[PATCH 12/32] x86/amd: Stop using 32-bit MSR interfaces
From: Juergen Gross
Date: Mon Jun 29 2026 - 02:10:41 EST
The 32-bit MSR interfaces rdmsr(), wrmsr() and rdmsr_safe() are
planned to be removed. Use the related 64-bit variants instead.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
arch/x86/kernel/cpu/amd.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 487ac147e11f..169e373418bb 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -113,7 +113,7 @@ static void init_amd_k5(struct cpuinfo_x86 *c)
static void init_amd_k6(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
- u32 l, h;
+ struct msr val;
int mbytes = get_num_physpages() >> (20-PAGE_SHIFT);
if (c->x86_model < 6) {
@@ -160,13 +160,13 @@ static void init_amd_k6(struct cpuinfo_x86 *c)
if (mbytes > 508)
mbytes = 508;
- rdmsr(MSR_K6_WHCR, l, h);
- if ((l&0x0000FFFF) == 0) {
+ rdmsrq(MSR_K6_WHCR, val.q);
+ if ((val.l & 0x0000FFFF) == 0) {
unsigned long flags;
- l = (1<<0)|((mbytes/4)<<1);
+ val.l = (1 << 0) | ((mbytes / 4) << 1);
local_irq_save(flags);
wbinvd();
- wrmsr(MSR_K6_WHCR, l, h);
+ wrmsrq(MSR_K6_WHCR, val.q);
local_irq_restore(flags);
pr_info("Enabling old style K6 write allocation for %d Mb\n",
mbytes);
@@ -181,13 +181,13 @@ static void init_amd_k6(struct cpuinfo_x86 *c)
if (mbytes > 4092)
mbytes = 4092;
- rdmsr(MSR_K6_WHCR, l, h);
- if ((l&0xFFFF0000) == 0) {
+ rdmsrq(MSR_K6_WHCR, val.q);
+ if ((val.l & 0xFFFF0000) == 0) {
unsigned long flags;
- l = ((mbytes>>2)<<22)|(1<<16);
+ val.l = ((mbytes >> 2) << 22) | (1 << 16);
local_irq_save(flags);
wbinvd();
- wrmsr(MSR_K6_WHCR, l, h);
+ wrmsrq(MSR_K6_WHCR, val.q);
local_irq_restore(flags);
pr_info("Enabling new style K6 write allocation for %d Mb\n",
mbytes);
@@ -207,7 +207,7 @@ static void init_amd_k6(struct cpuinfo_x86 *c)
static void init_amd_k7(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
- u32 l, h;
+ struct msr val;
/*
* Bit 15 of Athlon specific MSR 15, needs to be 0
@@ -228,11 +228,12 @@ static void init_amd_k7(struct cpuinfo_x86 *c)
* As per AMD technical note 27212 0.2
*/
if ((c->x86_model == 8 && c->x86_stepping >= 1) || (c->x86_model > 8)) {
- rdmsr(MSR_K7_CLK_CTL, l, h);
- if ((l & 0xfff00000) != 0x20000000) {
+ rdmsrq(MSR_K7_CLK_CTL, val.q);
+ if ((val.l & 0xfff00000) != 0x20000000) {
pr_info("CPU: CLK_CTL MSR was %x. Reprogramming to %x\n",
- l, ((l & 0x000fffff)|0x20000000));
- wrmsr(MSR_K7_CLK_CTL, (l & 0x000fffff)|0x20000000, h);
+ val.l, ((val.l & 0x000fffff) | 0x20000000));
+ val.l = (val.l & 0x000fffff) | 0x20000000;
+ wrmsrq(MSR_K7_CLK_CTL, val.q);
}
}
@@ -614,12 +615,13 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c)
static void early_init_amd(struct cpuinfo_x86 *c)
{
- u32 dummy;
+ u64 val;
if (c->x86 >= 0xf)
set_cpu_cap(c, X86_FEATURE_K8);
- rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);
+ rdmsrq_safe(MSR_AMD64_PATCH_LEVEL, &val);
+ c->microcode = (u32)val;
/*
* c->x86_power is 8000_0007 edx. Bit 8 is TSC runs at constant rate
--
2.54.0