From 80d3e73ad0648f558a067a9dbfe3bc80e6b614f8 Mon Sep 17 00:00:00 2001
From: Beniamin Sandu <beniaminsandu@gmail.com>
Date: Mon, 30 Oct 2023 19:15:56 +0000
Subject: [PATCH] AES-NI: use target attributes for x86 32-bit intrinsics

This way we build with 32-bit gcc/clang out of the box.
We also fallback to assembly for 64-bit clang-cl if needed cpu
flags are not provided, instead of throwing an error.

Upstream-Status: Backport [https://github.com/Mbed-TLS/mbedtls/commit/800f2b7c020678a84abfa9688962b91c36e6693d]

Signed-off-by: Beniamin Sandu <beniaminsandu@gmail.com>
---
 library/aesni.c | 20 ++++++++++++++++++++
 library/aesni.h |  8 +++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/library/aesni.c b/library/aesni.c
index 5f25a8249..481fa3822 100644
--- a/library/aesni.c
+++ b/library/aesni.c
@@ -41,6 +41,17 @@
 #include <immintrin.h>
 #endif

+#if defined(MBEDTLS_ARCH_IS_X86)
+#if defined(MBEDTLS_COMPILER_IS_GCC)
+#pragma GCC push_options
+#pragma GCC target ("pclmul,sse2,aes")
+#define MBEDTLS_POP_TARGET_PRAGMA
+#elif defined(__clang__)
+#pragma clang attribute push (__attribute__((target("pclmul,sse2,aes"))), apply_to=function)
+#define MBEDTLS_POP_TARGET_PRAGMA
+#endif
+#endif
+
 #if !defined(MBEDTLS_AES_USE_HARDWARE_ONLY)
 /*
  * AES-NI support detection routine
@@ -396,6 +407,15 @@ static void aesni_setkey_enc_256(unsigned char *rk_bytes,
 }
 #endif /* !MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH */

+#if defined(MBEDTLS_POP_TARGET_PRAGMA)
+#if defined(__clang__)
+#pragma clang attribute pop
+#elif defined(__GNUC__)
+#pragma GCC pop_options
+#endif
+#undef MBEDTLS_POP_TARGET_PRAGMA
+#endif
+
 #else /* MBEDTLS_AESNI_HAVE_CODE == 1 */

 #if defined(__has_feature)
diff --git a/library/aesni.h b/library/aesni.h
index ba1429029..37ae02c82 100644
--- a/library/aesni.h
+++ b/library/aesni.h
@@ -50,6 +50,10 @@
 #if defined(__GNUC__) && defined(__AES__) && defined(__PCLMUL__)
 #define MBEDTLS_AESNI_HAVE_INTRINSICS
 #endif
+/* For 32-bit, we only support intrinsics */
+#if defined(MBEDTLS_ARCH_IS_X86) && (defined(__GNUC__) || defined(__clang__))
+#define MBEDTLS_AESNI_HAVE_INTRINSICS
+#endif

 /* Choose the implementation of AESNI, if one is available.
  *
@@ -60,13 +64,11 @@
 #if defined(MBEDTLS_AESNI_HAVE_INTRINSICS)
 #define MBEDTLS_AESNI_HAVE_CODE 2 // via intrinsics
 #elif defined(MBEDTLS_HAVE_ASM) && \
-    defined(__GNUC__) && defined(MBEDTLS_ARCH_IS_X64)
+    (defined(__GNUC__) || defined(__clang__)) && defined(MBEDTLS_ARCH_IS_X64)
 /* Can we do AESNI with inline assembly?
  * (Only implemented with gas syntax, only for 64-bit.)
  */
 #define MBEDTLS_AESNI_HAVE_CODE 1 // via assembly
-#elif defined(__GNUC__)
-#   error "Must use `-mpclmul -msse2 -maes` for MBEDTLS_AESNI_C"
 #else
 #error "MBEDTLS_AESNI_C defined, but neither intrinsics nor assembly available"
 #endif
--
2.34.1