[MIPS] lockdep: Add STACKTRACE_SUPPORT and enable LOCKDEP_SUPPORT
Implement stacktrace interface by using unwind_stack() and enable lockdep
support in Kconfig.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/stacktrace.c b/arch/mips/kernel/stacktrace.c
new file mode 100644
index 0000000..f851d0c
--- /dev/null
+++ b/arch/mips/kernel/stacktrace.c
@@ -0,0 +1,111 @@
+/*
+ * arch/mips/kernel/stacktrace.c
+ *
+ * Stack trace management functions
+ *
+ * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ */
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <asm/stacktrace.h>
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer:
+ */
+static void save_raw_context_stack(struct stack_trace *trace,
+ unsigned int skip, unsigned long reg29)
+{
+ unsigned long *sp = (unsigned long *)reg29;
+ unsigned long addr;
+
+ while (!kstack_end(sp)) {
+ addr = *sp++;
+ if (__kernel_text_address(addr)) {
+ if (!skip)
+ trace->entries[trace->nr_entries++] = addr;
+ else
+ skip--;
+ if (trace->nr_entries >= trace->max_entries)
+ break;
+ }
+ }
+}
+
+static struct pt_regs * save_context_stack(struct stack_trace *trace,
+ unsigned int skip, struct task_struct *task, struct pt_regs *regs)
+{
+ unsigned long sp = regs->regs[29];
+#ifdef CONFIG_KALLSYMS
+ unsigned long ra = regs->regs[31];
+ unsigned long pc = regs->cp0_epc;
+ extern void ret_from_irq(void);
+
+ if (raw_show_trace || !__kernel_text_address(pc)) {
+ save_raw_context_stack(trace, skip, sp);
+ return NULL;
+ }
+ do {
+ if (!skip)
+ trace->entries[trace->nr_entries++] = pc;
+ else
+ skip--;
+ if (trace->nr_entries >= trace->max_entries)
+ break;
+ /*
+ * If we reached the bottom of interrupt context,
+ * return saved pt_regs.
+ */
+ if (pc == (unsigned long)ret_from_irq) {
+ unsigned long stack_page =
+ (unsigned long)task_stack_page(task);
+ if (!stack_page ||
+ sp < stack_page ||
+ sp > stack_page + THREAD_SIZE - 32)
+ break;
+ return (struct pt_regs *)sp;
+ }
+ pc = unwind_stack(task, &sp, pc, ra);
+ ra = 0;
+ } while (pc);
+#else
+ save_raw_context_stack(sp);
+#endif
+
+ return NULL;
+}
+
+/*
+ * 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)
+{
+ struct pt_regs dummyregs;
+ struct pt_regs *regs = &dummyregs;
+
+ WARN_ON(trace->nr_entries || !trace->max_entries);
+
+ if (task && task != current) {
+ regs->regs[29] = task->thread.reg29;
+ regs->regs[31] = 0;
+ regs->cp0_epc = task->thread.reg31;
+ } else {
+ if (!task)
+ task = current;
+ prepare_frametrace(regs);
+ }
+
+ while (1) {
+ regs = save_context_stack(trace, skip, task, regs);
+ if (!all_contexts || !regs ||
+ trace->nr_entries >= trace->max_entries)
+ break;
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+ if (trace->nr_entries >= trace->max_entries)
+ break;
+ skip = 0;
+ }
+}