244 lines
7.3 KiB
C
244 lines
7.3 KiB
C
/****************************************************************************
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* arch/arm/src/armv7-a/arm_addrenv_shm.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/irq.h>
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#include <nuttx/arch.h>
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#include <nuttx/sched.h>
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#include <nuttx/addrenv.h>
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#include "mmu.h"
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#include "addrenv.h"
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#include "pgalloc.h"
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#include "sched/sched.h"
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#if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_ARCH_VMA_MAPPING)
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: up_shmat
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*
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* Description:
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* Attach, i.e, map, on shared memory region to a user virtual address
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*
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* Input Parameters:
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* pages - A pointer to the first element in a array of physical address,
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* each corresponding to one page of memory.
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* npages - The number of pages in the list of physical pages to be mapped.
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* vaddr - The virtual address corresponding to the beginning of the
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* (contiguous) virtual address region.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned
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* on failure.
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*
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****************************************************************************/
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int up_shmat(uintptr_t *pages, unsigned int npages, uintptr_t vaddr)
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{
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struct tcb_s *tcb = this_task();
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uintptr_t l1entry;
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uintptr_t *l2table;
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uintptr_t paddr;
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unsigned int nmapped;
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/* Sanity checks */
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DEBUGASSERT(pages && npages > 0 && tcb && tcb->addrenv_own);
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DEBUGASSERT(vaddr >= CONFIG_ARCH_SHM_VBASE && vaddr < ARCH_SHM_VEND);
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DEBUGASSERT(MM_ISALIGNED(vaddr));
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/* Loop until all pages have been mapped into the caller's address space. */
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for (nmapped = 0; nmapped < npages; )
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{
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/* Has a level 1 page table entry been created for this virtual
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* address.
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*/
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l1entry = mmu_l1_getentry(vaddr);
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if (l1entry == 0)
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{
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/* No.. Allocate one physical page for the L2 page table */
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paddr = mm_pgalloc(1);
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if (!paddr)
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{
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return -ENOMEM;
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}
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DEBUGASSERT(MM_ISALIGNED(paddr));
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/* Get the virtual address corresponding to the physical page
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* address.
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*/
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l2table = (uintptr_t *)arm_pgvaddr(paddr);
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/* Initialize the page table */
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memset(l2table, 0, ENTRIES_PER_L2TABLE * sizeof(uintptr_t));
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/* In case first time set shm l1 entry */
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mmu_l1_setentry(paddr, vaddr, MMU_L1_PGTABFLAGS);
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}
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else
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{
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/* Get the physical address of the L2 page table from the L1 page
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* table entry.
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*/
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paddr = l1entry & PTE_SMALL_PADDR_MASK;
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/* Get the virtual address corresponding to the physical page\
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* address.
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*/
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l2table = (uintptr_t *)arm_pgvaddr(paddr);
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}
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/* Map the virtual address to this physical address */
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DEBUGASSERT(get_l2_entry(l2table, vaddr) == 0);
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paddr = *pages++;
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set_l2_entry(l2table, paddr, vaddr, MMU_L2_UDATAFLAGS);
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nmapped++;
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vaddr += MM_PGSIZE;
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/* Make sure that the initialized L2 table is flushed to physical
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* memory.
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*
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* REVISIT: We could be smarter in doing this. Currently, we may
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* flush the entire L2 page table numerous times.
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*/
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up_flush_dcache((uintptr_t)l2table,
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(uintptr_t)l2table +
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ENTRIES_PER_L2TABLE * sizeof(uintptr_t));
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}
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return OK;
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}
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/****************************************************************************
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* Name: up_shmdt
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*
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* Description:
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* Detach, i.e, unmap, on shared memory region from a user virtual address
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*
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* Input Parameters:
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* vaddr - The virtual address corresponding to the beginning of the
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* (contiguous) virtual address region.
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* npages - The number of pages to be unmapped
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned
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* on failure.
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*
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****************************************************************************/
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int up_shmdt(uintptr_t vaddr, unsigned int npages)
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{
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struct tcb_s *tcb = this_task();
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uintptr_t l1entry;
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uintptr_t *l2table;
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uintptr_t paddr;
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unsigned int nunmapped;
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/* Sanity checks */
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DEBUGASSERT(npages > 0 && tcb && tcb->addrenv_own);
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DEBUGASSERT(vaddr >= CONFIG_ARCH_SHM_VBASE && vaddr < ARCH_SHM_VEND);
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DEBUGASSERT(MM_ISALIGNED(vaddr));
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/* Loop until all pages have been unmapped from the caller's address
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* space.
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*/
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for (nunmapped = 0; nunmapped < npages; )
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{
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/* Get the level 1 page table entry for this virtual address */
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l1entry = mmu_l1_getentry(vaddr);
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DEBUGASSERT(l1entry != 0);
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/* Get the physical address of the L2 page table from the L1 page
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* table entry.
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*/
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paddr = l1entry & PTE_SMALL_PADDR_MASK;
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/* Get the virtual address corresponding to the physical page
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* address.
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*/
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l2table = (uintptr_t *)arm_pgvaddr(paddr);
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/* Unmap this virtual page address.
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*
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* REVISIT: Note that the page allocated for the level 2 page table
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* is not freed nor is the level 1 page table entry ever cleared.
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* This means that the 4KiB page is still allocated to the process
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* even though it may not contain any mappings and that the it will
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* persist until the process terminates. That is not all bad because
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* it means that we will be able to re-instantiate the shared memory
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* mapping very quickly.
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*/
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DEBUGASSERT(get_l2_entry(l2table, vaddr) != 0);
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clr_l2_entry(l2table, vaddr);
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nunmapped++;
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vaddr += MM_PGSIZE;
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/* Make sure that the modified L2 table is flushed to physical
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* memory.
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*
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* REVISIT: We could be smarter in doing this. Currently, we may
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* flush the entire L2 page table numerous times.
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*/
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up_flush_dcache((uintptr_t)l2table,
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(uintptr_t)l2table +
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ENTRIES_PER_L2TABLE * sizeof(uint32_t));
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}
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return OK;
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}
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#endif /* CONFIG_BUILD_KERNEL && CONFIG_ARCH_VMA_MAPPING */
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