The existing functions work but the register clobbers are wrong, so
strange bugs results.
The original functions were taken from a very old version of Linux.
Update them from Linux 6.13
Signed-off-by: Simon Glass <s...@chromium.org>
---
(no changes since v3)
Changes in v3:
- Add new patch to update cpuid_eax et al to work on amd64
arch/x86/include/asm/cpu.h | 75 +++++++++++++-------------------------
1 file changed, 25 insertions(+), 50 deletions(-)
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 1f1b545ea50..5d24c17f8a3 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -109,61 +109,36 @@ static inline struct cpuid_result cpuid_ext(int op,
unsigned ecx)
return result;
}
-/*
- * CPUID functions returning a single datum
- */
-static inline unsigned int cpuid_eax(unsigned int op)
+static inline void native_cpuid(unsigned int *eax, unsigned int *ebx,
+ unsigned int *ecx, unsigned int *edx)
{
- unsigned int eax;
-
- __asm__("mov %%ebx, %%edi;"
- "cpuid;"
- "mov %%edi, %%ebx;"
- : "=a" (eax)
- : "0" (op)
- : "ecx", "edx", "edi");
- return eax;
+ /* ecx is often an input as well as an output. */
+ asm volatile("cpuid"
+ : "=a" (*eax),
+ "=b" (*ebx),
+ "=c" (*ecx),
+ "=d" (*edx)
+ : "0" (*eax), "2" (*ecx)
+ : "memory");
}
-static inline unsigned int cpuid_ebx(unsigned int op)
-{
- unsigned int eax, ebx;
-
- __asm__("mov %%ebx, %%edi;"
- "cpuid;"
- "mov %%ebx, %%esi;"
- "mov %%edi, %%ebx;"
- : "=a" (eax), "=S" (ebx)
- : "0" (op)
- : "ecx", "edx", "edi");
- return ebx;
+#define native_cpuid_reg(reg) \
+static inline unsigned int cpuid_##reg(unsigned int op) \
+{ \
+ unsigned int eax = op, ebx, ecx = 0, edx; \
+ \
+ native_cpuid(&eax, &ebx, &ecx, &edx); \
+ \
+ return reg; \
}
-static inline unsigned int cpuid_ecx(unsigned int op)
-{
- unsigned int eax, ecx;
-
- __asm__("mov %%ebx, %%edi;"
- "cpuid;"
- "mov %%edi, %%ebx;"
- : "=a" (eax), "=c" (ecx)
- : "0" (op)
- : "edx", "edi");
- return ecx;
-}
-
-static inline unsigned int cpuid_edx(unsigned int op)
-{
- unsigned int eax, edx;
-
- __asm__("mov %%ebx, %%edi;"
- "cpuid;"
- "mov %%edi, %%ebx;"
- : "=a" (eax), "=d" (edx)
- : "0" (op)
- : "ecx", "edi");
- return edx;
-}
+/*
+ * Native CPUID functions returning a single datum.
+ */
+native_cpuid_reg(eax)
+native_cpuid_reg(ebx)
+native_cpuid_reg(ecx)
+native_cpuid_reg(edx)
#if CONFIG_IS_ENABLED(X86_64)
static inline int flag_is_changeable_p(u32 flag)
--
2.43.0
