perf tools: Allow generating per-arch syscall table arrays

Tools should use a mechanism similar to arch/x86/entry/syscalls/ to
generate a header file with the definitions for two variables:

static const char *syscalltbl_x86_64[] = {
[0] = "read",
[1] = "write",
<SNIP>
[324] = "membarrier",
[325] = "mlock2",
[326] = "copy_file_range",
};
static const int syscalltbl_x86_64_max_id = 326;

In a per arch file that should then be included in
tools/perf/util/syscalltbl.c.

First one will be for x86_64.

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/syscalltbl.c

···
  */
 
 #include "syscalltbl.h"
-#include <string.h>
-#include <libaudit.h>
+#include <stdlib.h>
 
+#ifdef HAVE_SYSCALL_TABLE
+#include <linux/compiler.h>
+#include <string.h>
+#include "util.h"
+
+struct syscall {
+	int id;
+	const char *name;
+};
+
+static int syscallcmpname(const void *vkey, const void *ventry)
+{
+	const char *key = vkey;
+	const struct syscall *entry = ventry;
+
+	return strcmp(key, entry->name);
+}
+
+static int syscallcmp(const void *va, const void *vb)
+{
+	const struct syscall *a = va, *b = vb;
+
+	return strcmp(a->name, b->name);
+}
+
+static int syscalltbl__init_native(struct syscalltbl *tbl)
+{
+	int nr_entries = 0, i, j;
+	struct syscall *entries;
+
+	for (i = 0; i <= syscalltbl_native_max_id; ++i)
+		if (syscalltbl_native[i])
+			++nr_entries;
+
+	entries = tbl->syscalls.entries = malloc(sizeof(struct syscall) * nr_entries);
+	if (tbl->syscalls.entries == NULL)
+		return -1;
+
+	for (i = 0, j = 0; i <= syscalltbl_native_max_id; ++i) {
+		if (syscalltbl_native[i]) {
+			entries[j].name = syscalltbl_native[i];
+			entries[j].id = i;
+			++j;
+		}
+	}
+
+	qsort(tbl->syscalls.entries, nr_entries, sizeof(struct syscall), syscallcmp);
+	tbl->syscalls.nr_entries = nr_entries;
+	return 0;
+}
 
 struct syscalltbl *syscalltbl__new(void)
 {
 	struct syscalltbl *tbl = malloc(sizeof(*tbl));
 	if (tbl) {
-		tbl->audit_machine = audit_detect_machine();
+		if (syscalltbl__init_native(tbl)) {
+			free(tbl);
+			return NULL;
+		}
 	}
+	return tbl;
+}
+
+void syscalltbl__delete(struct syscalltbl *tbl)
+{
+	zfree(&tbl->syscalls.entries);
+	free(tbl);
+}
+
+const char *syscalltbl__name(const struct syscalltbl *tbl __maybe_unused, int id)
+{
+	return id <= syscalltbl_native_max_id ? syscalltbl_native[id]: NULL;
+}
+
+int syscalltbl__id(struct syscalltbl *tbl, const char *name)
+{
+	struct syscall *sc = bsearch(name, tbl->syscalls.entries,
+				     tbl->syscalls.nr_entries, sizeof(*sc),
+				     syscallcmpname);
+
+	return sc ? sc->id : -1;
+}
+
+#else /* HAVE_SYSCALL_TABLE */
+
+#include <libaudit.h>
+
+struct syscalltbl *syscalltbl__new(void)
+{
+	struct syscalltbl *tbl = malloc(sizeof(*tbl));
+	if (tbl)
+		tbl->audit_machine = audit_detect_machine();
 	return tbl;
 }
 
···
 {
 	return audit_name_to_syscall(name, tbl->audit_machine);
 }
+#endif /* HAVE_SYSCALL_TABLE */

tools/perf/util/syscalltbl.h

···
 struct syscalltbl {
 	union {
 		int audit_machine;
+		struct {
+			int nr_entries;
+			void *entries;
+		} syscalls;
 	};
 };