diff options
Diffstat (limited to 'lib/alloc_tag.c')
| -rw-r--r-- | lib/alloc_tag.c | 1029 |
1 files changed, 0 insertions, 1029 deletions
diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c deleted file mode 100644 index e5b218176c5a..000000000000 --- a/lib/alloc_tag.c +++ /dev/null @@ -1,1029 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -#include <linux/alloc_tag.h> -#include <linux/execmem.h> -#include <linux/fs.h> -#include <linux/gfp.h> -#include <linux/kallsyms.h> -#include <linux/module.h> -#include <linux/page_ext.h> -#include <linux/pgalloc_tag.h> -#include <linux/proc_fs.h> -#include <linux/rcupdate.h> -#include <linux/seq_buf.h> -#include <linux/seq_file.h> -#include <linux/string_choices.h> -#include <linux/vmalloc.h> -#include <linux/kmemleak.h> - -#define ALLOCINFO_FILE_NAME "allocinfo" -#define MODULE_ALLOC_TAG_VMAP_SIZE (100000UL * sizeof(struct alloc_tag)) -#define SECTION_START(NAME) (CODETAG_SECTION_START_PREFIX NAME) -#define SECTION_STOP(NAME) (CODETAG_SECTION_STOP_PREFIX NAME) - -#ifdef CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT -static bool mem_profiling_support = true; -#else -static bool mem_profiling_support; -#endif - -/* - * Memory allocation profiling is permanently disabled and cannot be enabled. - * Must be called after setup_early_mem_profiling(). - */ -bool mem_alloc_profiling_permanently_disabled(void) -{ - return !mem_profiling_support; -} - -static struct codetag_type *alloc_tag_cttype; - -#ifdef CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU -DEFINE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag); -EXPORT_SYMBOL(_shared_alloc_tag); -#endif - -DEFINE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT, - mem_alloc_profiling_key); -EXPORT_SYMBOL(mem_alloc_profiling_key); - -DEFINE_STATIC_KEY_FALSE(mem_profiling_compressed); - -struct alloc_tag_kernel_section kernel_tags = { NULL, 0 }; -unsigned long alloc_tag_ref_mask; -int alloc_tag_ref_offs; - -struct allocinfo_private { - struct codetag_iterator iter; - struct codetag_iterator reported_iter; - bool print_header; -}; - -static void *allocinfo_start(struct seq_file *m, loff_t *pos) -{ - struct allocinfo_private *priv; - loff_t node = *pos; - - priv = (struct allocinfo_private *)m->private; - codetag_lock_module_list(alloc_tag_cttype); - if (node == 0) { - priv->print_header = true; - priv->iter = codetag_get_ct_iter(alloc_tag_cttype); - } else { - priv->iter = priv->reported_iter; - } - codetag_next_ct(&priv->iter); - return priv->iter.ct ? priv : NULL; -} - -static void *allocinfo_next(struct seq_file *m, void *arg, loff_t *pos) -{ - struct allocinfo_private *priv = (struct allocinfo_private *)arg; - struct codetag *ct; - - priv->reported_iter = priv->iter; - ct = codetag_next_ct(&priv->iter); - (*pos)++; - if (!ct) - return NULL; - - return priv; -} - -static void allocinfo_stop(struct seq_file *m, void *arg) -{ - codetag_unlock_module_list(alloc_tag_cttype); -} - -static void print_allocinfo_header(struct seq_buf *buf) -{ - /* Output format version, so we can change it. */ - seq_buf_printf(buf, "allocinfo - version: 2.0\n"); - seq_buf_printf(buf, "# <size> <calls> <tag info>\n"); -} - -static void alloc_tag_to_text(struct seq_buf *out, struct codetag *ct) -{ - struct alloc_tag *tag = ct_to_alloc_tag(ct); - struct alloc_tag_counters counter = alloc_tag_read(tag); - s64 bytes = counter.bytes; - - seq_buf_printf(out, "%12lli %8llu ", bytes, counter.calls); - codetag_to_text(out, ct); - if (unlikely(alloc_tag_is_inaccurate(tag))) - seq_buf_printf(out, " accurate:no"); - seq_buf_putc(out, ' '); - seq_buf_putc(out, '\n'); -} - -static int allocinfo_show(struct seq_file *m, void *arg) -{ - struct allocinfo_private *priv = (struct allocinfo_private *)arg; - char *bufp; - size_t n = seq_get_buf(m, &bufp); - struct seq_buf buf; - - seq_buf_init(&buf, bufp, n); - if (priv->print_header) { - print_allocinfo_header(&buf); - priv->print_header = false; - } - alloc_tag_to_text(&buf, priv->iter.ct); - seq_commit(m, seq_buf_used(&buf)); - return 0; -} - -static const struct seq_operations allocinfo_seq_op = { - .start = allocinfo_start, - .next = allocinfo_next, - .stop = allocinfo_stop, - .show = allocinfo_show, -}; - -size_t alloc_tag_top_users(struct codetag_bytes *tags, size_t count, bool can_sleep) -{ - struct codetag_iterator iter; - struct codetag *ct; - struct codetag_bytes n; - unsigned int i, nr = 0; - - if (IS_ERR_OR_NULL(alloc_tag_cttype)) - return 0; - - if (can_sleep) - codetag_lock_module_list(alloc_tag_cttype); - else if (!codetag_trylock_module_list(alloc_tag_cttype)) - return 0; - - iter = codetag_get_ct_iter(alloc_tag_cttype); - while ((ct = codetag_next_ct(&iter))) { - struct alloc_tag_counters counter = alloc_tag_read(ct_to_alloc_tag(ct)); - - n.ct = ct; - n.bytes = counter.bytes; - - for (i = 0; i < nr; i++) - if (n.bytes > tags[i].bytes) - break; - - if (i < count) { - nr -= nr == count; - memmove(&tags[i + 1], - &tags[i], - sizeof(tags[0]) * (nr - i)); - nr++; - tags[i] = n; - } - } - - codetag_unlock_module_list(alloc_tag_cttype); - - return nr; -} - -void pgalloc_tag_split(struct folio *folio, int old_order, int new_order) -{ - int i; - struct alloc_tag *tag; - unsigned int nr_pages = 1 << new_order; - - if (!mem_alloc_profiling_enabled()) - return; - - tag = __pgalloc_tag_get(&folio->page); - if (!tag) - return; - - for (i = nr_pages; i < (1 << old_order); i += nr_pages) { - union pgtag_ref_handle handle; - union codetag_ref ref; - - if (get_page_tag_ref(folio_page(folio, i), &ref, &handle)) { - /* Set new reference to point to the original tag */ - alloc_tag_ref_set(&ref, tag); - update_page_tag_ref(handle, &ref); - put_page_tag_ref(handle); - } - } -} - -void pgalloc_tag_swap(struct folio *new, struct folio *old) -{ - union pgtag_ref_handle handle_old, handle_new; - union codetag_ref ref_old, ref_new; - struct alloc_tag *tag_old, *tag_new; - - if (!mem_alloc_profiling_enabled()) - return; - - tag_old = __pgalloc_tag_get(&old->page); - if (!tag_old) - return; - tag_new = __pgalloc_tag_get(&new->page); - if (!tag_new) - return; - - if (!get_page_tag_ref(&old->page, &ref_old, &handle_old)) - return; - if (!get_page_tag_ref(&new->page, &ref_new, &handle_new)) { - put_page_tag_ref(handle_old); - return; - } - - /* - * Clear tag references to avoid debug warning when using - * __alloc_tag_ref_set() with non-empty reference. - */ - set_codetag_empty(&ref_old); - set_codetag_empty(&ref_new); - - /* swap tags */ - __alloc_tag_ref_set(&ref_old, tag_new); - update_page_tag_ref(handle_old, &ref_old); - __alloc_tag_ref_set(&ref_new, tag_old); - update_page_tag_ref(handle_new, &ref_new); - - put_page_tag_ref(handle_old); - put_page_tag_ref(handle_new); -} - -static void shutdown_mem_profiling(bool remove_file) -{ - if (mem_alloc_profiling_enabled()) - static_branch_disable(&mem_alloc_profiling_key); - - if (!mem_profiling_support) - return; - - if (remove_file) - remove_proc_entry(ALLOCINFO_FILE_NAME, NULL); - mem_profiling_support = false; -} - -void __init alloc_tag_sec_init(void) -{ - struct alloc_tag *last_codetag; - - if (!mem_profiling_support) - return; - - if (!static_key_enabled(&mem_profiling_compressed)) - return; - - kernel_tags.first_tag = (struct alloc_tag *)kallsyms_lookup_name( - SECTION_START(ALLOC_TAG_SECTION_NAME)); - last_codetag = (struct alloc_tag *)kallsyms_lookup_name( - SECTION_STOP(ALLOC_TAG_SECTION_NAME)); - kernel_tags.count = last_codetag - kernel_tags.first_tag; - - /* Check if kernel tags fit into page flags */ - if (kernel_tags.count > (1UL << NR_UNUSED_PAGEFLAG_BITS)) { - shutdown_mem_profiling(false); /* allocinfo file does not exist yet */ - pr_err("%lu allocation tags cannot be references using %d available page flag bits. Memory allocation profiling is disabled!\n", - kernel_tags.count, NR_UNUSED_PAGEFLAG_BITS); - return; - } - - alloc_tag_ref_offs = (LRU_REFS_PGOFF - NR_UNUSED_PAGEFLAG_BITS); - alloc_tag_ref_mask = ((1UL << NR_UNUSED_PAGEFLAG_BITS) - 1); - pr_debug("Memory allocation profiling compression is using %d page flag bits!\n", - NR_UNUSED_PAGEFLAG_BITS); -} - -#ifdef CONFIG_MODULES - -static struct maple_tree mod_area_mt = MTREE_INIT(mod_area_mt, MT_FLAGS_ALLOC_RANGE); -static struct vm_struct *vm_module_tags; -/* A dummy object used to indicate an unloaded module */ -static struct module unloaded_mod; -/* A dummy object used to indicate a module prepended area */ -static struct module prepend_mod; - -struct alloc_tag_module_section module_tags; - -static inline unsigned long alloc_tag_align(unsigned long val) -{ - if (!static_key_enabled(&mem_profiling_compressed)) { - /* No alignment requirements when we are not indexing the tags */ - return val; - } - - if (val % sizeof(struct alloc_tag) == 0) - return val; - return ((val / sizeof(struct alloc_tag)) + 1) * sizeof(struct alloc_tag); -} - -static bool ensure_alignment(unsigned long align, unsigned int *prepend) -{ - if (!static_key_enabled(&mem_profiling_compressed)) { - /* No alignment requirements when we are not indexing the tags */ - return true; - } - - /* - * If alloc_tag size is not a multiple of required alignment, tag - * indexing does not work. - */ - if (!IS_ALIGNED(sizeof(struct alloc_tag), align)) - return false; - - /* Ensure prepend consumes multiple of alloc_tag-sized blocks */ - if (*prepend) - *prepend = alloc_tag_align(*prepend); - - return true; -} - -static inline bool tags_addressable(void) -{ - unsigned long tag_idx_count; - - if (!static_key_enabled(&mem_profiling_compressed)) - return true; /* with page_ext tags are always addressable */ - - tag_idx_count = CODETAG_ID_FIRST + kernel_tags.count + - module_tags.size / sizeof(struct alloc_tag); - - return tag_idx_count < (1UL << NR_UNUSED_PAGEFLAG_BITS); -} - -static bool needs_section_mem(struct module *mod, unsigned long size) -{ - if (!mem_profiling_support) - return false; - - return size >= sizeof(struct alloc_tag); -} - -static bool clean_unused_counters(struct alloc_tag *start_tag, - struct alloc_tag *end_tag) -{ - struct alloc_tag *tag; - bool ret = true; - - for (tag = start_tag; tag <= end_tag; tag++) { - struct alloc_tag_counters counter; - - if (!tag->counters) - continue; - - counter = alloc_tag_read(tag); - if (!counter.bytes) { - free_percpu(tag->counters); - tag->counters = NULL; - } else { - ret = false; - } - } - - return ret; -} - -/* Called with mod_area_mt locked */ -static void clean_unused_module_areas_locked(void) -{ - MA_STATE(mas, &mod_area_mt, 0, module_tags.size); - struct module *val; - - mas_for_each(&mas, val, module_tags.size) { - struct alloc_tag *start_tag; - struct alloc_tag *end_tag; - - if (val != &unloaded_mod) - continue; - - /* Release area if all tags are unused */ - start_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index); - end_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last); - if (clean_unused_counters(start_tag, end_tag)) - mas_erase(&mas); - } -} - -/* Called with mod_area_mt locked */ -static bool find_aligned_area(struct ma_state *mas, unsigned long section_size, - unsigned long size, unsigned int prepend, unsigned long align) -{ - bool cleanup_done = false; - -repeat: - /* Try finding exact size and hope the start is aligned */ - if (!mas_empty_area(mas, 0, section_size - 1, prepend + size)) { - if (IS_ALIGNED(mas->index + prepend, align)) - return true; - - /* Try finding larger area to align later */ - mas_reset(mas); - if (!mas_empty_area(mas, 0, section_size - 1, - size + prepend + align - 1)) - return true; - } - - /* No free area, try cleanup stale data and repeat the search once */ - if (!cleanup_done) { - clean_unused_module_areas_locked(); - cleanup_done = true; - mas_reset(mas); - goto repeat; - } - - return false; -} - -static int vm_module_tags_populate(void) -{ - unsigned long phys_end = ALIGN_DOWN(module_tags.start_addr, PAGE_SIZE) + - (vm_module_tags->nr_pages << PAGE_SHIFT); - unsigned long new_end = module_tags.start_addr + module_tags.size; - - if (phys_end < new_end) { - struct page **next_page = vm_module_tags->pages + vm_module_tags->nr_pages; - unsigned long old_shadow_end = ALIGN(phys_end, MODULE_ALIGN); - unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN); - unsigned long more_pages; - unsigned long nr = 0; - - more_pages = ALIGN(new_end - phys_end, PAGE_SIZE) >> PAGE_SHIFT; - while (nr < more_pages) { - unsigned long allocated; - - allocated = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN, - NUMA_NO_NODE, more_pages - nr, next_page + nr); - - if (!allocated) - break; - nr += allocated; - } - - if (nr < more_pages || - vmap_pages_range(phys_end, phys_end + (nr << PAGE_SHIFT), PAGE_KERNEL, - next_page, PAGE_SHIFT) < 0) { - release_pages_arg arg = { .pages = next_page }; - - /* Clean up and error out */ - release_pages(arg, nr); - return -ENOMEM; - } - - vm_module_tags->nr_pages += nr; - - /* - * Kasan allocates 1 byte of shadow for every 8 bytes of data. - * When kasan_alloc_module_shadow allocates shadow memory, - * its unit of allocation is a page. - * Therefore, here we need to align to MODULE_ALIGN. - */ - if (old_shadow_end < new_shadow_end) - kasan_alloc_module_shadow((void *)old_shadow_end, - new_shadow_end - old_shadow_end, - GFP_KERNEL); - } - - /* - * Mark the pages as accessible, now that they are mapped. - * With hardware tag-based KASAN, marking is skipped for - * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc(). - */ - kasan_unpoison_vmalloc((void *)module_tags.start_addr, - new_end - module_tags.start_addr, - KASAN_VMALLOC_PROT_NORMAL); - - return 0; -} - -static void *reserve_module_tags(struct module *mod, unsigned long size, - unsigned int prepend, unsigned long align) -{ - unsigned long section_size = module_tags.end_addr - module_tags.start_addr; - MA_STATE(mas, &mod_area_mt, 0, section_size - 1); - unsigned long offset; - void *ret = NULL; - - /* If no tags return error */ - if (size < sizeof(struct alloc_tag)) - return ERR_PTR(-EINVAL); - - /* - * align is always power of 2, so we can use IS_ALIGNED and ALIGN. - * align 0 or 1 means no alignment, to simplify set to 1. - */ - if (!align) - align = 1; - - if (!ensure_alignment(align, &prepend)) { - shutdown_mem_profiling(true); - pr_err("%s: alignment %lu is incompatible with allocation tag indexing. Memory allocation profiling is disabled!\n", - mod->name, align); - return ERR_PTR(-EINVAL); - } - - mas_lock(&mas); - if (!find_aligned_area(&mas, section_size, size, prepend, align)) { - ret = ERR_PTR(-ENOMEM); - goto unlock; - } - - /* Mark found area as reserved */ - offset = mas.index; - offset += prepend; - offset = ALIGN(offset, align); - if (offset != mas.index) { - unsigned long pad_start = mas.index; - - mas.last = offset - 1; - mas_store(&mas, &prepend_mod); - if (mas_is_err(&mas)) { - ret = ERR_PTR(xa_err(mas.node)); - goto unlock; - } - mas.index = offset; - mas.last = offset + size - 1; - mas_store(&mas, mod); - if (mas_is_err(&mas)) { - mas.index = pad_start; - mas_erase(&mas); - ret = ERR_PTR(xa_err(mas.node)); - } - } else { - mas.last = offset + size - 1; - mas_store(&mas, mod); - if (mas_is_err(&mas)) - ret = ERR_PTR(xa_err(mas.node)); - } -unlock: - mas_unlock(&mas); - - if (IS_ERR(ret)) - return ret; - - if (module_tags.size < offset + size) { - int grow_res; - - module_tags.size = offset + size; - if (mem_alloc_profiling_enabled() && !tags_addressable()) { - shutdown_mem_profiling(true); - pr_warn("With module %s there are too many tags to fit in %d page flag bits. Memory allocation profiling is disabled!\n", - mod->name, NR_UNUSED_PAGEFLAG_BITS); - } - - grow_res = vm_module_tags_populate(); - if (grow_res) { - shutdown_mem_profiling(true); - pr_err("Failed to allocate memory for allocation tags in the module %s. Memory allocation profiling is disabled!\n", - mod->name); - return ERR_PTR(grow_res); - } - } - - return (struct alloc_tag *)(module_tags.start_addr + offset); -} - -static void release_module_tags(struct module *mod, bool used) -{ - MA_STATE(mas, &mod_area_mt, module_tags.size, module_tags.size); - struct alloc_tag *start_tag; - struct alloc_tag *end_tag; - struct module *val; - - mas_lock(&mas); - mas_for_each_rev(&mas, val, 0) - if (val == mod) - break; - - if (!val) /* module not found */ - goto out; - - if (!used) - goto release_area; - - start_tag = (struct alloc_tag *)(module_tags.start_addr + mas.index); - end_tag = (struct alloc_tag *)(module_tags.start_addr + mas.last); - if (!clean_unused_counters(start_tag, end_tag)) { - struct alloc_tag *tag; - - for (tag = start_tag; tag <= end_tag; tag++) { - struct alloc_tag_counters counter; - - if (!tag->counters) - continue; - - counter = alloc_tag_read(tag); - pr_info("%s:%u module %s func:%s has %llu allocated at module unload\n", - tag->ct.filename, tag->ct.lineno, tag->ct.modname, - tag->ct.function, counter.bytes); - } - } else { - used = false; - } -release_area: - mas_store(&mas, used ? &unloaded_mod : NULL); - val = mas_prev_range(&mas, 0); - if (val == &prepend_mod) - mas_store(&mas, NULL); -out: - mas_unlock(&mas); -} - -static int load_module(struct module *mod, struct codetag *start, struct codetag *stop) -{ - /* Allocate module alloc_tag percpu counters */ - struct alloc_tag *start_tag; - struct alloc_tag *stop_tag; - struct alloc_tag *tag; - - /* percpu counters for core allocations are already statically allocated */ - if (!mod) - return 0; - - start_tag = ct_to_alloc_tag(start); - stop_tag = ct_to_alloc_tag(stop); - for (tag = start_tag; tag < stop_tag; tag++) { - WARN_ON(tag->counters); - tag->counters = alloc_percpu(struct alloc_tag_counters); - if (!tag->counters) { - while (--tag >= start_tag) { - free_percpu(tag->counters); - tag->counters = NULL; - } - pr_err("Failed to allocate memory for allocation tag percpu counters in the module %s\n", - mod->name); - return -ENOMEM; - } - - /* - * Avoid a kmemleak false positive. The pointer to the counters is stored - * in the alloc_tag section of the module and cannot be directly accessed. - */ - kmemleak_ignore_percpu(tag->counters); - } - return 0; -} - -static void replace_module(struct module *mod, struct module *new_mod) -{ - MA_STATE(mas, &mod_area_mt, 0, module_tags.size); - struct module *val; - - mas_lock(&mas); - mas_for_each(&mas, val, module_tags.size) { - if (val != mod) - continue; - - mas_store_gfp(&mas, new_mod, GFP_KERNEL); - break; - } - mas_unlock(&mas); -} - -static int __init alloc_mod_tags_mem(void) -{ - /* Map space to copy allocation tags */ - vm_module_tags = execmem_vmap(MODULE_ALLOC_TAG_VMAP_SIZE); - if (!vm_module_tags) { - pr_err("Failed to map %lu bytes for module allocation tags\n", - MODULE_ALLOC_TAG_VMAP_SIZE); - module_tags.start_addr = 0; - return -ENOMEM; - } - - vm_module_tags->pages = kmalloc_objs(struct page *, - get_vm_area_size(vm_module_tags) >> PAGE_SHIFT, - GFP_KERNEL | __GFP_ZERO); - if (!vm_module_tags->pages) { - free_vm_area(vm_module_tags); - return -ENOMEM; - } - - module_tags.start_addr = (unsigned long)vm_module_tags->addr; - module_tags.end_addr = module_tags.start_addr + MODULE_ALLOC_TAG_VMAP_SIZE; - /* Ensure the base is alloc_tag aligned when required for indexing */ - module_tags.start_addr = alloc_tag_align(module_tags.start_addr); - - return 0; -} - -static void __init free_mod_tags_mem(void) -{ - release_pages_arg arg = { .pages = vm_module_tags->pages }; - - module_tags.start_addr = 0; - release_pages(arg, vm_module_tags->nr_pages); - kfree(vm_module_tags->pages); - free_vm_area(vm_module_tags); -} - -#else /* CONFIG_MODULES */ - -static inline int alloc_mod_tags_mem(void) { return 0; } -static inline void free_mod_tags_mem(void) {} - -#endif /* CONFIG_MODULES */ - -/* See: Documentation/mm/allocation-profiling.rst */ -static int __init setup_early_mem_profiling(char *str) -{ - bool compressed = false; - bool enable; - - if (!str || !str[0]) - return -EINVAL; - - if (!strncmp(str, "never", 5)) { - enable = false; - mem_profiling_support = false; - pr_info("Memory allocation profiling is disabled!\n"); - } else { - char *token = strsep(&str, ","); - - if (kstrtobool(token, &enable)) - return -EINVAL; - - if (str) { - - if (strcmp(str, "compressed")) - return -EINVAL; - - compressed = true; - } - mem_profiling_support = true; - pr_info("Memory allocation profiling is enabled %s compression and is turned %s!\n", - compressed ? "with" : "without", str_on_off(enable)); - } - - if (enable != mem_alloc_profiling_enabled()) { - if (enable) - static_branch_enable(&mem_alloc_profiling_key); - else - static_branch_disable(&mem_alloc_profiling_key); - } - if (compressed != static_key_enabled(&mem_profiling_compressed)) { - if (compressed) - static_branch_enable(&mem_profiling_compressed); - else - static_branch_disable(&mem_profiling_compressed); - } - - return 0; -} -early_param("sysctl.vm.mem_profiling", setup_early_mem_profiling); - -static __init bool need_page_alloc_tagging(void) -{ - if (static_key_enabled(&mem_profiling_compressed)) - return false; - - return mem_profiling_support; -} - -#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG -/* - * Track page allocations before page_ext is initialized. - * Some pages are allocated before page_ext becomes available, leaving - * their codetag uninitialized. Track these early PFNs so we can clear - * their codetag refs later to avoid warnings when they are freed. - * - * Each page is cast to a pfn_pool: the first few bytes hold metadata - * (next pointer and slot count), the remainder stores PFNs. - */ -struct pfn_pool { - struct pfn_pool *next; - atomic_t count; - unsigned long pfns[]; -}; - -#define PFN_POOL_SIZE ((PAGE_SIZE - offsetof(struct pfn_pool, pfns)) / \ - sizeof(unsigned long)) - -/* - * Skip early PFN recording for a page allocation. Reuses the - * %__GFP_NO_OBJ_EXT bit. Used by __alloc_tag_add_early_pfn() to avoid - * recursion when allocating pages for the early PFN tracking list - * itself. - * - * Codetags of the pages allocated with __GFP_NO_CODETAG should be - * cleared (via clear_page_tag_ref()) before freeing the pages to prevent - * alloc_tag_sub_check() from triggering a warning. - */ -#define __GFP_NO_CODETAG __GFP_NO_OBJ_EXT - -static struct pfn_pool *current_pfn_pool __initdata; - -static void __init __alloc_tag_add_early_pfn(unsigned long pfn) -{ - struct pfn_pool *pool; - int idx; - - do { - pool = READ_ONCE(current_pfn_pool); - if (!pool || atomic_read(&pool->count) >= PFN_POOL_SIZE) { - struct page *new_page = alloc_page(__GFP_HIGH | __GFP_NO_CODETAG); - struct pfn_pool *new; - - if (!new_page) { - pr_warn_once("early PFN tracking page allocation failed\n"); - return; - } - new = page_address(new_page); - new->next = pool; - atomic_set(&new->count, 0); - if (cmpxchg(¤t_pfn_pool, pool, new) != pool) { - clear_page_tag_ref(new_page); - __free_page(new_page); - continue; - } - pool = new; - } - idx = atomic_read(&pool->count); - if (idx >= PFN_POOL_SIZE) - continue; - if (atomic_cmpxchg(&pool->count, idx, idx + 1) == idx) - break; - } while (1); - - pool->pfns[idx] = pfn; -} - -typedef void alloc_tag_add_func(unsigned long pfn); -static alloc_tag_add_func __rcu *alloc_tag_add_early_pfn_ptr __refdata = - RCU_INITIALIZER(__alloc_tag_add_early_pfn); - -void alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags) -{ - alloc_tag_add_func *alloc_tag_add; - - if (static_key_enabled(&mem_profiling_compressed)) - return; - - /* Skip allocations for the tracking list itself to avoid recursion. */ - if (gfp_flags & __GFP_NO_CODETAG) - return; - - rcu_read_lock(); - alloc_tag_add = rcu_dereference(alloc_tag_add_early_pfn_ptr); - if (alloc_tag_add) - alloc_tag_add(pfn); - rcu_read_unlock(); -} - -static void __init clear_early_alloc_pfn_tag_refs(void) -{ - struct pfn_pool *pool, *next; - struct page *page; - int i; - - if (static_key_enabled(&mem_profiling_compressed)) - return; - - rcu_assign_pointer(alloc_tag_add_early_pfn_ptr, NULL); - /* Make sure we are not racing with __alloc_tag_add_early_pfn() */ - synchronize_rcu(); - - for (pool = current_pfn_pool; pool; pool = next) { - int nr_pfns = atomic_read(&pool->count); - - for (i = 0; i < nr_pfns; i++) { - unsigned long pfn = pool->pfns[i]; - - if (pfn_valid(pfn)) { - union pgtag_ref_handle handle; - union codetag_ref ref; - - if (get_page_tag_ref(pfn_to_page(pfn), &ref, &handle)) { - /* - * An early-allocated page could be freed and reallocated - * after its page_ext is initialized but before we clear it. - * In that case, it already has a valid tag set. - * We should not overwrite that valid tag - * with CODETAG_EMPTY. - * - * Note: there is still a small race window between checking - * ref.ct and calling set_codetag_empty(). We accept this - * race as it's unlikely and the extra complexity of atomic - * cmpxchg is not worth it for this debug-only code path. - */ - if (ref.ct) { - put_page_tag_ref(handle); - continue; - } - - set_codetag_empty(&ref); - update_page_tag_ref(handle, &ref); - put_page_tag_ref(handle); - } - } - } - - next = pool->next; - page = virt_to_page(pool); - clear_page_tag_ref(page); - __free_page(page); - } -} -#else /* !CONFIG_MEM_ALLOC_PROFILING_DEBUG */ -static inline void __init clear_early_alloc_pfn_tag_refs(void) {} -#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ - -static __init void init_page_alloc_tagging(void) -{ - clear_early_alloc_pfn_tag_refs(); -} - -struct page_ext_operations page_alloc_tagging_ops = { - .size = sizeof(union codetag_ref), - .need = need_page_alloc_tagging, - .init = init_page_alloc_tagging, -}; -EXPORT_SYMBOL(page_alloc_tagging_ops); - -#ifdef CONFIG_SYSCTL -/* - * Not using proc_do_static_key() directly to prevent enabling profiling - * after it was shut down. - */ -static int proc_mem_profiling_handler(const struct ctl_table *table, int write, - void *buffer, size_t *lenp, loff_t *ppos) -{ - if (write) { - /* - * Call from do_sysctl_args() which is a no-op since the same - * value was already set by setup_early_mem_profiling. - * Return success to avoid warnings from do_sysctl_args(). - */ - if (!current->mm) - return 0; - -#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG - /* User can't toggle profiling while debugging */ - return -EACCES; -#endif - if (!mem_profiling_support) - return -EINVAL; - } - - return proc_do_static_key(table, write, buffer, lenp, ppos); -} - - -static const struct ctl_table memory_allocation_profiling_sysctls[] = { - { - .procname = "mem_profiling", - .data = &mem_alloc_profiling_key, - .mode = 0644, - .proc_handler = proc_mem_profiling_handler, - }, -}; - -static void __init sysctl_init(void) -{ - register_sysctl_init("vm", memory_allocation_profiling_sysctls); -} -#else /* CONFIG_SYSCTL */ -static inline void sysctl_init(void) {} -#endif /* CONFIG_SYSCTL */ - -static int __init alloc_tag_init(void) -{ - const struct codetag_type_desc desc = { - .section = ALLOC_TAG_SECTION_NAME, - .tag_size = sizeof(struct alloc_tag), -#ifdef CONFIG_MODULES - .needs_section_mem = needs_section_mem, - .alloc_section_mem = reserve_module_tags, - .free_section_mem = release_module_tags, - .module_load = load_module, - .module_replaced = replace_module, -#endif - }; - int res; - - sysctl_init(); - - if (!mem_profiling_support) { - pr_info("Memory allocation profiling is not supported!\n"); - return 0; - } - - if (!proc_create_seq_private(ALLOCINFO_FILE_NAME, 0400, NULL, &allocinfo_seq_op, - sizeof(struct allocinfo_private), NULL)) { - pr_err("Failed to create %s file\n", ALLOCINFO_FILE_NAME); - shutdown_mem_profiling(false); - return -ENOMEM; - } - - res = alloc_mod_tags_mem(); - if (res) { - pr_err("Failed to reserve address space for module tags, errno = %d\n", res); - shutdown_mem_profiling(true); - return res; - } - - alloc_tag_cttype = codetag_register_type(&desc); - if (IS_ERR(alloc_tag_cttype)) { - pr_err("Allocation tags registration failed, errno = %pe\n", alloc_tag_cttype); - free_mod_tags_mem(); - shutdown_mem_profiling(true); - return PTR_ERR(alloc_tag_cttype); - } - - return 0; -} -module_init(alloc_tag_init); |