From f51a5c9235bbf9a8c3670278a6d8bbf2147e43b8 Mon Sep 17 00:00:00 2001
From: "Pavel I. Kryukov" <kryukov@frtk.ru>
Date: Mon, 19 Feb 2018 00:06:14 +0300
Subject: [PATCH] Add supports_sha_ni(void) function

It executes CPUID instruction to check whether
SHA extensions are supported by hosting CPU.
---
 ssh.h    |  2 ++
 sshsha.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/ssh.h b/ssh.h
index 2f946e83..013f4eb2 100644
--- a/ssh.h
+++ b/ssh.h
@@ -258,6 +258,8 @@ void hmacmd5_key(void *handle, void const *key, int len);
 void hmacmd5_do_hmac(void *handle, unsigned char const *blk, int len,
 		     unsigned char *hmac);
 
+int supports_sha_ni(void);
+
 typedef struct SHA_State {
     uint32 h[5];
     unsigned char block[64];
diff --git a/sshsha.c b/sshsha.c
index 711b08a6..5c0f69b4 100644
--- a/sshsha.c
+++ b/sshsha.c
@@ -461,3 +461,52 @@ const struct ssh_mac ssh_hmac_sha1_96_buggy = {
     12, 16,
     "bug-compatible HMAC-SHA1-96"
 };
+
+#ifdef COMPILER_SUPPORTS_SHA_NI
+
+/*
+ * Set target architecture for Clang and GCC
+ */
+#if !defined(__clang__) && defined(__GNUC__)
+#    pragma GCC target("sha")
+#    pragma GCC target("sse4.1")
+#endif
+
+#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 5))
+#    define FUNC_ISA __attribute__ ((target("sse4.1,sha")))
+#else
+#    define FUNC_ISA
+#endif
+
+/*
+ * Determinators of CPU type
+ */
+#if defined(__clang__) || defined(__GNUC__)
+
+#include <cpuid.h>
+int supports_sha_ni(void)
+{
+    unsigned int CPUInfo[4];
+    __cpuid_count(7, 0, CPUInfo[0], CPUInfo[1], CPUInfo[2], CPUInfo[3]);
+    return CPUInfo[1] & (1 << 29); /* SHA */
+}
+
+#else /* defined(__clang__) || defined(__GNUC__) */
+
+int supports_sha_ni(void)
+{
+    unsigned int CPUInfo[4];
+    __cpuidex(CPUInfo, 7, 0);
+    return CPUInfo[1] & (1 << 29); /* Check SHA */
+}
+
+#endif /* defined(__clang__) || defined(__GNUC__) */
+
+#else /* COMPILER_SUPPORTS_AES_NI */
+
+int supports_sha_ni(void)
+{
+    return 0;
+}
+
+#endif  /* COMPILER_SUPPORTS_AES_NI */