diff options
| author | Janakarajan Natarajan <Janakarajan.Natarajan@amd.com> | 2019-11-05 20:16:55 +0300 |
|---|---|---|
| committer | Shuah Khan <skhan@linuxfoundation.org> | 2019-11-06 03:22:56 +0300 |
| commit | 6af2ed53f0402c09b36d2b38698e18a25ca732a7 (patch) | |
| tree | ea83341eecb9c5b048929e9aa75abf140ae48a3c /tools/power/cpupower | |
| parent | 7adafe541fe5e015261a92d39db8b163db477337 (diff) | |
| download | linux-6af2ed53f0402c09b36d2b38698e18a25ca732a7.tar.xz | |
cpupower: mperf_monitor: Update cpupower to use the RDPRU instruction
AMD Zen 2 introduces the RDPRU instruction which can be used to access some
processor registers which are typically only accessible in privilege level
0. ECX specifies the register to read and EDX:EAX will contain the value read.
ECX: 0 - Register MPERF
1 - Register APERF
This has the added advantage of not having to use the msr module, since the
userspace to kernel transitions which occur during each read_msr() might
cause APERF and MPERF to go out of sync.
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Diffstat (limited to 'tools/power/cpupower')
| -rw-r--r-- | tools/power/cpupower/utils/helpers/cpuid.c | 4 | ||||
| -rw-r--r-- | tools/power/cpupower/utils/helpers/helpers.h | 1 | ||||
| -rw-r--r-- | tools/power/cpupower/utils/idle_monitor/mperf_monitor.c | 20 |
3 files changed, 25 insertions, 0 deletions
diff --git a/tools/power/cpupower/utils/helpers/cpuid.c b/tools/power/cpupower/utils/helpers/cpuid.c index 5cc39d4e23ed..73bfafc60e9b 100644 --- a/tools/power/cpupower/utils/helpers/cpuid.c +++ b/tools/power/cpupower/utils/helpers/cpuid.c @@ -131,6 +131,10 @@ out: if (ext_cpuid_level >= 0x80000007 && (cpuid_edx(0x80000007) & (1 << 9))) cpu_info->caps |= CPUPOWER_CAP_AMD_CBP; + + if (ext_cpuid_level >= 0x80000008 && + cpuid_ebx(0x80000008) & (1 << 4)) + cpu_info->caps |= CPUPOWER_CAP_AMD_RDPRU; } if (cpu_info->vendor == X86_VENDOR_INTEL) { diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h index 357b19bb136e..c258eeccd05f 100644 --- a/tools/power/cpupower/utils/helpers/helpers.h +++ b/tools/power/cpupower/utils/helpers/helpers.h @@ -69,6 +69,7 @@ enum cpupower_cpu_vendor {X86_VENDOR_UNKNOWN = 0, X86_VENDOR_INTEL, #define CPUPOWER_CAP_HAS_TURBO_RATIO 0x00000010 #define CPUPOWER_CAP_IS_SNB 0x00000020 #define CPUPOWER_CAP_INTEL_IDA 0x00000040 +#define CPUPOWER_CAP_AMD_RDPRU 0x00000080 #define CPUPOWER_AMD_CPBDIS 0x02000000 diff --git a/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c index afb2e6f8edd3..e7d48cb563c0 100644 --- a/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c +++ b/tools/power/cpupower/utils/idle_monitor/mperf_monitor.c @@ -19,6 +19,10 @@ #define MSR_APERF 0xE8 #define MSR_MPERF 0xE7 +#define RDPRU ".byte 0x0f, 0x01, 0xfd" +#define RDPRU_ECX_MPERF 0 +#define RDPRU_ECX_APERF 1 + #define MSR_TSC 0x10 #define MSR_AMD_HWCR 0xc0010015 @@ -89,6 +93,8 @@ static int mperf_get_tsc(unsigned long long *tsc) static int get_aperf_mperf(int cpu, unsigned long long *aval, unsigned long long *mval) { + unsigned long low_a, high_a; + unsigned long low_m, high_m; int ret; /* @@ -101,6 +107,20 @@ static int get_aperf_mperf(int cpu, unsigned long long *aval, return 1; } + if (cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_RDPRU) { + asm volatile(RDPRU + : "=a" (low_a), "=d" (high_a) + : "c" (RDPRU_ECX_APERF)); + asm volatile(RDPRU + : "=a" (low_m), "=d" (high_m) + : "c" (RDPRU_ECX_MPERF)); + + *aval = ((low_a) | (high_a) << 32); + *mval = ((low_m) | (high_m) << 32); + + return 0; + } + ret = read_msr(cpu, MSR_APERF, aval); ret |= read_msr(cpu, MSR_MPERF, mval); |