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4 Commits

Author SHA1 Message Date
Chang S. Bae
672365477a x86/fpu: Update XFD state where required 
The IA32_XFD_MSR allows to arm #NM traps for XSTATE components which are
enabled in XCR0. The register has to be restored before the tasks XSTATE is
restored. The life time rules are the same as for FPU state.

XFD is updated on return to userspace only when the FPU state of the task
is not up to date in the registers. It's updated before the XRSTORS so
that eventually enabled dynamic features are restored as well and not
brought into init state.

Also in signal handling for restoring FPU state from user space the
correctness of the XFD state has to be ensured.

Add it to CPU initialization and resume as well.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211021225527.10184-17-chang.seok.bae@intel.com
 2021-10-26 10:53:02 +02:00
Thomas Gleixner
eda32f4f93 x86/fpu: Rework restore_regs_from_fpstate() 
xfeatures_mask_fpstate() is no longer valid when dynamically enabled
features come into play.

Rework restore_regs_from_fpstate() so it takes a constant mask which will
then be applied against the maximum feature set so that the restore
operation brings all features which are not in the xsave buffer xfeature
bitmap into init state.

This ensures that if the previous task used a dynamically enabled feature
that the task which restores has all unused components properly initialized.

Cleanup the last user of xfeatures_mask_fpstate() as well and remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211014230739.461348278@linutronix.de
 2021-10-22 11:09:15 +02:00
Thomas Gleixner
18b3fa1ad1 x86/fpu: Convert restore_fpregs_from_fpstate() to struct fpstate 
Convert restore_fpregs_from_fpstate() and related code to the new
register storage mechanism in preparation for dynamically sized buffers.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145322.347395546@linutronix.de
 2021-10-20 22:26:38 +02:00
Thomas Gleixner
9848fb9683 x86/fpu: Move fpregs_restore_userregs() to core 
Only used internally in the FPU core code.

While at it, convert to the percpu accessors which verify preemption is
disabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011539.686806639@linutronix.de
 2021-10-20 15:27:28 +02:00