--- /dev/null
+/*
+ * 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;
+ }
+}
+
projects / linux-2.6 / commitdiff