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Linux 5.16 compat: don't use XSTATE_XSAVE to save FPU state

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Linux 5.16 moved XSTATE_XSAVE and XSTATE_XRESTORE out of our reach,
so add our own XSAVE{,OPT,S} code and use it for Linux 5.16.

Please note that this differs from previous behavior in that it
won't handle exceptions created by XSAVE an XRSTOR. This is sensible
for three reasons.

 - Exceptions during XSAVE and XRSTOR can only occur if the feature
   is not supported or enabled or the memory operand isn't aligned
   on a 64 byte boundary. If this happens something else went
   terribly wrong, and it may be better to stop execution.

 - Previously we just printed a warning and didn't handle the fault,
   this is arguable for the above reason.

 - All other *SAVE instruction also don't handle exceptions, so this
   at least aligns behavior.

Finally add a test to catch such a regression in the future.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Attila Fülöp <attila@fueloep.org>
Closes #13042
Closes #13059
This commit is contained in:
Attila Fülöp
2022-02-09 21:50:10 +01:00
committed by GitHub
parent e2909fae8f
commit 8e94ac0e36
9 changed files with 300 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files
config/toolchain-simd.m4
+66
View File
@@ -24,6 +24,9 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_TOOLCHAIN_SIMD], [
ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_AES
ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_PCLMULQDQ
ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_MOVBE
ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVE
ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVEOPT
ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVES
;;
esac
])
@@ -422,3 +425,66 @@ AC_DEFUN([ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_MOVBE], [
AC_MSG_RESULT([no])
])
])
dnl #
dnl # ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVE
dnl #
AC_DEFUN([ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVE], [
AC_MSG_CHECKING([whether host toolchain supports XSAVE])
AC_LINK_IFELSE([AC_LANG_SOURCE([
[
void main()
{
char b[4096] __attribute__ ((aligned (64)));
__asm__ __volatile__("xsave %[b]\n" : : [b] "m" (*b) : "memory");
}
]])], [
AC_MSG_RESULT([yes])
AC_DEFINE([HAVE_XSAVE], 1, [Define if host toolchain supports XSAVE])
], [
AC_MSG_RESULT([no])
])
])
dnl #
dnl # ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVEOPT
dnl #
AC_DEFUN([ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVEOPT], [
AC_MSG_CHECKING([whether host toolchain supports XSAVEOPT])
AC_LINK_IFELSE([AC_LANG_SOURCE([
[
void main()
{
char b[4096] __attribute__ ((aligned (64)));
__asm__ __volatile__("xsaveopt %[b]\n" : : [b] "m" (*b) : "memory");
}
]])], [
AC_MSG_RESULT([yes])
AC_DEFINE([HAVE_XSAVEOPT], 1, [Define if host toolchain supports XSAVEOPT])
], [
AC_MSG_RESULT([no])
])
])
dnl #
dnl # ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVES
dnl #
AC_DEFUN([ZFS_AC_CONFIG_TOOLCHAIN_CAN_BUILD_XSAVES], [
AC_MSG_CHECKING([whether host toolchain supports XSAVES])
AC_LINK_IFELSE([AC_LANG_SOURCE([
[
void main()
{
char b[4096] __attribute__ ((aligned (64)));
__asm__ __volatile__("xsaves %[b]\n" : : [b] "m" (*b) : "memory");
}
]])], [
AC_MSG_RESULT([yes])
AC_DEFINE([HAVE_XSAVES], 1, [Define if host toolchain supports XSAVES])
], [
AC_MSG_RESULT([no])
])
])