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| author | Chang S. Bae <chang.seok.bae@intel.com> | 2021-10-22 00:55:20 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-26 10:53:02 +0200 |
| commit | 672365477ae8afca5a1cca98c1deb733235e4525 (patch) | |
| tree | 9e41b4eb5c5a3dff90c0ceb443f071035bcc0d4a /arch/x86/kernel/fpu/signal.c | |
| parent | x86/fpu: Add sanity checks for XFD (diff) | |
| download | linux-672365477ae8afca5a1cca98c1deb733235e4525.tar.xz linux-672365477ae8afca5a1cca98c1deb733235e4525.zip | |
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
Diffstat (limited to 'arch/x86/kernel/fpu/signal.c')
| -rw-r--r-- | arch/x86/kernel/fpu/signal.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 16fdecd02341..cc977da6e128 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -282,6 +282,8 @@ static bool restore_fpregs_from_user(void __user *buf, u64 xrestore, retry: fpregs_lock(); + /* Ensure that XFD is up to date */ + xfd_update_state(fpu->fpstate); pagefault_disable(); ret = __restore_fpregs_from_user(buf, fpu->fpstate->user_xfeatures, xrestore, fx_only); |