[Xen-devel] [patch 5/8] Roll all the cpuid asm into one __cpuid call.

[Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>]

It's a little neater, and also means only one place to patch for
paravirtualization.

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>

---
 include/asm-i386/processor.h |   74 +++++++++++++++++++-----------------------
 1 file changed, 34 insertions(+), 40 deletions(-)


===================================================================
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -143,31 +143,37 @@ static inline void detect_ht(struct cpui
 #define X86_EFLAGS_VIP 0x00100000 /* Virtual Interrupt Pending */
 #define X86_EFLAGS_ID  0x00200000 /* CPUID detection flag */
 
-/*
- * Generic CPUID function
- * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx
- * resulting in stale register contents being returned.
- */
-static inline void cpuid(unsigned int op, unsigned int *eax, unsigned int 
*ebx, unsigned int *ecx, unsigned int *edx)
-{
+static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
+                          unsigned int *ecx, unsigned int *edx)
+{
+       /* ecx is often an input as well as an output. */
        __asm__("cpuid"
                : "=a" (*eax),
                  "=b" (*ebx),
                  "=c" (*ecx),
                  "=d" (*edx)
-               : "0" (op), "c"(0));
+               : "0" (*eax), "2" (*ecx));
+}
+
+/*
+ * Generic CPUID function
+ * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx
+ * resulting in stale register contents being returned.
+ */
+static inline void cpuid(unsigned int op, unsigned int *eax, unsigned int 
*ebx, unsigned int *ecx, unsigned int *edx)
+{
+       *eax = op;
+       *ecx = 0;
+       __cpuid(eax, ebx, ecx, edx);
 }
 
 /* Some CPUID calls want 'count' to be placed in ecx */
 static inline void cpuid_count(int op, int count, int *eax, int *ebx, int *ecx,
-               int *edx)
-{
-       __asm__("cpuid"
-               : "=a" (*eax),
-                 "=b" (*ebx),
-                 "=c" (*ecx),
-                 "=d" (*edx)
-               : "0" (op), "c" (count));
+                              int *edx)
+{
+       *eax = op;
+       *ecx = count;
+       __cpuid(eax, ebx, ecx, edx);
 }
 
 /*
@@ -175,42 +181,30 @@ static inline void cpuid_count(int op, i
  */
 static inline unsigned int cpuid_eax(unsigned int op)
 {
-       unsigned int eax;
-
-       __asm__("cpuid"
-               : "=a" (eax)
-               : "0" (op)
-               : "bx", "cx", "dx");
+       unsigned int eax, ebx, ecx, edx;
+
+       cpuid(op, &eax, &ebx, &ecx, &edx);
        return eax;
 }
 static inline unsigned int cpuid_ebx(unsigned int op)
 {
-       unsigned int eax, ebx;
-
-       __asm__("cpuid"
-               : "=a" (eax), "=b" (ebx)
-               : "0" (op)
-               : "cx", "dx" );
+       unsigned int eax, ebx, ecx, edx;
+
+       cpuid(op, &eax, &ebx, &ecx, &edx);
        return ebx;
 }
 static inline unsigned int cpuid_ecx(unsigned int op)
 {
-       unsigned int eax, ecx;
-
-       __asm__("cpuid"
-               : "=a" (eax), "=c" (ecx)
-               : "0" (op)
-               : "bx", "dx" );
+       unsigned int eax, ebx, ecx, edx;
+
+       cpuid(op, &eax, &ebx, &ecx, &edx);
        return ecx;
 }
 static inline unsigned int cpuid_edx(unsigned int op)
 {
-       unsigned int eax, edx;
-
-       __asm__("cpuid"
-               : "=a" (eax), "=d" (edx)
-               : "0" (op)
-               : "bx", "cx");
+       unsigned int eax, ebx, ecx, edx;
+
+       cpuid(op, &eax, &ebx, &ecx, &edx);
        return edx;
 }
 

--


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