This applies to 32 bit and 64 bit discover_x86_cpu_type()
implementations. In both cases %ebx was not being preserved as is
required by the ABI.
---
i386/i386/locore.S | 2 ++
x86_64/locore.S | 2 ++
2 files changed, 4 insertions(+)
diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index dc761991..9d2c702c 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -1234,7 +1234,9 @@ ENTRY(discover_x86_cpu_type)
/* We are a modern enough processor to have the CPUID instruction;
use it to find out what we are. */
0: movl $1,%eax /* Fetch CPU type info ... */
+ pushl %ebx /* Preserve to comply with ABI */
cpuid /* ... into eax */
+ popl %ebx
movl %ecx,cpu_features_ecx /* Keep a copy */
movl %edx,cpu_features_edx /* Keep a copy */
shrl $8,%eax /* Slide family bits down */
diff --git a/x86_64/locore.S b/x86_64/locore.S
index dd35d2f8..31a57688 100644
--- a/x86_64/locore.S
+++ b/x86_64/locore.S
@@ -1563,7 +1563,9 @@ ENTRY(discover_x86_cpu_type)
/* We are a modern enough processor to have the CPUID instruction;
use it to find out what we are. */
movl $1,%eax /* Fetch CPU type info ... */
+ pushq %rbx /* Preserve to comply with ABI */
cpuid /* ... into eax */
+ popq %rbx
movl %ecx,cpu_features_ecx /* Keep a copy */
movl %edx,cpu_features_edx /* Keep a copy */
shrl $8,%eax /* Slide family bits down */
--
2.47.3
