sh: Setup the frame register in asm code
In order to use DWARF unwinder info the frame register has to contain a
valid value. Whilst GCC takes care of this for C code, we have to do it
ourselves for assembly.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/entry-macros.S b/arch/sh/include/asm/entry-macros.S
index 1bdd938..64fd0de 100644
--- a/arch/sh/include/asm/entry-macros.S
+++ b/arch/sh/include/asm/entry-macros.S
@@ -108,3 +108,15 @@
#else
# define PREF(x) nop
#endif
+
+ /*
+ * Macro for use within assembly. Because the DWARF unwinder
+ * needs to use the frame register to unwind the stack, we
+ * need to setup r14 with the value of the stack pointer as
+ * the return address is usually on the stack somewhere.
+ */
+ .macro setup_frame_reg
+#ifdef CONFIG_DWARF_UNWINDER
+ mov r15, r14
+#endif
+ .endm
diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S
index 3cb531f..67ad646 100644
--- a/arch/sh/kernel/cpu/sh3/entry.S
+++ b/arch/sh/kernel/cpu/sh3/entry.S
@@ -137,6 +137,7 @@
mov #1, r5
call_dpf:
+ setup_frame_reg
mov.l 1f, r0
mov r5, r8
mov.l @r0, r6
diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S
index fc26ccd..b3b215f 100644
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -285,6 +285,7 @@
* system calls and debug traps through their respective jump tables.
*/
ENTRY(system_call)
+ setup_frame_reg
#if !defined(CONFIG_CPU_SH2)
mov.l 1f, r9
mov.l @r9, r8 ! Read from TRA (Trap Address) Register