The memmove function never had unwinding annotations added.
Currently, when accessing invalid pointer by memmove occurs the
backtrace shown will stop at memmove or some completely unrelated
function. Add unwinding annotations in hopes of getting a more
useful backtrace in following cases:
1. die on accessing invalid pointer by memmove
2. kprobe trapped at any instruction within memmove
3. interrupted at any instruction within memmove
Signed-off-by: Lin Yongting <linyongt...@gmail.com>
---
arch/arm/lib/memmove.S | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S
index d1fc0c0..69a9d47 100644
--- a/arch/arm/lib/memmove.S
+++ b/arch/arm/lib/memmove.S
@@ -12,6 +12,7 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
+#include <asm/unwind.h>
.text
@@ -27,12 +28,17 @@
*/
ENTRY(memmove)
+ UNWIND( .fnstart )
subs ip, r0, r1
cmphi r2, ip
bls memcpy
stmfd sp!, {r0, r4, lr}
+ UNWIND( .fnend )
+
+ UNWIND( .fnstart )
+ UNWIND( .save {r0, r4, lr} ) @ in first stmfd block
add r1, r1, r2
add r0, r0, r2
subs r2, r2, #4
@@ -45,6 +51,11 @@ ENTRY(memmove)
1: subs r2, r2, #(28)
stmfd sp!, {r5 - r8}
+ UNWIND( .fnend )
+
+ UNWIND( .fnstart )
+ UNWIND( .save {r0, r4, lr} )
+ UNWIND( .save {r5 - r8} ) @ in second stmfd block
blt 5f
CALGN( ands ip, r0, #31 )
@@ -97,6 +108,10 @@ ENTRY(memmove)
CALGN( bcs 2b )
7: ldmfd sp!, {r5 - r8}
+ UNWIND( .fnend ) @ end of second stmfd block
+
+ UNWIND( .fnstart )
+ UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
8: movs r2, r2, lsl #31
ldrneb r3, [r1, #-1]!
@@ -124,10 +139,13 @@ ENTRY(memmove)
ldr r3, [r1, #0]
beq 17f
blt 18f
+ UNWIND( .fnend )
.macro backward_copy_shift push pull
+ UNWIND( .fnstart )
+ UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
subs r2, r2, #28
blt 14f
@@ -137,6 +155,11 @@ ENTRY(memmove)
CALGN( bcc 15f )
11: stmfd sp!, {r5 - r9}
+ UNWIND( .fnend )
+
+ UNWIND( .fnstart )
+ UNWIND( .save {r0, r4, lr} )
+ UNWIND( .save {r5 - r9} ) @ in new second stmfd block
PLD( pld [r1, #-4] )
PLD( subs r2, r2, #96 )
@@ -171,6 +194,10 @@ ENTRY(memmove)
PLD( bge 13b )
ldmfd sp!, {r5 - r9}
+ UNWIND( .fnend ) @ end of the second stmfd
block
+
+ UNWIND( .fnstart )
+ UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
14: ands ip, r2, #28
beq 16f
@@ -186,6 +213,7 @@ ENTRY(memmove)
16: add r1, r1, #(\pull / 8)
b 8b
+ UNWIND( .fnend )
.endm
--
1.7.9.5
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