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- /*
- * Copyright (c) 2022 Agustina Arzille.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
- #include <kern/capability.h>
- #include <kern/cspace.h>
- #include <kern/ipc.h>
- #include <kern/task.h>
- #include <kern/thread.h>
- #include <kern/unwind.h>
- #include <kern/user.h>
- #include <machine/cpu.h>
- #include <vm/map.h>
- #include <vm/page.h>
- struct ipc_data
- {
- cpu_flags_t cpu_flags;
- uintptr_t va;
- int direction;
- int prot;
- void *ipc_pte;
- struct vm_page *page;
- };
- static void
- ipc_data_init (struct ipc_data *data, int direction)
- {
- data->direction = direction;
- data->prot = direction == IPC_COPY_FROM ? VM_PROT_READ : VM_PROT_RDWR;
- data->va = vm_map_ipc_addr ();
- data->ipc_pte = NULL;
- data->page = NULL;
- }
- static void
- ipc_data_intr_save (struct ipc_data *data)
- {
- cpu_intr_save (&data->cpu_flags);
- }
- static void
- ipc_data_intr_restore (struct ipc_data *data)
- {
- cpu_intr_restore (data->cpu_flags);
- }
- static void
- ipc_data_page_ref (struct ipc_data *data, phys_addr_t pa)
- {
- assert (!data->page);
- struct vm_page *page = vm_page_lookup (pa);
- assert (page);
- vm_page_ref (page);
- data->page = page;
- }
- static void
- ipc_data_page_unref (struct ipc_data *data)
- {
- assert (data->page);
- vm_page_unref (data->page);
- data->page = NULL;
- }
- static void
- ipc_data_pte_get (struct ipc_data *data)
- {
- thread_pin ();
- data->ipc_pte = pmap_ipc_pte_get ();
- }
- static void
- ipc_data_pte_map (struct ipc_data *data, phys_addr_t pa)
- {
- assert (thread_pinned () || !cpu_intr_enabled ());
- pmap_ipc_pte_set (data->ipc_pte, data->va, pa);
- }
- static void
- ipc_data_pte_put (struct ipc_data *data)
- {
- pmap_ipc_pte_put (data->ipc_pte);
- thread_unpin ();
- data->ipc_pte = NULL;
- }
- static void
- ipc_data_fini (void *arg)
- {
- struct ipc_data *data = arg;
- if (data->ipc_pte)
- ipc_data_pte_put (data);
- if (data->page)
- vm_page_unref (data->page);
- }
- static int
- ipc_iov_iter_refill (struct task *task, struct ipc_iov_iter *it)
- {
- uint32_t cnt = MIN (it->end - it->cur, IPC_IOV_ITER_CACHE_SIZE),
- off = IPC_IOV_ITER_CACHE_SIZE - cnt,
- bsize = cnt * sizeof (struct iovec);
- ssize_t ret = ipc_bcopy (task, it->begin + it->cur, bsize,
- &it->cache[off], bsize, IPC_COPY_FROM);
- if (ret < 0 || (ret % sizeof (struct iovec)) != 0)
- return (-EFAULT);
- it->cur += cnt;
- it->cache_idx = off;
- return (0);
- }
- static int
- ipc_map_errno (int err)
- {
- switch (err)
- {
- case EACCES:
- return (-EPERM);
- case EFAULT:
- return (-ENXIO);
- default:
- return (-err);
- }
- }
- /*
- * Get the physical address associated to a remote virtual address, faulting
- * in the necessary pages in case they aren't resident already. This function
- * disables interrupts but doesn't restore them when done.
- */
- static int
- ipc_map_addr (struct vm_map *map, const void *addr,
- struct ipc_data *data, phys_addr_t *pap)
- {
- ipc_data_intr_save (data);
- int error = pmap_extract_check (map->pmap, (uintptr_t)addr,
- data->prot & VM_PROT_WRITE, pap);
- if (error == EACCES)
- return (-EPERM);
- else if (error)
- { // Need to fault in the destination address.
- error = vm_map_fault (map, (uintptr_t)addr, data->prot);
- if (error)
- {
- ipc_data_intr_restore (data);
- return (ipc_map_errno (error));
- }
- /*
- * Since we're running with interrupts disabled, and the address
- * has been faulted in, this call cannot fail.
- */
- error = pmap_extract (map->pmap, (uintptr_t)addr, pap);
- assert (! error);
- }
- return (0);
- }
- static ssize_t
- ipc_bcopyv_impl (struct vm_map *r_map, const struct iovec *r_v,
- const struct iovec *l_v, struct ipc_data *data)
- {
- size_t page_off = (uintptr_t)r_v->iov_base % PAGE_SIZE,
- ret = MIN (PAGE_SIZE - page_off, MIN (r_v->iov_len, l_v->iov_len));
- phys_addr_t pa;
- int error = ipc_map_addr (r_map, r_v->iov_base, data, &pa);
- if (error)
- return (error);
- ipc_data_pte_get (data);
- ipc_data_page_ref (data, pa);
- ipc_data_pte_map (data, pa);
- ipc_data_intr_restore (data);
- if (data->direction == IPC_COPY_TO)
- memcpy ((void *)(data->va + page_off), l_v->iov_base, ret);
- else
- memcpy ((void *)l_v->iov_base, (void *)(data->va + page_off), ret);
- ipc_data_pte_put (data);
- ipc_data_page_unref (data);
- return ((ssize_t)ret);
- }
- static struct iovec*
- ipc_iov_iter_next (struct ipc_iov_iter *it)
- { // Get the next iovec from a local iterator, or NULL if exhausted.
- while (1)
- {
- if (it->head.iov_len)
- return (&it->head);
- else if (it->cur < it->end)
- it->head = it->begin[it->cur++];
- else
- return (NULL);
- }
- }
- static struct iovec*
- ipc_iov_iter_next_remote (struct ipc_iov_iter *it,
- struct task *task, ssize_t *outp)
- { // Same as above, only for a remote iterator.
- while (1)
- {
- if (it->head.iov_len)
- return (&it->head);
- else if (it->cache_idx < IPC_IOV_ITER_CACHE_SIZE)
- it->head = it->cache[it->cache_idx++];
- else if (it->cur >= it->end)
- return (NULL);
- else
- {
- int error = ipc_iov_iter_refill (task, it);
- if (error)
- {
- *outp = error;
- return (NULL);
- }
- }
- }
- }
- ssize_t
- ipc_iov_iter_copy (struct task *r_task, struct ipc_iov_iter *r_it,
- struct ipc_iov_iter *l_it, int direction)
- {
- struct ipc_data data;
- ipc_data_init (&data, direction);
- struct unw_fixup fixup;
- int error = unw_fixup_save (&fixup);
- if (unlikely (error))
- {
- ipc_data_fini (&data);
- return (-error);
- }
- for (ssize_t ret = 0 ; ; )
- {
- struct iovec *lv = ipc_iov_iter_next (l_it);
- if (! lv)
- return (ret);
- struct iovec *rv = ipc_iov_iter_next_remote (r_it, r_task, &ret);
- if (! rv)
- return (ret);
- ssize_t tmp = ipc_bcopyv_impl (r_task->map, rv, lv, &data);
- if (tmp < 0)
- return (tmp);
- else if (unlikely ((ret += tmp) < 0))
- return (-EOVERFLOW);
- iovec_adv (lv, tmp);
- iovec_adv (rv, tmp);
- }
- }
- ssize_t
- ipc_bcopy (struct task *r_task, void *r_ptr, size_t r_size,
- void *l_ptr, size_t l_size, int direction)
- {
- struct ipc_data data;
- struct unw_fixup fixup;
- int error = unw_fixup_save (&fixup);
- if (unlikely (error))
- {
- ipc_data_fini (&data);
- return (-error);
- }
- ipc_data_init (&data, direction);
- struct iovec r_v = IOVEC (r_ptr, r_size), l_v = IOVEC (l_ptr, l_size);
- for (ssize_t ret = 0 ; ; )
- {
- if (!r_v.iov_len || !l_v.iov_len)
- return (ret);
- ssize_t tmp = ipc_bcopyv_impl (r_task->map, &r_v, &l_v, &data);
- if (tmp < 0)
- return (tmp);
- else if (unlikely ((ret += tmp) < 0))
- return (-EOVERFLOW);
- iovec_adv (&r_v, tmp);
- iovec_adv (&l_v, tmp);
- }
- }
- static void
- ipc_cspace_guard_fini (struct adaptive_lock **lockp)
- {
- if (*lockp)
- adaptive_lock_release (*lockp);
- }
- static void
- ipc_cap_iter_cleanup (struct cspace *sp, struct ipc_cap_iter *it, uint32_t idx)
- {
- for (; it->cur != idx; --it->cur)
- {
- _Auto mp = it->begin + it->cur - 1;
- cspace_rem_locked (sp, mp->cap);
- }
- }
- static int
- ipc_cap_copy_impl (struct task *r_task, struct ipc_cap_iter *r_it,
- struct ipc_cap_iter *l_it, int direction)
- {
- struct ipc_cap_iter *in_it, *out_it;
- struct cspace *in_cs, *out_cs;
- if (direction == IPC_COPY_FROM)
- {
- in_it = r_it, out_it = l_it;
- in_cs = &r_task->caps, out_cs = cspace_self ();
- }
- else
- {
- in_it = l_it, out_it = r_it;
- in_cs = cspace_self (), out_cs = &r_task->caps;
- }
- uint32_t prev = out_it->cur;
- int rv = 0;
- struct adaptive_lock *lock CLEANUP (ipc_cspace_guard_fini) = &out_cs->lock;
- ADAPTIVE_LOCK_GUARD (&in_cs->lock);
- if (likely (in_cs != out_cs))
- adaptive_lock_acquire (lock);
- else
- lock = NULL;
- for (; ipc_cap_iter_size (in_it) && ipc_cap_iter_size (out_it);
- ++in_it->cur, ++out_it->cur, ++rv)
- {
- int capx = in_it->begin[in_it->cur].cap;
- _Auto cap = cspace_get (in_cs, capx);
- if (unlikely (! cap))
- {
- ipc_cap_iter_cleanup (out_cs, out_it, prev);
- return (-EBADF);
- }
- _Auto outp = out_it->begin + out_it->cur;
- capx = cspace_add_free_locked (out_cs, cap, outp->flags);
- cap_base_rel (cap);
- if (unlikely (capx < 0))
- {
- ipc_cap_iter_cleanup (out_cs, out_it, prev);
- return (capx);
- }
- outp->cap = capx;
- }
- return (rv);
- }
- #define IPC_ITER_LOOP(type, fn) \
- struct ipc_msg_##type tmp[16], *ptr = tmp; \
- int len = ipc_##type##_iter_size (r_it), size = len * sizeof (*ptr); \
- \
- if (unlikely (len > (int)ARRAY_SIZE (tmp))) \
- { \
- _Auto page = vm_page_alloc (vm_page_order (size), \
- VM_PAGE_SEL_DIRECTMAP, \
- VM_PAGE_KERNEL, VM_PAGE_SLEEP); \
- if (! page) \
- return (-ENOMEM); \
- \
- ptr = vm_page_direct_ptr (page); \
- } \
- \
- int rv = ipc_bcopy (r_task, r_it->begin + r_it->cur, size, \
- ptr, size, IPC_COPY_FROM); \
- \
- if (unlikely (rv < 0)) \
- { \
- if (ptr != tmp) \
- vm_page_free (vm_page_lookup (vm_page_direct_pa ((uintptr_t)ptr)), \
- vm_page_order (size), VM_PAGE_SLEEP); \
- \
- return (rv); \
- } \
- \
- struct ipc_##type##_iter aux = \
- { \
- .begin = ptr, \
- .cur = 0, \
- .end = r_it->end - r_it->cur \
- }; \
- \
- rv = fn (r_task, &aux, l_it, direction); \
- if (rv >= 0) \
- { \
- len = rv * sizeof (*ptr); \
- if (ipc_bcopy (r_task, r_it->begin + r_it->cur, len, \
- ptr, len, IPC_COPY_TO) > 0) \
- r_it->cur += aux.cur; \
- } \
- \
- if (ptr != tmp) \
- vm_page_free (vm_page_lookup (vm_page_direct_pa ((uintptr_t)ptr)), \
- vm_page_order (size), VM_PAGE_SLEEP); \
- \
- return (rv)
- int
- ipc_cap_iter_copy (struct task *r_task, struct ipc_cap_iter *r_it,
- struct ipc_cap_iter *l_it, int direction)
- {
- IPC_ITER_LOOP (cap, ipc_cap_copy_impl);
- }
- int
- ipc_vme_iter_copy (struct task *r_task, struct ipc_vme_iter *r_it,
- struct ipc_vme_iter *l_it, int direction)
- {
- #define ipc_vme_copy_impl(task, r_it, l_it, dir) \
- vm_map_iter_copy ((task)->map, (r_it), (l_it), (dir))
- IPC_ITER_LOOP (vme, ipc_vme_copy_impl);
- #undef ipc_vme_copy_impl
- }
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