New patch to review for coreboot: 3b05660 Make cpuid functions usable when compiled with PIC

[Stefan Reinauer]

Stefan Reinauer ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/764

-gerrit

commit 3b0566044cdf94f37e3227b4423dd4d84735d064
Author: Duncan Laurie 
Date:   Mon Jan 9 22:00:30 2012 -0800

Make cpuid functions usable when compiled with PIC

This avoids using EBX and instead uses EDI where possible,
    and ESI when necessary to get the EBX value out.

This allows me to enable -fpic for SMM TSEG code.

Change-Id: I10dbded3f3ad98a39ba7b53da59af6ca3145e2e5
    Signed-off-by: Duncan Laurie 
---
 src/arch/x86/include/arch/cpu.h |   57 ++++++++++++++++++++++++++++++--------
 1 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/src/arch/x86/include/arch/cpu.h b/src/arch/x86/include/arch/cpu.h
index 85357d7..508b7d6 100644
--- a/src/arch/x86/include/arch/cpu.h
+++ b/src/arch/x86/include/arch/cpu.h
@@ -36,12 +36,36 @@ static inline struct cpuid_result cpuid(int op)
 {
    struct cpuid_result result;
    asm volatile(
-		"cpuid"
+		"mov %%ebx, %%edi;"
+		"cpuid;"
+		"mov %%ebx, %%esi;"
+		"mov %%edi, %%ebx;"
    	: "=a" (result.eax),
-		  "=b" (result.ebx),
+		  "=S" (result.ebx),
    	  "=c" (result.ecx),
    	  "=d" (result.edx)
-		: "0" (op));
+		: "0" (op)
+		: "edi");
+	return result;
+}
+
+/*
+ * Generic Extended CPUID function
+ */
+static inline struct cpuid_result cpuid_ext(int op, unsigned ecx)
+{
+	struct cpuid_result result;
+	asm volatile(
+		"mov %%ebx, %%edi;"
+		"cpuid;"
+		"mov %%ebx, %%esi;"
+		"mov %%edi, %%ebx;"
+		: "=a" (result.eax),
+		  "=S" (result.ebx),
+		  "=c" (result.ecx),
+		  "=d" (result.edx)
+		: "0" (op), "2" (ecx)
+		: "edi");
    return result;
 }

@@ -52,10 +76,12 @@ static inline unsigned int cpuid_eax(unsigned int op)
 {
    unsigned int eax;

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

@@ -63,10 +89,13 @@ static inline unsigned int cpuid_ebx(unsigned int op)
 {
    unsigned int eax, ebx;

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

@@ -74,10 +103,12 @@ static inline unsigned int cpuid_ecx(unsigned int op)
 {
    unsigned int eax, ecx;

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

@@ -85,10 +116,12 @@ static inline unsigned int cpuid_edx(unsigned int op)
 {
    unsigned int eax, edx;

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