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 tixy@linaro.org Signed-off-by: Taras Kondratiuk taras.kondratiuk@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" \