Messages in this thread | | | Date | Thu, 28 Sep 2017 13:42:31 +0100 | From | Dave Martin <> | Subject | Re: [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions |
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On Thu, Sep 28, 2017 at 11:55:47AM +0100, Will Deacon wrote: > There are a couple of problems with the decodecode script and arm64: > > 1. AArch64 objdump refuses to disassemble .4byte directives as instructions, > insisting that they are data values and displaying them as: > > a94153f3 .word 0xa94153f3 <-- trapping instruction > > This is resolved by using the .inst directive instead. > > 2. Disassembly of branch instructions attempts to provide the target as > an offset from a symbol, e.g.: > > 0: 34000082 cbz w2, 10 <.text+0x10> > > however this falls foul of the grep -v, which matches lines containing > ".text" and ends up removing all branch instructions from the dump.
Any idea why this doesn't affect other arches too ... or does it?
> This patch resolves both issues by using the .inst directive for 4-byte > quantities on arm64 and stripping the resulting binaries (as is done on > arm already) to remove the mapping symbols. > > Signed-off-by: Will Deacon <will.deacon@arm.com> > > --- > scripts/decodecode | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/scripts/decodecode b/scripts/decodecode > index d8824f37acce..67214ec5b2cb 100755 > --- a/scripts/decodecode > +++ b/scripts/decodecode > @@ -58,6 +58,14 @@ disas() { > ${CROSS_COMPILE}strip $1.o > fi > > + if [ "$ARCH" = "arm64" ]; then > + if [ $width -eq 4 ]; then > + type=inst
Can we merge with arm here, or does arm still support toolchains that don't have .inst? Anyway, no big deal.
> + fi > + > + ${CROSS_COMPILE}strip $1.o > + fi > + > ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \ > grep -v "/tmp\|Disassembly\|\.text\|^$" > $1.dis 2>&1
FWIW,
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Here's hoping someone runs this as a CGI script somewhere ;)
Cheers ---Dave
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