Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Avoid save/restoring AMX registers to avoid a SPR erratum #15168

Merged
merged 1 commit into from
Aug 26, 2023
Merged

Avoid save/restoring AMX registers to avoid a SPR erratum #15168

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
19 changes: 14 additions & 5 deletions include/os/linux/kernel/linux/simd_x86.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,15 @@
#error "Toolchain needs to support the XSAVE assembler instruction"
#endif

#ifndef XFEATURE_MASK_XTILE
/*
* For kernels where this doesn't exist yet, we still don't want to break
* by save/restoring this broken nonsense.
* See issue #14989 or Intel errata SPR4 for why
*/
#define XFEATURE_MASK_XTILE 0x60000
#endif

#include <linux/mm.h>
#include <linux/slab.h>

Expand Down Expand Up @@ -315,18 +324,18 @@ kfpu_begin(void)
uint8_t *state = zfs_kfpu_fpregs[smp_processor_id()];
#if defined(HAVE_XSAVES)
if (static_cpu_has(X86_FEATURE_XSAVES)) {
kfpu_do_xsave("xsaves", state, ~0);
kfpu_do_xsave("xsaves", state, ~XFEATURE_MASK_XTILE);
return;
}
#endif
#if defined(HAVE_XSAVEOPT)
if (static_cpu_has(X86_FEATURE_XSAVEOPT)) {
kfpu_do_xsave("xsaveopt", state, ~0);
kfpu_do_xsave("xsaveopt", state, ~XFEATURE_MASK_XTILE);
return;
}
#endif
if (static_cpu_has(X86_FEATURE_XSAVE)) {
kfpu_do_xsave("xsave", state, ~0);
kfpu_do_xsave("xsave", state, ~XFEATURE_MASK_XTILE);
} else if (static_cpu_has(X86_FEATURE_FXSR)) {
kfpu_save_fxsr(state);
} else {
Expand Down Expand Up @@ -376,12 +385,12 @@ kfpu_end(void)
uint8_t *state = zfs_kfpu_fpregs[smp_processor_id()];
#if defined(HAVE_XSAVES)
if (static_cpu_has(X86_FEATURE_XSAVES)) {
kfpu_do_xrstor("xrstors", state, ~0);
kfpu_do_xrstor("xrstors", state, ~XFEATURE_MASK_XTILE);
goto out;
}
#endif
if (static_cpu_has(X86_FEATURE_XSAVE)) {
kfpu_do_xrstor("xrstor", state, ~0);
kfpu_do_xrstor("xrstor", state, ~XFEATURE_MASK_XTILE);
} else if (static_cpu_has(X86_FEATURE_FXSR)) {
kfpu_restore_fxsr(state);
} else {
Expand Down