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author | Taras Kondratiuk <taras.kondratiuk@linaro.org> | 2013-11-08 18:29:29 +0000 |
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committer | Victor Kamensky <victor.kamensky@linaro.org> | 2014-02-12 16:35:32 -0800 |
commit | 0fba4e3d6e9f821c8340ca0242caa180aef56af2 (patch) | |
tree | 2ecc738105bf1a397f2c9d233752036341c5b511 | |
parent | 4b69be18e448a35ef1164faeac459fb2499f81e4 (diff) |
ARM: kprobes-test: Workaround GAS .align bugtracking-be_arm-ll-20140416.0tracking-be_arm-ll-20140415.0tracking-be_arm-ll-20140411.1tracking-be_arm-ll-20140411.0tracking-be_arm-ll-20140409.0tracking-be_arm-ll-20140407.0tracking-be_arm-ll-20140406.0tracking-be_arm-ll-20140401.0tracking-be_arm-ll-20140321.0tracking-be_arm-ll-20140319.0tracking-be_arm-ll-20140317.0tracking-be_arm-ll-20140314.0tracking-be_arm-ll-20140311.0tracking-be_arm-ll-20140306.0tracking-be_arm-ll-20140304.0tracking-be_arm-ll-20140228.0tracking-be_arm-ll-20140218.0tracking-be_arm-ll-20140217.0tracking-be_arm-ll-20140216.0tracking-be_arm-ll-20140213.0
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 d190290bb9c7..0b75fae11449 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" \ |