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 (file)
--- 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 (file)
--- a/arch/sh/kernel/cpu/sh3/entry.S
+++ b/arch/sh/kernel/cpu/sh3/entry.S
@@ -137,6 +137,7 @@ ENTRY(tlb_protection_violation_store)
         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 (file)
--- a/arch/sh/kernel/entry-common.S
+++ b/arch/sh/kernel/entry-common.S
@@ -285,6 +285,7 @@ ret_from_fork:
  * 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