17c7900f8SJosh Poimboeuf #include <linux/sched.h> 229930025SIngo Molnar #include <linux/sched/task.h> 368db0cf1SIngo Molnar #include <linux/sched/task_stack.h> 4a8b7a923SJosh Poimboeuf #include <linux/interrupt.h> 5a8b7a923SJosh Poimboeuf #include <asm/sections.h> 67c7900f8SJosh Poimboeuf #include <asm/ptrace.h> 77c7900f8SJosh Poimboeuf #include <asm/bitops.h> 87c7900f8SJosh Poimboeuf #include <asm/stacktrace.h> 97c7900f8SJosh Poimboeuf #include <asm/unwind.h> 107c7900f8SJosh Poimboeuf 117c7900f8SJosh Poimboeuf #define FRAME_HEADER_SIZE (sizeof(long) * 2) 127c7900f8SJosh Poimboeuf 13ee9f8fceSJosh Poimboeuf unsigned long unwind_get_return_address(struct unwind_state *state) 14ee9f8fceSJosh Poimboeuf { 15ee9f8fceSJosh Poimboeuf if (unwind_done(state)) 16ee9f8fceSJosh Poimboeuf return 0; 17ee9f8fceSJosh Poimboeuf 18ee9f8fceSJosh Poimboeuf return __kernel_text_address(state->ip) ? state->ip : 0; 19ee9f8fceSJosh Poimboeuf } 20ee9f8fceSJosh Poimboeuf EXPORT_SYMBOL_GPL(unwind_get_return_address); 21ee9f8fceSJosh Poimboeuf 22ee9f8fceSJosh Poimboeuf unsigned long *unwind_get_return_address_ptr(struct unwind_state *state) 23ee9f8fceSJosh Poimboeuf { 24ee9f8fceSJosh Poimboeuf if (unwind_done(state)) 25ee9f8fceSJosh Poimboeuf return NULL; 26ee9f8fceSJosh Poimboeuf 27ee9f8fceSJosh Poimboeuf return state->regs ? &state->regs->ip : state->bp + 1; 28ee9f8fceSJosh Poimboeuf } 2984936118SJosh Poimboeuf 30aa4f8534SJosh Poimboeuf static void unwind_dump(struct unwind_state *state) 318b5e99f0SJosh Poimboeuf { 328b5e99f0SJosh Poimboeuf static bool dumped_before = false; 338b5e99f0SJosh Poimboeuf bool prev_zero, zero = false; 34aa4f8534SJosh Poimboeuf unsigned long word, *sp; 35262fa734SJosh Poimboeuf struct stack_info stack_info = {0}; 36262fa734SJosh Poimboeuf unsigned long visit_mask = 0; 378b5e99f0SJosh Poimboeuf 388b5e99f0SJosh Poimboeuf if (dumped_before) 398b5e99f0SJosh Poimboeuf return; 408b5e99f0SJosh Poimboeuf 418b5e99f0SJosh Poimboeuf dumped_before = true; 428b5e99f0SJosh Poimboeuf 434ea3d741SJosh Poimboeuf printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n", 448b5e99f0SJosh Poimboeuf state->stack_info.type, state->stack_info.next_sp, 458b5e99f0SJosh Poimboeuf state->stack_mask, state->graph_idx); 468b5e99f0SJosh Poimboeuf 47262fa734SJosh Poimboeuf for (sp = state->orig_sp; sp; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { 48262fa734SJosh Poimboeuf if (get_stack_info(sp, state->task, &stack_info, &visit_mask)) 49262fa734SJosh Poimboeuf break; 50262fa734SJosh Poimboeuf 51262fa734SJosh Poimboeuf for (; sp < stack_info.end; sp++) { 52262fa734SJosh Poimboeuf 538b5e99f0SJosh Poimboeuf word = READ_ONCE_NOCHECK(*sp); 548b5e99f0SJosh Poimboeuf 558b5e99f0SJosh Poimboeuf prev_zero = zero; 568b5e99f0SJosh Poimboeuf zero = word == 0; 578b5e99f0SJosh Poimboeuf 588b5e99f0SJosh Poimboeuf if (zero) { 598b5e99f0SJosh Poimboeuf if (!prev_zero) 609b135b23SJosh Poimboeuf printk_deferred("%p: %0*x ...\n", 619b135b23SJosh Poimboeuf sp, BITS_PER_LONG/4, 0); 628b5e99f0SJosh Poimboeuf continue; 638b5e99f0SJosh Poimboeuf } 648b5e99f0SJosh Poimboeuf 659b135b23SJosh Poimboeuf printk_deferred("%p: %0*lx (%pB)\n", 669b135b23SJosh Poimboeuf sp, BITS_PER_LONG/4, word, (void *)word); 678b5e99f0SJosh Poimboeuf } 688b5e99f0SJosh Poimboeuf } 69262fa734SJosh Poimboeuf } 708b5e99f0SJosh Poimboeuf 7124d86f59SJosh Poimboeuf static size_t regs_size(struct pt_regs *regs) 7224d86f59SJosh Poimboeuf { 7324d86f59SJosh Poimboeuf /* x86_32 regs from kernel mode are two words shorter: */ 7424d86f59SJosh Poimboeuf if (IS_ENABLED(CONFIG_X86_32) && !user_mode(regs)) 7524d86f59SJosh Poimboeuf return sizeof(*regs) - 2*sizeof(long); 7624d86f59SJosh Poimboeuf 7724d86f59SJosh Poimboeuf return sizeof(*regs); 7824d86f59SJosh Poimboeuf } 7924d86f59SJosh Poimboeuf 80a8b7a923SJosh Poimboeuf static bool in_entry_code(unsigned long ip) 81a8b7a923SJosh Poimboeuf { 82a8b7a923SJosh Poimboeuf char *addr = (char *)ip; 83a8b7a923SJosh Poimboeuf 84a8b7a923SJosh Poimboeuf if (addr >= __entry_text_start && addr < __entry_text_end) 85a8b7a923SJosh Poimboeuf return true; 86a8b7a923SJosh Poimboeuf 87a8b7a923SJosh Poimboeuf if (addr >= __irqentry_text_start && addr < __irqentry_text_end) 88a8b7a923SJosh Poimboeuf return true; 89a8b7a923SJosh Poimboeuf 90a8b7a923SJosh Poimboeuf return false; 91a8b7a923SJosh Poimboeuf } 92a8b7a923SJosh Poimboeuf 93b0d50c7bSJosh Poimboeuf static inline unsigned long *last_frame(struct unwind_state *state) 94b0d50c7bSJosh Poimboeuf { 95b0d50c7bSJosh Poimboeuf return (unsigned long *)task_pt_regs(state->task) - 2; 96b0d50c7bSJosh Poimboeuf } 97b0d50c7bSJosh Poimboeuf 98519fb5c3SJosh Poimboeuf static bool is_last_frame(struct unwind_state *state) 99519fb5c3SJosh Poimboeuf { 100519fb5c3SJosh Poimboeuf return state->bp == last_frame(state); 101519fb5c3SJosh Poimboeuf } 102519fb5c3SJosh Poimboeuf 10387a6b297SJosh Poimboeuf #ifdef CONFIG_X86_32 10487a6b297SJosh Poimboeuf #define GCC_REALIGN_WORDS 3 10587a6b297SJosh Poimboeuf #else 10687a6b297SJosh Poimboeuf #define GCC_REALIGN_WORDS 1 10787a6b297SJosh Poimboeuf #endif 10887a6b297SJosh Poimboeuf 109b0d50c7bSJosh Poimboeuf static inline unsigned long *last_aligned_frame(struct unwind_state *state) 110b0d50c7bSJosh Poimboeuf { 111b0d50c7bSJosh Poimboeuf return last_frame(state) - GCC_REALIGN_WORDS; 112b0d50c7bSJosh Poimboeuf } 113b0d50c7bSJosh Poimboeuf 114519fb5c3SJosh Poimboeuf static bool is_last_aligned_frame(struct unwind_state *state) 115acb4608aSJosh Poimboeuf { 116b0d50c7bSJosh Poimboeuf unsigned long *last_bp = last_frame(state); 117b0d50c7bSJosh Poimboeuf unsigned long *aligned_bp = last_aligned_frame(state); 118acb4608aSJosh Poimboeuf 1198023e0e2SJosh Poimboeuf /* 120519fb5c3SJosh Poimboeuf * GCC can occasionally decide to realign the stack pointer and change 121519fb5c3SJosh Poimboeuf * the offset of the stack frame in the prologue of a function called 122519fb5c3SJosh Poimboeuf * by head/entry code. Examples: 12387a6b297SJosh Poimboeuf * 12487a6b297SJosh Poimboeuf * <start_secondary>: 12587a6b297SJosh Poimboeuf * push %edi 12687a6b297SJosh Poimboeuf * lea 0x8(%esp),%edi 12787a6b297SJosh Poimboeuf * and $0xfffffff8,%esp 12887a6b297SJosh Poimboeuf * pushl -0x4(%edi) 12987a6b297SJosh Poimboeuf * push %ebp 13087a6b297SJosh Poimboeuf * mov %esp,%ebp 13187a6b297SJosh Poimboeuf * 13287a6b297SJosh Poimboeuf * <x86_64_start_kernel>: 13387a6b297SJosh Poimboeuf * lea 0x8(%rsp),%r10 13487a6b297SJosh Poimboeuf * and $0xfffffffffffffff0,%rsp 13587a6b297SJosh Poimboeuf * pushq -0x8(%r10) 13687a6b297SJosh Poimboeuf * push %rbp 13787a6b297SJosh Poimboeuf * mov %rsp,%rbp 13887a6b297SJosh Poimboeuf * 139519fb5c3SJosh Poimboeuf * After aligning the stack, it pushes a duplicate copy of the return 140519fb5c3SJosh Poimboeuf * address before pushing the frame pointer. 1418023e0e2SJosh Poimboeuf */ 142519fb5c3SJosh Poimboeuf return (state->bp == aligned_bp && *(aligned_bp + 1) == *(last_bp + 1)); 143519fb5c3SJosh Poimboeuf } 144519fb5c3SJosh Poimboeuf 145519fb5c3SJosh Poimboeuf static bool is_last_ftrace_frame(struct unwind_state *state) 146519fb5c3SJosh Poimboeuf { 147519fb5c3SJosh Poimboeuf unsigned long *last_bp = last_frame(state); 148519fb5c3SJosh Poimboeuf unsigned long *last_ftrace_bp = last_bp - 3; 149519fb5c3SJosh Poimboeuf 150519fb5c3SJosh Poimboeuf /* 151519fb5c3SJosh Poimboeuf * When unwinding from an ftrace handler of a function called by entry 152519fb5c3SJosh Poimboeuf * code, the stack layout of the last frame is: 153519fb5c3SJosh Poimboeuf * 154519fb5c3SJosh Poimboeuf * bp 155519fb5c3SJosh Poimboeuf * parent ret addr 156519fb5c3SJosh Poimboeuf * bp 157519fb5c3SJosh Poimboeuf * function ret addr 158519fb5c3SJosh Poimboeuf * parent ret addr 159519fb5c3SJosh Poimboeuf * pt_regs 160519fb5c3SJosh Poimboeuf * ----------------- 161519fb5c3SJosh Poimboeuf */ 162519fb5c3SJosh Poimboeuf return (state->bp == last_ftrace_bp && 163519fb5c3SJosh Poimboeuf *state->bp == *(state->bp + 2) && 164519fb5c3SJosh Poimboeuf *(state->bp + 1) == *(state->bp + 4)); 165519fb5c3SJosh Poimboeuf } 166519fb5c3SJosh Poimboeuf 167519fb5c3SJosh Poimboeuf static bool is_last_task_frame(struct unwind_state *state) 168519fb5c3SJosh Poimboeuf { 169519fb5c3SJosh Poimboeuf return is_last_frame(state) || is_last_aligned_frame(state) || 170519fb5c3SJosh Poimboeuf is_last_ftrace_frame(state); 171acb4608aSJosh Poimboeuf } 172acb4608aSJosh Poimboeuf 173946c1911SJosh Poimboeuf /* 174946c1911SJosh Poimboeuf * This determines if the frame pointer actually contains an encoded pointer to 175946c1911SJosh Poimboeuf * pt_regs on the stack. See ENCODE_FRAME_POINTER. 176946c1911SJosh Poimboeuf */ 177*5c99b692SJosh Poimboeuf #ifdef CONFIG_X86_64 178946c1911SJosh Poimboeuf static struct pt_regs *decode_frame_pointer(unsigned long *bp) 179946c1911SJosh Poimboeuf { 180946c1911SJosh Poimboeuf unsigned long regs = (unsigned long)bp; 181946c1911SJosh Poimboeuf 182946c1911SJosh Poimboeuf if (!(regs & 0x1)) 183946c1911SJosh Poimboeuf return NULL; 184946c1911SJosh Poimboeuf 185946c1911SJosh Poimboeuf return (struct pt_regs *)(regs & ~0x1); 186946c1911SJosh Poimboeuf } 187*5c99b692SJosh Poimboeuf #else 188*5c99b692SJosh Poimboeuf static struct pt_regs *decode_frame_pointer(unsigned long *bp) 189*5c99b692SJosh Poimboeuf { 190*5c99b692SJosh Poimboeuf unsigned long regs = (unsigned long)bp; 191*5c99b692SJosh Poimboeuf 192*5c99b692SJosh Poimboeuf if (regs & 0x80000000) 193*5c99b692SJosh Poimboeuf return NULL; 194*5c99b692SJosh Poimboeuf 195*5c99b692SJosh Poimboeuf return (struct pt_regs *)(regs | 0x80000000); 196*5c99b692SJosh Poimboeuf } 197*5c99b692SJosh Poimboeuf #endif 198946c1911SJosh Poimboeuf 19962dd86acSJosh Poimboeuf #ifdef CONFIG_X86_32 20062dd86acSJosh Poimboeuf #define KERNEL_REGS_SIZE (sizeof(struct pt_regs) - 2*sizeof(long)) 20162dd86acSJosh Poimboeuf #else 20262dd86acSJosh Poimboeuf #define KERNEL_REGS_SIZE (sizeof(struct pt_regs)) 20362dd86acSJosh Poimboeuf #endif 20462dd86acSJosh Poimboeuf 2055ed8d8bbSJosh Poimboeuf static bool update_stack_state(struct unwind_state *state, 2065ed8d8bbSJosh Poimboeuf unsigned long *next_bp) 2077c7900f8SJosh Poimboeuf { 2087c7900f8SJosh Poimboeuf struct stack_info *info = &state->stack_info; 2095ed8d8bbSJosh Poimboeuf enum stack_type prev_type = info->type; 2105ed8d8bbSJosh Poimboeuf struct pt_regs *regs; 2116bcdf9d5SJosh Poimboeuf unsigned long *frame, *prev_frame_end, *addr_p, addr; 2125ed8d8bbSJosh Poimboeuf size_t len; 2135ed8d8bbSJosh Poimboeuf 2145ed8d8bbSJosh Poimboeuf if (state->regs) 2155ed8d8bbSJosh Poimboeuf prev_frame_end = (void *)state->regs + regs_size(state->regs); 2165ed8d8bbSJosh Poimboeuf else 2175ed8d8bbSJosh Poimboeuf prev_frame_end = (void *)state->bp + FRAME_HEADER_SIZE; 2185ed8d8bbSJosh Poimboeuf 2195ed8d8bbSJosh Poimboeuf /* Is the next frame pointer an encoded pointer to pt_regs? */ 2205ed8d8bbSJosh Poimboeuf regs = decode_frame_pointer(next_bp); 2215ed8d8bbSJosh Poimboeuf if (regs) { 2225ed8d8bbSJosh Poimboeuf frame = (unsigned long *)regs; 22362dd86acSJosh Poimboeuf len = KERNEL_REGS_SIZE; 224a8b7a923SJosh Poimboeuf state->got_irq = true; 2255ed8d8bbSJosh Poimboeuf } else { 2265ed8d8bbSJosh Poimboeuf frame = next_bp; 2275ed8d8bbSJosh Poimboeuf len = FRAME_HEADER_SIZE; 2285ed8d8bbSJosh Poimboeuf } 2297c7900f8SJosh Poimboeuf 2307c7900f8SJosh Poimboeuf /* 2315ed8d8bbSJosh Poimboeuf * If the next bp isn't on the current stack, switch to the next one. 2327c7900f8SJosh Poimboeuf * 2337c7900f8SJosh Poimboeuf * We may have to traverse multiple stacks to deal with the possibility 2345ed8d8bbSJosh Poimboeuf * that info->next_sp could point to an empty stack and the next bp 2355ed8d8bbSJosh Poimboeuf * could be on a subsequent stack. 2367c7900f8SJosh Poimboeuf */ 2375ed8d8bbSJosh Poimboeuf while (!on_stack(info, frame, len)) 2387c7900f8SJosh Poimboeuf if (get_stack_info(info->next_sp, state->task, info, 2397c7900f8SJosh Poimboeuf &state->stack_mask)) 2407c7900f8SJosh Poimboeuf return false; 2417c7900f8SJosh Poimboeuf 2425ed8d8bbSJosh Poimboeuf /* Make sure it only unwinds up and doesn't overlap the prev frame: */ 2435ed8d8bbSJosh Poimboeuf if (state->orig_sp && state->stack_info.type == prev_type && 2445ed8d8bbSJosh Poimboeuf frame < prev_frame_end) 2455ed8d8bbSJosh Poimboeuf return false; 2465ed8d8bbSJosh Poimboeuf 24762dd86acSJosh Poimboeuf /* 24862dd86acSJosh Poimboeuf * On 32-bit with user mode regs, make sure the last two regs are safe 24962dd86acSJosh Poimboeuf * to access: 25062dd86acSJosh Poimboeuf */ 25162dd86acSJosh Poimboeuf if (IS_ENABLED(CONFIG_X86_32) && regs && user_mode(regs) && 25262dd86acSJosh Poimboeuf !on_stack(info, frame, len + 2*sizeof(long))) 25362dd86acSJosh Poimboeuf return false; 25462dd86acSJosh Poimboeuf 2555ed8d8bbSJosh Poimboeuf /* Move state to the next frame: */ 2565ed8d8bbSJosh Poimboeuf if (regs) { 2575ed8d8bbSJosh Poimboeuf state->regs = regs; 2585ed8d8bbSJosh Poimboeuf state->bp = NULL; 2595ed8d8bbSJosh Poimboeuf } else { 2605ed8d8bbSJosh Poimboeuf state->bp = next_bp; 2615ed8d8bbSJosh Poimboeuf state->regs = NULL; 2625ed8d8bbSJosh Poimboeuf } 2635ed8d8bbSJosh Poimboeuf 2646bcdf9d5SJosh Poimboeuf /* Save the return address: */ 2656bcdf9d5SJosh Poimboeuf if (state->regs && user_mode(state->regs)) 2666bcdf9d5SJosh Poimboeuf state->ip = 0; 2676bcdf9d5SJosh Poimboeuf else { 2686bcdf9d5SJosh Poimboeuf addr_p = unwind_get_return_address_ptr(state); 2696bcdf9d5SJosh Poimboeuf addr = READ_ONCE_TASK_STACK(state->task, *addr_p); 2706bcdf9d5SJosh Poimboeuf state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, 2716bcdf9d5SJosh Poimboeuf addr, addr_p); 2726bcdf9d5SJosh Poimboeuf } 2736bcdf9d5SJosh Poimboeuf 2745ed8d8bbSJosh Poimboeuf /* Save the original stack pointer for unwind_dump(): */ 275262fa734SJosh Poimboeuf if (!state->orig_sp) 2765ed8d8bbSJosh Poimboeuf state->orig_sp = frame; 2778b5e99f0SJosh Poimboeuf 2787c7900f8SJosh Poimboeuf return true; 2797c7900f8SJosh Poimboeuf } 2807c7900f8SJosh Poimboeuf 2817c7900f8SJosh Poimboeuf bool unwind_next_frame(struct unwind_state *state) 2827c7900f8SJosh Poimboeuf { 283946c1911SJosh Poimboeuf struct pt_regs *regs; 2845ed8d8bbSJosh Poimboeuf unsigned long *next_bp; 2857c7900f8SJosh Poimboeuf 2867c7900f8SJosh Poimboeuf if (unwind_done(state)) 2877c7900f8SJosh Poimboeuf return false; 2887c7900f8SJosh Poimboeuf 2895ed8d8bbSJosh Poimboeuf /* Have we reached the end? */ 290946c1911SJosh Poimboeuf if (state->regs && user_mode(state->regs)) 291946c1911SJosh Poimboeuf goto the_end; 292946c1911SJosh Poimboeuf 293acb4608aSJosh Poimboeuf if (is_last_task_frame(state)) { 294acb4608aSJosh Poimboeuf regs = task_pt_regs(state->task); 295acb4608aSJosh Poimboeuf 296acb4608aSJosh Poimboeuf /* 297acb4608aSJosh Poimboeuf * kthreads (other than the boot CPU's idle thread) have some 298acb4608aSJosh Poimboeuf * partial regs at the end of their stack which were placed 299acb4608aSJosh Poimboeuf * there by copy_thread_tls(). But the regs don't have any 300acb4608aSJosh Poimboeuf * useful information, so we can skip them. 301acb4608aSJosh Poimboeuf * 302acb4608aSJosh Poimboeuf * This user_mode() check is slightly broader than a PF_KTHREAD 303acb4608aSJosh Poimboeuf * check because it also catches the awkward situation where a 304acb4608aSJosh Poimboeuf * newly forked kthread transitions into a user task by calling 305acb4608aSJosh Poimboeuf * do_execve(), which eventually clears PF_KTHREAD. 306acb4608aSJosh Poimboeuf */ 307acb4608aSJosh Poimboeuf if (!user_mode(regs)) 308acb4608aSJosh Poimboeuf goto the_end; 309acb4608aSJosh Poimboeuf 310acb4608aSJosh Poimboeuf /* 311acb4608aSJosh Poimboeuf * We're almost at the end, but not quite: there's still the 312acb4608aSJosh Poimboeuf * syscall regs frame. Entry code doesn't encode the regs 313acb4608aSJosh Poimboeuf * pointer for syscalls, so we have to set it manually. 314acb4608aSJosh Poimboeuf */ 315acb4608aSJosh Poimboeuf state->regs = regs; 316acb4608aSJosh Poimboeuf state->bp = NULL; 3176bcdf9d5SJosh Poimboeuf state->ip = 0; 318acb4608aSJosh Poimboeuf return true; 319acb4608aSJosh Poimboeuf } 320acb4608aSJosh Poimboeuf 3215ed8d8bbSJosh Poimboeuf /* Get the next frame pointer: */ 322946c1911SJosh Poimboeuf if (state->regs) 323946c1911SJosh Poimboeuf next_bp = (unsigned long *)state->regs->bp; 324946c1911SJosh Poimboeuf else 32584936118SJosh Poimboeuf next_bp = (unsigned long *)READ_ONCE_TASK_STACK(state->task, *state->bp); 3267c7900f8SJosh Poimboeuf 3275ed8d8bbSJosh Poimboeuf /* Move to the next frame if it's safe: */ 328a8b7a923SJosh Poimboeuf if (!update_stack_state(state, next_bp)) 329c32c47c6SJosh Poimboeuf goto bad_address; 330c32c47c6SJosh Poimboeuf 3317c7900f8SJosh Poimboeuf return true; 332946c1911SJosh Poimboeuf 333c32c47c6SJosh Poimboeuf bad_address: 334af085d90SJosh Poimboeuf state->error = true; 335af085d90SJosh Poimboeuf 336900742d8SJosh Poimboeuf /* 337900742d8SJosh Poimboeuf * When unwinding a non-current task, the task might actually be 338900742d8SJosh Poimboeuf * running on another CPU, in which case it could be modifying its 339900742d8SJosh Poimboeuf * stack while we're reading it. This is generally not a problem and 340900742d8SJosh Poimboeuf * can be ignored as long as the caller understands that unwinding 341900742d8SJosh Poimboeuf * another task will not always succeed. 342900742d8SJosh Poimboeuf */ 343900742d8SJosh Poimboeuf if (state->task != current) 344900742d8SJosh Poimboeuf goto the_end; 345900742d8SJosh Poimboeuf 346a8b7a923SJosh Poimboeuf /* 347a8b7a923SJosh Poimboeuf * Don't warn if the unwinder got lost due to an interrupt in entry 348b0d50c7bSJosh Poimboeuf * code or in the C handler before the first frame pointer got set up: 349a8b7a923SJosh Poimboeuf */ 350a8b7a923SJosh Poimboeuf if (state->got_irq && in_entry_code(state->ip)) 351a8b7a923SJosh Poimboeuf goto the_end; 352b0d50c7bSJosh Poimboeuf if (state->regs && 353b0d50c7bSJosh Poimboeuf state->regs->sp >= (unsigned long)last_aligned_frame(state) && 354b0d50c7bSJosh Poimboeuf state->regs->sp < (unsigned long)task_pt_regs(state->task)) 355b0d50c7bSJosh Poimboeuf goto the_end; 356a8b7a923SJosh Poimboeuf 35724d86f59SJosh Poimboeuf if (state->regs) { 35824d86f59SJosh Poimboeuf printk_deferred_once(KERN_WARNING 35924d86f59SJosh Poimboeuf "WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n", 36024d86f59SJosh Poimboeuf state->regs, state->task->comm, 3615ed8d8bbSJosh Poimboeuf state->task->pid, next_bp); 362aa4f8534SJosh Poimboeuf unwind_dump(state); 36324d86f59SJosh Poimboeuf } else { 364c32c47c6SJosh Poimboeuf printk_deferred_once(KERN_WARNING 365c32c47c6SJosh Poimboeuf "WARNING: kernel stack frame pointer at %p in %s:%d has bad value %p\n", 366c32c47c6SJosh Poimboeuf state->bp, state->task->comm, 3675ed8d8bbSJosh Poimboeuf state->task->pid, next_bp); 368aa4f8534SJosh Poimboeuf unwind_dump(state); 36924d86f59SJosh Poimboeuf } 370946c1911SJosh Poimboeuf the_end: 371946c1911SJosh Poimboeuf state->stack_info.type = STACK_TYPE_UNKNOWN; 372946c1911SJosh Poimboeuf return false; 3737c7900f8SJosh Poimboeuf } 3747c7900f8SJosh Poimboeuf EXPORT_SYMBOL_GPL(unwind_next_frame); 3757c7900f8SJosh Poimboeuf 3767c7900f8SJosh Poimboeuf void __unwind_start(struct unwind_state *state, struct task_struct *task, 3777c7900f8SJosh Poimboeuf struct pt_regs *regs, unsigned long *first_frame) 3787c7900f8SJosh Poimboeuf { 3795ed8d8bbSJosh Poimboeuf unsigned long *bp; 380946c1911SJosh Poimboeuf 3817c7900f8SJosh Poimboeuf memset(state, 0, sizeof(*state)); 3827c7900f8SJosh Poimboeuf state->task = task; 383a8b7a923SJosh Poimboeuf state->got_irq = (regs); 3847c7900f8SJosh Poimboeuf 3855ed8d8bbSJosh Poimboeuf /* Don't even attempt to start from user mode regs: */ 3867c7900f8SJosh Poimboeuf if (regs && user_mode(regs)) { 3877c7900f8SJosh Poimboeuf state->stack_info.type = STACK_TYPE_UNKNOWN; 3887c7900f8SJosh Poimboeuf return; 3897c7900f8SJosh Poimboeuf } 3907c7900f8SJosh Poimboeuf 391946c1911SJosh Poimboeuf bp = get_frame_pointer(task, regs); 3927c7900f8SJosh Poimboeuf 3935ed8d8bbSJosh Poimboeuf /* Initialize stack info and make sure the frame data is accessible: */ 3945ed8d8bbSJosh Poimboeuf get_stack_info(bp, state->task, &state->stack_info, 3957c7900f8SJosh Poimboeuf &state->stack_mask); 3965ed8d8bbSJosh Poimboeuf update_stack_state(state, bp); 3977c7900f8SJosh Poimboeuf 3987c7900f8SJosh Poimboeuf /* 3997c7900f8SJosh Poimboeuf * The caller can provide the address of the first frame directly 4007c7900f8SJosh Poimboeuf * (first_frame) or indirectly (regs->sp) to indicate which stack frame 4017c7900f8SJosh Poimboeuf * to start unwinding at. Skip ahead until we reach it. 4027c7900f8SJosh Poimboeuf */ 4037c7900f8SJosh Poimboeuf while (!unwind_done(state) && 4047c7900f8SJosh Poimboeuf (!on_stack(&state->stack_info, first_frame, sizeof(long)) || 4057c7900f8SJosh Poimboeuf state->bp < first_frame)) 4067c7900f8SJosh Poimboeuf unwind_next_frame(state); 4077c7900f8SJosh Poimboeuf } 4087c7900f8SJosh Poimboeuf EXPORT_SYMBOL_GPL(__unwind_start); 409