/****************************************************************************
* arch/arm/src/armv7/arm_addrenv_shm.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include <nuttx/addrenv.h>
#include "mmu.h"
#include "cache.h"
#include "addrenv.h"
#include "pgalloc.h"
#if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_MM_SHM)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_shmat
*
* Description:
* Attach, i.e, map, on shared memory region to a user virtual address
*
* Input Parameters:
* pages - A pointer to the first element in a array of physical address,
* each corresponding to one page of memory.
* npages - The number of pages in the list of physical pages to be mapped.
* vaddr - The virtual address corresponding to the beginning of the
* (contiguous) virtual address region.
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
int up_shmat(FAR uintptr_t *pages, unsigned int npages, uintptr_t vaddr)
{
FAR struct tcb_s *tcb = sched_self();
FAR struct task_group_s *group;
FAR uintptr_t *l1entry;
FAR uint32_t *l2table;
irqstate_t flags;
uintptr_t paddr;
#ifndef CONFIG_ARCH_PGPOOL_MAPPING
uint32_t l1save;
#endif
unsigned int nmapped;
unsigned int shmndx;
shmvdbg("pages=%p npages=%d vaddr=%08lx\n",
pages, npages, (unsigned long)vaddr);
/* Sanity checks */
DEBUGASSERT(pages && npages > 0 && tcb && tcb->group);
DEBUGASSERT(vaddr >= CONFIG_ARCH_SHM_VBASE && vaddr < ARCH_SHM_VEND);
DEBUGASSERT(MM_ISALIGNED(vaddr));
group = tcb->group;
/* Loop until all pages have been mapped into the caller's address space. */
for (nmapped = 0; nmapped < npages; )
{
/* Get the shm[] index associated with the virtual address */
shmndx = (vaddr - CONFIG_ARCH_SHM_VBASE) >> SECTION_SHIFT;
/* Has a level 1 page table entry been created for this virtual address */
l1entry = group->tg_addrenv.shm[shmndx];
if (l1entry == NULL)
{
/* No.. Allocate one physical page for the L2 page table */
paddr = mm_pgalloc(1);
if (!paddr)
{
return -ENOMEM;
}
DEBUGASSERT(MM_ISALIGNED(paddr));
/* We need to be more careful after we begin modifying
* global resources.
*/
flags = irqsave();
group->tg_addrenv.shm[shmndx] = (FAR uintptr_t *)paddr;
#ifdef CONFIG_ARCH_PGPOOL_MAPPING
/* Get the virtual address corresponding to the physical page
* address.
*/
l2table = (FAR uint32_t *)arm_pgvaddr(paddr);
#else
/* Temporarily map the page into the virtual address space */
l1save = mmu_l1_getentry(ARCH_SCRATCH_VBASE);
mmu_l1_setentry(paddr & ~SECTION_MASK, ARCH_SCRATCH_VBASE,
MMU_MEMFLAGS);
l2table = (FAR uint32_t *)
(ARCH_SCRATCH_VBASE | (paddr & SECTION_MASK));
#endif
/* Initialize the page table */
memset(l2table, 0, ENTRIES_PER_L2TABLE * sizeof(uint32_t));
}
else
{
/* Get the physical address of the L2 page table from the L1 page
* table entry.
*/
paddr = (uintptr_t)l1entry & ~SECTION_MASK;
flags = irqsave();
#ifdef CONFIG_ARCH_PGPOOL_MAPPING
/* Get the virtual address corresponding to the physical page\
* address.
*/
l2table = (FAR uint32_t *)arm_pgvaddr(paddr);
#else
/* Temporarily map the page into the virtual address space */
l1save = mmu_l1_getentry(ARCH_SCRATCH_VBASE);
mmu_l1_setentry(paddr & ~SECTION_MASK, ARCH_SCRATCH_VBASE,
MMU_MEMFLAGS);
l2table = (FAR uint32_t *)
(ARCH_SCRATCH_VBASE | (paddr & SECTION_MASK));
#endif
}
/* Map the virtual address to this physical address */
DEBUGASSERT(get_l2_entry(l2table, vaddr) == 0);
paddr = *pages++;
set_l2_entry(l2table, paddr, vaddr, MMU_MEMFLAGS);
nmapped++;
vaddr += MM_PGSIZE;
/* Make sure that the initialized L2 table is flushed to physical
* memory.
*
* REVISIT: We could be smarter in doing this. Currently, we may
* flush the entire L2 page table numerous times.
*/
arch_flush_dcache((uintptr_t)l2table,
(uintptr_t)l2table +
ENTRIES_PER_L2TABLE * sizeof(uint32_t));
#ifndef CONFIG_ARCH_PGPOOL_MAPPING
/* Restore the scratch section L1 page table entry */
mmu_l1_restore(ARCH_SCRATCH_VBASE, l1save);
#endif
irqrestore(flags);
}
return OK;
}
/****************************************************************************
* Name: up_shmdt
*
* Description:
* Detach, i.e, unmap, on shared memory region from a user virtual address
*
* Input Parameters:
* vaddr - The virtual address corresponding to the beginning of the
* (contiguous) virtual address region.
* npages - The number of pages to be unmapped
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
int up_shmdt(uintptr_t vaddr, unsigned int npages)
{
FAR struct tcb_s *tcb = sched_self();
FAR struct task_group_s *group;
FAR uintptr_t *l1entry;
FAR uint32_t *l2table;
irqstate_t flags;
uintptr_t paddr;
#ifndef CONFIG_ARCH_PGPOOL_MAPPING
uint32_t l1save;
#endif
unsigned int nunmapped;
unsigned int shmndx;
shmvdbg("npages=%d vaddr=%08lx\n", npages, (unsigned long)vaddr);
/* Sanity checks */
DEBUGASSERT(npages > 0 && tcb && tcb->group);
DEBUGASSERT(vaddr >= CONFIG_ARCH_SHM_VBASE && vaddr < ARCH_SHM_VEND);
DEBUGASSERT(MM_ISALIGNED(vaddr));
group = tcb->group;
/* Loop until all pages have been unmapped from the caller's address
* space.
*/
for (nunmapped = 0; nunmapped < npages; )
{
/* Get the shm[] index associated with the virtual address */
shmndx = (vaddr - CONFIG_ARCH_SHM_VBASE) >> SECTION_SHIFT;
/* Get the level 1 page table entry for this virtual address */
l1entry = group->tg_addrenv.shm[shmndx];
DEBUGASSERT(l1entry != NULL);
/* Get the physical address of the L2 page table from the L1 page
* table entry.
*/
paddr = (uintptr_t)l1entry & ~SECTION_MASK;
flags = irqsave();
#ifdef CONFIG_ARCH_PGPOOL_MAPPING
/* Get the virtual address corresponding to the physical page\
* address.
*/
l2table = (FAR uint32_t *)arm_pgvaddr(paddr);
#else
/* Temporarily map the page into the virtual address space */
l1save = mmu_l1_getentry(ARCH_SCRATCH_VBASE);
mmu_l1_setentry(paddr & ~SECTION_MASK, ARCH_SCRATCH_VBASE,
MMU_MEMFLAGS);
l2table = (FAR uint32_t *)
(ARCH_SCRATCH_VBASE | (paddr & SECTION_MASK));
#endif
/* Unmap this virtual page address.
*
* REVISIT: Note that the page allocated for the level 2 page table
* is not freed nor is the level 1 page table entry ever cleared.
* This means that the 4KiB page is still allocated to the process
* even though it may not contain any mappings and that the it will
* persist until the process terminates. That is not all bad because
* it means that we will be able to re-instantiate the shared memory
* mapping very quickly.
*/
DEBUGASSERT(get_l2_entry(l2table, vaddr) != 0);
clr_l2_entry(l2table, vaddr);
nunmapped++;
vaddr += MM_PGSIZE;
/* Make sure that the modified L2 table is flushed to physical
* memory.
*
* REVISIT: We could be smarter in doing this. Currently, we may
* flush the entire L2 page table numerous times.
*/
arch_flush_dcache((uintptr_t)l2table,
(uintptr_t)l2table +
ENTRIES_PER_L2TABLE * sizeof(uint32_t));
#ifndef CONFIG_ARCH_PGPOOL_MAPPING
/* Restore the scratch section L1 page table entry */
mmu_l1_restore(ARCH_SCRATCH_VBASE, l1save);
#endif
irqrestore(flags);
}
return OK;
}
#endif /* CONFIG_BUILD_KERNEL && CONFIG_MM_SHM */
