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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>
This commit is contained in:
Laura Abbott 2011-05-27 17:23:16 +01:00 committed by Russell King
parent 45b95235b0
commit 81479c246c
1 changed files with 20 additions and 5 deletions
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25
arch/arm/lib/lib1funcs.S
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@ -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)