From 8a60fde969ce30d14afd12aededf2f00ebc5d82d Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Thu, 16 Feb 2023 04:36:20 +0100
Subject: [PATCH] btrfs-progs: crypto: use common CPU feature detection for
 crc32c

The crc32c selection has been already using the pointer-based approach
so drop the cpuid detection and use our common code for that.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 crypto/crc32c.c | 45 +++++++++------------------------------------
 crypto/crc32c.h |  2 +-
 crypto/hash.c   |  7 ++++++-
 crypto/hash.h   |  1 +
 4 files changed, 17 insertions(+), 38 deletions(-)

diff --git a/crypto/crc32c.c b/crypto/crc32c.c
index 3afa2ad6..dc948e08 100644
--- a/crypto/crc32c.c
+++ b/crypto/crc32c.c
@@ -10,6 +10,7 @@
 
 #include <inttypes.h>
 #include "crypto/crc32c.h"
+#include "common/cpu-utils.h"
 
 uint32_t __crc32c_le(uint32_t crc, unsigned char const *data, uint32_t length);
 static uint32_t (*crc_function)(uint32_t crc, unsigned char const *data, uint32_t length) = __crc32c_le;
@@ -34,9 +35,6 @@ static uint32_t (*crc_function)(uint32_t crc, unsigned char const *data, uint32_
 #define SCALE_F 4
 #endif
 
-static int crc32c_probed = 0;
-static int crc32c_intel_available = 0;
-
 static uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
 					uint32_t length)
 {
@@ -78,45 +76,20 @@ static uint32_t crc32c_intel(uint32_t crc, unsigned char const *data, uint32_t l
 	return crc;
 }
 
-static void do_cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx,
-		     unsigned int *edx)
+void crc32c_init_accel(void)
 {
-	int id = *eax;
-
-	asm("movl %4, %%eax;"
-	    "cpuid;"
-	    "movl %%eax, %0;"
-	    "movl %%ebx, %1;"
-	    "movl %%ecx, %2;"
-	    "movl %%edx, %3;"
-		: "=r" (*eax), "=r" (*ebx), "=r" (*ecx), "=r" (*edx)
-		: "r" (id)
-		: "eax", "ebx", "ecx", "edx");
-}
-
-static void crc32c_intel_probe(void)
-{
-	if (!crc32c_probed) {
-		unsigned int eax, ebx, ecx, edx;
-
-		eax = 1;
-
-		do_cpuid(&eax, &ebx, &ecx, &edx);
-		crc32c_intel_available = (ecx & (1 << 20)) != 0;
-		crc32c_probed = 1;
-	}
-}
-
-void crc32c_optimization_init(void)
-{
-	crc32c_intel_probe();
-	if (crc32c_intel_available)
+	/* CRC32 is in SSE4.2 */
+	if (cpu_has_feature(CPU_FLAG_SSE42))
 		crc_function = crc32c_intel;
+	else
+		crc_function = __crc32c_le;
 }
+
 #else
 
-void crc32c_optimization_init(void)
+void crc32c_init_accel(void)
 {
+	crc_function = __crc32c_le;
 }
 
 #endif /* __x86_64__ */
diff --git a/crypto/crc32c.h b/crypto/crc32c.h
index 261624ea..f9901771 100644
--- a/crypto/crc32c.h
+++ b/crypto/crc32c.h
@@ -22,7 +22,7 @@
 #include <inttypes.h>
 
 uint32_t crc32c_le(uint32_t seed, unsigned char const *data, uint32_t length);
-void crc32c_optimization_init(void);
+void crc32c_init_accel(void);
 
 #define crc32c(seed, data, length) crc32c_le(seed, (unsigned char const *)data, length)
 
diff --git a/crypto/hash.c b/crypto/hash.c
index ee47a7d1..e8ca18c9 100644
--- a/crypto/hash.c
+++ b/crypto/hash.c
@@ -22,11 +22,16 @@
 
 void hash_init_accel(void)
 {
-	crc32c_optimization_init();
+	crc32c_init_accel();
 	blake2_init_accel();
 	sha256_init_accel();
 }
 
+void hash_init_crc32c(void)
+{
+	crc32c_init_accel();
+}
+
 void hash_init_blake2(void)
 {
 	blake2_init_accel();
diff --git a/crypto/hash.h b/crypto/hash.h
index 7aafc3df..b3aab2c8 100644
--- a/crypto/hash.h
+++ b/crypto/hash.h
@@ -27,6 +27,7 @@ int hash_sha256(const u8 *buf, size_t length, u8 *out);
 int hash_blake2b(const u8 *buf, size_t length, u8 *out);
 
 void hash_init_accel(void);
+void hash_init_crc32c(void);
 void hash_init_blake2(void);
 void hash_init_sha256(void);