[patch 05/19] POWERPC: Fix handling of stfiwx math emulation

[Greg KH]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Kumar Gala <[EMAIL PROTECTED]>

patch ba02946a903015840ef672ccc9dc8620a7e83de6 in mainline

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 <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>

---
 arch/powerpc/math-emu/math.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

--- a/arch/powerpc/math-emu/math.c
+++ b/arch/powerpc/math-emu/math.c
@@ -407,11 +407,16 @@ 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:

-- 
-
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