Patch "powerpc: Fix emulation of mcrf in emulate_step()" has been added to the 4.12-stable tree

Patch "powerpc: Fix emulation of mcrf in emulate_step()" has been added to the 4.12-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    powerpc: Fix emulation of mcrf in emulate_step()

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-fix-emulation-of-mcrf-in-emulate_step.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 87c4b83e0fe234a1f0eed131ab6fa232036860d5 Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@samba.org>
Date: Thu, 15 Jun 2017 09:46:38 +1000
Subject: powerpc: Fix emulation of mcrf in emulate_step()

From: Anton Blanchard <anton@samba.org>

commit 87c4b83e0fe234a1f0eed131ab6fa232036860d5 upstream.

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: cf87c3f6b647 ("powerpc: Emulate icbi, mcrf and conditional-trap instructions")
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>

---
 arch/powerpc/lib/sstep.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op
 	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;


Patches currently in stable-queue which might be from anton@samba.org are

queue-4.12/powerpc-fix-emulation-of-mfocrf-in-emulate_step.patch
queue-4.12/powerpc-fix-emulation-of-mcrf-in-emulate_step.patch