Commit fb556d25 authored by Anton Blanchard's avatar Anton Blanchard Committed by Sasha Levin

powerpc: Fix emulation of mcrf in emulate_step()

[ Upstream commit 87c4b83e ]

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: cf87c3f6 ("powerpc: Emulate icbi, mcrf and conditional-trap instructions")
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
Acked-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent f9b66deb
......@@ -687,8 +687,10 @@ int __kprobes 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;
......
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