diff options
Diffstat (limited to 'arch/x86_64/kernel/stacktrace.c')
| -rw-r--r-- | arch/x86_64/kernel/stacktrace.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/stacktrace.c b/arch/x86_64/kernel/stacktrace.c new file mode 100644 index 00000000000..32cf55eb9af --- /dev/null +++ b/arch/x86_64/kernel/stacktrace.c @@ -0,0 +1,221 @@ +/* + * arch/x86_64/kernel/stacktrace.c + * + * Stack trace management functions + * + * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> + */ +#include <linux/sched.h> +#include <linux/stacktrace.h> + +#include <asm/smp.h> + +static inline int +in_range(unsigned long start, unsigned long addr, unsigned long end) +{ + return addr >= start && addr <= end; +} + +static unsigned long +get_stack_end(struct task_struct *task, unsigned long stack) +{ + unsigned long stack_start, stack_end, flags; + int i, cpu; + + /* + * The most common case is that we are in the task stack: + */ + stack_start = (unsigned long)task->thread_info; + stack_end = stack_start + THREAD_SIZE; + + if (in_range(stack_start, stack, stack_end)) + return stack_end; + + /* + * We are in an interrupt if irqstackptr is set: + */ + raw_local_irq_save(flags); + cpu = safe_smp_processor_id(); + stack_end = (unsigned long)cpu_pda(cpu)->irqstackptr; + + if (stack_end) { + stack_start = stack_end & ~(IRQSTACKSIZE-1); + if (in_range(stack_start, stack, stack_end)) + goto out_restore; + /* + * We get here if we are in an IRQ context but we + * are also in an exception stack. + */ + } + + /* + * Iterate over all exception stacks, and figure out whether + * 'stack' is in one of them: + */ + for (i = 0; i < N_EXCEPTION_STACKS; i++) { + /* + * set 'end' to the end of the exception stack. + */ + stack_end = per_cpu(init_tss, cpu).ist[i]; + stack_start = stack_end - EXCEPTION_STKSZ; + + /* + * Is 'stack' above this exception frame's end? + * If yes then skip to the next frame. + */ + if (stack >= stack_end) + continue; + /* + * Is 'stack' above this exception frame's start address? + * If yes then we found the right frame. + */ + if (stack >= stack_start) + goto out_restore; + + /* + * 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 (i == DEBUG_STACK - 1 && stack >= stack_end - DEBUG_STKSZ) { + /* + * Black magic. A large debug stack is composed of + * multiple exception stack entries, which we + * iterate through now. Dont look: + */ + do { + stack_end -= EXCEPTION_STKSZ; + stack_start -= EXCEPTION_STKSZ; + } while (stack < stack_start); + + goto out_restore; + } +#endif + } + /* + * Ok, 'stack' is not pointing to any of the system stacks. + */ + stack_end = 0; + +out_restore: + raw_local_irq_restore(flags); + + return stack_end; +} + + +/* + * Save stack-backtrace addresses into a stack_trace buffer: + */ +static inline unsigned long +save_context_stack(struct stack_trace *trace, unsigned int skip, + unsigned long stack, unsigned long stack_end) +{ + unsigned long addr; + +#ifdef CONFIG_FRAME_POINTER + unsigned long prev_stack = 0; + + while (in_range(prev_stack, stack, stack_end)) { + pr_debug("stack: %p\n", (void *)stack); + addr = (unsigned long)(((unsigned long *)stack)[1]); + pr_debug("addr: %p\n", (void *)addr); + if (!skip) + trace->entries[trace->nr_entries++] = addr-1; + else + skip--; + if (trace->nr_entries >= trace->max_entries) + break; + if (!addr) + return 0; + /* + * Stack frames must go forwards (otherwise a loop could + * happen if the stackframe is corrupted), so we move + * prev_stack forwards: + */ + prev_stack = stack; + stack = (unsigned long)(((unsigned long *)stack)[0]); + } + pr_debug("invalid: %p\n", (void *)stack); +#else + while (stack < stack_end) { + addr = ((unsigned long *)stack)[0]; + stack += sizeof(long); + if (__kernel_text_address(addr)) { + if (!skip) + trace->entries[trace->nr_entries++] = addr-1; + else + skip--; + if (trace->nr_entries >= trace->max_entries) + break; + } + } +#endif + return stack; +} + +#define MAX_STACKS 10 + +/* + * Save stack-backtrace addresses into a stack_trace buffer. + * If all_contexts is set, all contexts (hardirq, softirq and process) + * are saved. If not set then only the current context is saved. + */ +void save_stack_trace(struct stack_trace *trace, + struct task_struct *task, int all_contexts, + unsigned int skip) +{ + unsigned long stack = (unsigned long)&stack; + int i, nr_stacks = 0, stacks_done[MAX_STACKS]; + + WARN_ON(trace->nr_entries || !trace->max_entries); + + if (!task) + task = current; + + pr_debug("task: %p, ti: %p\n", task, task->thread_info); + + if (!task || task == current) { + /* Grab rbp right from our regs: */ + asm ("mov %%rbp, %0" : "=r" (stack)); + pr_debug("rbp: %p\n", (void *)stack); + } else { + /* rbp is the last reg pushed by switch_to(): */ + stack = task->thread.rsp; + pr_debug("other task rsp: %p\n", (void *)stack); + stack = (unsigned long)(((unsigned long *)stack)[0]); + pr_debug("other task rbp: %p\n", (void *)stack); + } + + while (1) { + unsigned long stack_end = get_stack_end(task, stack); + + pr_debug("stack: %p\n", (void *)stack); + pr_debug("stack end: %p\n", (void *)stack_end); + + /* + * Invalid stack addres? + */ + if (!stack_end) + return; + /* + * Were we in this stack already? (recursion) + */ + for (i = 0; i < nr_stacks; i++) + if (stacks_done[i] == stack_end) + return; + stacks_done[nr_stacks] = stack_end; + + stack = save_context_stack(trace, skip, stack, stack_end); + if (!all_contexts || !stack || + trace->nr_entries >= trace->max_entries) + return; + trace->entries[trace->nr_entries++] = ULONG_MAX; + if (trace->nr_entries >= trace->max_entries) + return; + if (++nr_stacks >= MAX_STACKS) + return; + } +} + |