Small constant-sized flushcache copies currently inline only the 4, 8, and 16-byte cases. Larger constant sizes fall back to __memcpy_flushcache() even when the destination is naturally aligned.
Factor the movnti sequences into 4/8/16/32/64-byte helpers and extend the inline fastpath coverage to the additional aligned constant sizes 32, 48, 64, 80, and 96 bytes. Keep the existing 4/8/16-byte cases handled directly in memcpy_flushcache() so they do not pick up the extra alignment gating used by the larger fixed-size helpers. Because memcpy_streaming() maps aligned transfers to memcpy_flushcache(), these additional fixed-size cases also stay on the inline movnti path for that helper. Issue the stores in ascending address order so write-combining sees a forward stream. Keep all other sizes on __memcpy_flushcache(), and keep zero-length copies returning immediately. Signed-off-by: Li Zhe <[email protected]> --- arch/x86/include/asm/string_64.h | 122 ++++++++++++++++++++++++++----- 1 file changed, 104 insertions(+), 18 deletions(-) diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h index aee63108577f..16d1aac2da24 100644 --- a/arch/x86/include/asm/string_64.h +++ b/arch/x86/include/asm/string_64.h @@ -83,24 +83,6 @@ int strcmp(const char *cs, const char *ct); #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE #define __HAVE_ARCH_MEMCPY_FLUSHCACHE 1 void __memcpy_flushcache(void *dst, const void *src, size_t cnt); -static __always_inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) -{ - if (__builtin_constant_p(cnt)) { - switch (cnt) { - case 4: - asm ("movntil %1, %0" : "=m"(*(u32 *)dst) : "r"(*(u32 *)src)); - return; - case 8: - asm ("movntiq %1, %0" : "=m"(*(u64 *)dst) : "r"(*(u64 *)src)); - return; - case 16: - asm ("movntiq %1, %0" : "=m"(*(u64 *)dst) : "r"(*(u64 *)src)); - asm ("movntiq %1, %0" : "=m"(*(u64 *)(dst + 8)) : "r"(*(u64 *)(src + 8))); - return; - } - } - __memcpy_flushcache(dst, src, cnt); -} /* * Only map memcpy_streaming() to memcpy_flushcache() when the destination @@ -115,6 +97,110 @@ static __always_inline bool memcpy_flushcache_nt_safe(const void *dst, return cnt && IS_ALIGNED(d, 8) && IS_ALIGNED(cnt, 4); } +static __always_inline void memcpy_flushcache_4(void *dst, const void *src) +{ + asm volatile("movntil %1, %0" + : "=m"(*(u32 *)dst) + : "r"(*(const u32 *)src) + : "memory"); +} + +static __always_inline void memcpy_flushcache_8(void *dst, const void *src) +{ + asm volatile("movntiq %1, %0" + : "=m"(*(u64 *)dst) + : "r"(*(const u64 *)src) + : "memory"); +} + +static __always_inline void memcpy_flushcache_16(void *dst, + const void *src) +{ + memcpy_flushcache_8(dst, src); + memcpy_flushcache_8(dst + 8, src + 8); +} + +static __always_inline void memcpy_flushcache_32(void *dst, + const void *src) +{ + memcpy_flushcache_16(dst, src); + memcpy_flushcache_16(dst + 16, src + 16); +} + +static __always_inline void memcpy_flushcache_64(void *dst, + const void *src) +{ + memcpy_flushcache_32(dst, src); + memcpy_flushcache_32(dst + 32, src + 32); +} + +/* + * Keep the additional aligned fixed-size cases on the inline movnti path. + * Leave the existing 4/8/16-byte cases handled directly in + * memcpy_flushcache() so they do not pick up the extra alignment gating + * used by the larger fixed-size helpers. + */ +static __always_inline int memcpy_flushcache_large(void *dst, + const void *src, + size_t cnt) +{ + unsigned long d = (unsigned long)dst; + char *dptr = dst; + const char *sptr = src; + + if (!IS_ALIGNED(d, 8)) + return 0; + + switch (cnt) { + case 32: + memcpy_flushcache_32(dptr, sptr); + return 1; + case 48: + memcpy_flushcache_32(dptr, sptr); + memcpy_flushcache_16(dptr + 32, sptr + 32); + return 1; + case 64: + memcpy_flushcache_64(dptr, sptr); + return 1; + case 80: + memcpy_flushcache_64(dptr, sptr); + memcpy_flushcache_16(dptr + 64, sptr + 64); + return 1; + case 96: + memcpy_flushcache_64(dptr, sptr); + memcpy_flushcache_32(dptr + 64, sptr + 64); + return 1; + } + + return 0; +} + +static __always_inline void memcpy_flushcache(void *dst, const void *src, + size_t cnt) +{ + if (!cnt) + return; + + if (__builtin_constant_p(cnt)) { + switch (cnt) { + case 4: + memcpy_flushcache_4(dst, src); + return; + case 8: + memcpy_flushcache_8(dst, src); + return; + case 16: + memcpy_flushcache_16(dst, src); + return; + } + + if (memcpy_flushcache_large(dst, src, cnt)) + return; + } + + __memcpy_flushcache(dst, src, cnt); +} + #define __HAVE_ARCH_MEMCPY_STREAMING 1 static __always_inline void memcpy_streaming(void *dst, const void *src, size_t cnt) -- 2.20.1
