linux-kernel - [PATCH v3 09/10] perf env: Set kernel bit mode

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Message-Id: <20210704071644.107397-10-leo.yan@linaro.org>
Date:   Sun,  4 Jul 2021 15:16:43 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org
Cc:     Leo Yan <leo.yan@...aro.org>
Subject: [PATCH v3 09/10] perf env: Set kernel bit mode

It's useful to know that the kernel is running in 32-bit or 64-bit
mode.  E.g. We can decide perf tool is running in compat mode when
detects kernel is running in 64-bit mode and the tool is in 32-bit
mode with the compiler macro BITS_PER_LONG is 32.

This patch adds a global variable "kernel_is_64_bit", during the
environment initialization for the session, the kernel running mode
is decided by checking the architecture string.

Signed-off-by: Leo Yan <leo.yan@...aro.org>
---
 tools/perf/util/env.c | 17 ++++++++++++++++-
 tools/perf/util/env.h |  1 +
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index ebc5e9ad35db..345635a2e842 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -11,6 +11,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+int kernel_is_64_bit;
 struct perf_env perf_env;
 
 #ifdef HAVE_LIBBPF_SUPPORT
@@ -172,6 +173,19 @@ static void perf_env__purge_bpf(struct perf_env *env __maybe_unused)
 }
 #endif // HAVE_LIBBPF_SUPPORT
 
+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))
+		kernel_is_64_bit = 1;
+	else
+		kernel_is_64_bit = 0;
+}
+
 void perf_env__exit(struct perf_env *env)
 {
 	int i;
@@ -217,13 +231,14 @@ 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
+	perf_env__init_kernel_mode(env);
 }
 
 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..cc989ff49740 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -139,6 +139,7 @@ enum perf_compress_type {
 struct bpf_prog_info_node;
 struct btf_node;
 
+extern int kernel_is_64_bit;
 extern struct perf_env perf_env;
 
 void perf_env__exit(struct perf_env *env);
-- 
2.25.1