![Hemant Kumar](/assets/img/avatar_default.png)
This patch serves the initial support to identify and list SDT events in binaries. When programs containing SDT markers are compiled, gcc with the help of assembler directives identifies them and places them in the section ".note.stapsdt". To find these markers from the binaries, one needs to traverse through this section and parse the relevant details like the name, type and location of the marker. Also, the original location could be skewed due to the effect of prelinking. If that is the case, the locations need to be adjusted. The functions in this patch open a given ELF, find out the SDT section, parse the relevant details, adjust the location (if necessary) and populate them in a list. A typical note entry in ".note.stapsdt" section is as follows : |--nhdr.n_namesz--| ------------------------------------ | nhdr | "stapsdt" | ----- |----------------------------------| | | <location> <base_address> | | | <semaphore> | nhdr.n_descsize | "provider_name" "note_name" | | | <args> | ----- |----------------------------------| | nhdr | "stapsdt" | |... The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note. After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments. Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/146736022628.27797.1201368329092908163.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
368 lines
9.4 KiB
C
368 lines
9.4 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 "../perf.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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#include <byteswap.h>
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#include <libgen.h>
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#include "build-id.h"
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#include "event.h"
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#include "util.h"
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#ifdef HAVE_LIBELF_SUPPORT
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#include <libelf.h>
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#include <gelf.h>
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#endif
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#include <elf.h>
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#include "dso.h"
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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 HAVE_LIBELF_MMAP_SUPPORT
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# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP
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#else
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# define PERF_ELF_C_READ_MMAP ELF_C_READ
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#endif
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#ifdef HAVE_LIBELF_SUPPORT
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Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
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GElf_Shdr *shp, const char *name, size_t *idx);
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#endif
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#ifndef DMGL_PARAMS
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#define DMGL_NO_OPTS 0 /* For readability... */
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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 DSO__NAME_KALLSYMS "[kernel.kallsyms]"
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#define DSO__NAME_KCORE "[kernel.kcore]"
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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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u8 arch_sym;
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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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void symbols__delete(struct rb_root *symbols);
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/* symbols__for_each_entry - iterate over symbols (rb_root)
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*
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* @symbols: the rb_root of symbols
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* @pos: the 'struct symbol *' to use as a loop cursor
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* @nd: the 'struct rb_node *' to use as a temporary storage
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*/
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#define symbols__for_each_entry(symbols, pos, nd) \
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for (nd = rb_first(symbols); \
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nd && (pos = rb_entry(nd, struct symbol, rb_node)); \
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nd = rb_next(nd))
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static inline size_t symbol__size(const struct symbol *sym)
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{
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return sym->end - sym->start;
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}
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struct strlist;
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struct intlist;
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struct symbol_conf {
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unsigned short priv_size;
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unsigned short nr_events;
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bool try_vmlinux_path,
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force,
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ignore_vmlinux,
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ignore_vmlinux_buildid,
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show_kernel_path,
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use_modules,
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allow_aliases,
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sort_by_name,
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show_nr_samples,
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show_total_period,
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use_callchain,
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cumulate_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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annotate_asm_raw,
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annotate_src,
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event_group,
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demangle,
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demangle_kernel,
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filter_relative,
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show_hist_headers,
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branch_callstack,
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has_filter,
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show_ref_callgraph,
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hide_unresolved,
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raw_trace,
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report_hierarchy;
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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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*pid_list_str,
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*tid_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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*dso_from_list,
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*dso_to_list,
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*sym_from_list,
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*sym_to_list;
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struct intlist *pid_list,
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*tid_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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struct symbol_name_rb_node {
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struct rb_node rb_node;
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struct symbol sym;
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};
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static inline int __symbol__join_symfs(char *bf, size_t size, const char *path)
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{
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return path__join(bf, size, symbol_conf.symfs, path);
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}
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#define symbol__join_symfs(bf, path) __symbol__join_symfs(bf, sizeof(bf), path)
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extern int vmlinux_path__nr_entries;
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extern char **vmlinux_path;
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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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};
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struct addr_map_symbol {
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struct map *map;
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struct symbol *sym;
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u64 addr;
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u64 al_addr;
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};
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struct branch_info {
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struct addr_map_symbol from;
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struct addr_map_symbol to;
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struct branch_flags flags;
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char *srcline_from;
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char *srcline_to;
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};
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struct mem_info {
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struct addr_map_symbol iaddr;
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struct addr_map_symbol daddr;
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union perf_mem_data_src data_src;
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};
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struct addr_location {
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struct machine *machine;
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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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u8 filtered;
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u8 cpumode;
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s32 cpu;
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s32 socket;
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};
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struct symsrc {
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char *name;
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int fd;
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enum dso_binary_type type;
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#ifdef HAVE_LIBELF_SUPPORT
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Elf *elf;
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GElf_Ehdr ehdr;
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Elf_Scn *opdsec;
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size_t opdidx;
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GElf_Shdr opdshdr;
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Elf_Scn *symtab;
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GElf_Shdr symshdr;
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Elf_Scn *dynsym;
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size_t dynsym_idx;
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GElf_Shdr dynshdr;
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bool adjust_symbols;
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bool is_64_bit;
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#endif
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};
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void symsrc__destroy(struct symsrc *ss);
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int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
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enum dso_binary_type type);
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bool symsrc__has_symtab(struct symsrc *ss);
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bool symsrc__possibly_runtime(struct symsrc *ss);
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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, bool vmlinux_allocated,
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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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bool no_kcore, 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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void dso__insert_symbol(struct dso *dso, enum map_type type,
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struct symbol *sym);
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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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struct symbol *symbol__next_by_name(struct symbol *sym);
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struct symbol *dso__first_symbol(struct dso *dso, enum map_type type);
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struct symbol *dso__next_symbol(struct symbol *sym);
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enum dso_type dso__type_fd(int fd);
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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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int modules__parse(const char *filename, void *arg,
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int (*process_module)(void *arg, const char *name,
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u64 start));
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int filename__read_debuglink(const char *filename, char *debuglink,
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size_t size);
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struct perf_env;
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int symbol__init(struct perf_env *env);
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void symbol__exit(void);
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void symbol__elf_init(void);
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struct symbol *symbol__new(u64 start, u64 len, u8 binding, const char *name);
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size_t __symbol__fprintf_symname_offs(const struct symbol *sym,
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const struct addr_location *al,
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bool unknown_as_addr, FILE *fp);
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size_t symbol__fprintf_symname_offs(const struct symbol *sym,
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const struct addr_location *al, FILE *fp);
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size_t __symbol__fprintf_symname(const struct symbol *sym,
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const struct addr_location *al,
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bool unknown_as_addr, FILE *fp);
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size_t symbol__fprintf_symname(const struct symbol *sym, FILE *fp);
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size_t symbol__fprintf(struct symbol *sym, FILE *fp);
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bool symbol_type__is_a(char symbol_type, enum map_type map_type);
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bool symbol__restricted_filename(const char *filename,
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const char *restricted_filename);
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bool symbol__is_idle(struct symbol *sym);
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int symbol__config_symfs(const struct option *opt __maybe_unused,
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const char *dir, int unset __maybe_unused);
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int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
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struct symsrc *runtime_ss, symbol_filter_t filter,
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int kmodule);
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int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss,
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struct map *map, symbol_filter_t filter);
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void symbols__insert(struct rb_root *symbols, struct symbol *sym);
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void symbols__fixup_duplicate(struct rb_root *symbols);
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void symbols__fixup_end(struct rb_root *symbols);
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void __map_groups__fixup_end(struct map_groups *mg, enum map_type type);
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typedef int (*mapfn_t)(u64 start, u64 len, u64 pgoff, void *data);
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int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
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bool *is_64_bit);
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#define PERF_KCORE_EXTRACT "/tmp/perf-kcore-XXXXXX"
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struct kcore_extract {
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char *kcore_filename;
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u64 addr;
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u64 offs;
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u64 len;
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char extract_filename[sizeof(PERF_KCORE_EXTRACT)];
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int fd;
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};
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int kcore_extract__create(struct kcore_extract *kce);
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void kcore_extract__delete(struct kcore_extract *kce);
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int kcore_copy(const char *from_dir, const char *to_dir);
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int compare_proc_modules(const char *from, const char *to);
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int setup_list(struct strlist **list, const char *list_str,
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const char *list_name);
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int setup_intlist(struct intlist **list, const char *list_str,
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const char *list_name);
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#ifdef HAVE_LIBELF_SUPPORT
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bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
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void arch__sym_update(struct symbol *s, GElf_Sym *sym);
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#endif
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#define SYMBOL_A 0
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#define SYMBOL_B 1
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int arch__choose_best_symbol(struct symbol *syma, struct symbol *symb);
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/* structure containing an SDT note's info */
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struct sdt_note {
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char *name; /* name of the note*/
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char *provider; /* provider name */
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bool bit32; /* whether the location is 32 bits? */
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union { /* location, base and semaphore addrs */
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Elf64_Addr a64[3];
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Elf32_Addr a32[3];
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} addr;
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struct list_head note_list; /* SDT notes' list */
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};
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int get_sdt_note_list(struct list_head *head, const char *target);
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int cleanup_sdt_note_list(struct list_head *sdt_notes);
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int sdt_notes__get_count(struct list_head *start);
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#define SDT_BASE_SCN ".stapsdt.base"
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#define SDT_NOTE_SCN ".note.stapsdt"
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#define SDT_NOTE_TYPE 3
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#define SDT_NOTE_NAME "stapsdt"
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#define NR_ADDR 3
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#endif /* __PERF_SYMBOL */
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