| Message ID | 20170614234639.11997-1-anton@ozlabs.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 87c4b83e0fe234a1f0eed131ab6fa232036860d5 |
| Headers | show |
Hi Anton, On Thu, Jun 15, 2017 at 09:46:38AM +1000, Anton Blanchard wrote: > The mcrf emulation code was looking at the CR fields in the reverse > order. It also relied on reserved fields being zero which is somewhat > fragile, so fix that too. It masked out the reserved bits. I find the new code to be less readable (but also more correct ;-) ). Maybe there should be (inline) helper function to insert/extract CR fields? Segher > --- a/arch/powerpc/lib/sstep.c > +++ b/arch/powerpc/lib/sstep.c > @@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs, > case 19: > switch ((instr >> 1) & 0x3ff) { > case 0: /* mcrf */ > - rd = (instr >> 21) & 0x1c; > - ra = (instr >> 16) & 0x1c; > + rd = 7 - ((instr >> 23) & 0x7); > + ra = 7 - ((instr >> 18) & 0x7); > + rd *= 4; > + ra *= 4; > val = (regs->ccr >> ra) & 0xf; > regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd); > goto instr_done;
Hi Segher, > On Thu, Jun 15, 2017 at 09:46:38AM +1000, Anton Blanchard wrote: > > The mcrf emulation code was looking at the CR fields in the reverse > > order. It also relied on reserved fields being zero which is > > somewhat fragile, so fix that too. > > It masked out the reserved bits. I find the new code to be less > readable (but also more correct ;-) ). Thanks for that, not sure how I missed it :) I'll respin a simpler patch. > Maybe there should be (inline) > helper function to insert/extract CR fields? That would be nice, there are quite a few places that could use it. Anton > Segher > > > > --- a/arch/powerpc/lib/sstep.c > > +++ b/arch/powerpc/lib/sstep.c > > @@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op *op, > > struct pt_regs *regs, case 19: > > switch ((instr >> 1) & 0x3ff) { > > case 0: /* mcrf */ > > - rd = (instr >> 21) & 0x1c; > > - ra = (instr >> 16) & 0x1c; > > + rd = 7 - ((instr >> 23) & 0x7); > > + ra = 7 - ((instr >> 18) & 0x7); > > + rd *= 4; > > + ra *= 4; > > val = (regs->ccr >> ra) & 0xf; > > regs->ccr = (regs->ccr & ~(0xfUL << rd)) | > > (val << rd); goto instr_done; >
On Thu, Jun 15, 2017 at 04:47:29PM +1000, Anton Blanchard wrote: > > Maybe there should be (inline) > > helper function to insert/extract CR fields? > > That would be nice, there are quite a few places that could use it. Like patch 2/2, hint hint. Segher
On 2017/06/15 09:46AM, Anton Blanchard wrote: > From: Anton Blanchard <anton@samba.org> > > The mcrf emulation code was looking at the CR fields in the reverse > order. It also relied on reserved fields being zero which is somewhat > fragile, so fix that too. Yikes! Amazing catch! Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Thanks, Naveen > > Cc: stable@vger.kernel.org > Signed-off-by: Anton Blanchard <anton@samba.org> > --- > arch/powerpc/lib/sstep.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c > index 33117f8a0882..fb84f51b1f0b 100644 > --- a/arch/powerpc/lib/sstep.c > +++ b/arch/powerpc/lib/sstep.c > @@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs, > case 19: > switch ((instr >> 1) & 0x3ff) { > case 0: /* mcrf */ > - rd = (instr >> 21) & 0x1c; > - ra = (instr >> 16) & 0x1c; > + rd = 7 - ((instr >> 23) & 0x7); > + ra = 7 - ((instr >> 18) & 0x7); > + rd *= 4; > + ra *= 4; > val = (regs->ccr >> ra) & 0xf; > regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd); > goto instr_done; > -- > 2.11.0 >
On Wed, 2017-06-14 at 23:46:38 UTC, Anton Blanchard wrote: > From: Anton Blanchard <anton@samba.org> > > The mcrf emulation code was looking at the CR fields in the reverse > order. It also relied on reserved fields being zero which is somewhat > fragile, so fix that too. > > Cc: stable@vger.kernel.org > Signed-off-by: Anton Blanchard <anton@samba.org> > Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/87c4b83e0fe234a1f0eed131ab6fa2 cheers
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index 33117f8a0882..fb84f51b1f0b 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs, case 19: switch ((instr >> 1) & 0x3ff) { case 0: /* mcrf */ - rd = (instr >> 21) & 0x1c; - ra = (instr >> 16) & 0x1c; + rd = 7 - ((instr >> 23) & 0x7); + ra = 7 - ((instr >> 18) & 0x7); + rd *= 4; + ra *= 4; val = (regs->ccr >> ra) & 0xf; regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd); goto instr_done;