Patch "powerpc: Fix emulation of mcrf in emulate_step()" has been added to the 4.4-stable tree

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 4.4-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-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Anton Blanchard <[email protected]>
Date: Thu, 15 Jun 2017 09:46:38 +1000
Subject: powerpc: Fix emulation of mcrf in emulate_step()

From: Anton Blanchard <[email protected]>

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.

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

@@ -687,8 +687,10 @@ int __kprobes analyse_instr(struct instr
 	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 [email protected] are

queue-4.4/powerpc-fix-emulation-of-mfocrf-in-emulate_step.patch queue-4.4/powerpc-fix-emulation-of-mcrf-in-emulate_step.patch