static void vfp_thread_copy(struct thread_info *thread)
{
struct thread_info *parent = current_thread_info();
vfp_sync_hwstate(parent);
thread->vfpstate = parent->vfpstate;
}
/*
* VFP register get/set implementations.
*
* With respect to the kernel, struct user_fp is divided into three chunks:
* 16 or 32 real VFP registers (d0-d15 or d0-31)
* These are transferred to/from the real registers in the task's
* vfp_hard_struct. The number of registers depends on the kernel
* configuration.
*
* 16 or 0 fake VFP registers (d16-d31 or empty)
* i.e., the user_vfp structure has space for 32 registers even if
* the kernel doesn't have them all.
*
* vfp_get() reads this chunk as zero where applicable
* vfp_set() ignores this chunk
*
* 1 word for the FPSCR
*
* The bounds-checking logic built into user_regset_copyout and friends
* means that we can make a simple sequence of calls to map the relevant data
* to/from the specified slice of the user regset structure.
*/
static int vfp_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
int ret;
struct thread_info *thread = task_thread_info(target);
struct vfp_hard_struct const *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);
vfp_sync_hwstate(thread);
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&vfp->fpregs,
user_fpregs_offset,
user_fpregs_offset + sizeof(vfp->fpregs));
if (ret)
return ret;
ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
user_fpregs_offset + sizeof(vfp->fpregs),
user_fpscr_offset);
if (ret)
return ret;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&vfp->fpscr,
user_fpscr_offset,
user_fpscr_offset + sizeof(vfp->fpscr));
}
int vfp_preserve_user_clear_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;
int err = 0;
vfp_sync_hwstate(thread);
err |= __copy_to_user(&ufp->fpregs, &hwstate->fpregs,
sizeof(hwstate->fpregs));
__put_user_error(hwstate->fpscr, &ufp->fpscr, err);
__put_user_error(hwstate->fpexc, &ufp_exc->fpexc, err);
__put_user_error(hwstate->fpinst, &ufp_exc->fpinst, err);
__put_user_error(hwstate->fpinst2, &ufp_exc->fpinst2, err);
if (err)
return -EFAULT;
vfp_flush_hwstate(thread);
hwstate->fpscr &= ~(FPSCR_LENGTH_MASK | FPSCR_STRIDE_MASK);
return 0;
}
static int preserve_vfp_context(struct vfp_sigframe __user *frame)
{
struct thread_info *thread = current_thread_info();
struct vfp_hard_struct *h = &thread->vfpstate.hard;
const unsigned long magic = VFP_MAGIC;
const unsigned long size = VFP_STORAGE_SIZE;
int err = 0;
vfp_sync_hwstate(thread);
__put_user_error(magic, &frame->magic, err);
__put_user_error(size, &frame->size, err);
/*
* Copy the floating point registers. There can be unused
* registers see asm/hwcap.h for details.
*/
err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs,
sizeof(h->fpregs));
/*
* Copy the status and control register.
*/
__put_user_error(h->fpscr, &frame->ufp.fpscr, err);
/*
* Copy the exception registers.
*/
__put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err);
__put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
__put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
return err ? -EFAULT : 0;
}
static void vfp_thread_copy(struct thread_info *thread)
{
struct thread_info *parent = current_thread_info();
vfp_sync_hwstate(parent);
thread->vfpstate = parent->vfpstate;
#ifdef CONFIG_SMP
thread->vfpstate.hard.cpu = NR_CPUS;
#endif
}
/*
* Save the current VFP state into the provided structures and prepare
* for entry into a new function (signal handler).
*/
int vfp_preserve_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;
int err = 0;
/* Ensure that the saved hwstate is up-to-date. */
vfp_sync_hwstate(thread);
/*
* Copy the floating point registers. There can be unused
* registers see asm/hwcap.h for details.
*/
err |= __copy_to_user(&ufp->fpregs, &hwstate->fpregs,
sizeof(hwstate->fpregs));
/*
* Copy the status and control register.
*/
__put_user_error(hwstate->fpscr, &ufp->fpscr, err);
/*
* Copy the exception registers.
*/
__put_user_error(hwstate->fpexc, &ufp_exc->fpexc, err);
__put_user_error(hwstate->fpinst, &ufp_exc->fpinst, err);
__put_user_error(hwstate->fpinst2, &ufp_exc->fpinst2, err);
if (err)
return -EFAULT;
/* Ensure that VFP is disabled. */
vfp_flush_hwstate(thread);
/*
* As per the PCS, clear the length and stride bits before entry
* to the signal handler.
*/
hwstate->fpscr &= ~(FPSCR_LENGTH_MASK | FPSCR_STRIDE_MASK);
/*
* Disable VFP in the hwstate so that we can detect if it was
* used by the signal handler.
*/
hwstate->fpexc &= ~FPEXC_EN;
return 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; */
struct vfp_hard_struct new_vfp;
const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
vfp_sync_hwstate(thread);
new_vfp = thread->vfpstate.hard;
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);
thread->vfpstate.hard = new_vfp;
return 0;
}