4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Anton Blanchard <anton@xxxxxxxxx>
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@xxxxxxxxx>
Acked-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -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;