| Message ID | 1382125235.2206.24.camel@tmusta-sc.rchland.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
On Fri, 2013-10-18 at 14:40 -0500, Tom Musta wrote: > This patch modifies the endian chicken switch in the single step > emulation code (emulate_step()). The old (big endian) code bailed > early if a load or store instruction was to be emulated in little > endian mode. > > The new code modifies the check and only bails in a cross-endian > situation (LE mode in a kernel compiled for BE and vice verse). I get a malformed patch error, looks like it got wrapped. Cheers, Ben. > Signed-off-by: Tom Musta <tmusta@gmail.com> > --- > arch/powerpc/lib/sstep.c | 12 +++++++++--- > 1 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c > index b1faa15..5e0d0e9 100644 > --- a/arch/powerpc/lib/sstep.c > +++ b/arch/powerpc/lib/sstep.c > @@ -1222,12 +1222,18 @@ int __kprobes emulate_step(struct pt_regs *regs, > unsigned int instr) > } > > /* > - * Following cases are for loads and stores, so bail out > - * if we're in little-endian mode. > + * Following cases are for loads and stores and this > + * implementation does not support cross-endian. So > + * bail out if this is the case. > */ > +#ifdef __BIG_ENDIAN__ > if (regs->msr & MSR_LE) > return 0; > - > +#endif > +#ifdef __LITTLE_ENDIAN__ > + if (!regs->msr & MSR_LE) > + return 0; > +#endif > /* > * Save register RA in case it's an update form load or store > * and the access faults.
Tom Musta <tommusta@gmail.com> writes: > +#ifdef __LITTLE_ENDIAN__ > + if (!regs->msr & MSR_LE) That won't work. Andreas.
On 10/30/2013 12:43 PM, Andreas Schwab wrote: > Tom Musta <tommusta@gmail.com> writes: > >> +#ifdef __LITTLE_ENDIAN__ >> + if (!regs->msr & MSR_LE) > > That won't work. > > Andreas. > Please elaborate.
On Wed, Oct 30, 2013 at 8:35 PM, Tom Musta <tommusta@gmail.com> wrote: > On 10/30/2013 12:43 PM, Andreas Schwab wrote: >> >> Tom Musta <tommusta@gmail.com> writes: >> >>> +#ifdef __LITTLE_ENDIAN__ >>> + if (!regs->msr & MSR_LE) >> >> >> That won't work. >> >> Andreas. >> > > Please elaborate. You want to test for "!(regs & MSR_LE)". Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On 10/30/2013 2:43 PM, Geert Uytterhoeven wrote: > On Wed, Oct 30, 2013 at 8:35 PM, Tom Musta <tommusta@gmail.com> wrote: >> On 10/30/2013 12:43 PM, Andreas Schwab wrote: >>> >>> Tom Musta <tommusta@gmail.com> writes: >>> >>>> +#ifdef __LITTLE_ENDIAN__ >>>> + if (!regs->msr & MSR_LE) >>> >>> >>> That won't work. >>> >>> Andreas. >>> >> >> Please elaborate. > > You want to test for "!(regs & MSR_LE)". > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds > Thanks Adnreas and Geert. I will fix and resubmit.
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index b1faa15..5e0d0e9 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -1222,12 +1222,18 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) } /* - * Following cases are for loads and stores, so bail out - * if we're in little-endian mode. + * Following cases are for loads and stores and this + * implementation does not support cross-endian. So + * bail out if this is the case. */ +#ifdef __BIG_ENDIAN__ if (regs->msr & MSR_LE) return 0; - +#endif +#ifdef __LITTLE_ENDIAN__ + if (!regs->msr & MSR_LE) + return 0; +#endif /* * Save register RA in case it's an update form load or store
This patch modifies the endian chicken switch in the single step emulation code (emulate_step()). The old (big endian) code bailed early if a load or store instruction was to be emulated in little endian mode. The new code modifies the check and only bails in a cross-endian situation (LE mode in a kernel compiled for BE and vice verse). Signed-off-by: Tom Musta <tmusta@gmail.com> --- arch/powerpc/lib/sstep.c | 12 +++++++++--- 1 files changed, 9 insertions(+), 3 deletions(-) * and the access faults.