| Message ID | 20170928180135.GH9892@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Sep 28, 2017 at 07:01:35PM +0100, Will Deacon wrote: > On Thu, Sep 28, 2017 at 03:37:04PM +0100, Dave Martin wrote: > > On Thu, Sep 28, 2017 at 03:14:47PM +0100, Will Deacon wrote: > > > On Thu, Sep 28, 2017 at 01:42:31PM +0100, Dave Martin wrote: > > > > 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? > > > > > > I'm not sure, although I don't know how .inst works for architectures > > > with variable-length instructions and I *guess* the disassembly is less > > > fussy about data vs text for those targets. > > > > I rather meant the target disassembly for relative branches in the > > absence of labels. > > > > Anyway, I think this is at least harmless to other arches, and possibly > > helpful to them (if they disassemble those branch targets in the same > > sort of way). > > Ah, I see what you mean. Something like the fixup below on top. > > Will > > --->8 > > diff --git a/scripts/decodecode b/scripts/decodecode > index 67214ec5b2cb..f1ec57c3cbf7 100755 > --- a/scripts/decodecode > +++ b/scripts/decodecode > @@ -49,21 +49,14 @@ esac > > disas() { > ${CROSS_COMPILE}as $AFLAGS -o $1.o $1.s > /dev/null 2>&1 > + ${CROSS_COMPILE}strip $1.o > > - if [ "$ARCH" = "arm" ]; then > - if [ $width -eq 2 ]; then > - OBJDUMPFLAGS="-M force-thumb" > - fi > - > - ${CROSS_COMPILE}strip $1.o > + if [ "$ARCH" = "arm" -a $width -eq 2 ]; then > + OBJDUMPFLAGS="-M force-thumb" > fi > > - if [ "$ARCH" = "arm64" ]; then > - if [ $width -eq 4 ]; then > - type=inst > - fi > - > - ${CROSS_COMPILE}strip $1.o > + if [ "$ARCH" = "arm64" -a $width -eq 4 ]; then > + type=inst > fi Reasonable, though I guess it doesn't matter unless another arch really cares -- in which case someone will eventually spot the issue and probably write the same patch. Cheers ---Dave
diff --git a/scripts/decodecode b/scripts/decodecode index 67214ec5b2cb..f1ec57c3cbf7 100755 --- a/scripts/decodecode +++ b/scripts/decodecode @@ -49,21 +49,14 @@ esac disas() { ${CROSS_COMPILE}as $AFLAGS -o $1.o $1.s > /dev/null 2>&1 + ${CROSS_COMPILE}strip $1.o - if [ "$ARCH" = "arm" ]; then - if [ $width -eq 2 ]; then - OBJDUMPFLAGS="-M force-thumb" - fi - - ${CROSS_COMPILE}strip $1.o + if [ "$ARCH" = "arm" -a $width -eq 2 ]; then + OBJDUMPFLAGS="-M force-thumb" fi - if [ "$ARCH" = "arm64" ]; then - if [ $width -eq 4 ]; then - type=inst - fi - - ${CROSS_COMPILE}strip $1.o + if [ "$ARCH" = "arm64" -a $width -eq 4 ]; then + type=inst fi ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \