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powerpc: Fix emulation of mfocrf in emulate_step() 

From POWER4 onwards, mfocrf() only places the specified CR field into
the destination GPR, and the rest of it is set to 0. The PowerPC AS
from version 3.0 now requires this behaviour.

The emulation code currently puts the entire CR into the destination GPR.
Fix it.

Fixes: 6888199f7f ("[POWERPC] Emulate more instructions in software")
Cc: stable@vger.kernel.org # v2.6.22+
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 09:46:39 +10:00 committed by Michael Ellerman
parent 87c4b83e0f
commit 64e756c55a
1 changed files with 13 additions and 0 deletions
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13
arch/powerpc/lib/sstep.c
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@ -966,6 +966,19 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
#endif
case 19: /* mfcr */
if ((instr >> 20) & 1) {
imm = 0xf0000000UL;
for (sh = 0; sh < 8; ++sh) {
if (instr & (0x80000 >> sh)) {
regs->gpr[rd] = regs->ccr & imm;
break;
}
imm >>= 4;
}
goto instr_done;
}
regs->gpr[rd] = regs->ccr;
regs->gpr[rd] &= 0xffffffffUL;
goto instr_done;