* [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
@ 2017-09-28 10:55 ` Will Deacon
0 siblings, 0 replies; 12+ messages in thread
From: Will Deacon @ 2017-09-28 10:55 UTC (permalink / raw)
To: mmarek; +Cc: linux-arm-kernel, linux-kernel, akpm, Will Deacon
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.
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
+ fi
+
+ ${CROSS_COMPILE}strip $1.o
+ fi
+
${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \
grep -v "/tmp\|Disassembly\|\.text\|^$" > $1.dis 2>&1
}
--
2.1.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
@ 2017-09-28 10:55 ` Will Deacon
0 siblings, 0 replies; 12+ messages in thread
From: Will Deacon @ 2017-09-28 10:55 UTC (permalink / raw)
To: linux-arm-kernel
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.
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
+ fi
+
+ ${CROSS_COMPILE}strip $1.o
+ fi
+
${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \
grep -v "/tmp\|Disassembly\|\.text\|^$" > $1.dis 2>&1
}
--
2.1.4
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
2017-09-28 10:55 ` Will Deacon
@ 2017-09-28 12:42 ` Dave Martin
-1 siblings, 0 replies; 12+ messages in thread
From: Dave Martin @ 2017-09-28 12:42 UTC (permalink / raw)
To: Will Deacon; +Cc: mmarek, akpm, linux-kernel, linux-arm-kernel
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
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
@ 2017-09-28 12:42 ` Dave Martin
0 siblings, 0 replies; 12+ messages in thread
From: Dave Martin @ 2017-09-28 12:42 UTC (permalink / raw)
To: linux-arm-kernel
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
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
2017-09-28 12:42 ` Dave Martin
@ 2017-09-28 14:14 ` Will Deacon
-1 siblings, 0 replies; 12+ messages in thread
From: Will Deacon @ 2017-09-28 14:14 UTC (permalink / raw)
To: Dave Martin; +Cc: mmarek, akpm, linux-kernel, linux-arm-kernel
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.
> > 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.
I thought we still supported those, so I'd be reluctant to merge the
clauses unless it's broken (the script works as-is for me with arm). I'm
also not sure what we should do for 16-bit Thumb-2 encodings, where we
have inst.n and inst.w to contend with.
> > + 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>
Thanks!
Will
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
@ 2017-09-28 14:14 ` Will Deacon
0 siblings, 0 replies; 12+ messages in thread
From: Will Deacon @ 2017-09-28 14:14 UTC (permalink / raw)
To: linux-arm-kernel
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.
> > 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.
I thought we still supported those, so I'd be reluctant to merge the
clauses unless it's broken (the script works as-is for me with arm). I'm
also not sure what we should do for 16-bit Thumb-2 encodings, where we
have inst.n and inst.w to contend with.
> > + 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>
Thanks!
Will
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
2017-09-28 14:14 ` Will Deacon
@ 2017-09-28 14:37 ` Dave Martin
-1 siblings, 0 replies; 12+ messages in thread
From: Dave Martin @ 2017-09-28 14:37 UTC (permalink / raw)
To: Will Deacon; +Cc: mmarek, akpm, linux-kernel, linux-arm-kernel
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).
> > > 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.
>
> I thought we still supported those, so I'd be reluctant to merge the
> clauses unless it's broken (the script works as-is for me with arm). I'm
> also not sure what we should do for 16-bit Thumb-2 encodings, where we
> have inst.n and inst.w to contend with.
Fair enough. I suspected as much, too.
Cheers
---Dave
> > > + 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>
>
> Thanks!
>
> Will
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
@ 2017-09-28 14:37 ` Dave Martin
0 siblings, 0 replies; 12+ messages in thread
From: Dave Martin @ 2017-09-28 14:37 UTC (permalink / raw)
To: linux-arm-kernel
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).
> > > 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.
>
> I thought we still supported those, so I'd be reluctant to merge the
> clauses unless it's broken (the script works as-is for me with arm). I'm
> also not sure what we should do for 16-bit Thumb-2 encodings, where we
> have inst.n and inst.w to contend with.
Fair enough. I suspected as much, too.
Cheers
---Dave
> > > + 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>
>
> Thanks!
>
> Will
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
2017-09-28 14:37 ` Dave Martin
@ 2017-09-28 18:01 ` Will Deacon
-1 siblings, 0 replies; 12+ messages in thread
From: Will Deacon @ 2017-09-28 18:01 UTC (permalink / raw)
To: Dave Martin; +Cc: mmarek, akpm, linux-kernel, linux-arm-kernel
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
${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
@ 2017-09-28 18:01 ` Will Deacon
0 siblings, 0 replies; 12+ messages in thread
From: Will Deacon @ 2017-09-28 18:01 UTC (permalink / raw)
To: linux-arm-kernel
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
${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
2017-09-28 18:01 ` Will Deacon
@ 2017-09-29 10:07 ` Dave Martin
-1 siblings, 0 replies; 12+ messages in thread
From: Dave Martin @ 2017-09-29 10:07 UTC (permalink / raw)
To: Will Deacon; +Cc: mmarek, akpm, linux-kernel, linux-arm-kernel
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
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions
@ 2017-09-29 10:07 ` Dave Martin
0 siblings, 0 replies; 12+ messages in thread
From: Dave Martin @ 2017-09-29 10:07 UTC (permalink / raw)
To: linux-arm-kernel
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
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2017-09-29 10:07 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-09-28 10:55 [PATCH] scripts/decodecode: Fix decoding for AArch64 (arm64) instructions Will Deacon
2017-09-28 10:55 ` Will Deacon
2017-09-28 12:42 ` Dave Martin
2017-09-28 12:42 ` Dave Martin
2017-09-28 14:14 ` Will Deacon
2017-09-28 14:14 ` Will Deacon
2017-09-28 14:37 ` Dave Martin
2017-09-28 14:37 ` Dave Martin
2017-09-28 18:01 ` Will Deacon
2017-09-28 18:01 ` Will Deacon
2017-09-29 10:07 ` Dave Martin
2017-09-29 10:07 ` Dave Martin
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