X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=crc%2Fcrc32c-intel.c;h=8a6e6dcefb749b41ed5ecddb7035ae6a8c247adf;hb=dd366728eb503e6344215ae6ec153c7ab6eafd9b;hp=c0abe73ad7a85ac5bb794f3e50b6137b796391df;hpb=3845591fadea480177223e28c9d1c03642d34f0e;p=fio.git

diff --git a/crc/crc32c-intel.c b/crc/crc32c-intel.c
index c0abe73a..8a6e6dce 100644
--- a/crc/crc32c-intel.c
+++ b/crc/crc32c-intel.c
@@ -1,4 +1,11 @@
 #include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include "crc32c.h"
 
 /*
  * Based on a posting to lkml by Austin Zhang <austin.zhang@intel.com>
@@ -11,6 +18,10 @@
  * Volume 2A: Instruction Set Reference, A-M
  */
 
+int crc32c_intel_available = 0;
+
+#ifdef ARCH_HAVE_SSE4_2
+
 #if BITS_PER_LONG == 64
 #define REX_PRE "0x48, "
 #define SCALE_F 8
@@ -19,8 +30,10 @@
 #define SCALE_F 4
 #endif
 
-uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
-				 unsigned long length)
+static int crc32c_probed;
+
+static uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
+					unsigned long length)
 {
 	while (length--) {
 		__asm__ __volatile__(
@@ -64,3 +77,34 @@ uint32_t crc32c_intel(unsigned char const *data, unsigned long length)
 
 	return crc;
 }
+
+static void do_cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx,
+		     unsigned int *edx)
+{
+	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");
+}
+
+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;
+	}
+}
+
+#endif /* ARCH_HAVE_SSE */