From 6aacb5a3b0bccfa207ef2710f106020c1d749f1d Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 11 Dec 2019 11:04:37 +0000 Subject: drm/i915: Align start for memcpy_from_wc The movntqda requires 16-byte alignment for the source pointer. Avoid falling back to clflush if the source pointer is misaligned by doing the doing a small uncached memcpy to fixup the alignments. v2: Turn the unaligned copy into a genuine helper Signed-off-by: Chris Wilson Reviewed-by: Joonas Lahtinen Link: https://patchwork.freedesktop.org/patch/msgid/20191211110437.4082687-5-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_memcpy.c | 75 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 71 insertions(+), 4 deletions(-) (limited to 'drivers/gpu/drm/i915/i915_memcpy.c') diff --git a/drivers/gpu/drm/i915/i915_memcpy.c b/drivers/gpu/drm/i915/i915_memcpy.c index 07b04b0acb77..fdd550405fd3 100644 --- a/drivers/gpu/drm/i915/i915_memcpy.c +++ b/drivers/gpu/drm/i915/i915_memcpy.c @@ -27,6 +27,12 @@ #include "i915_memcpy.h" +#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) +#define CI_BUG_ON(expr) BUG_ON(expr) +#else +#define CI_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr) +#endif + static DEFINE_STATIC_KEY_FALSE(has_movntdqa); #ifdef CONFIG_AS_MOVNTDQA @@ -34,7 +40,6 @@ static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) { kernel_fpu_begin(); - len >>= 4; while (len >= 4) { asm("movntdqa (%0), %%xmm0\n" "movntdqa 16(%0), %%xmm1\n" @@ -59,6 +64,38 @@ static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) kernel_fpu_end(); } + +static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len) +{ + kernel_fpu_begin(); + + while (len >= 4) { + asm("movntdqa (%0), %%xmm0\n" + "movntdqa 16(%0), %%xmm1\n" + "movntdqa 32(%0), %%xmm2\n" + "movntdqa 48(%0), %%xmm3\n" + "movups %%xmm0, (%1)\n" + "movups %%xmm1, 16(%1)\n" + "movups %%xmm2, 32(%1)\n" + "movups %%xmm3, 48(%1)\n" + :: "r" (src), "r" (dst) : "memory"); + src += 64; + dst += 64; + len -= 4; + } + while (len--) { + asm("movntdqa (%0), %%xmm0\n" + "movups %%xmm0, (%1)\n" + :: "r" (src), "r" (dst) : "memory"); + src += 16; + dst += 16; + } + + kernel_fpu_end(); +} +#else +static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len) {} +static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len) {} #endif /** @@ -83,17 +120,47 @@ bool i915_memcpy_from_wc(void *dst, const void *src, unsigned long len) if (unlikely(((unsigned long)dst | (unsigned long)src | len) & 15)) return false; -#ifdef CONFIG_AS_MOVNTDQA if (static_branch_likely(&has_movntdqa)) { if (likely(len)) - __memcpy_ntdqa(dst, src, len); + __memcpy_ntdqa(dst, src, len >> 4); return true; } -#endif return false; } +/** + * i915_unaligned_memcpy_from_wc: perform a mostly accelerated read from WC + * @dst: destination pointer + * @src: source pointer + * @len: how many bytes to copy + * + * Like i915_memcpy_from_wc(), the unaligned variant copies @len bytes from + * @src to @dst using * non-temporal instructions where available, but + * accepts that its arguments may not be aligned, but are valid for the + * potential 16-byte read past the end. + */ +void i915_unaligned_memcpy_from_wc(void *dst, void *src, unsigned long len) +{ + unsigned long addr; + + CI_BUG_ON(!i915_has_memcpy_from_wc()); + + addr = (unsigned long)src; + if (!IS_ALIGNED(addr, 16)) { + unsigned long x = min(ALIGN(addr, 16) - addr, len); + + memcpy(dst, src, x); + + len -= x; + dst += x; + src += x; + } + + if (likely(len)) + __memcpy_ntdqu(dst, src, DIV_ROUND_UP(len, 16)); +} + void i915_memcpy_init_early(struct drm_i915_private *dev_priv) { /* -- cgit v1.2.3