perf symbols: Simplify symbol machinery setup

And also express its configuration toggles via a struct.

Now all one has to do is to call symbol__init(NULL) if the
defaults are OK, or pass a struct symbol_conf pointer with the
desired configuration.

If a tool uses kernel_maps__find_symbol() to look at the kernel
and modules mappings for a symbol but didn't call symbol__init()
first, that will generate a one time warning too, alerting the
subcommand developer that symbol__init() must be called.

Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Frédéric Weisbecker <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
LKML-Reference: <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

tools/perf/builtin-annotate.c

···
 static int		full_paths;
 
 static int		print_line;
-static bool		use_modules;
 
 static unsigned long	page_size;
 static unsigned long	mmap_window = 32;
-const char		*vmlinux_name;
 
 struct sym_hist {
 	u64		sum;
···
 struct sym_priv {
 	struct sym_hist	*hist;
 	struct sym_ext	*ext;
+};
+
+static struct symbol_conf symbol_conf = {
+	.priv_size	  = sizeof(struct sym_priv),
+	.try_vmlinux_path = true,
 };
 
 static const char *sym_hist_filter;
···
 		exit(0);
 	}
 
-	if (kernel_maps__init(vmlinux_name, true, use_modules) < 0) {
-		pr_err("failed to create kernel maps for symbol resolution\b");
-		return -1;
-	}
-
 remap:
 	buf = (char *)mmap(NULL, page_size * mmap_window, PROT_READ,
 			   MAP_SHARED, input, offset);
···
 		    "be more verbose (show symbol address, etc)"),
 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
 		    "dump raw trace in ASCII"),
-	OPT_STRING('k', "vmlinux", &vmlinux_name, "file", "vmlinux pathname"),
-	OPT_BOOLEAN('m', "modules", &use_modules,
+	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
+		   "file", "vmlinux pathname"),
+	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
 		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
 	OPT_BOOLEAN('l', "print-line", &print_line,
 		    "print matching source lines (may be slow)"),
···
 
 int cmd_annotate(int argc, const char **argv, const char *prefix __used)
 {
-	symbol__init(sizeof(struct sym_priv));
+	if (symbol__init(&symbol_conf) < 0)
+		return -1;
 
 	page_size = getpagesize();
 

tools/perf/builtin-kmem.c

···
 	register_idle_thread();
 	register_perf_file_handler(&file_handler);
 
-	return mmap_dispatch_perf_file(&header, input_name, NULL, false, 0, 0,
+	return mmap_dispatch_perf_file(&header, input_name, 0, 0,
 				       &cwdlen, &cwd);
 }
 

tools/perf/builtin-report.c

···
 static struct strlist	*dso_list, *comm_list, *sym_list;
 
 static int		force;
-static bool		use_modules;
 
 static int		full_paths;
 static int		show_nr_samples;
···
 static int		exclude_other = 1;
 
 static char		callchain_default_opt[] = "fractal,0.5";
-const char		*vmlinux_name;
 
 static struct perf_header *header;
 
 static u64		sample_type;
+
+struct symbol_conf	symbol_conf;
 
 
 static size_t
···
 
 	register_perf_file_handler(&file_handler);
 
-	ret = mmap_dispatch_perf_file(&header, input_name, vmlinux_name,
-				      !vmlinux_name, force,
+	ret = mmap_dispatch_perf_file(&header, input_name, force,
 				      full_paths, &cwdlen, &cwd);
 	if (ret)
 		return ret;
···
 		    "be more verbose (show symbol address, etc)"),
 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
 		    "dump raw trace in ASCII"),
-	OPT_STRING('k', "vmlinux", &vmlinux_name, "file", "vmlinux pathname"),
+	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
+		   "file", "vmlinux pathname"),
 	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
-	OPT_BOOLEAN('m', "modules", &use_modules,
+	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
 		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
 	OPT_BOOLEAN('n', "show-nr-samples", &show_nr_samples,
 		    "Show a column with the number of samples"),
···
 
 int cmd_report(int argc, const char **argv, const char *prefix __used)
 {
-	symbol__init(0);
+	if (symbol__init(&symbol_conf) < 0)
+		return -1;
 
 	argc = parse_options(argc, argv, options, report_usage, 0);
 

tools/perf/builtin-sched.c

···
 	register_idle_thread();
 	register_perf_file_handler(&file_handler);
 
-	return mmap_dispatch_perf_file(&header, input_name, NULL, false, 0, 0,
+	return mmap_dispatch_perf_file(&header, input_name, 0, 0,
 				       &cwdlen, &cwd);
 }
 

tools/perf/builtin-top.c

···
 static bool			hide_kernel_symbols		=  false;
 static bool			hide_user_symbols		=  false;
 static struct winsize		winsize;
-const char 			*vmlinux_name;
+struct symbol_conf		symbol_conf;
 
 /*
  * Source
···
 
 static inline struct symbol *sym_entry__symbol(struct sym_entry *self)
 {
-       return ((void *)self) + symbol__priv_size;
+       return ((void *)self) + symbol_conf.priv_size;
 }
 
 static void get_term_dimensions(struct winsize *ws)
···
 
 	fprintf(stdout, "\t[f]     profile display filter (count).    \t(%d)\n", count_filter);
 
-	if (vmlinux_name) {
+	if (symbol_conf.vmlinux_name) {
 		fprintf(stdout, "\t[F]     annotate display filter (percent). \t(%d%%)\n", sym_pcnt_filter);
 		fprintf(stdout, "\t[s]     annotate symbol.                   \t(%s)\n", name?: "NULL");
 		fprintf(stdout, "\t[S]     stop annotation.\n");
···
 		case 'F':
 		case 's':
 		case 'S':
-			return vmlinux_name ? 1 : 0;
+			return symbol_conf.vmlinux_name ? 1 : 0;
 		default:
 			break;
 	}
···
 			    "system-wide collection from all CPUs"),
 	OPT_INTEGER('C', "CPU", &profile_cpu,
 		    "CPU to profile on"),
-	OPT_STRING('k', "vmlinux", &vmlinux_name, "file", "vmlinux pathname"),
+	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
+		   "file", "vmlinux pathname"),
 	OPT_BOOLEAN('K', "hide_kernel_symbols", &hide_kernel_symbols,
 		    "hide kernel symbols"),
 	OPT_INTEGER('m', "mmap-pages", &mmap_pages,
···
 
 int cmd_top(int argc, const char **argv, const char *prefix __used)
 {
-	int counter, err;
+	int counter;
 
 	page_size = sysconf(_SC_PAGE_SIZE);
 
···
 	if (!nr_counters)
 		nr_counters = 1;
 
-	symbol__init(sizeof(struct sym_entry) +
-		     (nr_counters + 1) * sizeof(unsigned long));
+	symbol_conf.priv_size = (sizeof(struct sym_entry) +
+				 (nr_counters + 1) * sizeof(unsigned long));
+	if (symbol_conf.vmlinux_name == NULL)
+		symbol_conf.try_vmlinux_path = true;
+	if (symbol__init(&symbol_conf) < 0)
+		return -1;
 
 	if (delay_secs < 1)
 		delay_secs = 1;
 
-	err = kernel_maps__init(vmlinux_name, !vmlinux_name, true);
-	if (err < 0)
-		return err;
 	parse_source(sym_filter_entry);
 
 	/*

tools/perf/builtin-trace.c

···
 	register_idle_thread();
 	register_perf_file_handler(&file_handler);
 
-	return mmap_dispatch_perf_file(&header, input_name, NULL, false,
+	return mmap_dispatch_perf_file(&header, input_name,
 				       0, 0, &cwdlen, &cwd);
 }
 

tools/perf/util/data_map.c

···
 
 int mmap_dispatch_perf_file(struct perf_header **pheader,
 			    const char *input_name,
-			    const char *vmlinux_name,
-			    bool try_vmlinux_path,
 			    int force,
 			    int full_paths,
 			    int *cwdlen,
···
 	if (curr_handler->sample_type_check &&
 	    curr_handler->sample_type_check(sample_type) < 0)
 		goto out_delete;
-
-	err = -ENOMEM;
-	if (kernel_maps__init(vmlinux_name, try_vmlinux_path, true) < 0) {
-		pr_err("failed to setup the kernel maps to resolve symbols\n");
-		goto out_delete;
-	}
 
 	if (!full_paths) {
 		if (getcwd(__cwd, sizeof(__cwd)) == NULL) {

tools/perf/util/data_map.h

···
 void register_perf_file_handler(struct perf_file_handler *handler);
 int mmap_dispatch_perf_file(struct perf_header **pheader,
 			    const char *input_name,
-			    const char *vmlinux_name,
-			    bool try_vmlinux_path,
 			    int force,
 			    int full_paths,
 			    int *cwdlen,

tools/perf/util/header.c

···
 
 		buildid_sec = &feat_sec[idx++];
 
-		/*
-		 * Read the kernel buildid nad the list of loaded modules with
-		 * its build_ids:
-		 */
-		kernel_maps__init(NULL, false, true);
-
 		/* Write build-ids */
 		buildid_sec->offset = lseek(fd, 0, SEEK_CUR);
 		err = dsos__write_buildid_table(fd);

tools/perf/util/include/asm/bug.h

···
+#ifndef _PERF_ASM_GENERIC_BUG_H
+#define _PERF_ASM_GENERIC_BUG_H
+
+#define __WARN_printf(arg...)	do { fprintf(stderr, arg); } while (0)
+
+#define WARN(condition, format...) ({		\
+	int __ret_warn_on = !!(condition);	\
+	if (unlikely(__ret_warn_on))		\
+		__WARN_printf(format);		\
+	unlikely(__ret_warn_on);		\
+})
+
+#define WARN_ONCE(condition, format...)	({	\
+	static int __warned;			\
+	int __ret_warn_once = !!(condition);	\
+						\
+	if (unlikely(__ret_warn_once))		\
+		if (WARN(!__warned, format)) 	\
+			__warned = 1;		\
+	unlikely(__ret_warn_once);		\
+})
+#endif

tools/perf/util/symbol.c

···
 
 #include "debug.h"
 
+#include <asm/bug.h>
 #include <libelf.h>
 #include <gelf.h>
 #include <elf.h>
···
 unsigned int symbol__priv_size;
 static int vmlinux_path__nr_entries;
 static char **vmlinux_path;
+
+static struct symbol_conf symbol_conf__defaults = {
+	.use_modules	  = true,
+	.try_vmlinux_path = true,
+};
 
 static struct rb_root kernel_maps;
 
···
 	if (map) {
 		ip = map->map_ip(map, ip);
 		return map__find_symbol(map, ip, filter);
-	}
+	} else
+		WARN_ONCE(RB_EMPTY_ROOT(&kernel_maps),
+			  "Empty kernel_maps, was symbol__init() called?\n");
 
 	return NULL;
 }
···
 	return ret;
 }
 
-static int kernel_maps__create_kernel_map(const char *vmlinux_name)
+static int kernel_maps__create_kernel_map(const struct symbol_conf *conf)
 {
-	struct dso *kernel = dso__new(vmlinux_name ?: "[kernel.kallsyms]");
+	struct dso *kernel = dso__new(conf->vmlinux_name ?: "[kernel.kallsyms]");
 
 	if (kernel == NULL)
 		return -1;
···
 	return -1;
 }
 
-int kernel_maps__init(const char *vmlinux_name, bool try_vmlinux_path,
-		      bool use_modules)
+static int kernel_maps__init(const struct symbol_conf *conf)
 {
-	if (try_vmlinux_path && vmlinux_path__init() < 0)
+	const struct symbol_conf *pconf = conf ?: &symbol_conf__defaults;
+
+	symbol__priv_size = pconf->priv_size;
+
+	if (pconf->try_vmlinux_path && vmlinux_path__init() < 0)
 		return -1;
 
-	if (kernel_maps__create_kernel_map(vmlinux_name) < 0) {
+	if (kernel_maps__create_kernel_map(pconf) < 0) {
 		vmlinux_path__exit();
 		return -1;
 	}
 
-	if (use_modules && kernel_maps__create_module_maps() < 0)
+	if (pconf->use_modules && kernel_maps__create_module_maps() < 0)
 		pr_debug("Failed to load list of modules in use, "
 			 "continuing...\n");
 	/*
···
 	return 0;
 }
 
-void symbol__init(unsigned int priv_size)
+int symbol__init(struct symbol_conf *conf)
 {
 	elf_version(EV_CURRENT);
-	symbol__priv_size = priv_size;
+	return kernel_maps__init(conf);
 }

tools/perf/util/symbol.h

···
 	char		name[0];
 };
 
+struct symbol_conf {
+	unsigned short	priv_size;
+	bool		try_vmlinux_path,
+			use_modules;
+	const char	*vmlinux_name;
+};
+
 extern unsigned int symbol__priv_size;
 
 static inline void *symbol__priv(struct symbol *self)
···
 bool dsos__read_build_ids(void);
 int build_id__sprintf(u8 *self, int len, char *bf);
 
-int kernel_maps__init(const char *vmlinux_name, bool try_vmlinux_path,
-		      bool use_modules);
 size_t kernel_maps__fprintf(FILE *fp);
 
-void symbol__init(unsigned int priv_size);
+int symbol__init(struct symbol_conf *conf);
 
 extern struct list_head dsos;
 extern struct map *kernel_map;