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crypto: simd,testmgr - introduce crypto_simd_usable()

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So that the no-SIMD fallback code can be tested by the crypto
self-tests, add a macro crypto_simd_usable() which wraps may_use_simd(),
but also returns false if the crypto self-tests have set a per-CPU bool
to disable SIMD in crypto code on the current CPU.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2019-03-12 22:12:47 -07:00 committed by Herbert Xu
parent 580e295178
commit b55e1a3954
2 changed files with 49 additions and 1 deletions
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26
crypto/testmgr.c
View File

@ -37,6 +37,7 @@
#include <crypto/akcipher.h>
#include <crypto/kpp.h>
#include <crypto/acompress.h>
#include <crypto/internal/simd.h>
#include "internal.h"
@ -52,6 +53,9 @@ MODULE_PARM_DESC(noextratests, "disable expensive crypto self-tests");
static unsigned int fuzz_iterations = 100;
module_param(fuzz_iterations, uint, 0644);
MODULE_PARM_DESC(fuzz_iterations, "number of fuzz test iterations");
DEFINE_PER_CPU(bool, crypto_simd_disabled_for_test);
EXPORT_PER_CPU_SYMBOL_GPL(crypto_simd_disabled_for_test);
#endif
#ifdef CONFIG_CRYPTO_MANAGER_DISABLE_TESTS
@ -838,7 +842,27 @@ static void generate_random_testvec_config(struct testvec_config *cfg,
WARN_ON_ONCE(!valid_testvec_config(cfg));
}
#endif /* CONFIG_CRYPTO_MANAGER_EXTRA_TESTS */
static void crypto_disable_simd_for_test(void)
{
preempt_disable();
__this_cpu_write(crypto_simd_disabled_for_test, true);
}
static void crypto_reenable_simd_for_test(void)
{
__this_cpu_write(crypto_simd_disabled_for_test, false);
preempt_enable();
}
#else /* !CONFIG_CRYPTO_MANAGER_EXTRA_TESTS */
static void crypto_disable_simd_for_test(void)
{
}
static void crypto_reenable_simd_for_test(void)
{
}
#endif /* !CONFIG_CRYPTO_MANAGER_EXTRA_TESTS */
static int check_nonfinal_hash_op(const char *op, int err,
u8 *result, unsigned int digestsize,

24
include/crypto/internal/simd.h
View File

@ -6,6 +6,9 @@
#ifndef _CRYPTO_INTERNAL_SIMD_H
#define _CRYPTO_INTERNAL_SIMD_H
#include <linux/percpu.h>
#include <linux/types.h>
/* skcipher support */
struct simd_skcipher_alg;
@ -42,4 +45,25 @@ int simd_register_aeads_compat(struct aead_alg *algs, int count,
void simd_unregister_aeads(struct aead_alg *algs, int count,
struct simd_aead_alg **simd_algs);
/*
* crypto_simd_usable() - is it allowed at this time to use SIMD instructions or
* access the SIMD register file?
*
* This delegates to may_use_simd(), except that this also returns false if SIMD
* in crypto code has been temporarily disabled on this CPU by the crypto
* self-tests, in order to test the no-SIMD fallback code. This override is
* currently limited to configurations where the extra self-tests are enabled,
* because it might be a bit too invasive to be part of the regular self-tests.
*
* This is a macro so that <asm/simd.h>, which some architectures don't have,
* doesn't have to be included directly here.
*/
#ifdef CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
DECLARE_PER_CPU(bool, crypto_simd_disabled_for_test);
#define crypto_simd_usable() \
(may_use_simd() && !this_cpu_read(crypto_simd_disabled_for_test))
#else
#define crypto_simd_usable() may_use_simd()
#endif
#endif /* _CRYPTO_INTERNAL_SIMD_H */