int mpx_enable_management(void)
{
void __user *bd_base = MPX_INVALID_BOUNDS_DIR;
struct mm_struct *mm = current->mm;
int ret = 0;
/*
* runtime in the userspace will be responsible for allocation of
* the bounds directory. Then, it will save the base of the bounds
* directory into XSAVE/XRSTOR Save Area and enable MPX through
* XRSTOR instruction.
*
* The copy_xregs_to_kernel() beneath get_xsave_field_ptr() is
* expected to be relatively expensive. Storing the bounds
* directory here means that we do not have to do xsave in the
* unmap path; we can just use mm->bd_addr instead.
*/
bd_base = mpx_get_bounds_dir();
down_write(&mm->mmap_sem);
mm->bd_addr = bd_base;
if (mm->bd_addr == MPX_INVALID_BOUNDS_DIR)
ret = -ENXIO;
up_write(&mm->mmap_sem);
return ret;
}
int mpx_enable_management(void)
{
void __user *bd_base = MPX_INVALID_BOUNDS_DIR;
struct mm_struct *mm = current->mm;
int ret = 0;
/*
* runtime in the userspace will be responsible for allocation of
* the bounds directory. Then, it will save the base of the bounds
* directory into XSAVE/XRSTOR Save Area and enable MPX through
* XRSTOR instruction.
*
* The copy_xregs_to_kernel() beneath get_xsave_field_ptr() is
* expected to be relatively expensive. Storing the bounds
* directory here means that we do not have to do xsave in the
* unmap path; we can just use mm->context.bd_addr instead.
*/
bd_base = mpx_get_bounds_dir();
down_write(&mm->mmap_sem);
/* MPX doesn't support addresses above 47 bits yet. */
if (find_vma(mm, DEFAULT_MAP_WINDOW)) {
pr_warn_once("%s (%d): MPX cannot handle addresses "
"above 47-bits. Disabling.",
current->comm, current->pid);
ret = -ENXIO;
goto out;
}
mm->context.bd_addr = bd_base;
if (mm->context.bd_addr == MPX_INVALID_BOUNDS_DIR)
ret = -ENXIO;
out:
up_write(&mm->mmap_sem);
return ret;
}
