X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fcpuid%2Fcpuid.c;h=35e0b7ae8d779b8f371f4707d621db270146e304;hp=6133e13f03c420144348f8d08ea9901d643985f9;hb=9c0951e6f63564cf6c655680fd518c37e666bd78;hpb=659efe73b8aa2cf479a8e13f81752b47d1154afc

diff --git a/ccan/cpuid/cpuid.c b/ccan/cpuid/cpuid.c
index 6133e13f..35e0b7ae 100644
--- a/ccan/cpuid/cpuid.c
+++ b/ccan/cpuid/cpuid.c
@@ -90,45 +90,64 @@ static struct {
 	{ CEF_XOP, 		1 << 11, 	false }
 };
 
-static bool has_feature(int feature, uint32_t ecx, uint32_t edx)
-{
-	int i;
-
-	for (i = 0; i < sizeof(features) / sizeof(features[0]); ++i) {
-		if (features[i].feature == feature) {
-			if (features[i].use_edx)
-				return (edx & features[i].mask);
-			else
-				return (ecx & features[i].mask);
-		}
-	}
-
-	return false;
-}
-
 bool cpuid_is_supported(void)
 {
-	int ret = 0;
+	/* The following assembly code uses EAX as the return value,
+	 * but we store the value of EAX into ret since GCC uses EAX
+	 * as the return register for every C function.  That's a double
+	 * operation, but there's no other way to do this unless doing this
+	 * function entirely in assembly.
+	 *
+	 * The following assembly code has been shamelessly stolen from:
+	 * 	http://wiki.osdev.org/CPUID
+	 * and converted to work with AT&T syntax.
+	 *
+	 * This check is to make sure that the compiler is actually compiling
+	 * for 64-bit.
+	 *
+	 * The compiler can be 32-bit and the system 64-bit so the 
+	 * following would be true:
+	 * 	#if defined(__x86_64) ...
+	 */
+
+#if UINTPTR_MAX == 0xffffffffffffffff
+#define ASM_PUSHF 	"pushfq\n\t"
+#define ASM_POPF	"popfq\n\t"
+#define ASM_PUSHEAX 	"pushq %%rax\n\t"
+#define ASM_POPEAX 	"popq %%rax\n\t"
+#define ASM_PUSHECX 	"pushq %%rcx\n\t"
+#elif UINTPTR_MAX == 0xffffffff
+#define ASM_PUSHF 	"pushfl\n\t"
+#define ASM_POPF	"popfl\n\t"
+#define ASM_PUSHEAX 	"pushl %%eax\n\t"
+#define ASM_POPEAX 	"popl %%eax\n\t"
+#define ASM_PUSHECX 	"pushl %%ecx\n\t"
+#endif
 
+	int ret = 0;
 	asm volatile(
-		"pushfl\n\t"
-		"popl %%eax\n\t"
+		ASM_PUSHF
+		ASM_POPEAX
 		"movl %%eax, %%ecx\n\t"
 		"xorl $0x200000, %%eax\n\t"
-		"pushl %%eax\n\t"
-		"popfl\n\t"
-
-		"pushfl\n\t"
-		"popl %%eax\n\t"
+		ASM_PUSHEAX
+		ASM_POPF
+		ASM_PUSHF
+		ASM_POPEAX
 		"xorl %%ecx, %%eax\n\t"
 		"shrl $21, %%eax\n\t"
 		"andl $1, %%eax\n\t"
-		"pushl %%ecx\n\t"
-		"popfl\n\t"
-
+		ASM_PUSHECX
+		ASM_POPF
 		: "=a" (ret)
 	);
 
+#undef ASM_PUSHF
+#undef ASM_POPF
+#undef ASM_PUSHEAX
+#undef ASM_POPEAX
+#undef ASM_PUSHECX
+
 	return !!ret;
 }
 
@@ -142,14 +161,22 @@ bool cpuid_test_feature(cpuid_t feature)
 
 bool cpuid_has_feature(int feature, bool extended)
 {
-	uint32_t eax, ebx, ecx, edx;
+	uint32_t eax, ebx, ecx, edx, i;
 
 	if (!extended)
 		___cpuid(CPU_PROCINFO_AND_FEATUREBITS, &eax, &ebx, &ecx, &edx);
 	else
 		___cpuid(CPU_EXTENDED_PROC_INFO_FEATURE_BITS, &eax, &ebx, &ecx, &edx);
 
-	return has_feature(feature, ecx, edx);
+	for (i = 0; i < sizeof(features) / sizeof(features[0]); ++i) {
+		if (features[i].feature == feature) {
+			if (features[i].use_edx)
+				return (edx & features[i].mask);
+			else
+				return (ecx & features[i].mask);
+		}
+	}
+	return false;
 }
 
 static const char *const cpuids[] = {
@@ -182,8 +209,6 @@ cputype_t cpuid_get_cpu_type(void)
 		uint32_t i;
 
 		___cpuid(CPU_VENDORID, &i, &u.bufu32[0], &u.bufu32[2], &u.bufu32[1]);
-		u.buf[12] = '\0';
-
 		for (i = 0; i < sizeof(cpuids) / sizeof(cpuids[0]); ++i) {
 			if (strncmp(cpuids[i], u.buf, 12) == 0) {
 				cputype = (cputype_t)i;
@@ -225,9 +250,16 @@ void cpuid(cpuid_t info, uint32_t *buf)
 		return;
 
 	if (info == CPU_PROC_BRAND_STRING) {
-		___cpuid(CPU_PROC_BRAND_STRING,  	  &buf[0], &buf[1], &buf[2],  &buf[3]);
-		___cpuid(CPU_PROC_BRAND_STRING_INTERNAL0, &buf[4], &buf[5], &buf[6],  &buf[7]);
-		___cpuid(CPU_PROC_BRAND_STRING_INTERNAL1, &buf[8], &buf[9], &buf[10], &buf[11]);
+		static char cached[48] = { 0 };
+		if (cached[0] == '\0') {
+			___cpuid(CPU_PROC_BRAND_STRING,		  &buf[0], &buf[1], &buf[2],  &buf[3]);
+			___cpuid(CPU_PROC_BRAND_STRING_INTERNAL0, &buf[4], &buf[5], &buf[6],  &buf[7]);
+			___cpuid(CPU_PROC_BRAND_STRING_INTERNAL1, &buf[8], &buf[9], &buf[10], &buf[11]);
+
+			memcpy(cached, buf, sizeof cached);
+		} else
+			buf = (uint32_t *)cached;
+
 		return;
 	} else if (info == CPU_HIGHEST_EXTENDED_FUNCTION_SUPPORTED) {
 		*buf = cpuid_highest_ext_func_supported();
@@ -281,4 +313,3 @@ void cpuid(cpuid_t info, uint32_t *buf)
 }
 
 #endif
-