1  _start:
 2      la x1, trap_handler
 3      csrw mtvec, x1
 4  
 5      # PMP Entry 0: [0, 0x10000), TOR, RWX
 6      li x1, 0x10000 >> 2
 7      csrw pmpaddr0, x1
 8      li x1, 0b00001111
 9      csrw pmpcfg0, x1
10  
11      li x1, 0b11 << 11
12      csrc mstatus, x1  # Set transfer to User mode to mpp
13  
14      la x1, user_code
15      csrw mepc, x1
16      mret              # Go to user_code in user mode
17  
18  user_code:
19      li x1, 0x20000
20      jalr x0, x1, 0 # Jump to address outside PMP region
21      j fail
22  
23  trap_handler:
24      csrr x1, mcause
25      li x2, 1
26      bne x1, x2, fail  # Check if it is a ACCESS fault
27      j pass
28  
29  fail:
30      j fail
31  
32  pass:
33      li x1, 1
34      j pass