vm.h

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/* SPDX-License-Identifier: BSD-4-Clause-UC */
 
#ifndef _VM_H
#define _VM_H
 
#include <string.h>
#include <stdint.h>
#include <arch/encoding.h>
 
#define EXTRACT_FIELD(val, which) (((val) & (which)) / ((which) & ~((which)-1)))
#define INSERT_FIELD(val, which, fieldval) (((val) & ~(which)) | ((fieldval) * ((which) & ~((which)-1))))
 
void mstatus_init(void); // need to setup mstatus so we know we have virtual memory
 
#define DEFINE_MPRV_READ_FLAGS(name, type, insn, flags)                 \
        static inline type name(type *p);                               \
        static inline type name(type *p)                                \
        {                                                               \
                size_t mprv = flags;                                    \
                type value;                                             \
                asm (                                                   \
                        "csrs           mstatus, %1\n"                  \
                        STRINGIFY(insn) " %0, 0(%2)\n"                  \
                        "csrc           mstatus, %1\n"                  \
                        : "=&r"(value) : "r"(mprv), "r"(p) : "memory"   \
                );                                                      \
                return value;                                           \
        }
 
#define DEFINE_MPRV_READ(name, type, insn) \
        DEFINE_MPRV_READ_FLAGS(name, type, insn, MSTATUS_MPRV)
 
#define DEFINE_MPRV_READ_MXR(name, type, insn) \
        DEFINE_MPRV_READ_FLAGS(name, type, insn, MSTATUS_MPRV | MSTATUS_MXR)
 
#define DEFINE_MPRV_WRITE(name, type, insn)                             \
        static inline void name(type *p, type value);                   \
        static inline void name(type *p, type value)                    \
        {                                                               \
                size_t mprv = MSTATUS_MPRV;                             \
                asm (                                                   \
                        "csrs           mstatus, %0\n"                  \
                        STRINGIFY(insn) " %1, 0(%2)\n"                  \
                        "csrc           mstatus, %0\n"                  \
                        :: "r"(mprv), "r"(value), "r"(p) : "memory"     \
                );                                                      \
        }
 
/*
 * mprv_{read,write}_* - Modified privilege memory access functions.
 *
 * These inline functions perform a read or write memory operation with the
 * mstatus.MPRV bit set. This causes the memory protections and translation of
 * the previous mode (e.g. U-mode, if we're handling a trap from U-mode) to be
 * applied.
 *
 * The user of these functions must make sure to avoid trap loops through
 * unaligned memory accesses.
 */
DEFINE_MPRV_READ(mprv_read_u8, uint8_t, lbu)
DEFINE_MPRV_READ(mprv_read_u16, uint16_t, lhu)
DEFINE_MPRV_READ(mprv_read_u32, uint32_t, lwu)
DEFINE_MPRV_READ(mprv_read_u64, uint64_t, ld)
DEFINE_MPRV_READ(mprv_read_long, long, ld)
DEFINE_MPRV_READ(mprv_read_ulong, unsigned long, ld)
DEFINE_MPRV_READ_MXR(mprv_read_mxr_u8, uint8_t, lbu)
DEFINE_MPRV_READ_MXR(mprv_read_mxr_u16, uint16_t, lhu)
DEFINE_MPRV_READ_MXR(mprv_read_mxr_u32, uint32_t, lwu)
DEFINE_MPRV_READ_MXR(mprv_read_mxr_u64, uint64_t, ld)
DEFINE_MPRV_READ_MXR(mprv_read_mxr_long, long, ld)
DEFINE_MPRV_READ_MXR(mprv_read_mxr_ulong, unsigned long, ld)
DEFINE_MPRV_WRITE(mprv_write_u8, uint8_t, sb)
DEFINE_MPRV_WRITE(mprv_write_u16, uint16_t, sh)
DEFINE_MPRV_WRITE(mprv_write_u32, uint32_t, sw)
DEFINE_MPRV_WRITE(mprv_write_u64, uint64_t, sd)
DEFINE_MPRV_WRITE(mprv_write_long, long, sd)
DEFINE_MPRV_WRITE(mprv_write_ulong, unsigned long, sd)
 
#if __riscv_xlen == 32
        DEFINE_MPRV_READ(mprv_read_uintptr_t, uintptr_t, lw)
        DEFINE_MPRV_READ(mprv_write_uintptr_t, uintptr_t, sw)
#elif __riscv_xlen == 64
        DEFINE_MPRV_READ(mprv_read_uintptr_t, uintptr_t, ld)
        DEFINE_MPRV_READ(mprv_write_uintptr_t, uintptr_t, sd)
#endif
 
#undef DEFINE_MPRV_READ_FLAGS
#undef DEFINE_MPRV_READ
#undef DEFINE_MPRV_READ_MXR
#undef DEFINE_MPRV_WRITE
 
#endif