On Wed, Apr 21, 2021 at 09:42:15PM +0800, Fontenot, Nathan wrote:
On 4/20/2021 9:38 PM, Huang Rui wrote:
Some AMD Ryzen generations has different calculation method on maximum perf. 255 is not for all asics, some specific generations should use 166 as the maximum perf. Otherwise, it will report incorrect frequency value like below:
~ → lscpu | grep MHz CPU MHz: 3400.000 CPU max MHz: 7228.3198 CPU min MHz: 2200.0000
Fixes: 41ea667227ba ("x86, sched: Calculate frequency invariance for AMD systems") Fixes: 3c55e94c0ade ("cpufreq: ACPI: Extend frequency tables to cover boost frequencies")
Reported-by: Jason Bagavatsingham jason.bagavatsingham@gmail.com Tested-by: Jason Bagavatsingham jason.bagavatsingham@gmail.com Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211791 Signed-off-by: Huang Rui ray.huang@amd.com Cc: Alex Deucher alexander.deucher@amd.com Cc: Nathan Fontenot nathan.fontenot@amd.com Cc: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc: Borislav Petkov bp@suse.de Cc: x86@kernel.org Cc: stable@vger.kernel.org
Changes from V1 -> V2:
- Enhance the commit message.
- Move amd_get_highest_perf() into amd.c.
- Refine the implementation of switch-case.
- Cc stable mail list.
arch/x86/include/asm/processor.h | 2 ++ arch/x86/kernel/cpu/amd.c | 22 ++++++++++++++++++++++ arch/x86/kernel/smpboot.c | 2 +- drivers/cpufreq/acpi-cpufreq.c | 19 +++++++++++++++++++ 4 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index f1b9ed5efaa9..908bcaea1361 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -804,8 +804,10 @@ DECLARE_PER_CPU(u64, msr_misc_features_shadow); #ifdef CONFIG_CPU_SUP_AMD extern u32 amd_get_nodes_per_socket(void); +extern u32 amd_get_highest_perf(void); #else static inline u32 amd_get_nodes_per_socket(void) { return 0; } +static inline u32 amd_get_highest_perf(void) { return 0; } #endif static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 347a956f71ca..aadb691d9357 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1170,3 +1170,25 @@ void set_dr_addr_mask(unsigned long mask, int dr) break; } }
+u32 amd_get_highest_perf(void) +{
- struct cpuinfo_x86 *c = &boot_cpu_data;
- u32 cppc_max_perf = 225;
- switch (c->x86) {
- case 0x17:
if ((c->x86_model >= 0x30 && c->x86_model < 0x40) ||(c->x86_model >= 0x70 && c->x86_model < 0x80))cppc_max_perf = 166;break;- case 0x19:
if ((c->x86_model >= 0x20 && c->x86_model < 0x30) ||(c->x86_model >= 0x40 && c->x86_model < 0x70))cppc_max_perf = 166;break;- }
- return cppc_max_perf;
+} +EXPORT_SYMBOL_GPL(amd_get_highest_perf);
Should this be an update to cpp_get_perf_caps()?
This approach would ensure that all callers have the correct value and remove the need to fix up individual callers to use this new routine to get the correct value.
It's a good idea to modify cppc_get_perf_caps() to correct the right highest perf. I would like to keep amd_get_highest_perf() function in amd.c as well because it can be called in other spaces without querying an ACPI register in case only wants to get highest perf value.
---
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 69057fcd2c04..58e72b6e222f 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1107,8 +1107,12 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps) } }
- cpc_read(cpunum, highest_reg, &high); - perf_caps->highest_perf = high; + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { + perf_caps->highest_perf = amd_get_highest_perf(); + } else { + cpc_read(cpunum, highest_reg, &high); + perf_caps->highest_perf = high; + }
cpc_read(cpunum, lowest_reg, &low); perf_caps->lowest_perf = low;
---
Thanks, Ray