ARM: 6945/1: Add unwinding support for division functions

The software division functions never had unwinding annotations
added. Currently, when a division by zero occurs the backtrace shown
will stop at Ldiv0 or some completely unrelated function. Add
unwinding annotations in hopes of getting a more useful backtrace
when a division by zero occurs.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 20 insertions, 5 deletions

diff --git a/arch/arm/lib/lib1funcs.S b/arch/arm/lib/lib1funcs.S
index 6dc06487f3c3..c562f649734c 100644
--- a/arch/arm/lib/lib1funcs.S
+++ b/arch/arm/lib/lib1funcs.S
@@ -35,7 +35,7 @@ Boston, MA 02111-1307, USA.  */
 
 #include <linux/linkage.h>
 #include <asm/assembler.h>
-
+#include <asm/unwind.h>
 
 .macro ARM_DIV_BODY dividend, divisor, result, curbit
 
@@ -207,6 +207,7 @@ Boston, MA 02111-1307, USA.  */
 
 ENTRY(__udivsi3)
 ENTRY(__aeabi_uidiv)
+UNWIND(.fnstart)
 
         subs    r2, r1, #1
         moveq   pc, lr
@@ -230,10 +231,12 @@ ENTRY(__aeabi_uidiv)
         mov     r0, r0, lsr r2
         mov     pc, lr
 
+UNWIND(.fnend)
 ENDPROC(__udivsi3)
 ENDPROC(__aeabi_uidiv)
 
 ENTRY(__umodsi3)
+UNWIND(.fnstart)
 
         subs    r2, r1, #1                      @ compare divisor with 1
         bcc     Ldiv0
@@ -247,10 +250,12 @@ ENTRY(__umodsi3)
 
         mov     pc, lr
 
+UNWIND(.fnend)
 ENDPROC(__umodsi3)
 
 ENTRY(__divsi3)
 ENTRY(__aeabi_idiv)
+UNWIND(.fnstart)
 
         cmp     r1, #0
         eor     ip, r0, r1                      @ save the sign of the result.
@@ -287,10 +292,12 @@ ENTRY(__aeabi_idiv)
         rsbmi   r0, r0, #0
         mov     pc, lr
 
+UNWIND(.fnend)
 ENDPROC(__divsi3)
 ENDPROC(__aeabi_idiv)
 
 ENTRY(__modsi3)
+UNWIND(.fnstart)
 
         cmp     r1, #0
         beq     Ldiv0
@@ -310,11 +317,14 @@ ENTRY(__modsi3)
         rsbmi   r0, r0, #0
         mov     pc, lr
 
+UNWIND(.fnend)
 ENDPROC(__modsi3)
 
 #ifdef CONFIG_AEABI
 
 ENTRY(__aeabi_uidivmod)
+UNWIND(.fnstart)
+UNWIND(.save {r0, r1, ip, lr}   )
 
         stmfd   sp!, {r0, r1, ip, lr}
         bl      __aeabi_uidiv
@@ -323,10 +333,12 @@ ENTRY(__aeabi_uidivmod)
         sub     r1, r1, r3
         mov     pc, lr
 
+UNWIND(.fnend)
 ENDPROC(__aeabi_uidivmod)
 
 ENTRY(__aeabi_idivmod)
-
+UNWIND(.fnstart)
+UNWIND(.save {r0, r1, ip, lr}   )
         stmfd   sp!, {r0, r1, ip, lr}
         bl      __aeabi_idiv
         ldmfd   sp!, {r1, r2, ip, lr}
@@ -334,15 +346,18 @@ ENTRY(__aeabi_idivmod)
         sub     r1, r1, r3
         mov     pc, lr
 
+UNWIND(.fnend)
 ENDPROC(__aeabi_idivmod)
 
 #endif
 
 Ldiv0:
-
+UNWIND(.fnstart)
+UNWIND(.pad #4)
+UNWIND(.save {lr})
         str     lr, [sp, #-8]!
         bl      __div0
         mov     r0, #0                  @ About as wrong as it could be.
         ldr     pc, [sp], #8
-
-
+UNWIND(.fnend)
+ENDPROC(Ldiv0)