[PATCH] x86/process: Convert rdmsr() to rdmsrq() in arch_post_acpi_subsys_init()
From: HyeongJun An
Date: Thu Jun 04 2026 - 11:10:38 EST
arch_post_acpi_subsys_init() reads MSR_K8_INT_PENDING_MSG with rdmsr()
into a lo/hi pair but only uses the low 32 bits: K8_INTP_C1E_ACTIVE_MASK
(0x18000000) lies entirely within them. The 'hi' half is never consumed,
which triggers a -Wunused-but-set-variable warning under W=1:
arch/x86/kernel/process.c: In function 'arch_post_acpi_subsys_init':
arch/x86/kernel/process.c:972:17: warning: variable 'hi' set but not used
Read the full MSR into a single u64 with rdmsrq() and test the mask
against it, dropping the now-unnecessary lo/hi variables.
No functional change intended.
Signed-off-by: HyeongJun An <sammiee5311@xxxxxxxxx>
---
arch/x86/kernel/process.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 4c718f8adc59..a554f19c9973 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -969,7 +969,7 @@ void amd_e400_c1e_apic_setup(void)
void __init arch_post_acpi_subsys_init(void)
{
- u32 lo, hi;
+ u64 val;
if (!boot_cpu_has_bug(X86_BUG_AMD_E400))
return;
@@ -979,8 +979,8 @@ void __init arch_post_acpi_subsys_init(void)
* the machine is affected K8_INTP_C1E_ACTIVE_MASK bits are set in
* MSR_K8_INT_PENDING_MSG.
*/
- rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
- if (!(lo & K8_INTP_C1E_ACTIVE_MASK))
+ rdmsrq(MSR_K8_INT_PENDING_MSG, val);
+ if (!(val & K8_INTP_C1E_ACTIVE_MASK))
return;
boot_cpu_set_bug(X86_BUG_AMD_APIC_C1E);
--
2.43.0