From 3a95887e27ab7c2492b7c9c831805e9f1794863b Mon Sep 17 00:00:00 2001 From: Uros Bizjak Date: Wed, 5 Aug 2020 13:17:29 +0200 Subject: [PATCH] crypto: x86/crc32c-intel - Use CRC32 mnemonic Current minimum required version of binutils is 2.23, which supports CRC32 instruction mnemonic. Replace the byte-wise specification of CRC32 with this proper mnemonic. The compiler is now able to pass memory operand to the instruction, so there is no need for a temporary register anymore. Some examples of the improvement: 12a: 48 8b 08 mov (%rax),%rcx 12d: f2 48 0f 38 f1 f1 crc32q %rcx,%rsi 133: 48 83 c0 08 add $0x8,%rax 137: 48 39 d0 cmp %rdx,%rax 13a: 75 ee jne 12a to: 125: f2 48 0f 38 f1 06 crc32q (%rsi),%rax 12b: 48 83 c6 08 add $0x8,%rsi 12f: 48 39 d6 cmp %rdx,%rsi 132: 75 f1 jne 125 and: 146: 0f b6 08 movzbl (%rax),%ecx 149: f2 0f 38 f0 f1 crc32b %cl,%esi 14e: 48 83 c0 01 add $0x1,%rax 152: 48 39 d0 cmp %rdx,%rax 155: 75 ef jne 146 to: 13b: f2 0f 38 f0 02 crc32b (%rdx),%eax 140: 48 83 c2 01 add $0x1,%rdx 144: 48 39 ca cmp %rcx,%rdx 147: 75 f2 jne 13b As the compiler has some more freedom w.r.t. register allocation, there is also a couple of reg-reg moves removed. There are no hidden states for CRC32 insn, so there is no need to mark assembly as volatile. v2: Introduce CRC32_INST define. Signed-off-by: Uros Bizjak CC: Herbert Xu CC: "David S. Miller" CC: Thomas Gleixner CC: Ingo Molnar CC: Borislav Petkov CC: "H. Peter Anvin" Signed-off-by: Herbert Xu --- arch/x86/crypto/crc32c-intel_glue.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/arch/x86/crypto/crc32c-intel_glue.c b/arch/x86/crypto/crc32c-intel_glue.c index d2d069b..feccb52 100644 --- a/arch/x86/crypto/crc32c-intel_glue.c +++ b/arch/x86/crypto/crc32c-intel_glue.c @@ -28,9 +28,9 @@ #define SCALE_F sizeof(unsigned long) #ifdef CONFIG_X86_64 -#define REX_PRE "0x48, " +#define CRC32_INST "crc32q %1, %q0" #else -#define REX_PRE +#define CRC32_INST "crc32l %1, %0" #endif #ifdef CONFIG_X86_64 @@ -48,11 +48,8 @@ asmlinkage unsigned int crc_pcl(const u8 *buffer, int len, static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length) { while (length--) { - __asm__ __volatile__( - ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" - :"=S"(crc) - :"0"(crc), "c"(*data) - ); + asm("crc32b %1, %0" + : "+r" (crc) : "rm" (*data)); data++; } @@ -66,11 +63,8 @@ static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len unsigned long *ptmp = (unsigned long *)p; while (iquotient--) { - __asm__ __volatile__( - ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" - :"=S"(crc) - :"0"(crc), "c"(*ptmp) - ); + asm(CRC32_INST + : "+r" (crc) : "rm" (*ptmp)); ptmp++; } -- 2.7.4