pmp_test.c

#include <stdio.h>
#include <stdint.h>

// Function to enable PMP and set permissions for region 0
void enable_pmp(uintptr_t start, uintptr_t end, uint8_t permissions) {
    uint8_t pmpcfg = (permissions << 3) | 0x01;
    uintptr_t pmpaddr = ((start >> 2) << 2) | 0x08;

    // Calculate the PMP address mask
    uintptr_t pmpmask = ((end - start) >> 2) - 1;

    // Write the configuration and address values to PMP registers
    asm volatile ("csrw pmpcfg0, %0" : : "r" (pmpcfg));
    asm volatile ("csrw pmpaddr0, %0" : : "r" (pmpaddr | pmpmask));
}

int main() {
    // Enable PMP for region 0 with start and end addresses
    enable_pmp(0x1000, 0x2000, 0x03); // Permission: Read-Write (0x03)

    // Access a memory location within the protected region (success case)
    uint32_t *ptr = (uint32_t *)0x1500;
    *ptr = 0xDEADBEEF;
    printf("Success: Accessed protected memory region. Value: 0x%x\n", *ptr);

    // Access a memory location outside the protected region (failure case)
    uint32_t *ptr2 = (uint32_t *)0x3000;
    *ptr2 = 0x12345678;
    printf("Failure: Accessed unprotected memory region. Value: 0x%x\n", *ptr2);

    return 0;
}