1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/types.h> 3 #include <linux/string.h> 4 #include <stdlib.h> 5 6 #include "../../util/machine.h" 7 #include "../../util/map.h" 8 #include "../../util/symbol.h" 9 #include "../../util/sane_ctype.h" 10 11 #include <symbol/kallsyms.h> 12 13 #if defined(__x86_64__) 14 15 struct extra_kernel_map_info { 16 int cnt; 17 int max_cnt; 18 struct extra_kernel_map *maps; 19 bool get_entry_trampolines; 20 u64 entry_trampoline; 21 }; 22 23 static int add_extra_kernel_map(struct extra_kernel_map_info *mi, u64 start, 24 u64 end, u64 pgoff, const char *name) 25 { 26 if (mi->cnt >= mi->max_cnt) { 27 void *buf; 28 size_t sz; 29 30 mi->max_cnt = mi->max_cnt ? mi->max_cnt * 2 : 32; 31 sz = sizeof(struct extra_kernel_map) * mi->max_cnt; 32 buf = realloc(mi->maps, sz); 33 if (!buf) 34 return -1; 35 mi->maps = buf; 36 } 37 38 mi->maps[mi->cnt].start = start; 39 mi->maps[mi->cnt].end = end; 40 mi->maps[mi->cnt].pgoff = pgoff; 41 strlcpy(mi->maps[mi->cnt].name, name, KMAP_NAME_LEN); 42 43 mi->cnt += 1; 44 45 return 0; 46 } 47 48 static int find_extra_kernel_maps(void *arg, const char *name, char type, 49 u64 start) 50 { 51 struct extra_kernel_map_info *mi = arg; 52 53 if (!mi->entry_trampoline && kallsyms2elf_binding(type) == STB_GLOBAL && 54 !strcmp(name, "_entry_trampoline")) { 55 mi->entry_trampoline = start; 56 return 0; 57 } 58 59 if (is_entry_trampoline(name)) { 60 u64 end = start + page_size; 61 62 return add_extra_kernel_map(mi, start, end, 0, name); 63 } 64 65 return 0; 66 } 67 68 int machine__create_extra_kernel_maps(struct machine *machine, 69 struct dso *kernel) 70 { 71 struct extra_kernel_map_info mi = { .cnt = 0, }; 72 char filename[PATH_MAX]; 73 int ret; 74 int i; 75 76 machine__get_kallsyms_filename(machine, filename, PATH_MAX); 77 78 if (symbol__restricted_filename(filename, "/proc/kallsyms")) 79 return 0; 80 81 ret = kallsyms__parse(filename, &mi, find_extra_kernel_maps); 82 if (ret) 83 goto out_free; 84 85 if (!mi.entry_trampoline) 86 goto out_free; 87 88 for (i = 0; i < mi.cnt; i++) { 89 struct extra_kernel_map *xm = &mi.maps[i]; 90 91 xm->pgoff = mi.entry_trampoline; 92 ret = machine__create_extra_kernel_map(machine, kernel, xm); 93 if (ret) 94 goto out_free; 95 } 96 97 machine->trampolines_mapped = mi.cnt; 98 out_free: 99 free(mi.maps); 100 return ret; 101 } 102 103 #endif 104