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/* Copyright 2018 SiFive, Inc */
/* SPDX-License-Identifier: Apache-2.0 */
#ifndef METAL__PMP_H
#define METAL__PMP_H
/*!
* @file metal/pmp.h
*
* @brief API for Configuring Physical Memory Protection on RISC-V Cores
*
* The Physical Memory Protection (PMP) interface on RISC-V cores
* is a form of memory protection unit which allows for a finite number
* of physical memory regions to be configured with certain access
* permissions.
*
* Additional information about the use and configuration rules for PMPs
* can be found by reading the RISC-V Privileged Architecture Specification.
*/
#include <stddef.h>
#include <metal/machine.h>
struct metal_pmp;
/*!
* @brief Set of available PMP addressing modes
*/
enum metal_pmp_address_mode {
/*! @brief Disable the PMP region */
METAL_PMP_OFF = 0,
/*! @brief Use Top-of-Range mode */
METAL_PMP_TOR = 1,
/*! @brief Use naturally-aligned 4-byte region mode */
METAL_PMP_NA4 = 2,
/*! @brief Use naturally-aligned power-of-two mode */
METAL_PMP_NAPOT = 3
};
/*!
* @brief Configuration for a PMP region
*/
struct metal_pmp_config {
/*! @brief Sets whether reads to the PMP region succeed */
int R : 1;
/*! @brief Sets whether writes to the PMP region succeed */
int W : 1;
/*! @brief Sets whether the PMP region is executable */
int X : 1;
/*! @brief Sets the addressing mode of the PMP region */
enum metal_pmp_address_mode A : 2;
int _pad : 2;
/*! @brief Sets whether the PMP region is locked */
enum metal_pmp_locked {
METAL_PMP_UNLOCKED = 0,
METAL_PMP_LOCKED = 1
} L : 1;
};
/*!
* @brief A handle for the PMP device
*/
struct metal_pmp {
/* The minimum granularity of the PMP region. Set by metal_pmp_init */
uintptr_t _granularity[METAL_MAX_CORES];
};
/*!
* @brief Get the PMP device handle
*/
struct metal_pmp *metal_pmp_get_device(void);
/*!
* @brief Initialize the PMP
* @param pmp The PMP device handle to be initialized
*
* The PMP initialization routine is optional and may be called as many times
* as is desired. The effect of the initialization routine is to attempt to set
* all regions to unlocked and disabled, as well as to clear the X, W, and R
* bits. Only the pmp configuration of the hart which executes the routine will
* be affected.
*
* If any regions are fused to preset values by the implementation or locked,
* those PMP regions will silently remain uninitialized.
*/
void metal_pmp_init(struct metal_pmp *pmp);
/*!
* @brief Configure a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to configure
* @param config The desired configuration of the PMP region
* @param address The desired address of the PMP region
* @return 0 upon success
*/
int metal_pmp_set_region(struct metal_pmp *pmp, unsigned int region, struct metal_pmp_config config, size_t address);
/*!
* @brief Get the configuration for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to read
* @param config Variable to store the PMP region configuration
* @param address Variable to store the PMP region address
* @return 0 if the region is read successfully
*/
int metal_pmp_get_region(struct metal_pmp *pmp, unsigned int region, struct metal_pmp_config *config, size_t *address);
/*!
* @brief Lock a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to lock
* @return 0 if the region is successfully locked
*/
int metal_pmp_lock(struct metal_pmp *pmp, unsigned int region);
/*!
* @brief Set the address for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to set
* @param address The desired address of the PMP region
* @return 0 if the address is successfully set
*/
int metal_pmp_set_address(struct metal_pmp *pmp, unsigned int region, size_t address);
/*!
* @brief Get the address of a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to read
* @return The address of the PMP region, or 0 if the region could not be read
*/
size_t metal_pmp_get_address(struct metal_pmp *pmp, unsigned int region);
/*!
* @brief Set the addressing mode of a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to set
* @param mode The PMP addressing mode to set
* @return 0 if the addressing mode is successfully set
*/
int metal_pmp_set_address_mode(struct metal_pmp *pmp, unsigned int region, enum metal_pmp_address_mode mode);
/*!
* @brief Get the addressing mode of a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to read
* @return The address mode of the PMP region
*/
enum metal_pmp_address_mode metal_pmp_get_address_mode(struct metal_pmp *pmp, unsigned int region);
/*!
* @brief Set the executable bit for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to set
* @param X The desired value of the executable bit
* @return 0 if the executable bit is successfully set
*/
int metal_pmp_set_executable(struct metal_pmp *pmp, unsigned int region, int X);
/*!
* @brief Get the executable bit for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to read
* @return the value of the executable bit
*/
int metal_pmp_get_executable(struct metal_pmp *pmp, unsigned int region);
/*!
* @brief Set the writable bit for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to set
* @param W The desired value of the writable bit
* @return 0 if the writable bit is successfully set
*/
int metal_pmp_set_writeable(struct metal_pmp *pmp, unsigned int region, int W);
/*!
* @brief Get the writable bit for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to read
* @return the value of the writable bit
*/
int metal_pmp_get_writeable(struct metal_pmp *pmp, unsigned int region);
/*!
* @brief Set the readable bit for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to set
* @param R The desired value of the readable bit
* @return 0 if the readable bit is successfully set
*/
int metal_pmp_set_readable(struct metal_pmp *pmp, unsigned int region, int R);
/*!
* @brief Set the readable bit for a PMP region
* @param pmp The PMP device handle
* @param region The PMP region to read
* @return the value of the readable bit
*/
int metal_pmp_get_readable(struct metal_pmp *pmp, unsigned int region);
#endif
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