ec80fde746
Perf uses /proc/modules to figure out where kernel modules are loaded. With the advent of kptr_restrict, non root users get zeroes for all module start addresses. So check if kptr_restrict is non zero and don't generate the syntethic PERF_RECORD_MMAP events for them. Warn the user about it in perf record and in perf report. In perf report the reference relocation symbol being zero means that kptr_restrict was set, thus /proc/kallsyms has only zeroed addresses, so don't use it to fixup symbol addresses when using a valid kallsyms (in the buildid cache) or vmlinux (in the vmlinux path) build-id located automatically or specified by the user. Provide an explanation about it in 'perf report' if kernel samples were taken, checking if a suitable vmlinux or kallsyms was found/specified. Restricted /proc/kallsyms don't go to the buildid cache anymore. Example: [acme@emilia ~]$ perf record -F 100000 sleep 1 WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted, check /proc/sys/kernel/kptr_restrict. Samples in kernel functions may not be resolved if a suitable vmlinux file is not found in the buildid cache or in the vmlinux path. Samples in kernel modules won't be resolved at all. If some relocation was applied (e.g. kexec) symbols may be misresolved even with a suitable vmlinux or kallsyms file. [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.005 MB perf.data (~231 samples) ] [acme@emilia ~]$ [acme@emilia ~]$ perf report --stdio Kernel address maps (/proc/{kallsyms,modules}) were restricted, check /proc/sys/kernel/kptr_restrict before running 'perf record'. If some relocation was applied (e.g. kexec) symbols may be misresolved. Samples in kernel modules can't be resolved as well. # Events: 13 cycles # # Overhead Command Shared Object Symbol # ........ ....... ................. ..................... # 20.24% sleep [kernel.kallsyms] [k] page_fault 20.04% sleep [kernel.kallsyms] [k] filemap_fault 19.78% sleep [kernel.kallsyms] [k] __lru_cache_add 19.69% sleep ld-2.12.so [.] memcpy 14.71% sleep [kernel.kallsyms] [k] dput 4.70% sleep [kernel.kallsyms] [k] flush_signal_handlers 0.73% sleep [kernel.kallsyms] [k] perf_event_comm 0.11% sleep [kernel.kallsyms] [k] native_write_msr_safe # # (For a higher level overview, try: perf report --sort comm,dso) # [acme@emilia ~]$ This is because it found a suitable vmlinux (build-id checked) in /lib/modules/2.6.39-rc7+/build/vmlinux (use -v in perf report to see the long file name). If we remove that file from the vmlinux path: [root@emilia ~]# mv /lib/modules/2.6.39-rc7+/build/vmlinux \ /lib/modules/2.6.39-rc7+/build/vmlinux.OFF [acme@emilia ~]$ perf report --stdio [kernel.kallsyms] with build id 57298cdbe0131f6871667ec0eaab4804dcf6f562 not found, continuing without symbols Kernel address maps (/proc/{kallsyms,modules}) were restricted, check /proc/sys/kernel/kptr_restrict before running 'perf record'. As no suitable kallsyms nor vmlinux was found, kernel samples can't be resolved. Samples in kernel modules can't be resolved as well. # Events: 13 cycles # # Overhead Command Shared Object Symbol # ........ ....... ................. ...... # 80.31% sleep [kernel.kallsyms] [k] 0xffffffff8103425a 19.69% sleep ld-2.12.so [.] memcpy # # (For a higher level overview, try: perf report --sort comm,dso) # [acme@emilia ~]$ Reported-by: Stephane Eranian <eranian@google.com> Suggested-by: David Miller <davem@davemloft.net> Cc: Dave Jones <davej@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Kees Cook <kees.cook@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> Link: http://lkml.kernel.org/n/tip-mt512joaxxbhhp1odop04yit@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
245 lines
6.4 KiB
C
245 lines
6.4 KiB
C
#ifndef __PERF_SYMBOL
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#define __PERF_SYMBOL 1
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#include <linux/types.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include "map.h"
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include <stdio.h>
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#ifdef HAVE_CPLUS_DEMANGLE
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extern char *cplus_demangle(const char *, int);
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static inline char *bfd_demangle(void __used *v, const char *c, int i)
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{
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return cplus_demangle(c, i);
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}
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#else
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#ifdef NO_DEMANGLE
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static inline char *bfd_demangle(void __used *v, const char __used *c,
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int __used i)
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{
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return NULL;
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}
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#else
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#include <bfd.h>
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#endif
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#endif
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int hex2u64(const char *ptr, u64 *val);
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char *strxfrchar(char *s, char from, char to);
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/*
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* libelf 0.8.x and earlier do not support ELF_C_READ_MMAP;
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* for newer versions we can use mmap to reduce memory usage:
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*/
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#ifdef LIBELF_NO_MMAP
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# define PERF_ELF_C_READ_MMAP ELF_C_READ
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#else
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# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
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#endif
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#ifndef DMGL_PARAMS
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#define DMGL_PARAMS (1 << 0) /* Include function args */
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#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
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#endif
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#define BUILD_ID_SIZE 20
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/** struct symbol - symtab entry
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*
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* @ignore - resolvable but tools ignore it (e.g. idle routines)
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*/
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struct symbol {
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struct rb_node rb_node;
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u64 start;
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u64 end;
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u16 namelen;
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u8 binding;
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bool ignore;
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char name[0];
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};
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void symbol__delete(struct symbol *sym);
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struct strlist;
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struct symbol_conf {
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unsigned short priv_size;
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bool try_vmlinux_path,
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use_modules,
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sort_by_name,
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show_nr_samples,
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use_callchain,
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exclude_other,
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show_cpu_utilization,
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initialized,
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kptr_restrict;
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const char *vmlinux_name,
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*kallsyms_name,
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*source_prefix,
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*field_sep;
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const char *default_guest_vmlinux_name,
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*default_guest_kallsyms,
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*default_guest_modules;
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const char *guestmount;
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const char *dso_list_str,
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*comm_list_str,
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*sym_list_str,
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*col_width_list_str;
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struct strlist *dso_list,
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*comm_list,
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*sym_list;
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const char *symfs;
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};
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extern struct symbol_conf symbol_conf;
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static inline void *symbol__priv(struct symbol *sym)
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{
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return ((void *)sym) - symbol_conf.priv_size;
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}
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struct ref_reloc_sym {
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const char *name;
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u64 addr;
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u64 unrelocated_addr;
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};
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struct map_symbol {
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struct map *map;
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struct symbol *sym;
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bool unfolded;
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bool has_children;
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};
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struct addr_location {
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struct thread *thread;
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struct map *map;
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struct symbol *sym;
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u64 addr;
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char level;
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bool filtered;
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u8 cpumode;
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s32 cpu;
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};
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enum dso_kernel_type {
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DSO_TYPE_USER = 0,
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DSO_TYPE_KERNEL,
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DSO_TYPE_GUEST_KERNEL
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};
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struct dso {
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struct list_head node;
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struct rb_root symbols[MAP__NR_TYPES];
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struct rb_root symbol_names[MAP__NR_TYPES];
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enum dso_kernel_type kernel;
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u8 adjust_symbols:1;
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u8 has_build_id:1;
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u8 hit:1;
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u8 annotate_warned:1;
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u8 sname_alloc:1;
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u8 lname_alloc:1;
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unsigned char symtab_type;
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u8 sorted_by_name;
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u8 loaded;
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u8 build_id[BUILD_ID_SIZE];
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const char *short_name;
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char *long_name;
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u16 long_name_len;
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u16 short_name_len;
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char name[0];
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};
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struct dso *dso__new(const char *name);
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struct dso *dso__new_kernel(const char *name);
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void dso__delete(struct dso *dso);
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int dso__name_len(const struct dso *dso);
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bool dso__loaded(const struct dso *dso, enum map_type type);
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bool dso__sorted_by_name(const struct dso *dso, enum map_type type);
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static inline void dso__set_loaded(struct dso *dso, enum map_type type)
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{
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dso->loaded |= (1 << type);
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}
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void dso__sort_by_name(struct dso *dso, enum map_type type);
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struct dso *__dsos__findnew(struct list_head *head, const char *name);
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int dso__load(struct dso *dso, struct map *map, symbol_filter_t filter);
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int dso__load_vmlinux(struct dso *dso, struct map *map,
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const char *vmlinux, symbol_filter_t filter);
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int dso__load_vmlinux_path(struct dso *dso, struct map *map,
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symbol_filter_t filter);
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int dso__load_kallsyms(struct dso *dso, const char *filename, struct map *map,
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symbol_filter_t filter);
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int machine__load_kallsyms(struct machine *machine, const char *filename,
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enum map_type type, symbol_filter_t filter);
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int machine__load_vmlinux_path(struct machine *machine, enum map_type type,
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symbol_filter_t filter);
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size_t __dsos__fprintf(struct list_head *head, FILE *fp);
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size_t machine__fprintf_dsos_buildid(struct machine *machine,
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FILE *fp, bool with_hits);
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size_t machines__fprintf_dsos(struct rb_root *machines, FILE *fp);
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size_t machines__fprintf_dsos_buildid(struct rb_root *machines,
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FILE *fp, bool with_hits);
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size_t dso__fprintf_buildid(struct dso *dso, FILE *fp);
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size_t dso__fprintf_symbols_by_name(struct dso *dso,
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enum map_type type, FILE *fp);
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size_t dso__fprintf(struct dso *dso, enum map_type type, FILE *fp);
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enum symtab_type {
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SYMTAB__KALLSYMS = 0,
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SYMTAB__GUEST_KALLSYMS,
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SYMTAB__JAVA_JIT,
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SYMTAB__BUILD_ID_CACHE,
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SYMTAB__FEDORA_DEBUGINFO,
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SYMTAB__UBUNTU_DEBUGINFO,
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SYMTAB__BUILDID_DEBUGINFO,
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SYMTAB__SYSTEM_PATH_DSO,
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SYMTAB__GUEST_KMODULE,
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SYMTAB__SYSTEM_PATH_KMODULE,
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SYMTAB__NOT_FOUND,
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};
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char dso__symtab_origin(const struct dso *dso);
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void dso__set_long_name(struct dso *dso, char *name);
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void dso__set_build_id(struct dso *dso, void *build_id);
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void dso__read_running_kernel_build_id(struct dso *dso,
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struct machine *machine);
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struct symbol *dso__find_symbol(struct dso *dso, enum map_type type,
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u64 addr);
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struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
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const char *name);
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int filename__read_build_id(const char *filename, void *bf, size_t size);
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int sysfs__read_build_id(const char *filename, void *bf, size_t size);
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bool __dsos__read_build_ids(struct list_head *head, bool with_hits);
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int build_id__sprintf(const u8 *build_id, int len, char *bf);
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int kallsyms__parse(const char *filename, void *arg,
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int (*process_symbol)(void *arg, const char *name,
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char type, u64 start, u64 end));
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void machine__destroy_kernel_maps(struct machine *machine);
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int __machine__create_kernel_maps(struct machine *machine, struct dso *kernel);
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int machine__create_kernel_maps(struct machine *machine);
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int machines__create_kernel_maps(struct rb_root *machines, pid_t pid);
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int machines__create_guest_kernel_maps(struct rb_root *machines);
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void machines__destroy_guest_kernel_maps(struct rb_root *machines);
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int symbol__init(void);
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void symbol__exit(void);
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bool symbol_type__is_a(char symbol_type, enum map_type map_type);
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size_t machine__fprintf_vmlinux_path(struct machine *machine, FILE *fp);
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#endif /* __PERF_SYMBOL */
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