[src/trunk]: src/sys/arch/mips/mips Load curlwp into a0 to call fpu_save(curl...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/df6d68a61a61
branches:  trunk
changeset: 837758:df6d68a61a61
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Wed Dec 19 15:10:46 2018 +0000

description:
Load curlwp into a0 to call fpu_save(curlwp), not fpu_save(garbage).

The lwp argument to fpu_save was added by chuq in revision 1.14 of
mips_fpu.c, but this call was not updated to pass it.  This is the
correct lwp to pass because we are in the middle of executing a
kernel-emulated fp instruction, so curlwp must own the fpu state, and
we are trying to write the fp registers to memory so we can adjust
them there when ctc1 would fail.

Fixes PR port-cobalt/53090, PR port-sgimips/53791.

diffstat:

 sys/arch/mips/mips/fp.S |  3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diffs (17 lines):

diff -r 4e0904e241e4 -r df6d68a61a61 sys/arch/mips/mips/fp.S
--- a/sys/arch/mips/mips/fp.S   Wed Dec 19 14:07:51 2018 +0000
+++ b/sys/arch/mips/mips/fp.S   Wed Dec 19 15:10:46 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fp.S,v 1.48 2017/02/27 06:57:45 chs Exp $      */
+/*     $NetBSD: fp.S,v 1.49 2018/12/19 15:10:46 riastradh Exp $        */
 
 /*
  * Copyright (c) 1992, 1993
@@ -2827,6 +2827,7 @@
         * ctc1 with fpe bits set causes FPE in kernel mode panic on 5231.
         */
        REG_S   a2, CALLFRAME_SIZ + 3*SZREG(sp)
+       move    a0, MIPS_CURLWP                 # get current lwp
        jal     _C_LABEL(fpu_save)              # on RM5231
 
        REG_L   a2, CALLFRAME_SIZ + 3*SZREG(sp)