3  * Generic stack depot for storing stack traces.
5  * Some debugging tools need to save stack traces of certain events which can
7  * free stacks for each object, but storing two stack traces per object
11  * Instead, stack depot maintains a hashtable of unique stacktraces. Since alloc
40 #define STACK_ALLOC_ORDER 2 /* 'Slab' size order for stack depot, 4 pages */
67 	u32 size;			/* Number of frames in the stack */
118 /* Allocation of a new stack in raw storage */
122 	struct stack_record *stack;  in depot_alloc_stack()  local
123 	size_t required_size = struct_size(stack, entries, size);  in depot_alloc_stack()
129 			WARN_ONCE(1, "Stack depot reached limit capacity");  in depot_alloc_stack()
146 	stack = stack_slabs[depot_index] + depot_offset;  in depot_alloc_stack()
148 	stack->hash = hash;  in depot_alloc_stack()
149 	stack->size = size;  in depot_alloc_stack()
150 	stack->handle.slabindex = depot_index;  in depot_alloc_stack()
151 	stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN;  in depot_alloc_stack()
152 	stack->handle.valid = 1;  in depot_alloc_stack()
153 	stack->handle.extra = 0;  in depot_alloc_stack()
154 	memcpy(stack->entries, entries, flex_array_size(stack, entries, size));  in depot_alloc_stack()
157 	return stack;  in depot_alloc_stack()
179 		pr_info("Stack Depot is disabled\n");  in is_stack_depot_disabled()
223 		pr_err("Stack Depot hash table allocation failed, disabling\n");  in stack_depot_early_init()
258 		pr_info("Stack Depot allocating hash table of %lu entries with kvcalloc\n",  in stack_depot_init()
262 			pr_err("Stack Depot hash table allocation failed, disabling\n");  in stack_depot_init()
273 /* Calculate hash for a stack */
296 /* Find a stack that is equal to the one stored in entries in the hash */
313  * stack_depot_snprint - print stack entries from a depot into a buffer
315  * @handle:	Stack depot handle which was returned from
338  * stack_depot_print - print stack entries from a depot
340  * @stack:		Stack depot handle which was returned from
344 void stack_depot_print(depot_stack_handle_t stack)  in stack_depot_print()  argument
349 	nr_entries = stack_depot_fetch(stack, &entries);  in stack_depot_print()
356  * stack_depot_fetch - Fetch stack entries from a depot
358  * @handle:		Stack depot handle which was returned from
370 	struct stack_record *stack;  in stack_depot_fetch()  local
377 		WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n",  in stack_depot_fetch()
384 	stack = slab + offset;  in stack_depot_fetch()
386 	*entries = stack->entries;  in stack_depot_fetch()
387 	return stack->size;  in stack_depot_fetch()
392  * __stack_depot_save - Save a stack trace from an array
398  * @can_alloc:		Allocate stack slabs (increased chance of failure if false)
400  * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is
401  * %true, is allowed to replenish the stack slab pool in case no space is left
403  * any allocations and will fail if no space is left to store the stack trace.
405  * If the stack trace in @entries is from an interrupt, only the portion up to
409  * bits of the stack handle, and retrieved using stack_depot_get_extra_bits()
417  * Return: The handle of the stack struct stored in depot, 0 on failure.
432 	 * If this stack trace is from an interrupt, including anything before  in __stack_depot_save()
448 	 * Fast path: look the stack trace up without locking.  in __stack_depot_save()
458 	 * Check if the current or the next stack slab need to be initialized.  in __stack_depot_save()
496 		 * We didn't need to store this stack trace, but let's keep  in __stack_depot_save()
518  * stack_depot_save - Save a stack trace from an array
527  * Return: The handle of the stack struct stored in depot, 0 on failure.