sh: Handle the DWARF op, DW_CFA_undefined

Allow a DWARF register to have an undefined value. When applied to the
DWARF return address register this lets lets us label a function as
having no direct caller, e.g. kernel_thread_helper().

Signed-off-by: Matt Fleming <matt@console-pimps.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/sh/include/asm/dwarf.h b/arch/sh/include/asm/dwarf.h
index 8b0bcc087385..c367ed3373c5 100644
--- a/arch/sh/include/asm/dwarf.h
+++ b/arch/sh/include/asm/dwarf.h
@@ -297,6 +297,7 @@ struct dwarf_reg {
         unsigned long flags;
 #define DWARF_REG_OFFSET        (1 << 0)
 #define DWARF_VAL_OFFSET        (1 << 1)
+#define DWARF_UNDEFINED         (1 << 2)
 };
 
 /*
@@ -370,6 +371,7 @@ extern struct dwarf_frame *dwarf_unwind_stack(unsigned long,
 #define CFI_DEF_CFA     .cfi_def_cfa
 #define CFI_REGISTER    .cfi_register
 #define CFI_REL_OFFSET  .cfi_rel_offset
+#define CFI_UNDEFINED   .cfi_undefined
 
 #else
 
@@ -383,6 +385,7 @@ extern struct dwarf_frame *dwarf_unwind_stack(unsigned long,
 #define CFI_DEF_CFA     CFI_IGNORE
 #define CFI_REGISTER    CFI_IGNORE
 #define CFI_REL_OFFSET  CFI_IGNORE
+#define CFI_UNDEFINED   CFI_IGNORE
 
 #ifndef __ASSEMBLY__
 static inline void dwarf_unwinder_init(void)