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| author |   Taras Kondratiuk <taras.kondratiuk@linaro.org> | 2013-11-08 18:29:29 +0000 |
|---|---|---|
| committer |   Taras Kondratiuk <taras@ti.com> | 2014-04-01 16:48:27 +0300 |
| commit | 41b5368f31f86a1c2be2bb16a1cf18d23f1223d4 (patch) | |
| tree | 19bb9fd519dba304852611c94aa2aedb288309ba | |
| parent | ARM: kprobes-test: use <asm/opcodes.h> for Thumb instruction building (diff) | |
| download | linux-dev-41b5368f31f86a1c2be2bb16a1cf18d23f1223d4.tar.xz linux-dev-41b5368f31f86a1c2be2bb16a1cf18d23f1223d4.zip | |
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 <ben.dooks@codethink.co.uk>
Acked-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Taras Kondratiuk <taras.kondratiuk@linaro.org>
| -rw-r--r-- | arch/arm/kernel/kprobes-test.c | 2 | ||||
| -rw-r--r-- | 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 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" \ |