commit 5511a34566aa455512a704604a11120dee426631
author Gilles Peskine <Gilles.Peskine@arm.com> Fri Mar 10 22:29:32 2023 +0100
committer Tom Cosgrove <tom.cosgrove@arm.com> Fri Mar 17 16:31:12 2023 +0000
tree f5ab1adef3cbcdab31b5f976277a7b2ca518780b
parent 2808a6047cc5ff0fc8fe48502d59ee113c7c89d8

New preprocessor symbol indicating that AESNI support is present

The configuration symbol MBEDTLS_AESNI_C requests AESNI support, but it is
ignored if the platform doesn't have AESNI. This allows keeping
MBEDTLS_AESNI_C enabled (as it is in the default build) when building for
platforms other than x86_64, or when MBEDTLS_HAVE_ASM is disabled.

To facilitate maintenance, always use the symbol MBEDTLS_AESNI_HAVE_CODE to
answer the question "can I call mbedtls_aesni_xxx functions?", rather than
repeating the check `defined(MBEDTLS_AESNI_C) && ...`.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

include/mbedtls/aesni.h

diff --git a/include/mbedtls/aesni.h b/include/mbedtls/aesni.h
index 653b146..b3d49e4 100644
--- a/include/mbedtls/aesni.h
+++ b/include/mbedtls/aesni.h
@@ -36,13 +36,30 @@
 #define MBEDTLS_AESNI_AES      0x02000000u
 #define MBEDTLS_AESNI_CLMUL    0x00000002u
 
-#if defined(MBEDTLS_HAVE_ASM) && defined(__GNUC__) &&  \
+#if defined(MBEDTLS_HAVE_ASM) && defined(__GNUC__) && \
     (defined(__amd64__) || defined(__x86_64__))   &&  \
     !defined(MBEDTLS_HAVE_X86_64)
 #define MBEDTLS_HAVE_X86_64
 #endif
 
+#if defined(MBEDTLS_AESNI_C)
+
 #if defined(MBEDTLS_HAVE_X86_64)
+#define MBEDTLS_AESNI_HAVE_CODE // via assembly
+#endif
+
+#if defined(_MSC_VER)
+#define MBEDTLS_HAVE_AESNI_INTRINSICS
+#endif
+#if defined(__GNUC__) && defined(__AES__)
+#define MBEDTLS_HAVE_AESNI_INTRINSICS
+#endif
+
+#if defined(MBEDTLS_HAVE_AESNI_INTRINSICS)
+#define MBEDTLS_AESNI_HAVE_CODE // via intrinsics
+#endif
+
+#if defined(MBEDTLS_AESNI_HAVE_CODE)
 
 #ifdef __cplusplus
 extern "C" {
@@ -131,6 +148,7 @@
 }
 #endif
 
-#endif /* MBEDTLS_HAVE_X86_64 */
+#endif /* MBEDTLS_AESNI_HAVE_CODE */
+#endif  /* MBEDTLS_AESNI_C */
 
 #endif /* MBEDTLS_AESNI_H */

library/aes.c

diff --git a/library/aes.c b/library/aes.c
index bcdf3c7..66c697a 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -550,7 +550,7 @@
 #endif
     ctx->rk = RK = ctx->buf;
 
-#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
+#if defined(MBEDTLS_AESNI_HAVE_CODE)
     if (mbedtls_aesni_has_support(MBEDTLS_AESNI_AES)) {
         return mbedtls_aesni_setkey_enc((unsigned char *) ctx->rk, key, keybits);
     }
@@ -658,7 +658,7 @@
 
     ctx->nr = cty.nr;
 
-#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
+#if defined(MBEDTLS_AESNI_HAVE_CODE)
     if (mbedtls_aesni_has_support(MBEDTLS_AESNI_AES)) {
         mbedtls_aesni_inverse_key((unsigned char *) ctx->rk,
                                   (const unsigned char *) cty.rk, ctx->nr);
@@ -978,7 +978,7 @@
     AES_VALIDATE_RET(mode == MBEDTLS_AES_ENCRYPT ||
                      mode == MBEDTLS_AES_DECRYPT);
 
-#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
+#if defined(MBEDTLS_AESNI_HAVE_CODE)
     if (mbedtls_aesni_has_support(MBEDTLS_AESNI_AES)) {
         return mbedtls_aesni_crypt_ecb(ctx, mode, input, output);
     }

library/gcm.c

diff --git a/library/gcm.c b/library/gcm.c
index f7db0d4..2778012 100644
--- a/library/gcm.c
+++ b/library/gcm.c
@@ -93,7 +93,7 @@
     ctx->HL[8] = vl;
     ctx->HH[8] = vh;
 
-#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
+#if defined(MBEDTLS_AESNI_HAVE_CODE)
     /* With CLMUL support, we need only h, not the rest of the table */
     if (mbedtls_aesni_has_support(MBEDTLS_AESNI_CLMUL)) {
         return 0;
@@ -190,7 +190,7 @@
     unsigned char lo, hi, rem;
     uint64_t zh, zl;
 
-#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
+#if defined(MBEDTLS_AESNI_HAVE_CODE)
     if (mbedtls_aesni_has_support(MBEDTLS_AESNI_CLMUL)) {
         unsigned char h[16];
 
@@ -202,7 +202,7 @@
         mbedtls_aesni_gcm_mult(output, x, h);
         return;
     }
-#endif /* MBEDTLS_AESNI_C && MBEDTLS_HAVE_X86_64 */
+#endif /* MBEDTLS_AESNI_HAVE_CODE */
 
     lo = x[15] & 0xf;