From: Taras Kondratiuk Date: Fri, 8 Nov 2013 18:29:29 +0000 (+0000) Subject: ARM: kprobes-test: Workaround GAS .align bug X-Git-Tag: firefly_0821_release~176^2~4085^2^2^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=41b5368f31f86a1c2be2bb16a1cf18d23f1223d4;p=firefly-linux-kernel-4.4.55.git ARM: kprobes-test: Workaround GAS .align bug 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: Ben Dooks Acked-by: Jon Medhurst Signed-off-by: Taras Kondratiuk --- diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c index 6e60a349aed9..379639998d5a 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 e28a869b1ae4..eecc90a0fd91 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" \