target/linux/leon/patches-5.15/0010-sparc32-leon-Handle-self-clearing-FSR.ftt-when-savin.patch

   1 From ce71c62289d17a6e7d809759f6b10297bb066d11 Mon Sep 17 00:00:00 2001
   2 From: Andreas Larsson <andreas@gaisler.com>
   3 Date: Wed, 20 Sep 2017 09:10:46 +0200
   4 Subject: [PATCH 10/32] sparc32,leon: Handle self clearing FSR.ftt when saving
   5  FPU registers
   6
   7 GRFPU self clears the ftt field after a STFSR. Make sure that the ftt
   8 field is not for cases with multiple STFSRs.
   9
  10 Signed-off-by: Andreas Larsson <andreas@gaisler.com>
  11 ---
  12  arch/sparc/kernel/entry.S | 8 +++++++-
  13  1 file changed, 7 insertions(+), 1 deletion(-)
  14
  15 diff --git a/arch/sparc/kernel/entry.S b/arch/sparc/kernel/entry.S
  16 index b56f489e38bb..87c68aeeb794 100644
  17 --- a/arch/sparc/kernel/entry.S
  18 +++ b/arch/sparc/kernel/entry.S
  19 @@ -1062,6 +1062,7 @@ fpsave:
  20         st      %fsr, [%o1]     ! this can trap on us if fpu is in bogon state
  21         ld      [%o1], %g1
  22         set     0x2000, %g4
  23 +       set     0x1c000, %g5
  24         andcc   %g1, %g4, %g0
  25         be      2f
  26          mov    0, %g2
  27 @@ -1072,6 +1073,10 @@ fpsave:
  28  fpsave_magic:
  29         st      %fsr, [%o1]
  30         ld      [%o1], %g3
  31 +       andn    %g3, %g5, %g3 /* ftt gets cleared on stfsr for GRFPU... */
  32 +       and     %g1, %g5, %g1
  33 +       or      %g1, %g3, %g3
  34 +       st      %g3, [%o1]    /* ... so set ftt field from first fsr read */
  35         andcc   %g3, %g4, %g0
  36         add     %g2, 1, %g2
  37         bne     1b
  38 @@ -1108,8 +1113,9 @@ fpsave_catch:
  39          st     %fsr, [%o1]
  40
  41  fpsave_catch2:
  42 +       st      %fsr, [%o1] /* In this case, this is the first successful fsr read */
  43         b       fpsave + 4
  44 -        st     %fsr, [%o1]
  45 +        ld     [%o1], %g1 /* so take care of it for GRFPU ftt field handling */
  46
  47         /* void fpload(unsigned long *fpregs, unsigned long *fsr); */
  48
  49 --
  50 2.34.1
  51