commit ba02946a903015840ef672ccc9dc8620a7e83de6
author Kumar Gala <galak@kernel.crashing.org> Thu Oct 11 17:07:34 2007 -0500
committer Kumar Gala <galak@kernel.crashing.org> Tue Oct 16 09:05:24 2007 -0500
tree db338f067ef63fae6b9c7a5dd51b99b1539f8a57
parent 65a6ec0d72a07f16719e9b7a96e1c4bae044b591

[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.

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

arch/powerpc/math-emu/math.c

diff --git a/arch/powerpc/math-emu/math.c b/arch/powerpc/math-emu/math.c
index 69058b2..381306b 100644
--- a/arch/powerpc/math-emu/math.c
+++ b/arch/powerpc/math-emu/math.c
@@ -407,11 +407,16 @@
 
 	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: