From c3e1e8cf006bf8ed7e32b57ed00a1fe3ed2b1a08 Mon Sep 17 00:00:00 2001 From: James Clark Date: Wed, 16 Aug 2023 12:47:43 +0100 Subject: [PATCH] perf arm64: Allow version comparisons of CPU IDs Currently variant and revision fields are masked out of the MIDR so it's not possible to compare different versions of the same CPU. In a later commit a workaround will be removed just for N2 r0p3, so enable comparisons on version. This has the side effect of changing the MIDR stored in the header of the perf.data file to no longer have masked version fields. It also affects the lookups in mapfile.csv, but as that currently only has zeroed version fields, it has no actual effect. The mapfile.csv documentation also states to zero the version fields, so unless this isn't done it will continue to have no effect. There is an existing weak default strcmp_cpuid_str() function, and an x86 version. This adds another version for arm64. Signed-off-by: James Clark Reviewed-by: John Garry Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andrii Nakryiko Cc: Eduard Zingerman Cc: Haixin Yu Cc: Ian Rogers Cc: Ingo Molnar Cc: Jing Zhang Cc: Jiri Olsa Cc: Kajol Jain Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Namhyung Kim Cc: Nick Forrington Cc: Peter Zijlstra Cc: Rob Herring Cc: Sohom Datta Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230816114841.1679234-2-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/arch/arm64/util/header.c | 67 ++++++++++++++++++++++++++++--------- 1 file changed, 52 insertions(+), 15 deletions(-) diff --git a/tools/perf/arch/arm64/util/header.c b/tools/perf/arch/arm64/util/header.c index 80b9f62..a2eef9e 100644 --- a/tools/perf/arch/arm64/util/header.c +++ b/tools/perf/arch/arm64/util/header.c @@ -1,3 +1,6 @@ +#include +#include +#include #include #include #include @@ -10,15 +13,14 @@ #define MIDR "/regs/identification/midr_el1" #define MIDR_SIZE 19 -#define MIDR_REVISION_MASK 0xf -#define MIDR_VARIANT_SHIFT 20 -#define MIDR_VARIANT_MASK (0xf << MIDR_VARIANT_SHIFT) +#define MIDR_REVISION_MASK GENMASK(3, 0) +#define MIDR_VARIANT_MASK GENMASK(23, 20) static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map *cpus) { const char *sysfs = sysfs__mountpoint(); - u64 midr = 0; int cpu; + int ret = EINVAL; if (!sysfs || sz < MIDR_SIZE) return EINVAL; @@ -44,22 +46,13 @@ static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map *cpus) } fclose(file); - /* Ignore/clear Variant[23:20] and - * Revision[3:0] of MIDR - */ - midr = strtoul(buf, NULL, 16); - midr &= (~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK)); - scnprintf(buf, MIDR_SIZE, "0x%016lx", midr); /* got midr break loop */ + ret = 0; break; } perf_cpu_map__put(cpus); - - if (!midr) - return EINVAL; - - return 0; + return ret; } int get_cpuid(char *buf, size_t sz) @@ -99,3 +92,47 @@ char *get_cpuid_str(struct perf_pmu *pmu) return buf; } + +/* + * Return 0 if idstr is a higher or equal to version of the same part as + * mapcpuid. Therefore, if mapcpuid has 0 for revision and variant then any + * version of idstr will match as long as it's the same CPU type. + * + * Return 1 if the CPU type is different or the version of idstr is lower. + */ +int strcmp_cpuid_str(const char *mapcpuid, const char *idstr) +{ + u64 map_id = strtoull(mapcpuid, NULL, 16); + char map_id_variant = FIELD_GET(MIDR_VARIANT_MASK, map_id); + char map_id_revision = FIELD_GET(MIDR_REVISION_MASK, map_id); + u64 id = strtoull(idstr, NULL, 16); + char id_variant = FIELD_GET(MIDR_VARIANT_MASK, id); + char id_revision = FIELD_GET(MIDR_REVISION_MASK, id); + u64 id_fields = ~(MIDR_VARIANT_MASK | MIDR_REVISION_MASK); + + /* Compare without version first */ + if ((map_id & id_fields) != (id & id_fields)) + return 1; + + /* + * ID matches, now compare version. + * + * Arm revisions (like r0p0) are compared here like two digit semver + * values eg. 1.3 < 2.0 < 2.1 < 2.2. + * + * r = high value = 'Variant' field in MIDR + * p = low value = 'Revision' field in MIDR + * + */ + if (id_variant > map_id_variant) + return 0; + + if (id_variant == map_id_variant && id_revision >= map_id_revision) + return 0; + + /* + * variant is less than mapfile variant or variants are the same but + * the revision doesn't match. Return no match. + */ + return 1; +} -- 2.7.4