1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/compiler.h>
  3#include <linux/rbtree.h>
  4#include <inttypes.h>
  5#include <string.h>
  6#include "map.h"
  7#include "symbol.h"
  8#include "util.h"
  9#include "tests.h"
 10#include "debug.h"
 11#include "machine.h"
 12
 13#define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))
 14
 15int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused)
 16{
 17	int err = -1;
 18	struct rb_node *nd;
 19	struct symbol *sym;
 20	struct map *kallsyms_map, *vmlinux_map, *map;
 21	struct machine kallsyms, vmlinux;
 22	enum map_type type = MAP__FUNCTION;
 23	struct maps *maps = &vmlinux.kmaps.maps[type];
 24	u64 mem_start, mem_end;
 25	bool header_printed;
 26
 27	/*
 28	 * Step 1:
 29	 *
 30	 * Init the machines that will hold kernel, modules obtained from
 31	 * both vmlinux + .ko files and from /proc/kallsyms split by modules.
 32	 */
 33	machine__init(&kallsyms, "", HOST_KERNEL_ID);
 34	machine__init(&vmlinux, "", HOST_KERNEL_ID);
 35
 36	/*
 37	 * Step 2:
 38	 *
 39	 * Create the kernel maps for kallsyms and the DSO where we will then
 40	 * load /proc/kallsyms. Also create the modules maps from /proc/modules
 41	 * and find the .ko files that match them in /lib/modules/`uname -r`/.
 42	 */
 43	if (machine__create_kernel_maps(&kallsyms) < 0) {
 44		pr_debug("machine__create_kernel_maps ");
 45		goto out;
 46	}
 47
 48	/*
 49	 * Step 3:
 50	 *
 51	 * Load and split /proc/kallsyms into multiple maps, one per module.
 52	 * Do not use kcore, as this test was designed before kcore support
 53	 * and has parts that only make sense if using the non-kcore code.
 54	 * XXX: extend it to stress the kcorre code as well, hint: the list
 55	 * of modules extracted from /proc/kcore, in its current form, can't
 56	 * be compacted against the list of modules found in the "vmlinux"
 57	 * code and with the one got from /proc/modules from the "kallsyms" code.
 58	 */
 59	if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type) <= 0) {
 60		pr_debug("dso__load_kallsyms ");
 61		goto out;
 62	}
 63
 64	/*
 65	 * Step 4:
 66	 *
 67	 * kallsyms will be internally on demand sorted by name so that we can
 68	 * find the reference relocation * symbol, i.e. the symbol we will use
 69	 * to see if the running kernel was relocated by checking if it has the
 70	 * same value in the vmlinux file we load.
 71	 */
 72	kallsyms_map = machine__kernel_map(&kallsyms);
 73
 74	/*
 75	 * Step 5:
 76	 *
 77	 * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
 78	 */
 79	if (machine__create_kernel_maps(&vmlinux) < 0) {
 80		pr_debug("machine__create_kernel_maps ");
 81		goto out;
 82	}
 83
 84	vmlinux_map = machine__kernel_map(&vmlinux);
 85
 86	/*
 87	 * Step 6:
 88	 *
 89	 * Locate a vmlinux file in the vmlinux path that has a buildid that
 90	 * matches the one of the running kernel.
 91	 *
 92	 * While doing that look if we find the ref reloc symbol, if we find it
 93	 * we'll have its ref_reloc_symbol.unrelocated_addr and then
 94	 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
 95	 * to fixup the symbols.
 96	 */
 97	if (machine__load_vmlinux_path(&vmlinux, type) <= 0) {
 98		pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
 99		err = TEST_SKIP;
100		goto out;
101	}
102
103	err = 0;
104	/*
105	 * Step 7:
106	 *
107	 * Now look at the symbols in the vmlinux DSO and check if we find all of them
108	 * in the kallsyms dso. For the ones that are in both, check its names and
109	 * end addresses too.
110	 */
111	for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) {
112		struct symbol *pair, *first_pair;
113
114		sym  = rb_entry(nd, struct symbol, rb_node);
115
116		if (sym->start == sym->end)
117			continue;
118
119		mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start);
120		mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end);
121
122		first_pair = machine__find_kernel_symbol(&kallsyms, type,
123							 mem_start, NULL);
124		pair = first_pair;
125
126		if (pair && UM(pair->start) == mem_start) {
127next_pair:
128			if (arch__compare_symbol_names(sym->name, pair->name) == 0) {
129				/*
130				 * kallsyms don't have the symbol end, so we
131				 * set that by using the next symbol start - 1,
132				 * in some cases we get this up to a page
133				 * wrong, trace_kmalloc when I was developing
134				 * this code was one such example, 2106 bytes
135				 * off the real size. More than that and we
136				 * _really_ have a problem.
137				 */
138				s64 skew = mem_end - UM(pair->end);
139				if (llabs(skew) >= page_size)
140					pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
141						 mem_start, sym->name, mem_end,
142						 UM(pair->end));
143
144				/*
145				 * Do not count this as a failure, because we
146				 * could really find a case where it's not
147				 * possible to get proper function end from
148				 * kallsyms.
149				 */
150				continue;
151			} else {
152				pair = machine__find_kernel_symbol_by_name(&kallsyms, type, sym->name, NULL);
153				if (pair) {
154					if (UM(pair->start) == mem_start)
155						goto next_pair;
156
157					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
158						 mem_start, sym->name, pair->name);
159				} else {
160					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
161						 mem_start, sym->name, first_pair->name);
162				}
163
164				continue;
165			}
166		} else
167			pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
168				 mem_start, sym->name);
169
170		err = -1;
171	}
172
173	if (verbose <= 0)
174		goto out;
175
176	header_printed = false;
177
178	for (map = maps__first(maps); map; map = map__next(map)) {
179		struct map *
180		/*
181		 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
182		 * the kernel will have the path for the vmlinux file being used,
183		 * so use the short name, less descriptive but the same ("[kernel]" in
184		 * both cases.
185		 */
186		pair = map_groups__find_by_name(&kallsyms.kmaps, type,
187						(map->dso->kernel ?
188							map->dso->short_name :
189							map->dso->name));
190		if (pair) {
191			pair->priv = 1;
192		} else {
193			if (!header_printed) {
194				pr_info("WARN: Maps only in vmlinux:\n");
195				header_printed = true;
196			}
197			map__fprintf(map, stderr);
198		}
199	}
200
201	header_printed = false;
202
203	for (map = maps__first(maps); map; map = map__next(map)) {
204		struct map *pair;
205
206		mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start);
207		mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end);
208
209		pair = map_groups__find(&kallsyms.kmaps, type, mem_start);
210		if (pair == NULL || pair->priv)
211			continue;
212
213		if (pair->start == mem_start) {
214			if (!header_printed) {
215				pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
216				header_printed = true;
217			}
218
219			pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
220				map->start, map->end, map->pgoff, map->dso->name);
221			if (mem_end != pair->end)
222				pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64,
223					pair->start, pair->end, pair->pgoff);
224			pr_info(" %s\n", pair->dso->name);
225			pair->priv = 1;
226		}
227	}
228
229	header_printed = false;
230
231	maps = &kallsyms.kmaps.maps[type];
232
233	for (map = maps__first(maps); map; map = map__next(map)) {
234		if (!map->priv) {
235			if (!header_printed) {
236				pr_info("WARN: Maps only in kallsyms:\n");
237				header_printed = true;
238			}
239			map__fprintf(map, stderr);
240		}
241	}
242out:
243	machine__exit(&kallsyms);
244	machine__exit(&vmlinux);
245	return err;
246}