[POWERPC] Stacktrace support for lockdep

This adds stacktrace support for powerpc, which will be needed for
lockdep.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 7f2f126d1c2bbfad899be6ad37b04e8b8a2c78d3..ecca20d17a7b815bf5b8353339acd801d9f3e01c 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -49,6 +49,10 @@ config IRQ_PER_CPU
        bool
        default y
 
+config STACKTRACE_SUPPORT
+       bool
+       default y
+
 config RWSEM_GENERIC_SPINLOCK
        bool
 

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index c1baf9d5903feaac10959b604d8a92ca5671c91e..5183a9012a08ae45f637c8b6a183f6eed1733635 100644 (file)
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_BOOTX_TEXT)      += btext.o
 obj-$(CONFIG_SMP)              += smp.o
 obj-$(CONFIG_KPROBES)          += kprobes.o
 obj-$(CONFIG_PPC_UDBG_16550)   += legacy_serial.o udbg_16550.o
+obj-$(CONFIG_STACKTRACE)       += stacktrace.o
 
 pci64-$(CONFIG_PPC64)          += pci_dn.o isa-bridge.o
 obj-$(CONFIG_PCI)              += pci_$(CONFIG_WORD_SIZE).o $(pci64-y) \

diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
new file mode 100644 (file)
index 0000000..e3638ee
--- /dev/null
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -0,0 +1,47 @@
+/*
+ * Stack trace utility
+ *
+ * Copyright 2008 Christoph Hellwig, IBM Corp.
+ *
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <asm/ptrace.h>
+#include <asm/asm-offsets.h>
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+void save_stack_trace(struct stack_trace *trace)
+{
+       unsigned long sp;
+
+       asm("mr %0,1" : "=r" (sp));
+
+       for (;;) {
+               unsigned long *stack = (unsigned long *) sp;
+               unsigned long newsp, ip;
+
+               if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
+                       return;
+
+               newsp = stack[0];
+               ip = stack[STACK_FRAME_LR_SAVE];
+
+               if (!trace->skip)
+                       trace->entries[trace->nr_entries++] = ip;
+               else
+                       trace->skip--;
+
+               if (trace->nr_entries >= trace->max_entries)
+                       return;
+
+               sp = newsp;
+       }
+}