uml: Add support for CONFIG_STACKTRACE

Add stacktrace support for User Mode Linux

---
 arch/um/Kconfig.common           |  3 +-
 arch/um/include/asm/stacktrace.h | 42 +++++++++++++++++++++
 arch/um/kernel/Makefile          |  1 +
 arch/um/kernel/stacktrace.c      | 80 ++++++++++++++++++++++++++++++++++++++++
 arch/um/kernel/sysrq.c           | 69 +++++++++-------------------------
 5 files changed, 142 insertions(+), 53 deletions(-)
 create mode 100644 arch/um/include/asm/stacktrace.h
 create mode 100644 arch/um/kernel/stacktrace.c

index 6915d28..87bc868 100644
@@ -39,7 +39,8 @@ config LOCKDEP_SUPPORT
 
 config STACKTRACE_SUPPORT
 	bool
-	default n
+	default y
+	select STACKTRACE
 
 config GENERIC_CALIBRATE_DELAY
 	bool

index d8b78a0..2d840a0 100644
@@ -19,6 +19,7 @@ obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
 obj-$(CONFIG_GPROF)	+= gprof_syms.o
 obj-$(CONFIG_GCOV)	+= gmon_syms.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+obj-$(CONFIG_STACKTRACE) += stacktrace.o
 
 USER_OBJS := config.o
 

2.1.0.rc2.206.gedb03e5