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| author | Uros Bizjak <ubizjak@gmail.com> | 2020-08-05 14:17:29 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2020-08-21 07:45:28 +0300 |
| commit | 3a95887e27ab7c2492b7c9c831805e9f1794863b (patch) | |
| tree | f32c749dc30e0037aec1967bebc19b92f578feba /arch/x86/crypto | |
| parent | 1d8b41ff6991bcff5864c42807f811d2304f4355 (diff) | |
| download | linux-3a95887e27ab7c2492b7c9c831805e9f1794863b.tar.xz | |
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 <crc32c_intel_update+0x1a>
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 <crc32c_intel_update+0x15>
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 <crc32c_intel_update+0x36>
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 <crc32c_intel_update+0x2b>
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 <ubizjak@gmail.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'arch/x86/crypto')
| -rw-r--r-- | arch/x86/crypto/crc32c-intel_glue.c | 18 |
1 files changed, 6 insertions, 12 deletions
diff --git a/arch/x86/crypto/crc32c-intel_glue.c b/arch/x86/crypto/crc32c-intel_glue.c index d2d069bd459b..feccb5254c7e 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++; } |