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Date: Mon, 30 Apr 2012 16:51:15 -0700
From: Jim Kukunas <james.t.kukunas@...ux.intel.com>
To: neilb@...e.de
Cc: linux-raid@...r.kernel.org, hpa@...or.com,
linux-kernel@...r.kernel.org
Subject: [PATCH] arch/x86: use kernel_fpu_[begin|end] for RAID5 checksumming
Currently, the SSE and AVX xor functions manually save and restore the
[X|Y]MM registers. Instead, we should use kernel_fpu_[begin|end].
This patch sacrifices some throughput,~5-10% for AVX and ~2% for SSE, in
exchange for safety against future FPU corruption bugs.
Patch applies to md/for-next.
Signed-off-by: Jim Kukunas <james.t.kukunas@...ux.intel.com>
---
arch/x86/include/asm/xor_32.h | 56 +++++-------------------------------
arch/x86/include/asm/xor_64.h | 61 ++++++---------------------------------
arch/x86/include/asm/xor_avx.h | 55 ++++++++----------------------------
3 files changed, 30 insertions(+), 142 deletions(-)
diff --git a/arch/x86/include/asm/xor_32.h b/arch/x86/include/asm/xor_32.h
index 4545708..aabd585 100644
--- a/arch/x86/include/asm/xor_32.h
+++ b/arch/x86/include/asm/xor_32.h
@@ -534,38 +534,6 @@ static struct xor_block_template xor_block_p5_mmx = {
* Copyright (C) 1999 Zach Brown (with obvious credit due Ingo)
*/
-#define XMMS_SAVE \
-do { \
- preempt_disable(); \
- cr0 = read_cr0(); \
- clts(); \
- asm volatile( \
- "movups %%xmm0,(%0) ;\n\t" \
- "movups %%xmm1,0x10(%0) ;\n\t" \
- "movups %%xmm2,0x20(%0) ;\n\t" \
- "movups %%xmm3,0x30(%0) ;\n\t" \
- : \
- : "r" (xmm_save) \
- : "memory"); \
-} while (0)
-
-#define XMMS_RESTORE \
-do { \
- asm volatile( \
- "sfence ;\n\t" \
- "movups (%0),%%xmm0 ;\n\t" \
- "movups 0x10(%0),%%xmm1 ;\n\t" \
- "movups 0x20(%0),%%xmm2 ;\n\t" \
- "movups 0x30(%0),%%xmm3 ;\n\t" \
- : \
- : "r" (xmm_save) \
- : "memory"); \
- write_cr0(cr0); \
- preempt_enable(); \
-} while (0)
-
-#define ALIGN16 __attribute__((aligned(16)))
-
#define OFFS(x) "16*("#x")"
#define PF_OFFS(x) "256+16*("#x")"
#define PF0(x) " prefetchnta "PF_OFFS(x)"(%1) ;\n"
@@ -587,10 +555,8 @@ static void
xor_sse_2(unsigned long bytes, unsigned long *p1, unsigned long *p2)
{
unsigned long lines = bytes >> 8;
- char xmm_save[16*4] ALIGN16;
- int cr0;
- XMMS_SAVE;
+ kernel_fpu_begin();
asm volatile(
#undef BLOCK
@@ -633,7 +599,7 @@ xor_sse_2(unsigned long bytes, unsigned long *p1, unsigned long *p2)
:
: "memory");
- XMMS_RESTORE;
+ kernel_fpu_end();
}
static void
@@ -641,10 +607,8 @@ xor_sse_3(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3)
{
unsigned long lines = bytes >> 8;
- char xmm_save[16*4] ALIGN16;
- int cr0;
- XMMS_SAVE;
+ kernel_fpu_begin();
asm volatile(
#undef BLOCK
@@ -694,7 +658,7 @@ xor_sse_3(unsigned long bytes, unsigned long *p1, unsigned long *p2,
:
: "memory" );
- XMMS_RESTORE;
+ kernel_fpu_end();
}
static void
@@ -702,10 +666,8 @@ xor_sse_4(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3, unsigned long *p4)
{
unsigned long lines = bytes >> 8;
- char xmm_save[16*4] ALIGN16;
- int cr0;
- XMMS_SAVE;
+ kernel_fpu_begin();
asm volatile(
#undef BLOCK
@@ -762,7 +724,7 @@ xor_sse_4(unsigned long bytes, unsigned long *p1, unsigned long *p2,
:
: "memory" );
- XMMS_RESTORE;
+ kernel_fpu_end();
}
static void
@@ -770,10 +732,8 @@ xor_sse_5(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3, unsigned long *p4, unsigned long *p5)
{
unsigned long lines = bytes >> 8;
- char xmm_save[16*4] ALIGN16;
- int cr0;
- XMMS_SAVE;
+ kernel_fpu_begin();
/* Make sure GCC forgets anything it knows about p4 or p5,
such that it won't pass to the asm volatile below a
@@ -850,7 +810,7 @@ xor_sse_5(unsigned long bytes, unsigned long *p1, unsigned long *p2,
like assuming they have some legal value. */
asm("" : "=r" (p4), "=r" (p5));
- XMMS_RESTORE;
+ kernel_fpu_end();
}
static struct xor_block_template xor_block_pIII_sse = {
diff --git a/arch/x86/include/asm/xor_64.h b/arch/x86/include/asm/xor_64.h
index b9b2323..715f904 100644
--- a/arch/x86/include/asm/xor_64.h
+++ b/arch/x86/include/asm/xor_64.h
@@ -34,41 +34,7 @@
* no advantages to be gotten from x86-64 here anyways.
*/
-typedef struct {
- unsigned long a, b;
-} __attribute__((aligned(16))) xmm_store_t;
-
-/* Doesn't use gcc to save the XMM registers, because there is no easy way to
- tell it to do a clts before the register saving. */
-#define XMMS_SAVE \
-do { \
- preempt_disable(); \
- asm volatile( \
- "movq %%cr0,%0 ;\n\t" \
- "clts ;\n\t" \
- "movups %%xmm0,(%1) ;\n\t" \
- "movups %%xmm1,0x10(%1) ;\n\t" \
- "movups %%xmm2,0x20(%1) ;\n\t" \
- "movups %%xmm3,0x30(%1) ;\n\t" \
- : "=&r" (cr0) \
- : "r" (xmm_save) \
- : "memory"); \
-} while (0)
-
-#define XMMS_RESTORE \
-do { \
- asm volatile( \
- "sfence ;\n\t" \
- "movups (%1),%%xmm0 ;\n\t" \
- "movups 0x10(%1),%%xmm1 ;\n\t" \
- "movups 0x20(%1),%%xmm2 ;\n\t" \
- "movups 0x30(%1),%%xmm3 ;\n\t" \
- "movq %0,%%cr0 ;\n\t" \
- : \
- : "r" (cr0), "r" (xmm_save) \
- : "memory"); \
- preempt_enable(); \
-} while (0)
+#include <asm/i387.h>
#define OFFS(x) "16*("#x")"
#define PF_OFFS(x) "256+16*("#x")"
@@ -91,10 +57,8 @@ static void
xor_sse_2(unsigned long bytes, unsigned long *p1, unsigned long *p2)
{
unsigned int lines = bytes >> 8;
- unsigned long cr0;
- xmm_store_t xmm_save[4];
- XMMS_SAVE;
+ kernel_fpu_begin();
asm volatile(
#undef BLOCK
@@ -135,7 +99,7 @@ xor_sse_2(unsigned long bytes, unsigned long *p1, unsigned long *p2)
: [inc] "r" (256UL)
: "memory");
- XMMS_RESTORE;
+ kernel_fpu_end();
}
static void
@@ -143,10 +107,8 @@ xor_sse_3(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3)
{
unsigned int lines = bytes >> 8;
- xmm_store_t xmm_save[4];
- unsigned long cr0;
- XMMS_SAVE;
+ kernel_fpu_begin();
asm volatile(
#undef BLOCK
@@ -194,7 +156,8 @@ xor_sse_3(unsigned long bytes, unsigned long *p1, unsigned long *p2,
[p1] "+r" (p1), [p2] "+r" (p2), [p3] "+r" (p3)
: [inc] "r" (256UL)
: "memory");
- XMMS_RESTORE;
+
+ kernel_fpu_end();
}
static void
@@ -202,10 +165,8 @@ xor_sse_4(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3, unsigned long *p4)
{
unsigned int lines = bytes >> 8;
- xmm_store_t xmm_save[4];
- unsigned long cr0;
- XMMS_SAVE;
+ kernel_fpu_begin();
asm volatile(
#undef BLOCK
@@ -261,7 +222,7 @@ xor_sse_4(unsigned long bytes, unsigned long *p1, unsigned long *p2,
: [inc] "r" (256UL)
: "memory" );
- XMMS_RESTORE;
+ kernel_fpu_end();
}
static void
@@ -269,10 +230,8 @@ xor_sse_5(unsigned long bytes, unsigned long *p1, unsigned long *p2,
unsigned long *p3, unsigned long *p4, unsigned long *p5)
{
unsigned int lines = bytes >> 8;
- xmm_store_t xmm_save[4];
- unsigned long cr0;
- XMMS_SAVE;
+ kernel_fpu_begin();
asm volatile(
#undef BLOCK
@@ -336,7 +295,7 @@ xor_sse_5(unsigned long bytes, unsigned long *p1, unsigned long *p2,
: [inc] "r" (256UL)
: "memory");
- XMMS_RESTORE;
+ kernel_fpu_end();
}
static struct xor_block_template xor_block_sse = {
diff --git a/arch/x86/include/asm/xor_avx.h b/arch/x86/include/asm/xor_avx.h
index 2510d35..8d2795a 100644
--- a/arch/x86/include/asm/xor_avx.h
+++ b/arch/x86/include/asm/xor_avx.h
@@ -17,35 +17,8 @@
#ifdef CONFIG_AS_AVX
-#include <linux/compiler.h>
#include <asm/i387.h>
-#define ALIGN32 __aligned(32)
-
-#define YMM_SAVED_REGS 4
-
-#define YMMS_SAVE \
-do { \
- preempt_disable(); \
- cr0 = read_cr0(); \
- clts(); \
- asm volatile("vmovaps %%ymm0, %0" : "=m" (ymm_save[0]) : : "memory"); \
- asm volatile("vmovaps %%ymm1, %0" : "=m" (ymm_save[32]) : : "memory"); \
- asm volatile("vmovaps %%ymm2, %0" : "=m" (ymm_save[64]) : : "memory"); \
- asm volatile("vmovaps %%ymm3, %0" : "=m" (ymm_save[96]) : : "memory"); \
-} while (0);
-
-#define YMMS_RESTORE \
-do { \
- asm volatile("sfence" : : : "memory"); \
- asm volatile("vmovaps %0, %%ymm3" : : "m" (ymm_save[96])); \
- asm volatile("vmovaps %0, %%ymm2" : : "m" (ymm_save[64])); \
- asm volatile("vmovaps %0, %%ymm1" : : "m" (ymm_save[32])); \
- asm volatile("vmovaps %0, %%ymm0" : : "m" (ymm_save[0])); \
- write_cr0(cr0); \
- preempt_enable(); \
-} while (0);
-
#define BLOCK4(i) \
BLOCK(32 * i, 0) \
BLOCK(32 * (i + 1), 1) \
@@ -60,10 +33,9 @@ do { \
static void xor_avx_2(unsigned long bytes, unsigned long *p0, unsigned long *p1)
{
- unsigned long cr0, lines = bytes >> 9;
- char ymm_save[32 * YMM_SAVED_REGS] ALIGN32;
+ unsigned long lines = bytes >> 9;
- YMMS_SAVE
+ kernel_fpu_begin();
while (lines--) {
#undef BLOCK
@@ -82,16 +54,15 @@ do { \
p1 = (unsigned long *)((uintptr_t)p1 + 512);
}
- YMMS_RESTORE
+ kernel_fpu_end();
}
static void xor_avx_3(unsigned long bytes, unsigned long *p0, unsigned long *p1,
unsigned long *p2)
{
- unsigned long cr0, lines = bytes >> 9;
- char ymm_save[32 * YMM_SAVED_REGS] ALIGN32;
+ unsigned long lines = bytes >> 9;
- YMMS_SAVE
+ kernel_fpu_begin();
while (lines--) {
#undef BLOCK
@@ -113,16 +84,15 @@ do { \
p2 = (unsigned long *)((uintptr_t)p2 + 512);
}
- YMMS_RESTORE
+ kernel_fpu_end();
}
static void xor_avx_4(unsigned long bytes, unsigned long *p0, unsigned long *p1,
unsigned long *p2, unsigned long *p3)
{
- unsigned long cr0, lines = bytes >> 9;
- char ymm_save[32 * YMM_SAVED_REGS] ALIGN32;
+ unsigned long lines = bytes >> 9;
- YMMS_SAVE
+ kernel_fpu_begin();
while (lines--) {
#undef BLOCK
@@ -147,16 +117,15 @@ do { \
p3 = (unsigned long *)((uintptr_t)p3 + 512);
}
- YMMS_RESTORE
+ kernel_fpu_end();
}
static void xor_avx_5(unsigned long bytes, unsigned long *p0, unsigned long *p1,
unsigned long *p2, unsigned long *p3, unsigned long *p4)
{
- unsigned long cr0, lines = bytes >> 9;
- char ymm_save[32 * YMM_SAVED_REGS] ALIGN32;
+ unsigned long lines = bytes >> 9;
- YMMS_SAVE
+ kernel_fpu_begin();
while (lines--) {
#undef BLOCK
@@ -184,7 +153,7 @@ do { \
p4 = (unsigned long *)((uintptr_t)p4 + 512);
}
- YMMS_RESTORE
+ kernel_fpu_end();
}
static struct xor_block_template xor_block_avx = {
--
1.7.8.6
--
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