch/x86/kernel/kvm.c */ -static __always_inline int __test_and_clear_bit(long nr, volatile unsigned long *addr) +static __always_inline bool __test_and_clear_bit(long nr, volatile unsigned long *addr) { - unsigned char oldbit; + bool oldbit; asm volatile("btr %2,%1\n\t" "setc %0" @@ -280,9 +280,9 @@ static __always_inline int __test_and_clear_bit(long nr, volatile unsigned long } /* WARNING: non atomic and it can be reordered! */ -static __always_inline int __test_and_change_bit(long nr, volatile unsigned long *addr) +static __always_inline bool __test_and_change_bit(long nr, volatile unsigned long *addr) { - unsigned char oldbit; + bool oldbit; asm volatile("btc %2,%1\n\t" "setc %0" @@ -300,20 +300,20 @@ static __always_inline int __test_and_change_bit(long nr, volatile unsigned long * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ -static __always_inline int test_and_change_bit(long nr, volatile unsigned long *addr) +static __always_inline bool test_and_change_bit(long nr, volatile unsigned long *addr) { GEN_BINARY_RMWcc(LOCK_PREFIX "btc", *addr, "Ir", nr, "%0", "c"); } -static __always_inline int constant_test_bit(long nr, const volatile unsigned long *addr) +static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) { return ((1UL << (nr & (BITS_PER_LONG-1))) & (addr[nr >> _BITOPS_LONG_SHIFT])) != 0; } -static __always_inline int variable_test_bit(long nr, volatile const unsigned long *addr) +static __always_inline bool variable_test_bit(long nr, volatile const unsigned long *addr) { - unsigned char oldbit; + bool oldbit; asm volatile("bt %2,%1\n\t" "setc %0" @@ -329,7 +329,7 @@ static __always_inline int variable_test_bit(long nr, volatile const unsigned lo * @nr: bit number to test * @addr: Address to start counting from */ -static int test_bit(int nr, const volatile unsigned long *addr); +static bool test_bit(int nr, const volatile unsigned long *addr); #endif #define test_bit(nr, addr) \ -- cgit v1.2.1