debian/patches/ppc64el-disable-vsx.patch

   1 From 8d1ce15f28e65998352a3b4f11f9f08700027afa Mon Sep 17 00:00:00 2001
   2 From: Paulo Flabiano Smorigo <pfsmorigo@linux.vnet.ibm.com>
   3 Date: Thu, 25 Sep 2014 19:33:39 -0300
   4 Subject: Disable VSX instruction
   5
   6 VSX bit is enabled by default for Power7 and Power8 CPU models,
   7 so we need to disable them in order to avoid instruction exceptions.
   8 Kernel will activate it when necessary.
   9
  10 * grub-core/kern/powerpc/ieee1275/startup.S: Disable VSX.
  11
  12 Also-By: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
  13 Also-By: Colin Watson <cjwatson@debian.org>
  14
  15 Origin: other, https://lists.gnu.org/archive/html/grub-devel/2014-09/msg00078.html
  16 Last-Update: 2015-01-27
  17
  18 Patch-Name: ppc64el-disable-vsx.patch
  19 ---
  20  grub-core/kern/powerpc/ieee1275/startup.S | 12 ++++++++++++
  21  1 file changed, 12 insertions(+)
  22
  23 diff --git a/grub-core/kern/powerpc/ieee1275/startup.S b/grub-core/kern/powerpc/ieee1275/startup.S
  24 index 21c884b43..de9a9601a 100644
  25 --- a/grub-core/kern/powerpc/ieee1275/startup.S
  26 +++ b/grub-core/kern/powerpc/ieee1275/startup.S
  27 @@ -20,6 +20,8 @@
  28  #include <grub/symbol.h>
  29  #include <grub/offsets.h>
  30
  31 +#define MSR_VSX 0x80
  32 +
  33  .extern __bss_start
  34  .extern _end
  35
  36 @@ -28,6 +30,16 @@
  37         .globl  start, _start
  38  start:
  39  _start:
  40 + _start:
  41 +
  42 +    /* Disable VSX instruction */
  43 +       mfmsr  0
  44 +       oris   0,0,MSR_VSX
  45 +       /* The "VSX Available" bit is in the lower half of the MSR, so we
  46 +          don't need mtmsrd, which in any case won't work in 32-bit mode.  */
  47 +       mtmsr  0
  48 +       isync
  49 +
  50         li      2, 0
  51         li      13, 0
  52