[PATCH 4.15 113/163] MIPS: CPS: Fix MIPS_ISA_LEVEL_RAW fallout

Greg Kroah-Hartman
2018-02-21T12:49:02Z

From: James Hogan <jhogan@kernel.org>

commit 8dbc1864b74f5dea5a3f7c30ca8fd358a675132f upstream.

Commit 17278a91e04f ("MIPS: CPS: Fix r1 .set mt assembler warning")
added .set MIPS_ISA_LEVEL_RAW to silence warnings about .set mt on r1,
however this can result in a MOVE being encoded as a 64-bit DADDU
instruction on certain version of binutils (e.g. 2.22), and reserved
instruction exceptions at runtime on 32-bit hardware.

Reduce the sizes of the push/pop sections to include only instructions
that are part of the MT ASE or which won't convert to 64-bit
instructions after .set mips64r2/mips64r6.

Reported-by: Greg Ungerer <gerg@linux-m68k.org>
Fixes: 17278a91e04f ("MIPS: CPS: Fix r1 .set mt assembler warning")
Signed-off-by: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.15
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Patchwork: https://patchwork.linux-mips.org/patch/18578/
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/mips/kernel/cps-vec.S | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

--- a/arch/mips/kernel/cps-vec.S
+++ b/arch/mips/kernel/cps-vec.S
@@ -388,15 +388,16 @@ LEAF(mips_cps_boot_vpes)

#elif defined(CONFIG_MIPS_MT)

- .set push
- .set MIPS_ISA_LEVEL_RAW
- .set mt
-
/* If the core doesn't support MT then return */
has_mt t0, 5f

/* Enter VPE configuration state */
+ .set push
+ .set MIPS_ISA_LEVEL_RAW
+ .set mt
dvpe
+ .set pop
+
PTR_LA t1, 1f
jr.hb t1
nop
@@ -422,6 +423,10 @@ LEAF(mips_cps_boot_vpes)
mtc0 t0, CP0_VPECONTROL
ehb

+ .set push
+ .set MIPS_ISA_LEVEL_RAW
+ .set mt
+
/* Skip the VPE if its TC is not halted */
mftc0 t0, CP0_TCHALT
beqz t0, 2f
@@ -495,6 +500,8 @@ LEAF(mips_cps_boot_vpes)
ehb
evpe

+ .set pop
+
/* Check whether this VPE is meant to be running */
li t0, 1
sll t0, t0, a1
@@ -509,7 +516,7 @@ LEAF(mips_cps_boot_vpes)
1: jr.hb t0
nop

-2: .set pop
+2:

#endif /* CONFIG_MIPS_MT_SMP */