[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>

1 files changed, 44 insertions, 0 deletions

diff --git a/include/asm-mips/stacktrace.h b/include/asm-mips/stacktrace.h
new file mode 100644
index 000000000000..231f6f897a61
--- /dev/null
+++ b/include/asm-mips/stacktrace.h
@@ -0,0 +1,44 @@
+#ifndef _ASM_STACKTRACE_H
+#define _ASM_STACKTRACE_H
+
+#include <asm/ptrace.h>
+
+#ifdef CONFIG_KALLSYMS
+extern int raw_show_trace;
+extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+                                  unsigned long pc, unsigned long ra);
+#else
+#define raw_show_trace 1
+#define unwind_stack(task, sp, pc, ra)  0
+#endif
+
+static __always_inline void prepare_frametrace(struct pt_regs *regs)
+{
+#ifndef CONFIG_KALLSYMS
+        /*
+         * Remove any garbage that may be in regs (specially func
+         * addresses) to avoid show_raw_backtrace() to report them
+         */
+        memset(regs, 0, sizeof(*regs));
+#endif
+        __asm__ __volatile__(
+                ".set push\n\t"
+                ".set noat\n\t"
+#ifdef CONFIG_64BIT
+                "1: dla $1, 1b\n\t"
+                "sd $1, %0\n\t"
+                "sd $29, %1\n\t"
+                "sd $31, %2\n\t"
+#else
+                "1: la $1, 1b\n\t"
+                "sw $1, %0\n\t"
+                "sw $29, %1\n\t"
+                "sw $31, %2\n\t"
+#endif
+                ".set pop\n\t"
+                : "=m" (regs->cp0_epc),
+                "=m" (regs->regs[29]), "=m" (regs->regs[31])
+                : : "memory");
+}
+
+#endif /* _ASM_STACKTRACE_H */