diff options
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.c')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 77739b0a56d5..3d38558d594f 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1464,6 +1464,53 @@ static int xstate_request_perm(unsigned long idx) spin_unlock_irq(¤t->sighand->siglock); return ret; } + +/* Place holder for now */ +static int fpstate_realloc(u64 xfeatures, unsigned int ksize, + unsigned int usize) +{ + return -ENOMEM; +} + +int xfd_enable_feature(u64 xfd_err) +{ + u64 xfd_event = xfd_err & XFEATURE_MASK_USER_DYNAMIC; + unsigned int ksize, usize; + struct fpu *fpu; + + if (!xfd_event) { + pr_err_once("XFD: Invalid xfd error: %016llx\n", xfd_err); + return 0; + } + + /* Protect against concurrent modifications */ + spin_lock_irq(¤t->sighand->siglock); + + /* If not permitted let it die */ + if ((xstate_get_host_group_perm() & xfd_event) != xfd_event) { + spin_unlock_irq(¤t->sighand->siglock); + return -EPERM; + } + + fpu = ¤t->group_leader->thread.fpu; + ksize = fpu->perm.__state_size; + usize = fpu->perm.__user_state_size; + /* + * The feature is permitted. State size is sufficient. Dropping + * the lock is safe here even if more features are added from + * another task, the retrieved buffer sizes are valid for the + * currently requested feature(s). + */ + spin_unlock_irq(¤t->sighand->siglock); + + /* + * Try to allocate a new fpstate. If that fails there is no way + * out. + */ + if (fpstate_realloc(xfd_event, ksize, usize)) + return -EFAULT; + return 0; +} #else /* CONFIG_X86_64 */ static inline int xstate_request_perm(unsigned long idx) { |