156 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			156 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
 | |
|  * This program is free software; you can redistribute it and/or modify
 | |
|  * it under the terms of the GNU General Public License, version 2, as
 | |
|  * published by the Free Software Foundation.
 | |
|  *
 | |
|  * Copyright (C) 2015 Naveen N. Rao, IBM Corporation
 | |
|  */
 | |
| 
 | |
| #include "debug.h"
 | |
| #include "symbol.h"
 | |
| #include "map.h"
 | |
| #include "probe-event.h"
 | |
| #include "probe-file.h"
 | |
| 
 | |
| #ifdef HAVE_LIBELF_SUPPORT
 | |
| bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 | |
| {
 | |
| 	return ehdr.e_type == ET_EXEC ||
 | |
| 	       ehdr.e_type == ET_REL ||
 | |
| 	       ehdr.e_type == ET_DYN;
 | |
| }
 | |
| 
 | |
| #endif
 | |
| 
 | |
| int arch__choose_best_symbol(struct symbol *syma,
 | |
| 			     struct symbol *symb __maybe_unused)
 | |
| {
 | |
| 	char *sym = syma->name;
 | |
| 
 | |
| #if !defined(_CALL_ELF) || _CALL_ELF != 2
 | |
| 	/* Skip over any initial dot */
 | |
| 	if (*sym == '.')
 | |
| 		sym++;
 | |
| #endif
 | |
| 
 | |
| 	/* Avoid "SyS" kernel syscall aliases */
 | |
| 	if (strlen(sym) >= 3 && !strncmp(sym, "SyS", 3))
 | |
| 		return SYMBOL_B;
 | |
| 	if (strlen(sym) >= 10 && !strncmp(sym, "compat_SyS", 10))
 | |
| 		return SYMBOL_B;
 | |
| 
 | |
| 	return SYMBOL_A;
 | |
| }
 | |
| 
 | |
| #if !defined(_CALL_ELF) || _CALL_ELF != 2
 | |
| /* Allow matching against dot variants */
 | |
| int arch__compare_symbol_names(const char *namea, const char *nameb)
 | |
| {
 | |
| 	/* Skip over initial dot */
 | |
| 	if (*namea == '.')
 | |
| 		namea++;
 | |
| 	if (*nameb == '.')
 | |
| 		nameb++;
 | |
| 
 | |
| 	return strcmp(namea, nameb);
 | |
| }
 | |
| 
 | |
| int arch__compare_symbol_names_n(const char *namea, const char *nameb,
 | |
| 				 unsigned int n)
 | |
| {
 | |
| 	/* Skip over initial dot */
 | |
| 	if (*namea == '.')
 | |
| 		namea++;
 | |
| 	if (*nameb == '.')
 | |
| 		nameb++;
 | |
| 
 | |
| 	return strncmp(namea, nameb, n);
 | |
| }
 | |
| 
 | |
| const char *arch__normalize_symbol_name(const char *name)
 | |
| {
 | |
| 	/* Skip over initial dot */
 | |
| 	if (name && *name == '.')
 | |
| 		name++;
 | |
| 	return name;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #if defined(_CALL_ELF) && _CALL_ELF == 2
 | |
| 
 | |
| #ifdef HAVE_LIBELF_SUPPORT
 | |
| void arch__sym_update(struct symbol *s, GElf_Sym *sym)
 | |
| {
 | |
| 	s->arch_sym = sym->st_other;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #define PPC64LE_LEP_OFFSET	8
 | |
| 
 | |
| void arch__fix_tev_from_maps(struct perf_probe_event *pev,
 | |
| 			     struct probe_trace_event *tev, struct map *map,
 | |
| 			     struct symbol *sym)
 | |
| {
 | |
| 	int lep_offset;
 | |
| 
 | |
| 	/*
 | |
| 	 * When probing at a function entry point, we normally always want the
 | |
| 	 * LEP since that catches calls to the function through both the GEP and
 | |
| 	 * the LEP. Hence, we would like to probe at an offset of 8 bytes if
 | |
| 	 * the user only specified the function entry.
 | |
| 	 *
 | |
| 	 * However, if the user specifies an offset, we fall back to using the
 | |
| 	 * GEP since all userspace applications (objdump/readelf) show function
 | |
| 	 * disassembly with offsets from the GEP.
 | |
| 	 */
 | |
| 	if (pev->point.offset || !map || !sym)
 | |
| 		return;
 | |
| 
 | |
| 	/* For kretprobes, add an offset only if the kernel supports it */
 | |
| 	if (!pev->uprobes && pev->point.retprobe) {
 | |
| #ifdef HAVE_LIBELF_SUPPORT
 | |
| 		if (!kretprobe_offset_is_supported())
 | |
| #endif
 | |
| 			return;
 | |
| 	}
 | |
| 
 | |
| 	lep_offset = PPC64_LOCAL_ENTRY_OFFSET(sym->arch_sym);
 | |
| 
 | |
| 	if (map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS)
 | |
| 		tev->point.offset += PPC64LE_LEP_OFFSET;
 | |
| 	else if (lep_offset) {
 | |
| 		if (pev->uprobes)
 | |
| 			tev->point.address += lep_offset;
 | |
| 		else
 | |
| 			tev->point.offset += lep_offset;
 | |
| 	}
 | |
| }
 | |
| 
 | |
| #ifdef HAVE_LIBELF_SUPPORT
 | |
| void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
 | |
| 					   int ntevs)
 | |
| {
 | |
| 	struct probe_trace_event *tev;
 | |
| 	struct map *map;
 | |
| 	struct symbol *sym = NULL;
 | |
| 	struct rb_node *tmp;
 | |
| 	int i = 0;
 | |
| 
 | |
| 	map = get_target_map(pev->target, pev->nsi, pev->uprobes);
 | |
| 	if (!map || map__load(map) < 0)
 | |
| 		return;
 | |
| 
 | |
| 	for (i = 0; i < ntevs; i++) {
 | |
| 		tev = &pev->tevs[i];
 | |
| 		map__for_each_symbol(map, sym, tmp) {
 | |
| 			if (map->unmap_ip(map, sym->start) == tev->point.address) {
 | |
| 				arch__fix_tev_from_maps(pev, tev, map, sym);
 | |
| 				break;
 | |
| 			}
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| #endif /* HAVE_LIBELF_SUPPORT */
 | |
| 
 | |
| #endif
 | 
