[PATCH] ARM: Add unwinding support for __memzero function
From: Lin Yongting <hidden>
Date: 2014-11-19 17:06:26
Also in:
lkml
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
The __memzero function never had unwinding annotations added. Currently, when accessing invalid pointer by __memzero occurs the backtrace shown will stop at __memzero 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 __memzero 2. kprobe trapped at any instruction within __memzero 3. interrupted at any instruction within __memzero Signed-off-by: Lin Yongting <redacted> --- arch/arm/lib/memzero.S | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/arch/arm/lib/memzero.S b/arch/arm/lib/memzero.S
index 385ccb3..0eded95 100644
--- a/arch/arm/lib/memzero.S
+++ b/arch/arm/lib/memzero.S@@ -9,6 +9,7 @@ */ #include <linux/linkage.h> #include <asm/assembler.h> +#include <asm/unwind.h> .text .align 5
@@ -18,6 +19,7 @@ * mis-aligned by, and r1 is the number of bytes. If r1 < 4, then we * don't bother; we use byte stores instead. */ +UNWIND( .fnstart ) 1: subs r1, r1, #4 @ 1 do we have enough blt 5f @ 1 bytes to align with? cmp r3, #2 @ 1
@@ -47,6 +49,9 @@ ENTRY(__memzero) * use the LR */ str lr, [sp, #-4]! @ 1 +UNWIND( .fnend ) +UNWIND( .fnstart ) +UNWIND( .save {lr} ) mov ip, r2 @ 1 mov lr, r2 @ 1
@@ -66,6 +71,7 @@ ENTRY(__memzero) tst r1, #16 @ 1 16 bytes or more? stmneia r0!, {r2, r3, ip, lr} @ 4 ldr lr, [sp], #4 @ 1 +UNWIND( .fnend ) #else
@@ -75,6 +81,9 @@ ENTRY(__memzero) */ stmfd sp!, {r4-r7, lr} +UNWIND( .fnend ) +UNWIND( .fnstart ) +UNWIND( .save {r4-r7, lr} ) mov r4, r2 mov r5, r2 mov r6, r2
@@ -105,9 +114,11 @@ ENTRY(__memzero) tst r1, #16 stmneia r0!, {r4-r7} ldmfd sp!, {r4-r7, lr} +UNWIND( .fnend ) #endif +UNWIND( .fnstart ) 4: tst r1, #8 @ 1 8 bytes or more? stmneia r0!, {r2, r3} @ 2 tst r1, #4 @ 1 4 bytes or more?
@@ -122,4 +133,5 @@ ENTRY(__memzero) tst r1, #1 @ 1 a byte left over strneb r2, [r0], #1 @ 1 ret lr @ 1 +UNWIND( .fnend ) ENDPROC(__memzero)
--
1.7.9.5