perf parse-regs: Introduce a weak function arch__sample_reg_masks()

Every architecture can provide a register list for sampling. If an
architecture doesn't support register sampling, it won't define the data
structure 'sample_reg_masks'. Consequently, any code using this
structure must be protected by the macro 'HAVE_PERF_REGS_SUPPORT'.

This patch defines a weak function, arch__sample_reg_masks(), which will
be replaced by an architecture-defined function for returning the
architecture's register list. With this refactoring, the function always
exists, the condition checking for 'HAVE_PERF_REGS_SUPPORT' is not
needed anymore, so remove it.

Signed-off-by: Leo Yan <leo.yan@linux.dev>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Ming Wang <wangming01@loongson.cn>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: linux-csky@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240214113947.240957-4-leo.yan@linux.dev

3 files changed, 12 insertions, 8 deletions

diff --git a/tools/perf/util/parse-regs-options.c b/tools/perf/util/parse-regs-options.c
index a4a100425b3a..cda1c620968e 100644
--- a/tools/perf/util/parse-regs-options.c
+++ b/tools/perf/util/parse-regs-options.c
@@ -46,22 +46,18 @@ __parse_regs(const struct option *opt, const char *str, int unset, bool intr)
 
 			if (!strcmp(s, "?")) {
 				fprintf(stderr, "available registers: ");
-#ifdef HAVE_PERF_REGS_SUPPORT
-				for (r = sample_reg_masks; r->name; r++) {
+				for (r = arch__sample_reg_masks(); r->name; r++) {
 					if (r->mask & mask)
 						fprintf(stderr, "%s ", r->name);
 				}
-#endif
 				fputc('\n', stderr);
 				/* just printing available regs */
 				goto error;
 			}
-#ifdef HAVE_PERF_REGS_SUPPORT
-			for (r = sample_reg_masks; r->name; r++) {
+			for (r = arch__sample_reg_masks(); r->name; r++) {
 				if ((r->mask & mask) && !strcasecmp(s, r->name))
 					break;
 			}
-#endif
 			if (!r || !r->name) {
 				ui__warning("Unknown register \"%s\", check man page or run \"perf record %s?\"\n",
 					    s, intr ? "-I" : "--user-regs=");
diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
index 64724eb58dd5..44b90bbf2d07 100644
--- a/tools/perf/util/perf_regs.c
+++ b/tools/perf/util/perf_regs.c
@@ -21,6 +21,15 @@ uint64_t __weak arch__user_reg_mask(void)
 	return 0;
 }
 
+static const struct sample_reg sample_reg_masks[] = {
+	SMPL_REG_END
+};
+
+const struct sample_reg * __weak arch__sample_reg_masks(void)
+{
+	return sample_reg_masks;
+}
+
 const char *perf_reg_name(int id, const char *arch)
 {
 	const char *reg_name = NULL;
diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
index 7fd0c7b4cec1..f2d0736d65cc 100644
--- a/tools/perf/util/perf_regs.h
+++ b/tools/perf/util/perf_regs.h
@@ -26,8 +26,7 @@ enum {
 int arch_sdt_arg_parse_op(char *old_op, char **new_op);
 uint64_t arch__intr_reg_mask(void);
 uint64_t arch__user_reg_mask(void);
-
-extern const struct sample_reg sample_reg_masks[];
+const struct sample_reg *arch__sample_reg_masks(void);
 
 const char *perf_reg_name(int id, const char *arch);
 int perf_reg_value(u64 *valp, struct regs_dump *regs, int id);