| /* |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs |
| */ |
| #include <linux/kallsyms.h> |
| #include <linux/kprobes.h> |
| #include <linux/uaccess.h> |
| #include <linux/hardirq.h> |
| #include <linux/kdebug.h> |
| #include <linux/module.h> |
| #include <linux/ptrace.h> |
| #include <linux/kexec.h> |
| #include <linux/sysfs.h> |
| #include <linux/bug.h> |
| #include <linux/nmi.h> |
| |
| #include <asm/stacktrace.h> |
| |
| |
| #define N_EXCEPTION_STACKS_END \ |
| (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2) |
| |
| static char x86_stack_ids[][8] = { |
| [ DEBUG_STACK-1 ] = "#DB", |
| [ NMI_STACK-1 ] = "NMI", |
| [ DOUBLEFAULT_STACK-1 ] = "#DF", |
| [ MCE_STACK-1 ] = "#MC", |
| #if DEBUG_STKSZ > EXCEPTION_STKSZ |
| [ N_EXCEPTION_STACKS ... |
| N_EXCEPTION_STACKS_END ] = "#DB[?]" |
| #endif |
| }; |
| |
| static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, |
| unsigned *usedp, char **idp) |
| { |
| unsigned k; |
| |
| /* |
| * Iterate over all exception stacks, and figure out whether |
| * 'stack' is in one of them: |
| */ |
| for (k = 0; k < N_EXCEPTION_STACKS; k++) { |
| unsigned long end = per_cpu(orig_ist, cpu).ist[k]; |
| /* |
| * Is 'stack' above this exception frame's end? |
| * If yes then skip to the next frame. |
| */ |
| if (stack >= end) |
| continue; |
| /* |
| * Is 'stack' above this exception frame's start address? |
| * If yes then we found the right frame. |
| */ |
| if (stack >= end - EXCEPTION_STKSZ) { |
| /* |
| * Make sure we only iterate through an exception |
| * stack once. If it comes up for the second time |
| * then there's something wrong going on - just |
| * break out and return NULL: |
| */ |
| if (*usedp & (1U << k)) |
| break; |
| *usedp |= 1U << k; |
| *idp = x86_stack_ids[k]; |
| return (unsigned long *)end; |
| } |
| /* |
| * If this is a debug stack, and if it has a larger size than |
| * the usual exception stacks, then 'stack' might still |
| * be within the lower portion of the debug stack: |
| */ |
| #if DEBUG_STKSZ > EXCEPTION_STKSZ |
| if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) { |
| unsigned j = N_EXCEPTION_STACKS - 1; |
| |
| /* |
| * Black magic. A large debug stack is composed of |
| * multiple exception stack entries, which we |
| * iterate through now. Dont look: |
| */ |
| do { |
| ++j; |
| end -= EXCEPTION_STKSZ; |
| x86_stack_ids[j][4] = '1' + |
| (j - N_EXCEPTION_STACKS); |
| } while (stack < end - EXCEPTION_STKSZ); |
| if (*usedp & (1U << j)) |
| break; |
| *usedp |= 1U << j; |
| *idp = x86_stack_ids[j]; |
| return (unsigned long *)end; |
| } |
| #endif |
| } |
| return NULL; |
| } |
| |
| static inline int |
| in_irq_stack(unsigned long *stack, unsigned long *irq_stack, |
| unsigned long *irq_stack_end) |
| { |
| return (stack >= irq_stack && stack < irq_stack_end); |
| } |
| |
| static const unsigned long irq_stack_size = |
| (IRQ_STACK_SIZE - 64) / sizeof(unsigned long); |
| |
| enum stack_type { |
| STACK_IS_UNKNOWN, |
| STACK_IS_NORMAL, |
| STACK_IS_EXCEPTION, |
| STACK_IS_IRQ, |
| }; |
| |
| static enum stack_type |
| analyze_stack(int cpu, struct task_struct *task, unsigned long *stack, |
| unsigned long **stack_end, unsigned long *irq_stack, |
| unsigned *used, char **id) |
| { |
| unsigned long addr; |
| |
| addr = ((unsigned long)stack & (~(THREAD_SIZE - 1))); |
| if ((unsigned long)task_stack_page(task) == addr) |
| return STACK_IS_NORMAL; |
| |
| *stack_end = in_exception_stack(cpu, (unsigned long)stack, |
| used, id); |
| if (*stack_end) |
| return STACK_IS_EXCEPTION; |
| |
| if (!irq_stack) |
| return STACK_IS_NORMAL; |
| |
| *stack_end = irq_stack; |
| irq_stack = irq_stack - irq_stack_size; |
| |
| if (in_irq_stack(stack, irq_stack, *stack_end)) |
| return STACK_IS_IRQ; |
| |
| return STACK_IS_UNKNOWN; |
| } |
| |
| /* |
| * x86-64 can have up to three kernel stacks: |
| * process stack |
| * interrupt stack |
| * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack |
| */ |
| |
| void dump_trace(struct task_struct *task, struct pt_regs *regs, |
| unsigned long *stack, unsigned long bp, |
| const struct stacktrace_ops *ops, void *data) |
| { |
| const unsigned cpu = get_cpu(); |
| struct thread_info *tinfo; |
| unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu); |
| unsigned long dummy; |
| unsigned used = 0; |
| int graph = 0; |
| int done = 0; |
| |
| if (!task) |
| task = current; |
| |
| if (!stack) { |
| if (regs) |
| stack = (unsigned long *)regs->sp; |
| else if (task != current) |
| stack = (unsigned long *)task->thread.sp; |
| else |
| stack = &dummy; |
| } |
| |
| if (!bp) |
| bp = stack_frame(task, regs); |
| /* |
| * Print function call entries in all stacks, starting at the |
| * current stack address. If the stacks consist of nested |
| * exceptions |
| */ |
| tinfo = task_thread_info(task); |
| while (!done) { |
| unsigned long *stack_end; |
| enum stack_type stype; |
| char *id; |
| |
| stype = analyze_stack(cpu, task, stack, &stack_end, |
| irq_stack, &used, &id); |
| |
| /* Default finish unless specified to continue */ |
| done = 1; |
| |
| switch (stype) { |
| |
| /* Break out early if we are on the thread stack */ |
| case STACK_IS_NORMAL: |
| break; |
| |
| case STACK_IS_EXCEPTION: |
| |
| if (ops->stack(data, id) < 0) |
| break; |
| |
| bp = ops->walk_stack(tinfo, stack, bp, ops, |
| data, stack_end, &graph); |
| ops->stack(data, "<EOE>"); |
| /* |
| * We link to the next stack via the |
| * second-to-last pointer (index -2 to end) in the |
| * exception stack: |
| */ |
| stack = (unsigned long *) stack_end[-2]; |
| done = 0; |
| break; |
| |
| case STACK_IS_IRQ: |
| |
| if (ops->stack(data, "IRQ") < 0) |
| break; |
| bp = ops->walk_stack(tinfo, stack, bp, |
| ops, data, stack_end, &graph); |
| /* |
| * We link to the next stack (which would be |
| * the process stack normally) the last |
| * pointer (index -1 to end) in the IRQ stack: |
| */ |
| stack = (unsigned long *) (stack_end[-1]); |
| irq_stack = NULL; |
| ops->stack(data, "EOI"); |
| done = 0; |
| break; |
| |
| case STACK_IS_UNKNOWN: |
| ops->stack(data, "UNK"); |
| break; |
| } |
| } |
| |
| /* |
| * This handles the process stack: |
| */ |
| bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph); |
| put_cpu(); |
| } |
| EXPORT_SYMBOL(dump_trace); |
| |
| void |
| show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, |
| unsigned long *sp, unsigned long bp, char *log_lvl) |
| { |
| unsigned long *irq_stack_end; |
| unsigned long *irq_stack; |
| unsigned long *stack; |
| int cpu; |
| int i; |
| |
| preempt_disable(); |
| cpu = smp_processor_id(); |
| |
| irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu)); |
| irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE); |
| |
| /* |
| * Debugging aid: "show_stack(NULL, NULL);" prints the |
| * back trace for this cpu: |
| */ |
| if (sp == NULL) { |
| if (task) |
| sp = (unsigned long *)task->thread.sp; |
| else |
| sp = (unsigned long *)&sp; |
| } |
| |
| stack = sp; |
| for (i = 0; i < kstack_depth_to_print; i++) { |
| if (stack >= irq_stack && stack <= irq_stack_end) { |
| if (stack == irq_stack_end) { |
| stack = (unsigned long *) (irq_stack_end[-1]); |
| pr_cont(" <EOI> "); |
| } |
| } else { |
| if (kstack_end(stack)) |
| break; |
| } |
| if ((i % STACKSLOTS_PER_LINE) == 0) { |
| if (i != 0) |
| pr_cont("\n"); |
| printk("%s %016lx", log_lvl, *stack++); |
| } else |
| pr_cont(" %016lx", *stack++); |
| touch_nmi_watchdog(); |
| } |
| preempt_enable(); |
| |
| pr_cont("\n"); |
| show_trace_log_lvl(task, regs, sp, bp, log_lvl); |
| } |
| |
| void show_regs(struct pt_regs *regs) |
| { |
| int i; |
| unsigned long sp; |
| |
| sp = regs->sp; |
| show_regs_print_info(KERN_DEFAULT); |
| __show_regs(regs, 1); |
| |
| /* |
| * When in-kernel, we also print out the stack and code at the |
| * time of the fault.. |
| */ |
| if (!user_mode(regs)) { |
| unsigned int code_prologue = code_bytes * 43 / 64; |
| unsigned int code_len = code_bytes; |
| unsigned char c; |
| u8 *ip; |
| |
| printk(KERN_DEFAULT "Stack:\n"); |
| show_stack_log_lvl(NULL, regs, (unsigned long *)sp, |
| 0, KERN_DEFAULT); |
| |
| printk(KERN_DEFAULT "Code: "); |
| |
| ip = (u8 *)regs->ip - code_prologue; |
| if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { |
| /* try starting at IP */ |
| ip = (u8 *)regs->ip; |
| code_len = code_len - code_prologue + 1; |
| } |
| for (i = 0; i < code_len; i++, ip++) { |
| if (ip < (u8 *)PAGE_OFFSET || |
| probe_kernel_address(ip, c)) { |
| pr_cont(" Bad RIP value."); |
| break; |
| } |
| if (ip == (u8 *)regs->ip) |
| pr_cont("<%02x> ", c); |
| else |
| pr_cont("%02x ", c); |
| } |
| } |
| pr_cont("\n"); |
| } |
| |
| int is_valid_bugaddr(unsigned long ip) |
| { |
| unsigned short ud2; |
| |
| if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2))) |
| return 0; |
| |
| return ud2 == 0x0b0f; |
| } |