136 lines
3.7 KiB
C
136 lines
3.7 KiB
C
/*
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* Copyright (c) 2020 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Routines for managing virtual address spaces
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*/
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#include <stdint.h>
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#include <kernel_arch_interface.h>
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#include <spinlock.h>
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#define LOG_LEVEL CONFIG_KERNEL_LOG_LEVEL
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#include <logging/log.h>
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LOG_MODULE_DECLARE(os);
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/* Spinlock to protect any globals in this file and serialize page table
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* updates in arch code
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*/
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static struct k_spinlock mm_lock;
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/*
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* Overall virtual memory map:
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*
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* +--------------+ <- CONFIG_KERNEL_VM_BASE
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* | Mapping for |
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* | all RAM |
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* | |
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* | |
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* +--------------+ <- mapping_limit
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* | Available |
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* | virtual mem |
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* | |
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* |..............| <- mapping_pos (grows downward as more mappings are made)
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* | Mapping |
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* +--------------+
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* | Mapping |
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* +--------------+
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* | ... |
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* +--------------+
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* | Mapping |
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* +--------------+ <- CONFIG_KERNEL_VM_LIMIT
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*
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* At the moment we just have one area for mappings and they are permanent.
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* This is under heavy development and may change.
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*/
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/* Current position for memory mappings in kernel memory.
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* At the moment, all kernel memory mappings are permanent.
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* k_mem_map() mappings start at the end of the address space, and grow
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* downward.
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*
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* The Kconfig value is inclusive so add one, even if it wraps around to 0.
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*/
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static uint8_t *mapping_pos =
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(uint8_t *)((uintptr_t)CONFIG_KERNEL_VM_LIMIT + 1UL);
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/* Lower-limit of virtual address mapping. Immediately below this is the
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* permanent mapping for all SRAM.
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*/
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static uint8_t *mapping_limit = (uint8_t *)((uintptr_t)CONFIG_KERNEL_VM_BASE +
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KB((size_t)CONFIG_SRAM_SIZE));
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size_t k_mem_region_align(uintptr_t *aligned_addr, size_t *aligned_size,
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uintptr_t phys_addr, size_t size, size_t align)
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{
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size_t addr_offset;
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/* The actual mapped region must be page-aligned. Round down the
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* physical address and pad the region size appropriately
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*/
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*aligned_addr = ROUND_DOWN(phys_addr, align);
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addr_offset = phys_addr - *aligned_addr;
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*aligned_size = ROUND_UP(size + addr_offset, align);
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return addr_offset;
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}
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void k_mem_map(uint8_t **virt_addr, uintptr_t phys_addr, size_t size,
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uint32_t flags)
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{
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uintptr_t aligned_addr, addr_offset;
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size_t aligned_size;
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int ret;
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k_spinlock_key_t key;
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uint8_t *dest_virt;
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addr_offset = k_mem_region_align(&aligned_addr, &aligned_size,
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phys_addr, size,
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CONFIG_MMU_PAGE_SIZE);
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key = k_spin_lock(&mm_lock);
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/* Carve out some unused virtual memory from the top of the
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* address space
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*/
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if ((mapping_pos - aligned_size) < mapping_limit) {
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LOG_ERR("insufficient kernel virtual address space");
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goto fail;
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}
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mapping_pos -= aligned_size;
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dest_virt = mapping_pos;
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LOG_DBG("arch_mem_map(%p, 0x%lx, %zu, %x) offset %lu\n", dest_virt,
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aligned_addr, aligned_size, flags, addr_offset);
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__ASSERT(dest_virt != NULL, "NULL page memory mapping");
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__ASSERT(aligned_size != 0, "0-length mapping at 0x%lx", aligned_addr);
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__ASSERT((uintptr_t)dest_virt <
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((uintptr_t)dest_virt + (aligned_size - 1)),
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"wraparound for virtual address %p (size %zu)",
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dest_virt, size);
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__ASSERT(aligned_addr < (aligned_addr + (size - 1)),
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"wraparound for physical address 0x%lx (size %zu)",
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aligned_addr, size);
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ret = arch_mem_map(dest_virt, aligned_addr, aligned_size, flags);
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k_spin_unlock(&mm_lock, key);
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if (ret == 0) {
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*virt_addr = dest_virt + addr_offset;
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} else {
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/* This happens if there is an insurmountable problem
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* with the selected cache modes or access flags
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* with no safe fallback
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*/
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LOG_ERR("arch_mem_map() to %p returned %d", dest_virt, ret);
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goto fail;
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}
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return;
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fail:
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LOG_ERR("memory mapping 0x%lx (size %zu, flags 0x%x) failed",
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phys_addr, size, flags);
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k_panic();
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}
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