[src/trunk]: src/sys/arch/sparc64/sparc64 sun4v: rft_kernel should pay attent...

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

details:   https://anonhg.NetBSD.org/src/rev/73ebade5edfc
branches:  trunk
changeset: 814060:73ebade5edfc
user:      palle <palle%NetBSD.org@localhost>
date:      Thu Mar 03 20:45:45 2016 +0000

description:
sun4v: rft_kernel should pay attention to the number of register windows that can be restored. We cannot rely on fill traps to occur, since sun4v only has two trap levels available in privileged 
mode. Based on code from OpenBSD. ok martin@

diffstat:

 sys/arch/sparc64/sparc64/locore.s |  47 +++++++++++++++++++++++++++++++++++++-
 1 files changed, 45 insertions(+), 2 deletions(-)

diffs (73 lines):

diff -r e3738bbc0020 -r 73ebade5edfc sys/arch/sparc64/sparc64/locore.s
--- a/sys/arch/sparc64/sparc64/locore.s Thu Mar 03 17:01:31 2016 +0000
+++ b/sys/arch/sparc64/sparc64/locore.s Thu Mar 03 20:45:45 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.s,v 1.388 2016/02/14 21:13:33 palle Exp $       */
+/*     $NetBSD: locore.s,v 1.389 2016/03/03 20:45:45 palle Exp $       */
 
 /*
  * Copyright (c) 2006-2010 Matthew R. Green
@@ -355,6 +355,35 @@
 #define CLRTT
 #endif
 
+
+/*
+ * Some macros to load and store a register window
+ */
+
+       .macro  SPILL storer,base,size,asi
+
+       .irpc n,01234567
+               \storer %l\n, [\base + (\n * \size)] \asi
+       .endr
+       .irpc n,01234567
+               \storer %i\n, [\base + ((8+\n) * \size)] \asi
+       .endr
+
+       .endm
+
+       
+       .macro FILL loader, base, size, asi
+       
+       .irpc n,01234567
+               \loader [\base + (\n * \size)] \asi, %l\n
+       .endr
+
+       .irpc n,01234567
+               \loader [\base + ((8+\n) * \size)] \asi, %i\n
+       .endr
+       
+       .endm
+       
 /*
  * Here are some oft repeated traps as macros.
  */
@@ -4079,12 +4108,26 @@
  *
  */
 rft_kernel:
-       rdpr    %tl, %g4                                ! Grab a set of trap registers
+       rdpr    %tl, %g4                        ! Grab a set of trap registers
        inc     %g4
        wrpr    %g4, %g0, %tl
        wrpr    %g3, 0, %tnpc
        wrpr    %g2, 0, %tpc
        wrpr    %g1, 0, %tstate
+
+       rdpr    %canrestore, %g2
+       brnz    %g2, 1f
+        nop
+
+       wr      %g0, ASI_NUCLEUS, %asi
+       rdpr    %cwp, %g1
+       dec     %g1
+       wrpr    %g1, %cwp
+       FILL    ldxa, %sp+BIAS, 8, %asi
+       restored
+       inc     %g1
+       wrpr    %g1, %cwp
+1:
        restore
        rdpr    %tstate, %g1                    ! Since we may have trapped our regs may be toast
        rdpr    %cwp, %g2