incubator-nuttx/arch/risc-v/include/arch.h

127 lines
3.9 KiB
C

/****************************************************************************
* arch/risc-v/include/arch.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/* This file should never be included directly but, rather,
* only indirectly through nuttx/arch.h
*/
#ifndef __ARCH_RISCV_INCLUDE_ARCH_H
#define __ARCH_RISCV_INCLUDE_ARCH_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifndef __ASSEMBLY__
# include <stdint.h>
# include <stddef.h>
#endif
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Provide the maximum amount of page table levels per MMU type */
#ifdef CONFIG_ARCH_MMU_TYPE_SV39
# define ARCH_PGT_MAX_LEVELS (3)
#elif CONFIG_ARCH_MMU_TYPE_SV32
# define ARCH_PGT_MAX_LEVELS (2)
#endif
/* Amount of static page tables allocated for an address environment */
#ifdef CONFIG_ARCH_ADDRENV
# define ARCH_SPGTS (ARCH_PGT_MAX_LEVELS - 1)
#endif
/****************************************************************************
* Public Types
****************************************************************************/
#ifdef CONFIG_ARCH_ADDRENV
#ifndef __ASSEMBLY__
/* A task group must have its L1 table in memory always, and the rest can
* be dynamically committed to memory (and even swapped).
*
* In this implementation level tables except the final level N are always
* kept in static memory, while the level N tables are always dynamically
* allocated. There is one static page per level in `spgtables[]`.
*
* The implications ? They depend on the MMU type.
*
* For Sv32 this means that:
* - A task can not have more than 4GB of memory allocated.
* - The minimum amount of memory needed for page tables per task is 8K,
* which gives access to 4MB of memory. This is plenty for many tasks.
*
* For Sv39 this means that:
* - A task can not have more than 1GB of memory allocated. This should be
* plenty enough...
* - The minimum amount of memory needed for page tables per task is 12K,
* which gives access to 2MB of memory. This is plenty for many tasks.
*/
struct arch_addrenv_s
{
/* Physical addresses of the static page tables (levels N-1) here, these
* are allocated when a task is created.
*/
uintptr_t spgtables[ARCH_SPGTS];
/* The text, data, heap bases and heap size here */
uintptr_t textvbase;
uintptr_t datavbase;
uintptr_t heapvbase;
size_t heapsize;
/* The page directory root (satp) value */
uintptr_t satp;
};
typedef struct arch_addrenv_s arch_addrenv_t;
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_ARCH_ADDRENV */
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* __ARCH_RISCV_INCLUDE_ARCH_H */