Commit 64e756c5 authored Jun 15, 2017 by Anton Blanchard Committed by Michael Ellerman Jul 12, 2017

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: 6888199f ("[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>

parent 87c4b83e

arch/powerpc/lib/sstep.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -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;

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