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

From: Greg Kroah-Hartman
Date: Sat Sep 26 2015 - 18:20:47 EST


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

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

From: Markos Chandras <markos.chandras@xxxxxxxxxx>

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.chandras@xxxxxxxxxx>
Fixes: c8a34581ec09 ("MIPS: Emulate the BC1{EQ,NE}Z FPU instructions")
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/10738/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
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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