text: // SPDX-License-Identifier: GPL-2.0
  #include <linux/compiler.h>
  #include <linux/rbtree.h>
  #include <inttypes.h>
  #include <string.h>
  #include "map.h"
  #include "symbol.h"
  #include "util.h"
  #include "tests.h"
  #include "debug.h"
  #include "machine.h"
  
  #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))
  
  int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused)
  {
  	int err = -1;
  	struct rb_node *nd;
  	struct symbol *sym;
  	struct map *kallsyms_map, *vmlinux_map, *map;
  	struct machine kallsyms, vmlinux;
  	struct maps *maps = machine__kernel_maps(&vmlinux);
  	u64 mem_start, mem_end;
  	bool header_printed;
  
  	/*
  	 * Step 1:
  	 *
  	 * Init the machines that will hold kernel, modules obtained from
  	 * both vmlinux + .ko files and from /proc/kallsyms split by modules.
  	 */
  	machine__init(&kallsyms, "", HOST_KERNEL_ID);
  	machine__init(&vmlinux, "", HOST_KERNEL_ID);
  
  	/*
  	 * Step 2:
  	 *
  	 * Create the kernel maps for kallsyms and the DSO where we will then
  	 * load /proc/kallsyms. Also create the modules maps from /proc/modules
  	 * and find the .ko files that match them in /lib/modules/`uname -r`/.
  	 */
  	if (machine__create_kernel_maps(&kallsyms) < 0) {
  		pr_debug("machine__create_kernel_maps ");
  		goto out;
  	}
  
  	/*
  	 * Step 3:
  	 *
  	 * Load and split /proc/kallsyms into multiple maps, one per module.
  	 * Do not use kcore, as this test was designed before kcore support
  	 * and has parts that only make sense if using the non-kcore code.
  	 * XXX: extend it to stress the kcorre code as well, hint: the list
  	 * of modules extracted from /proc/kcore, in its current form, can't
  	 * be compacted against the list of modules found in the "vmlinux"
  	 * code and with the one got from /proc/modules from the "kallsyms" code.
  	 */
  	if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms") <= 0) {
  		pr_debug("dso__load_kallsyms ");
  		goto out;
  	}
  
  	/*
  	 * Step 4:
  	 *
  	 * kallsyms will be internally on demand sorted by name so that we can
  	 * find the reference relocation * symbol, i.e. the symbol we will use
  	 * to see if the running kernel was relocated by checking if it has the
  	 * same value in the vmlinux file we load.
  	 */
  	kallsyms_map = machine__kernel_map(&kallsyms);
  
  	/*
  	 * Step 5:
  	 *
  	 * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
  	 */
  	if (machine__create_kernel_maps(&vmlinux) < 0) {
  		pr_debug("machine__create_kernel_maps ");
  		goto out;
  	}
  
  	vmlinux_map = machine__kernel_map(&vmlinux);
  
  	/*
  	 * Step 6:
  	 *
  	 * Locate a vmlinux file in the vmlinux path that has a buildid that
  	 * matches the one of the running kernel.
  	 *
  	 * While doing that look if we find the ref reloc symbol, if we find it
  	 * we'll have its ref_reloc_symbol.unrelocated_addr and then
  	 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
  	 * to fixup the symbols.
  	 */
  	if (machine__load_vmlinux_path(&vmlinux) <= 0) {
  		pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
  		err = TEST_SKIP;
  		goto out;
  	}
  
  	err = 0;
  	/*
  	 * Step 7:
  	 *
  	 * Now look at the symbols in the vmlinux DSO and check if we find all of them
  	 * in the kallsyms dso. For the ones that are in both, check its names and
  	 * end addresses too.
  	 */
  	map__for_each_symbol(vmlinux_map, sym, nd) {
  		struct symbol *pair, *first_pair;
  
  		sym  = rb_entry(nd, struct symbol, rb_node);
  
  		if (sym->start == sym->end)
  			continue;
  
  		mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start);
  		mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end);
  
  		first_pair = machine__find_kernel_symbol(&kallsyms, mem_start, NULL);
  		pair = first_pair;
  
  		if (pair && UM(pair->start) == mem_start) {
  next_pair:
  			if (arch__compare_symbol_names(sym->name, pair->name) == 0) {
  				/*
  				 * kallsyms don't have the symbol end, so we
  				 * set that by using the next symbol start - 1,
  				 * in some cases we get this up to a page
  				 * wrong, trace_kmalloc when I was developing
  				 * this code was one such example, 2106 bytes
  				 * off the real size. More than that and we
  				 * _really_ have a problem.
  				 */
  				s64 skew = mem_end - UM(pair->end);
  				if (llabs(skew) >= page_size)
  					pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
  						 mem_start, sym->name, mem_end,
  						 UM(pair->end));
  
  				/*
  				 * Do not count this as a failure, because we
  				 * could really find a case where it's not
  				 * possible to get proper function end from
  				 * kallsyms.
  				 */
  				continue;
  			} else {
  				pair = machine__find_kernel_symbol_by_name(&kallsyms, sym->name, NULL);
  				if (pair) {
  					if (UM(pair->start) == mem_start)
  						goto next_pair;
  
  					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
  						 mem_start, sym->name, pair->name);
  				} else {
  					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
  						 mem_start, sym->name, first_pair->name);
  				}
  
  				continue;
  			}
  		} else
  			pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
  				 mem_start, sym->name);
  
  		err = -1;
  	}
  
  	if (verbose <= 0)
  		goto out;
  
  	header_printed = false;
  
  	for (map = maps__first(maps); map; map = map__next(map)) {
  		struct map *
  		/*
  		 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
  		 * the kernel will have the path for the vmlinux file being used,
  		 * so use the short name, less descriptive but the same ("[kernel]" in
  		 * both cases.
  		 */
  		pair = map_groups__find_by_name(&kallsyms.kmaps,
  						(map->dso->kernel ?
  							map->dso->short_name :
  							map->dso->name));
  		if (pair) {
  			pair->priv = 1;
  		} else {
  			if (!header_printed) {
  				pr_info("WARN: Maps only in vmlinux:\n");
  				header_printed = true;
  			}
  			map__fprintf(map, stderr);
  		}
  	}
  
  	header_printed = false;
  
  	for (map = maps__first(maps); map; map = map__next(map)) {
  		struct map *pair;
  
  		mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start);
  		mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end);
  
  		pair = map_groups__find(&kallsyms.kmaps, mem_start);
  		if (pair == NULL || pair->priv)
  			continue;
  
  		if (pair->start == mem_start) {
  			if (!header_printed) {
  				pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
  				header_printed = true;
  			}
  
  			pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
  				map->start, map->end, map->pgoff, map->dso->name);
  			if (mem_end != pair->end)
  				pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64,
  					pair->start, pair->end, pair->pgoff);
  			pr_info(" %s\n", pair->dso->name);
  			pair->priv = 1;
  		}
  	}
  
  	header_printed = false;
  
  	maps = machine__kernel_maps(&kallsyms);
  
  	for (map = maps__first(maps); map; map = map__next(map)) {
  		if (!map->priv) {
  			if (!header_printed) {
  				pr_info("WARN: Maps only in kallsyms:\n");
  				header_printed = true;
  			}
  			map__fprintf(map, stderr);
  		}
  	}
  out:
  	machine__exit(&kallsyms);
  	machine__exit(&vmlinux);
  	return err;
  }
  