[PATCH 156/208] x86/fpu, crypto x86/sha256_ssse3: Simplify the sha256_ssse3_mod_init() xfeature checks

From: Ingo Molnar
Date: Tue May 05 2015 - 13:56:44 EST


Use the new 'cpu_has_xfeatures()' function to query AVX CPU support.

This has the following advantages to the driver:

- Decouples the driver from FPU internals: it's now only using <asm/fpu/api.h>.

- Removes detection complexity from the driver, no more raw XGETBV instruction

- Shrinks the code a bit.

- Standardizes feature name error message printouts across drivers

There are also advantages to the x86 FPU code: once all drivers
are decoupled from internals we can move them out of common
headers and we'll also be able to remove xcr.h.

Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/crypto/sha256_ssse3_glue.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/arch/x86/crypto/sha256_ssse3_glue.c b/arch/x86/crypto/sha256_ssse3_glue.c
index eb65522f02b8..f8097fc0d1d1 100644
--- a/arch/x86/crypto/sha256_ssse3_glue.c
+++ b/arch/x86/crypto/sha256_ssse3_glue.c
@@ -38,8 +38,6 @@
#include <crypto/sha.h>
#include <crypto/sha256_base.h>
#include <asm/fpu/api.h>
-#include <asm/xcr.h>
-#include <asm/fpu/xstate.h>
#include <linux/string.h>

asmlinkage void sha256_transform_ssse3(u32 *digest, const char *data,
@@ -132,15 +130,9 @@ static struct shash_alg algs[] = { {
#ifdef CONFIG_AS_AVX
static bool __init avx_usable(void)
{
- u64 xcr0;
-
- if (!cpu_has_avx || !cpu_has_osxsave)
- return false;
-
- xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
- if ((xcr0 & (XSTATE_SSE | XSTATE_YMM)) != (XSTATE_SSE | XSTATE_YMM)) {
- pr_info("AVX detected but unusable.\n");
-
+ if (!cpu_has_xfeatures(XSTATE_SSE | XSTATE_YMM, NULL)) {
+ if (cpu_has_avx)
+ pr_info("AVX detected but unusable.\n");
return false;
}

--
2.1.0

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