[PATCH] cpufreq: Simplify MSR read on the boot CPU

From: Chang S. Bae
Date: Wed Nov 06 2024 - 13:23:34 EST


Replace the 32-bit MSR access function with a 64-bit variant to simplify
the call site, eliminating unnecessary 32-bit value manipulations.

Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Cc: Rafael J. Wysocki <rafael@xxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
---
I've received feedback to use rdmsrl_on_cpu() instead of rdmsr_on_cpu()
for similar code in my feature-enabling series [1]. While auditing the
tree, I found this case as well, so here's another cleanup.

[1] https://lore.kernel.org/lkml/e9afefb7-3c4e-48ee-aab1-2f338c4e989d@xxxxxxxxx/
---
drivers/cpufreq/acpi-cpufreq.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 0f04feb6cafa..b942cd11e179 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -73,20 +73,17 @@ static unsigned int acpi_pstate_strict;

static bool boost_state(unsigned int cpu)
{
- u32 lo, hi;
u64 msr;

switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_INTEL:
case X86_VENDOR_CENTAUR:
case X86_VENDOR_ZHAOXIN:
- rdmsr_on_cpu(cpu, MSR_IA32_MISC_ENABLE, &lo, &hi);
- msr = lo | ((u64)hi << 32);
+ rdmsrl_on_cpu(cpu, MSR_IA32_MISC_ENABLE, &msr);
return !(msr & MSR_IA32_MISC_ENABLE_TURBO_DISABLE);
case X86_VENDOR_HYGON:
case X86_VENDOR_AMD:
- rdmsr_on_cpu(cpu, MSR_K7_HWCR, &lo, &hi);
- msr = lo | ((u64)hi << 32);
+ rdmsrl_on_cpu(cpu, MSR_K7_HWCR, &msr);
return !(msr & MSR_K7_HWCR_CPB_DIS);
}
return false;
--
2.34.1