[IA64] Add CONFIG_STACKTRACE_SUPPORT

Several Linux features are dependent on stack trace support. Add
it so they can be enabled.

Signed-off-by: Tony Luck <tony.luck@intel.com>

3 files changed, 43 insertions, 0 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index ba22849ee3ec..e93f44e62edb 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -62,6 +62,9 @@ config NEED_SG_DMA_LENGTH
 config SWIOTLB
        bool
 
+config STACKTRACE_SUPPORT
+        def_bool y
+
 config GENERIC_LOCKBREAK
         def_bool n
 
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
index db10b1e378b0..395c2f216dd8 100644
--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_AUDIT)		+= audit.o
 obj-$(CONFIG_PCI_MSI)           += msi_ia64.o
 mca_recovery-y                  += mca_drv.o mca_drv_asm.o
 obj-$(CONFIG_IA64_MC_ERR_INJECT)+= err_inject.o
+obj-$(CONFIG_STACKTRACE)        += stacktrace.o
 
 obj-$(CONFIG_PARAVIRT)          += paravirt.o paravirtentry.o \
                                    paravirt_patch.o
diff --git a/arch/ia64/kernel/stacktrace.c b/arch/ia64/kernel/stacktrace.c
new file mode 100644
index 000000000000..5af2783a87f4
--- /dev/null
+++ b/arch/ia64/kernel/stacktrace.c
@@ -0,0 +1,39 @@
+/*
+ * arch/ia64/kernel/stacktrace.c
+ *
+ * Stack trace management functions
+ *
+ */
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/module.h>
+
+static void
+ia64_do_save_stack(struct unw_frame_info *info, void *arg)
+{
+        struct stack_trace *trace = arg;
+        unsigned long ip;
+        int skip = trace->skip;
+
+        trace->nr_entries = 0;
+        do {
+                unw_get_ip(info, &ip);
+                if (ip == 0)
+                        break;
+                if (skip == 0) {
+                        trace->entries[trace->nr_entries++] = ip;
+                        if (trace->nr_entries == trace->max_entries)
+                                break;
+                } else
+                        skip--;
+        } while (unw_unwind(info) >= 0);
+}
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+void save_stack_trace(struct stack_trace *trace)
+{
+        unw_init_running(ia64_do_save_stack, trace);
+}
+EXPORT_SYMBOL(save_stack_trace);