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powerpc: Fix emulation of mcrf in emulate_step()

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The mcrf emulation code was using the CR field number directly as the shift
value, without taking into account that CR fields are numbered from 0-7 starting
at the high bits. That meant it was looking at the CR fields in the reverse
order.

Fixes: cf87c3f6b6 ("powerpc: Emulate icbi, mcrf and conditional-trap instructions")
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Anton Blanchard
2017-06-15 09:46:38 +10:00
committed by Michael Ellerman
parent 3f0bd8dad0
commit 87c4b83e0f
1 changed files with 4 additions and 2 deletions
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6
arch/powerpc/lib/sstep.c
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@@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
case 19: case 19:
switch ((instr >> 1) & 0x3ff) { switch ((instr >> 1) & 0x3ff) {
case 0: /* mcrf */ case 0: /* mcrf */
rd = (instr >> 21) & 0x1c; rd = 7 - ((instr >> 23) & 0x7);
ra = (instr >> 16) & 0x1c; ra = 7 - ((instr >> 18) & 0x7);
rd *= 4;
ra *= 4;
val = (regs->ccr >> ra) & 0xf; val = (regs->ccr >> ra) & 0xf;
regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd); regs->ccr = (regs->ccr & ~(0xfUL << rd)) | (val << rd);
goto instr_done; goto instr_done;