[PATCH 4.2 020/134] MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions

[Greg Kroah-Hartman]

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

------------------

From: Markos Chandras <markos.chand...@imgtec.com>

commit c909ca718e8f50cf484ef06a8dd935e738e8e53d upstream.

Commit c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
added support for emulating the new R6 BC1{EQ,NE}Z branches but it missed
the case where the instruction that caused the exception was not on a DS.

Signed-off-by: Markos Chandras <markos.chand...@imgtec.com>
Fixes: c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
Cc: linux-m...@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10738/
Signed-off-by: Ralf Baechle <r...@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/mips/math-emu/cp1emu.c |   20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -1181,6 +1181,24 @@ emul:
                        }
                        break;
 
+               case bc1eqz_op:
+               case bc1nez_op:
+                       if (!cpu_has_mips_r6 || delay_slot(xcp))
+                               return SIGILL;
+
+                       cond = likely = 0;
+                       switch (MIPSInst_RS(ir)) {
+                       case bc1eqz_op:
+                               if 
(get_fpr32(&current->thread.fpu.fpr[MIPSInst_RT(ir)], 0) & 0x1)
+                                   cond = 1;
+                               break;
+                       case bc1nez_op:
+                               if 
(!(get_fpr32(&current->thread.fpu.fpr[MIPSInst_RT(ir)], 0) & 0x1))
+                                   cond = 1;
+                               break;
+                       }
+                       goto branch_common;
+
                case bc_op:
                        if (delay_slot(xcp))
                                return SIGILL;
@@ -1207,7 +1225,7 @@ emul:
                        case bct_op:
                                break;
                        }
-
+branch_common:
                        set_delay_slot(xcp);
                        if (cond) {
                                /*


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