X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=mm%2Fkfence%2Fcore.c;h=2f9fdfde19416a1c271b3c45c7f1405807e84f77;hb=bee7fbc38579ba86948689107518c855247d0b49;hp=13128fa1306256e617a7641fcc78fcafa40fdc5d;hpb=c269497d248e43558aafc6b3f87b49d4dd3c2713;p=linux-2.6-microblaze.git diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 13128fa13062..2f9fdfde1941 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -38,14 +38,17 @@ #define KFENCE_WARN_ON(cond) \ ({ \ const bool __cond = WARN_ON(cond); \ - if (unlikely(__cond)) \ + if (unlikely(__cond)) { \ WRITE_ONCE(kfence_enabled, false); \ + disabled_by_warn = true; \ + } \ __cond; \ }) /* === Data ================================================================= */ static bool kfence_enabled __read_mostly; +static bool disabled_by_warn __read_mostly; unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL; EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */ @@ -55,6 +58,7 @@ EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */ #endif #define MODULE_PARAM_PREFIX "kfence." +static int kfence_enable_late(void); static int param_set_sample_interval(const char *val, const struct kernel_param *kp) { unsigned long num; @@ -65,10 +69,11 @@ static int param_set_sample_interval(const char *val, const struct kernel_param if (!num) /* Using 0 to indicate KFENCE is disabled. */ WRITE_ONCE(kfence_enabled, false); - else if (!READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) - return -EINVAL; /* Cannot (re-)enable KFENCE on-the-fly. */ *((unsigned long *)kp->arg) = num; + + if (num && !READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) + return disabled_by_warn ? -EINVAL : kfence_enable_late(); return 0; } @@ -90,8 +95,12 @@ module_param_cb(sample_interval, &sample_interval_param_ops, &kfence_sample_inte static unsigned long kfence_skip_covered_thresh __read_mostly = 75; module_param_named(skip_covered_thresh, kfence_skip_covered_thresh, ulong, 0644); +/* If true, use a deferrable timer. */ +static bool kfence_deferrable __read_mostly = IS_ENABLED(CONFIG_KFENCE_DEFERRABLE); +module_param_named(deferrable, kfence_deferrable, bool, 0444); + /* The pool of pages used for guard pages and objects. */ -char *__kfence_pool __ro_after_init; +char *__kfence_pool __read_mostly; EXPORT_SYMBOL(__kfence_pool); /* Export for test modules. */ /* @@ -532,17 +541,19 @@ static void rcu_guarded_free(struct rcu_head *h) kfence_guarded_free((void *)meta->addr, meta, false); } -static bool __init kfence_init_pool(void) +/* + * Initialization of the KFENCE pool after its allocation. + * Returns 0 on success; otherwise returns the address up to + * which partial initialization succeeded. + */ +static unsigned long kfence_init_pool(void) { unsigned long addr = (unsigned long)__kfence_pool; struct page *pages; int i; - if (!__kfence_pool) - return false; - if (!arch_kfence_init_pool()) - goto err; + return addr; pages = virt_to_page(addr); @@ -560,7 +571,7 @@ static bool __init kfence_init_pool(void) /* Verify we do not have a compound head page. */ if (WARN_ON(compound_head(&pages[i]) != &pages[i])) - goto err; + return addr; __SetPageSlab(&pages[i]); } @@ -573,7 +584,7 @@ static bool __init kfence_init_pool(void) */ for (i = 0; i < 2; i++) { if (unlikely(!kfence_protect(addr))) - goto err; + return addr; addr += PAGE_SIZE; } @@ -590,7 +601,7 @@ static bool __init kfence_init_pool(void) /* Protect the right redzone. */ if (unlikely(!kfence_protect(addr + PAGE_SIZE))) - goto err; + return addr; addr += 2 * PAGE_SIZE; } @@ -603,9 +614,21 @@ static bool __init kfence_init_pool(void) */ kmemleak_free(__kfence_pool); - return true; + return 0; +} + +static bool __init kfence_init_pool_early(void) +{ + unsigned long addr; + + if (!__kfence_pool) + return false; + + addr = kfence_init_pool(); + + if (!addr) + return true; -err: /* * Only release unprotected pages, and do not try to go back and change * page attributes due to risk of failing to do so as well. If changing @@ -618,6 +641,26 @@ err: return false; } +static bool kfence_init_pool_late(void) +{ + unsigned long addr, free_size; + + addr = kfence_init_pool(); + + if (!addr) + return true; + + /* Same as above. */ + free_size = KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool); +#ifdef CONFIG_CONTIG_ALLOC + free_contig_range(page_to_pfn(virt_to_page(addr)), free_size / PAGE_SIZE); +#else + free_pages_exact((void *)addr, free_size); +#endif + __kfence_pool = NULL; + return false; +} + /* === DebugFS Interface ==================================================== */ static int stats_show(struct seq_file *seq, void *v) @@ -701,6 +744,8 @@ late_initcall(kfence_debugfs_init); /* === Allocation Gate Timer ================================================ */ +static struct delayed_work kfence_timer; + #ifdef CONFIG_KFENCE_STATIC_KEYS /* Wait queue to wake up allocation-gate timer task. */ static DECLARE_WAIT_QUEUE_HEAD(allocation_wait); @@ -723,7 +768,6 @@ static DEFINE_IRQ_WORK(wake_up_kfence_timer_work, wake_up_kfence_timer); * avoids IPIs, at the cost of not immediately capturing allocations if the * instructions remain cached. */ -static struct delayed_work kfence_timer; static void toggle_allocation_gate(struct work_struct *work) { if (!READ_ONCE(kfence_enabled)) @@ -751,7 +795,6 @@ static void toggle_allocation_gate(struct work_struct *work) queue_delayed_work(system_unbound_wq, &kfence_timer, msecs_to_jiffies(kfence_sample_interval)); } -static DECLARE_DELAYED_WORK(kfence_timer, toggle_allocation_gate); /* === Public interface ===================================================== */ @@ -766,25 +809,77 @@ void __init kfence_alloc_pool(void) pr_err("failed to allocate pool\n"); } +static void kfence_init_enable(void) +{ + if (!IS_ENABLED(CONFIG_KFENCE_STATIC_KEYS)) + static_branch_enable(&kfence_allocation_key); + + if (kfence_deferrable) + INIT_DEFERRABLE_WORK(&kfence_timer, toggle_allocation_gate); + else + INIT_DELAYED_WORK(&kfence_timer, toggle_allocation_gate); + + WRITE_ONCE(kfence_enabled, true); + queue_delayed_work(system_unbound_wq, &kfence_timer, 0); + + pr_info("initialized - using %lu bytes for %d objects at 0x%p-0x%p\n", KFENCE_POOL_SIZE, + CONFIG_KFENCE_NUM_OBJECTS, (void *)__kfence_pool, + (void *)(__kfence_pool + KFENCE_POOL_SIZE)); +} + void __init kfence_init(void) { + stack_hash_seed = (u32)random_get_entropy(); + /* Setting kfence_sample_interval to 0 on boot disables KFENCE. */ if (!kfence_sample_interval) return; - stack_hash_seed = (u32)random_get_entropy(); - if (!kfence_init_pool()) { + if (!kfence_init_pool_early()) { pr_err("%s failed\n", __func__); return; } - if (!IS_ENABLED(CONFIG_KFENCE_STATIC_KEYS)) - static_branch_enable(&kfence_allocation_key); + kfence_init_enable(); +} + +static int kfence_init_late(void) +{ + const unsigned long nr_pages = KFENCE_POOL_SIZE / PAGE_SIZE; +#ifdef CONFIG_CONTIG_ALLOC + struct page *pages; + + pages = alloc_contig_pages(nr_pages, GFP_KERNEL, first_online_node, NULL); + if (!pages) + return -ENOMEM; + __kfence_pool = page_to_virt(pages); +#else + if (nr_pages > MAX_ORDER_NR_PAGES) { + pr_warn("KFENCE_NUM_OBJECTS too large for buddy allocator\n"); + return -EINVAL; + } + __kfence_pool = alloc_pages_exact(KFENCE_POOL_SIZE, GFP_KERNEL); + if (!__kfence_pool) + return -ENOMEM; +#endif + + if (!kfence_init_pool_late()) { + pr_err("%s failed\n", __func__); + return -EBUSY; + } + + kfence_init_enable(); + return 0; +} + +static int kfence_enable_late(void) +{ + if (!__kfence_pool) + return kfence_init_late(); + WRITE_ONCE(kfence_enabled, true); queue_delayed_work(system_unbound_wq, &kfence_timer, 0); - pr_info("initialized - using %lu bytes for %d objects at 0x%p-0x%p\n", KFENCE_POOL_SIZE, - CONFIG_KFENCE_NUM_OBJECTS, (void *)__kfence_pool, - (void *)(__kfence_pool + KFENCE_POOL_SIZE)); + return 0; } void kfence_shutdown_cache(struct kmem_cache *s)