[PATCH v1 1/3] perf env: Track kernel 64-bit mode in environment

Leo Yan
2021-08-09T11:27:47Z

It's useful to know that the kernel is running in 32-bit or 64-bit
mode. E.g. We can decide if perf tool is running in compat mode
based on the info.

This patch adds an item "kernel_is_64_bit" into session's environment
structure perf_env, its value is initialized based on the architecture
string.

Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
tools/perf/util/env.c | 24 +++++++++++++++++++++++-
tools/perf/util/env.h | 3 +++
2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index ab341050be46..8f7ff0035c41 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -219,13 +219,35 @@ void perf_env__exit(struct perf_env *env)
zfree(&env->hybrid_cpc_nodes);
}

-void perf_env__init(struct perf_env *env __maybe_unused)
+void perf_env__init(struct perf_env *env)
{
#ifdef HAVE_LIBBPF_SUPPORT
env->bpf_progs.infos = RB_ROOT;
env->bpf_progs.btfs = RB_ROOT;
init_rwsem(&env->bpf_progs.lock);
#endif
+ env->kernel_is_64_bit = -1;
+}
+
+static void perf_env__init_kernel_mode(struct perf_env *env)
+{
+ const char *arch = perf_env__raw_arch(env);
+
+ if (!strncmp(arch, "x86_64", 6) || !strncmp(arch, "aarch64", 7) ||
+ !strncmp(arch, "arm64", 5) || !strncmp(arch, "mips64", 6) ||
+ !strncmp(arch, "parisc64", 8) || !strncmp(arch, "riscv64", 7) ||
+ !strncmp(arch, "s390x", 5) || !strncmp(arch, "sparc64", 7))
+ env->kernel_is_64_bit = 1;
+ else
+ env->kernel_is_64_bit = 0;
+}
+
+int perf_env__kernel_is_64_bit(struct perf_env *env)
+{
+ if (env->kernel_is_64_bit == -1)
+ perf_env__init_kernel_mode(env);
+
+ return env->kernel_is_64_bit;
}

int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[])
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 6824a7423a2d..1f5175820a05 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -61,6 +61,7 @@ struct perf_env {
unsigned long long total_mem;
unsigned int msr_pmu_type;
unsigned int max_branches;
+ int kernel_is_64_bit;

int nr_cmdline;
int nr_sibling_cores;
@@ -143,6 +144,8 @@ extern struct perf_env perf_env;

void perf_env__exit(struct perf_env *env);

+int perf_env__kernel_is_64_bit(struct perf_env *env);
+
int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[]);

int perf_env__read_cpuid(struct perf_env *env);
--
2.25.1