From: Kumar Gala <galak@kernel.crashing.org>
Date: Thu, 18 Oct 2007 16:00:21 +0000 (+0200)
Subject: [POWERPC] Fix handling of stfiwx math emulation
X-Git-Tag: v2.6.16.56-rc1~18
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f772dcde07136d67393ad32b7572fdd7e180e556;p=thirdparty%2Fkernel%2Fstable.git

[POWERPC] Fix handling of stfiwx math emulation

Its legal for the stfiwx instruction to have RA = 0 as part of its
effective address calculation.  This is illegal for all other XE
form instructions.

Add code to compute the proper effective address for stfiwx if
RA = 0 rather than treating it as illegal.

Adrian Bunk:
Backported to 2.6.16.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
---

diff --git a/arch/ppc/math-emu/math.c b/arch/ppc/math-emu/math.c
index b7dff53a71031..66ad11f6d0c45 100644
--- a/arch/ppc/math-emu/math.c
+++ b/arch/ppc/math-emu/math.c
@@ -410,11 +410,16 @@ do_mathemu(struct pt_regs *regs)
 
 	case XE:
 		idx = (insn >> 16) & 0x1f;
-		if (!idx)
-			goto illegal;
-
 		op0 = (void *)&current->thread.fpr[(insn >> 21) & 0x1f];
-		op1 = (void *)(regs->gpr[idx] + regs->gpr[(insn >> 11) & 0x1f]);
+		if (!idx) {
+			if (((insn >> 1) & 0x3ff) == STFIWX)
+				op1 = (void *)(regs->gpr[(insn >> 11) & 0x1f]);
+			else
+				goto illegal;
+		} else {
+			op1 = (void *)(regs->gpr[idx] + regs->gpr[(insn >> 11) & 0x1f]);
+		}
+
 		break;
 
 	case XEU: