lkml.org 
[lkml]   [2020]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] drm/i915: check to see if the FPU is available before using it
Date
It's not safe to just grab the FPU willy nilly without first checking to
see if it's available. This patch adds the usual call to may_use_simd()
and falls back to boring memcpy if it's not available.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
drivers/gpu/drm/i915/i915_memcpy.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_memcpy.c b/drivers/gpu/drm/i915/i915_memcpy.c
index fdd550405fd3..7c0e022586bc 100644
--- a/drivers/gpu/drm/i915/i915_memcpy.c
+++ b/drivers/gpu/drm/i915/i915_memcpy.c
@@ -24,6 +24,7 @@

#include <linux/kernel.h>
#include <asm/fpu/api.h>
+#include <asm/simd.h>

#include "i915_memcpy.h"

@@ -38,6 +39,12 @@ static DEFINE_STATIC_KEY_FALSE(has_movntdqa);
#ifdef CONFIG_AS_MOVNTDQA
static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len)
{
+ if (unlikely(!may_use_simd())) {
+ memcpy(dst, src, len);
+ return;
+ }
+
+
kernel_fpu_begin();

while (len >= 4) {
@@ -67,6 +74,11 @@ static void __memcpy_ntdqa(void *dst, const void *src, unsigned long len)

static void __memcpy_ntdqu(void *dst, const void *src, unsigned long len)
{
+ if (unlikely(!may_use_simd())) {
+ memcpy(dst, src, len);
+ return;
+ }
+
kernel_fpu_begin();

while (len >= 4) {
--
2.26.0
\
 
 \ /
  Last update: 2020-03-28 01:04    [W:0.038 / U:1.868 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site