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powerpc: Fix emulation of mfocrf in emulate_step()

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commit 64e756c55aa46fc18fd53e8f3598b73b528d8637 upstream.

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")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Anton Blanchard 2017-06-15 09:46:39 +10:00 • committed by Greg Kroah-Hartman
parent 3977223229
commit 79afeb379c
1 changed files with 13 additions and 0 deletions
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13
arch/powerpc/lib/sstep.c
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@ -969,6 +969,19 @@ int __kprobes 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;