/* Sanitise and restore the current VFP state from the provided structures. */
int vfp_restore_user_hwstate(struct user_vfp __user *ufp,
struct user_vfp_exc __user *ufp_exc)
{
struct thread_info *thread = current_thread_info();
struct vfp_hard_struct *hwstate = &thread->vfpstate.hard;
unsigned long fpexc;
int err = 0;
/* Disable VFP to avoid corrupting the new thread state. */
vfp_flush_hwstate(thread);
/*
* Copy the floating point registers. There can be unused
* registers see asm/hwcap.h for details.
*/
err |= __copy_from_user(&hwstate->fpregs, &ufp->fpregs,
sizeof(hwstate->fpregs));
/*
* Copy the status and control register.
*/
__get_user_error(hwstate->fpscr, &ufp->fpscr, err);
/*
* Sanitise and restore the exception registers.
*/
__get_user_error(fpexc, &ufp_exc->fpexc, err);
/* Ensure the VFP is enabled. */
fpexc |= FPEXC_EN;
/* Ensure FPINST2 is invalid and the exception flag is cleared. */
fpexc &= ~(FPEXC_EX | FPEXC_FP2V);
hwstate->fpexc = fpexc;
__get_user_error(hwstate->fpinst, &ufp_exc->fpinst, err);
__get_user_error(hwstate->fpinst2, &ufp_exc->fpinst2, err);
return err ? -EFAULT : 0;
}
/*
* For vfp_set() a read-modify-write is done on the VFP registers,
* in order to avoid writing back a half-modified set of registers on
* failure.
*/
static int vfp_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
struct thread_info *thread = task_thread_info(target);
struct vfp_hard_struct new_vfp = thread->vfpstate.hard;
const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&new_vfp.fpregs,
user_fpregs_offset,
user_fpregs_offset + sizeof(new_vfp.fpregs));
if (ret)
return ret;
ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
user_fpregs_offset + sizeof(new_vfp.fpregs),
user_fpscr_offset);
if (ret)
return ret;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&new_vfp.fpscr,
user_fpscr_offset,
user_fpscr_offset + sizeof(new_vfp.fpscr));
if (ret)
return ret;
vfp_sync_hwstate(thread);
thread->vfpstate.hard = new_vfp;
vfp_flush_hwstate(thread);
return 0;
}