[M] Change in coreboot[master]: arch/x86/include/arch: fix assembly clobber for 64bit

[Martin L Roth (Code Review)]

Martin L Roth has submitted this change. ( https://review.coreboot.org/c/coreboot/+/66345 )

Change subject: arch/x86/include/arch: fix assembly clobber for 64bit
......................................................................

arch/x86/include/arch: fix assembly clobber for 64bit

the "x86 PIC code ebx" workaround done previously
by commit 689e31d18b0f ("Make cpuid functions usable
when compiled with PIC") does not work for x86_64
(the upper dword of rbx is set to 0)

the GCC bug that needed the workaround was fixed
in version 5 (see GCC bug 54232)

Change-Id: Iff1dd72c7423a3b385a000457bcd065cf7ed6b95
Signed-off-by: Matei Dibu 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66345
Reviewed-by: Angel Pons 
Tested-by: build bot (Jenkins) 
Reviewed-by: Elyes Haouas 
---
M src/arch/x86/include/arch/cpuid.h
1 file changed, 50 insertions(+), 44 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Elyes Haouas: Looks good to me, approved
  Angel Pons: Looks good to me, but someone else must approve

diff --git a/src/arch/x86/include/arch/cpuid.h b/src/arch/x86/include/arch/cpuid.h
index 27848a8..70a5beb 100644
--- a/src/arch/x86/include/arch/cpuid.h
+++ b/src/arch/x86/include/arch/cpuid.h
@@ -15,96 +15,80 @@
 /*
  * Generic CPUID function
  */
-static inline struct cpuid_result cpuid(int op)
+static inline struct cpuid_result cpuid(const uint32_t eax)
 {
    struct cpuid_result result;
    asm volatile(
-		"mov %%ebx, %%edi;"
    	"cpuid;"
-		"mov %%ebx, %%esi;"
-		"mov %%edi, %%ebx;"
    	: "=a" (result.eax),
-		  "=S" (result.ebx),
+		  "=b" (result.ebx),
    	  "=c" (result.ecx),
    	  "=d" (result.edx)
-		: "0" (op)
-		: "edi");
+		: "a" (eax));
    return result;
 }

/*
  * Generic Extended CPUID function
  */
-static inline struct cpuid_result cpuid_ext(int op, unsigned int ecx)
+static inline struct cpuid_result cpuid_ext(const uint32_t eax, const uint32_t ecx)
 {
    struct cpuid_result result;
    asm volatile(
-		"mov %%ebx, %%edi;"
    	"cpuid;"
-		"mov %%ebx, %%esi;"
-		"mov %%edi, %%ebx;"
    	: "=a" (result.eax),
-		  "=S" (result.ebx),
+		  "=b" (result.ebx),
    	  "=c" (result.ecx),
    	  "=d" (result.edx)
-		: "0" (op), "2" (ecx)
-		: "edi");
+		: "a" (eax), "c" (ecx));
    return result;
 }

/*
  * CPUID functions returning a single datum
  */
-static inline unsigned int cpuid_eax(unsigned int op)
+static inline uint32_t cpuid_eax(uint32_t eax)
 {
-	unsigned int eax;
-
-	__asm__("mov %%ebx, %%edi;"
+	asm volatile(
    	"cpuid;"
-		"mov %%edi, %%ebx;"
-		: "=a" (eax)
-		: "0" (op)
-		: "ecx", "edx", "edi");
+		: "+a" (eax)
+		:: "ebx", "ecx", "edx");
    return eax;
 }

-static inline unsigned int cpuid_ebx(unsigned int op)
+static inline uint32_t cpuid_ebx(const uint32_t eax)
 {
-	unsigned int eax, ebx;
+	uint32_t ebx;

-	__asm__("mov %%ebx, %%edi;"
+	asm volatile(
    	"cpuid;"
-		"mov %%ebx, %%esi;"
-		"mov %%edi, %%ebx;"
-		: "=a" (eax), "=S" (ebx)
-		: "0" (op)
-		: "ecx", "edx", "edi");
+		: "=b" (ebx)
+		: "a" (eax)
+		: "ecx", "edx");
    return ebx;
 }

-static inline unsigned int cpuid_ecx(unsigned int op)
+static inline uint32_t cpuid_ecx(const uint32_t eax)
 {
-	unsigned int eax, ecx;
+	uint32_t ecx;

-	__asm__("mov %%ebx, %%edi;"
+	asm volatile(
    	"cpuid;"
-		"mov %%edi, %%ebx;"
-		: "=a" (eax), "=c" (ecx)
-		: "0" (op)
-		: "edx", "edi");
+		: "=c" (ecx)
+		: "a" (eax)
+		: "ebx", "edx");
    return ecx;
 }

-static inline unsigned int cpuid_edx(unsigned int op)
+static inline uint32_t cpuid_edx(const uint32_t eax)
 {
-	unsigned int eax, edx;
+	uint32_t edx;

-	__asm__("mov %%ebx, %%edi;"
+	asm volatile(
    	"cpuid;"
-		"mov %%edi, %%ebx;"
-		: "=a" (eax), "=d" (edx)
-		: "0" (op)
-		: "ecx", "edi");
+		: "=d" (edx)
+		: "a" (eax)
+		: "ebx", "ecx");
    return edx;
 }