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 <l...@amacapital.net>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/crypto/cast5_avx_glue.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/x86/crypto/cast5_avx_glue.c b/arch/x86/crypto/cast5_avx_glue.c
index ca4f32e7a423..be00aa48b2b5 100644
--- a/arch/x86/crypto/cast5_avx_glue.c
+++ b/arch/x86/crypto/cast5_avx_glue.c
@@ -31,8 +31,7 @@
 #include <crypto/cast5.h>
 #include <crypto/cryptd.h>
 #include <crypto/ctr.h>
-#include <asm/xcr.h>
-#include <asm/fpu/xstate.h>
+#include <asm/fpu/api.h>
 #include <asm/crypto/glue_helper.h>
 
 #define CAST5_PARALLEL_BLOCKS 16
@@ -468,16 +467,10 @@ static struct crypto_alg cast5_algs[6] = { {
 
 static int __init cast5_init(void)
 {
-       u64 xcr0;
+       const char *feature_name;
 
-       if (!cpu_has_avx || !cpu_has_osxsave) {
-               pr_info("AVX instructions are not detected.\n");
-               return -ENODEV;
-       }
-
-       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, &feature_name)) {
+               pr_info("CPU feature '%s' is not supported.\n", feature_name);
                return -ENODEV;
        }
 
-- 
2.1.0

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