#include <asm/stacktrace.h>
+static char *exception_stack_names[N_EXCEPTION_STACKS] = {
+ [ DOUBLEFAULT_STACK-1 ] = "#DF",
+ [ NMI_STACK-1 ] = "NMI",
+ [ DEBUG_STACK-1 ] = "#DB",
+ [ MCE_STACK-1 ] = "#MC",
+};
-#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 exception_stack_sizes[N_EXCEPTION_STACKS] = {
+ [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
+ [DEBUG_STACK - 1] = DEBUG_STKSZ
};
-static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
- unsigned *usedp, char **idp)
+void stack_type_str(enum stack_type type, const char **begin, const char **end)
+{
+ BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
+
+ switch (type) {
+ case STACK_TYPE_IRQ:
+ *begin = "IRQ";
+ *end = "EOI";
+ break;
+ case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
+ *begin = exception_stack_names[type - STACK_TYPE_EXCEPTION];
+ *end = "EOE";
+ break;
+ default:
+ *begin = NULL;
+ *end = NULL;
+ }
+}
+
+static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
{
+ unsigned long *begin, *end;
+ struct pt_regs *regs;
unsigned k;
- /*
- * Iterate over all exception stacks, and figure out whether
- * 'stack' is in one of them:
- */
+ BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
+
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)
+ end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
+ begin = end - (exception_stack_sizes[k] / sizeof(long));
+ regs = (struct pt_regs *)end - 1;
+
+ if (stack < begin || 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
+
+ info->type = STACK_TYPE_EXCEPTION + k;
+ info->begin = begin;
+ info->end = end;
+ info->next_sp = (unsigned long *)regs->sp;
+
+ return true;
}
- return NULL;
+
+ return false;
}
-static inline int
-in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
- unsigned long *irq_stack_end)
+static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
{
- return (stack >= irq_stack && stack < irq_stack_end);
-}
+ unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
+ unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
-static const unsigned long irq_stack_size =
- (IRQ_STACK_SIZE - 64) / sizeof(unsigned long);
+ /*
+ * This is a software stack, so 'end' can be a valid stack pointer.
+ * It just means the stack is empty.
+ */
+ if (stack < begin || stack > end)
+ return false;
-enum stack_type {
- STACK_IS_UNKNOWN,
- STACK_IS_NORMAL,
- STACK_IS_EXCEPTION,
- STACK_IS_IRQ,
-};
+ info->type = STACK_TYPE_IRQ;
+ info->begin = begin;
+ info->end = end;
-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)
+ /*
+ * The next stack pointer is the first thing pushed by the entry code
+ * after switching to the irq stack.
+ */
+ info->next_sp = (unsigned long *)*(end - 1);
+
+ return true;
+}
+
+int get_stack_info(unsigned long *stack, struct task_struct *task,
+ struct stack_info *info, unsigned long *visit_mask)
{
- unsigned long addr;
+ if (!stack)
+ goto unknown;
+
+ task = task ? : current;
- addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
- if ((unsigned long)task_stack_page(task) == addr)
- return STACK_IS_NORMAL;
+ if (in_task_stack(stack, task, info))
+ goto recursion_check;
- *stack_end = in_exception_stack(cpu, (unsigned long)stack,
- used, id);
- if (*stack_end)
- return STACK_IS_EXCEPTION;
+ if (task != current)
+ goto unknown;
- if (!irq_stack)
- return STACK_IS_NORMAL;
+ if (in_exception_stack(stack, info))
+ goto recursion_check;
- *stack_end = irq_stack;
- irq_stack = irq_stack - irq_stack_size;
+ if (in_irq_stack(stack, info))
+ goto recursion_check;
+
+ goto unknown;
+
+recursion_check:
+ /*
+ * Make sure we don't iterate through any given stack more than once.
+ * If it comes up a second time then there's something wrong going on:
+ * just break out and report an unknown stack type.
+ */
+ if (visit_mask) {
+ if (*visit_mask & (1UL << info->type))
+ goto unknown;
+ *visit_mask |= 1UL << info->type;
+ }
- if (in_irq_stack(stack, irq_stack, *stack_end))
- return STACK_IS_IRQ;
+ return 0;
- return STACK_IS_UNKNOWN;
+unknown:
+ info->type = STACK_TYPE_UNKNOWN;
+ return -EINVAL;
}
/*
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
- const unsigned cpu = get_cpu();
- unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
- unsigned long dummy;
- unsigned used = 0;
+ unsigned long visit_mask = 0;
+ struct stack_info info;
int graph = 0;
int done = 0;
- if (!task)
- task = current;
+ task = task ? : current;
+ stack = stack ? : get_stack_pointer(task, regs);
+ bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
- 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
*/
while (!done) {
- unsigned long *stack_end;
- enum stack_type stype;
- char *id;
+ const char *begin_str, *end_str;
- stype = analyze_stack(cpu, task, stack, &stack_end,
- irq_stack, &used, &id);
+ get_stack_info(stack, task, &info, &visit_mask);
/* Default finish unless specified to continue */
done = 1;
- switch (stype) {
+ switch (info.type) {
/* Break out early if we are on the thread stack */
- case STACK_IS_NORMAL:
+ case STACK_TYPE_TASK:
break;
- case STACK_IS_EXCEPTION:
+ case STACK_TYPE_IRQ:
+ case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
+
+ stack_type_str(info.type, &begin_str, &end_str);
- if (ops->stack(data, id) < 0)
+ if (ops->stack(data, begin_str) < 0)
break;
bp = ops->walk_stack(task, 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;
+ data, &info, &graph);
- case STACK_IS_IRQ:
+ ops->stack(data, end_str);
- if (ops->stack(data, "IRQ") < 0)
- break;
- bp = ops->walk_stack(task, 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");
+ stack = info.next_sp;
done = 0;
break;
- case STACK_IS_UNKNOWN:
+ default:
ops->stack(data, "UNK");
break;
}
/*
* This handles the process stack:
*/
- bp = ops->walk_stack(task, stack, bp, ops, data, NULL, &graph);
- put_cpu();
+ bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
}
EXPORT_SYMBOL(dump_trace);
unsigned long *irq_stack_end;
unsigned long *irq_stack;
unsigned long *stack;
- int cpu;
int i;
- preempt_disable();
- cpu = smp_processor_id();
+ if (!try_get_task_stack(task))
+ return;
- irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
- irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
+ irq_stack_end = (unsigned long *)this_cpu_read(irq_stack_ptr);
+ irq_stack = irq_stack_end - (IRQ_STACK_SIZE / sizeof(long));
- /*
- * Debugging aid: "show_stack(NULL, NULL);" prints the
- * back trace for this cpu:
- */
- if (sp == NULL) {
- if (regs)
- sp = (unsigned long *)regs->sp;
- else if (task)
- sp = (unsigned long *)task->thread.sp;
- else
- sp = (unsigned long *)&sp;
- }
+ sp = sp ? : get_stack_pointer(task, regs);
stack = sp;
for (i = 0; i < kstack_depth_to_print; i++) {
stack++;
touch_nmi_watchdog();
}
- preempt_enable();
pr_cont("\n");
show_trace_log_lvl(task, regs, sp, bp, log_lvl);
+
+ put_task_stack(task);
}
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);
u8 *ip;
printk(KERN_DEFAULT "Stack:\n");
- show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
- 0, KERN_DEFAULT);
+ show_stack_log_lvl(current, regs, NULL, 0, KERN_DEFAULT);
printk(KERN_DEFAULT "Code: ");
projects / cascardo / linux.git / blobdiff