crypto: simd,testmgr - introduce crypto_simd_usable()

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>

1 files changed, 25 insertions, 1 deletions

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 5d56b2990762..52417dde811f 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -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,