By default if no fill symbol is given to .align directive in a code
section it fills gap with NOPs. If previous fragment is not
instruction-aligned, additional pre-alignment is done by zero bytes
before NOPs. These zero bytes are marked as data by special symbol $d in
symbol table. Unfortunately GAS assumes that there is only code in the
code section so it "puts back" code symbol $a at the end of this
pre-alignment. So if there is some data after alignment it will be
interpreted as code and will be swapped back to LE for BE8 system during
a final linking.
If explicit fill value is given to .align, the NOP-padding code is
skipped and symbol table does not get messed-up.
So the workaround for this issue:
Use explicit fill value if data should be aligned in the code section.
Acked-by: Jon Medhurst <t...@linaro.org>
Signed-off-by: Taras Kondratiuk <taras.kondrat...@linaro.org>
---
arch/arm/kernel/kprobes-test.c | 2 +-
arch/arm/kernel/kprobes-test.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c
index 0850c72..d2c2174 100644
--- a/arch/arm/kernel/kprobes-test.c
+++ b/arch/arm/kernel/kprobes-test.c
@@ -113,7 +113,7 @@
* @ start of inline data...
* .ascii "mov r0, r7" @ text title for test case
* .byte 0
- * .align 2
+ * .align 2, 0
*
* @ TEST_ARG_REG
* .byte ARG_TYPE_REG
diff --git a/arch/arm/kernel/kprobes-test.h b/arch/arm/kernel/kprobes-test.h
index e28a869..eecc90a 100644
--- a/arch/arm/kernel/kprobes-test.h
+++ b/arch/arm/kernel/kprobes-test.h
@@ -115,7 +115,7 @@ struct test_arg_end {
/* multiple strings to be concatenated. */ \
".ascii "#title" \n\t" \
".byte 0 \n\t" \
- ".align 2 \n\t"
+ ".align 2, 0 \n\t"
#define TEST_ARG_REG(reg, val) \
".byte "__stringify(ARG_TYPE_REG)" \n\t" \
--
1.7.9.5
--
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