zephyr/kernel/mmu.c

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/*
* Copyright (c) 2020 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*
* Routines for managing virtual address spaces
*/
#include <stdint.h>
#include <kernel_arch_interface.h>
#include <spinlock.h>
#define LOG_LEVEL CONFIG_KERNEL_LOG_LEVEL
#include <logging/log.h>
LOG_MODULE_DECLARE(os);
/* Spinlock to protect any globals in this file and serialize page table
* updates in arch code
*/
static struct k_spinlock mm_lock;
size_t k_mem_region_align(uintptr_t *aligned_addr, size_t *aligned_size,
uintptr_t phys_addr, size_t size, size_t align)
{
size_t addr_offset;
/* The actual mapped region must be page-aligned. Round down the
* physical address and pad the region size appropriately
*/
*aligned_addr = ROUND_DOWN(phys_addr, align);
addr_offset = phys_addr - *aligned_addr;
*aligned_size = ROUND_UP(size + addr_offset, align);
return addr_offset;
}
void k_mem_map(uint8_t **virt_addr, uintptr_t phys_addr, size_t size,
uint32_t flags)
{
uintptr_t aligned_addr, addr_offset;
size_t aligned_size;
int ret;
k_spinlock_key_t key;
uint8_t *dest_virt;
addr_offset = k_mem_region_align(&aligned_addr, &aligned_size,
phys_addr, size,
CONFIG_MMU_PAGE_SIZE);
/* Carve out some unused virtual memory from the top of the
* address space
*/
key = k_spin_lock(&mm_lock);
/* TODO: For now, do an identity mapping, we haven't implemented
* virtual memory yet
*/
dest_virt = (uint8_t *)aligned_addr;
LOG_DBG("arch_mem_map(%p, 0x%lx, %zu, %x) offset %lu\n", dest_virt,
aligned_addr, aligned_size, flags, addr_offset);
__ASSERT(dest_virt != NULL, "NULL memory mapping");
__ASSERT(aligned_size != 0, "0-length mapping at 0x%lx", aligned_addr);
ret = arch_mem_map(dest_virt, aligned_addr, aligned_size, flags);
k_spin_unlock(&mm_lock, key);
if (ret == 0) {
*virt_addr = dest_virt + addr_offset;
} else {
/* This happens if there is an insurmountable problem
* with the selected cache modes or access flags
* with no safe fallback
*/
LOG_ERR("arch_mem_map() to %p returned %d", dest_virt, ret);
goto fail;
}
return;
fail:
LOG_ERR("memory mapping 0x%lx (size %zu, flags 0x%x) failed",
phys_addr, size, flags);
k_panic();
}