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Date: Tue, 13 Jun 2017 10:58:28 -0500 From: Janakarajan Natarajan <Janakarajan.Natarajan@....com> To: linux-kernel@...r.kernel.org Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Borislav Petkov <bp@...en8.de>, Suravee Suthikulpanit <suravee.suthikulpanit@....com>, Janakarajan Natarajan <Janakarajan.Natarajan@....com> Subject: [PATCH v3 2/2] amd: uncore: Get correct number of cores sharing last level cache In Family 17h, the number of cores sharing a cache level is obtained from the Cache Properties CPUID leaf (0x8000001d) by passing in the cache level in ECX. In prior families, a cache level of 2 was used to determine this information. To get the right information, irrespective of Family, iterate over the cache levels using CPUID 0x8000001d. The last level cache is the last value to return a non-zero value in EAX. Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@....com> --- arch/x86/events/amd/uncore.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c index e34f8a6..a0b33de 100644 --- a/arch/x86/events/amd/uncore.c +++ b/arch/x86/events/amd/uncore.c @@ -400,11 +400,24 @@ static int amd_uncore_cpu_starting(unsigned int cpu) if (amd_uncore_llc) { unsigned int apicid = cpu_data(cpu).apicid; - unsigned int nshared; + unsigned int nshared, subleaf, prev_eax = 0; uncore = *per_cpu_ptr(amd_uncore_llc, cpu); - cpuid_count(0x8000001d, 2, &eax, &ebx, &ecx, &edx); - nshared = ((eax >> 14) & 0xfff) + 1; + /* + * Iterate over Cache Topology Definition leaves until no + * more cache descriptions are available. + */ + for(subleaf = 0; subleaf < 5; subleaf++) { + cpuid_count(0x8000001d, subleaf, &eax, &ebx, &ecx, &edx); + + /* EAX[0:4] gives type of cache */ + if (!(eax & 0x1f)) + break; + + prev_eax = eax; + } + nshared = ((prev_eax >> 14) & 0xfff) + 1; + uncore->id = apicid - (apicid % nshared); uncore = amd_uncore_find_online_sibling(uncore, amd_uncore_llc); -- 2.7.4
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