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ARM: 7668/1: fix memset-related crashes caused by recent GCC (4.7.2) opt... #245

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ARM: 7668/1: fix memset-related crashes caused by recent GCC (4.7.2) opt... #245

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85 changes: 44 additions & 41 deletions arch/arm/lib/memset.S
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Original file line number Diff line number Diff line change
Expand Up @@ -19,20 +19,24 @@
1: subs r2, r2, #4 @ 1 do we have enough
blt 5f @ 1 bytes to align with?
cmp r3, #2 @ 1
strltb r1, [r0], #1 @ 1
strleb r1, [r0], #1 @ 1
strb r1, [r0], #1 @ 1
strltb r1, [ip], #1 @ 1
strleb r1, [ip], #1 @ 1
strb r1, [ip], #1 @ 1
add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3))
/*
* The pointer is now aligned and the length is adjusted. Try doing the
* memset again.
*/

ENTRY(memset)
ands r3, r0, #3 @ 1 unaligned?
/*
* Preserve the contents of r0 for the return value.
*/
mov ip, r0
ands r3, ip, #3 @ 1 unaligned?
bne 1b @ 1
/*
* we know that the pointer in r0 is aligned to a word boundary.
* we know that the pointer in ip is aligned to a word boundary.
*/
orr r1, r1, r1, lsl #8
orr r1, r1, r1, lsl #16
Expand All @@ -43,29 +47,28 @@ ENTRY(memset)
#if ! CALGN(1)+0

/*
* We need an extra register for this loop - save the return address and
* use the LR
* We need 2 extra registers for this loop - use r8 and the LR
*/
str lr, [sp, #-4]!
mov ip, r1
stmfd sp!, {r8, lr}
mov r8, r1
mov lr, r1

2: subs r2, r2, #64
stmgeia r0!, {r1, r3, ip, lr} @ 64 bytes at a time.
stmgeia r0!, {r1, r3, ip, lr}
stmgeia r0!, {r1, r3, ip, lr}
stmgeia r0!, {r1, r3, ip, lr}
stmgeia ip!, {r1, r3, r8, lr} @ 64 bytes at a time.
stmgeia ip!, {r1, r3, r8, lr}
stmgeia ip!, {r1, r3, r8, lr}
stmgeia ip!, {r1, r3, r8, lr}
bgt 2b
ldmeqfd sp!, {pc} @ Now <64 bytes to go.
ldmeqfd sp!, {r8, pc} @ Now <64 bytes to go.
/*
* No need to correct the count; we're only testing bits from now on
*/
tst r2, #32
stmneia r0!, {r1, r3, ip, lr}
stmneia r0!, {r1, r3, ip, lr}
stmneia ip!, {r1, r3, r8, lr}
stmneia ip!, {r1, r3, r8, lr}
tst r2, #16
stmneia r0!, {r1, r3, ip, lr}
ldr lr, [sp], #4
stmneia ip!, {r1, r3, r8, lr}
ldmfd sp!, {r8, lr}

#else

Expand All @@ -74,54 +77,54 @@ ENTRY(memset)
* whole cache lines at once.
*/

stmfd sp!, {r4-r7, lr}
stmfd sp!, {r4-r8, lr}
mov r4, r1
mov r5, r1
mov r6, r1
mov r7, r1
mov ip, r1
mov r8, r1
mov lr, r1

cmp r2, #96
tstgt r0, #31
tstgt ip, #31
ble 3f

and ip, r0, #31
rsb ip, ip, #32
sub r2, r2, ip
movs ip, ip, lsl #(32 - 4)
stmcsia r0!, {r4, r5, r6, r7}
stmmiia r0!, {r4, r5}
tst ip, #(1 << 30)
mov ip, r1
strne r1, [r0], #4
and r8, ip, #31
rsb r8, r8, #32
sub r2, r2, r8
movs r8, r8, lsl #(32 - 4)
stmcsia ip!, {r4, r5, r6, r7}
stmmiia ip!, {r4, r5}
tst r8, #(1 << 30)
mov r8, r1
strne r1, [ip], #4

3: subs r2, r2, #64
stmgeia r0!, {r1, r3-r7, ip, lr}
stmgeia r0!, {r1, r3-r7, ip, lr}
stmgeia ip!, {r1, r3-r8, lr}
stmgeia ip!, {r1, r3-r8, lr}
bgt 3b
ldmeqfd sp!, {r4-r7, pc}
ldmeqfd sp!, {r4-r8, pc}

tst r2, #32
stmneia r0!, {r1, r3-r7, ip, lr}
stmneia ip!, {r1, r3-r8, lr}
tst r2, #16
stmneia r0!, {r4-r7}
ldmfd sp!, {r4-r7, lr}
stmneia ip!, {r4-r7}
ldmfd sp!, {r4-r8, lr}

#endif

4: tst r2, #8
stmneia r0!, {r1, r3}
stmneia ip!, {r1, r3}
tst r2, #4
strne r1, [r0], #4
strne r1, [ip], #4
/*
* When we get here, we've got less than 4 bytes to zero. We
* may have an unaligned pointer as well.
*/
5: tst r2, #2
strneb r1, [r0], #1
strneb r1, [r0], #1
strneb r1, [ip], #1
strneb r1, [ip], #1
tst r2, #1
strneb r1, [r0], #1
strneb r1, [ip], #1
mov pc, lr
ENDPROC(memset)