Implement Physical Memory Protection (PMP) Check for RISC-V

submissions/latifbhatti/explain_pmp_config.tex

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+\documentclass{article}
+\usepackage{array}
+\usepackage{geometry}
+\geometry{ margin=1in}
+\usepackage{longtable}
+\usepackage[longtable]{xcolor}
+\usepackage{booktabs} % For better table lines
+\usepackage[table]{xcolor} % Enable coloring for tables
+\usepackage{multirow} % For multi-row cells
+
+\begin{document}
+
+\section*{PMP Configuration Table}
+This table describes the PMP configuration values, their binary representation, and their corresponding status and examples.
+
+\scriptsize % Reduce font size for better fit
+\begin{longtable}{|>{\ttfamily}c|>{\ttfamily}c|c|c|c|c|c|c|p{5cm}|p{4cm}|}
+\hline
+\rowcolor{lightgray} % Shade header row
+\textbf{Hex} & \textbf{Binary} & \textbf{L} & \textbf{Reserved} & \textbf{A} & \textbf{X} & \textbf{W} & \textbf{R} & \textbf{Status} & \textbf{Example} \\
+\hline
+\endhead % Ensures the header repeats on every page
+
+0x0 & 00000000 & 0 & 000 & 00 & 0 & 0 & 0 & Disabled, no perms & Unused entry \\
+\hline
+0x1 & 00000001 & 0 & 000 & 00 & 0 & 0 & 1 & Disabled, read-only & Read-only mem \\
+\hline
+0x2 & 00000010 & 0 & 000 & 00 & 0 & 1 & 0 & Disabled, write-only & Write-only mem \\
+\hline
+0x3 & 00000011 & 0 & 000 & 00 & 0 & 1 & 1 & Disabled, read-write & Read-write mem \\
+\hline
+0x4 & 00000100 & 0 & 000 & 00 & 1 & 0 & 0 & Disabled, exec-only & Exec-only code \\
+\hline
+0x5 & 00000101 & 0 & 000 & 00 & 1 & 0 & 1 & Disabled, read-exec & Read-exec code \\
+\hline
+0x6 & 00000110 & 0 & 000 & 00 & 1 & 1 & 0 & Disabled, write-exec & Write-exec code \\
+\hline
+0x7 & 00000111 & 0 & 000 & 00 & 1 & 1 & 1 & Disabled, r-w-x & R-W-X code \\
+\hline
+0x8 & 00001000 & 0 & 000 & 01 & 0 & 0 & 0 & TOR, no perms & Unused TOR \\
+\hline
+0x9 & 00001001 & 0 & 000 & 01 & 0 & 0 & 1 & TOR, read-only & Read-only TOR \\
+\hline
+0xA & 00001010 & 0 & 000 & 01 & 0 & 1 & 0 & TOR, write-only & Write-only TOR \\
+\hline
+0xB & 00001011 & 0 & 000 & 01 & 0 & 1 & 1 & TOR, read-write & Read-write TOR \\
+\hline
+0xC & 00001100 & 0 & 000 & 01 & 1 & 0 & 0 & TOR, exec-only & Exec-only TOR \\
+\hline
+0xD & 00001101 & 0 & 000 & 01 & 1 & 0 & 1 & TOR, read-exec & Read-exec TOR \\
+\hline
+0xE & 00001110 & 0 & 000 & 01 & 1 & 1 & 0 & TOR, write-exec & Write-exec TOR \\
+\hline
+0xF & 00001111 & 0 & 000 & 01 & 1 & 1 & 1 & TOR, r-w-x & R-W-X TOR \\
+\hline
+0x10 & 00010000 & 0 & 000 & 10 & 0 & 0 & 0 & NA4, no perms & Unused NA4 \\
+\hline
+0x11 & 00010001 & 0 & 000 & 10 & 0 & 0 & 1 & NA4, read-only & Read-only NA4 \\
+\hline
+0x12 & 00010010 & 0 & 000 & 10 & 0 & 1 & 0 & NA4, write-only & Write-only NA4 \\
+\hline
+0x13 & 00010011 & 0 & 000 & 10 & 0 & 1 & 1 & NA4, read-write & Read-write NA4 \\
+\hline
+0x14 & 00010100 & 0 & 000 & 10 & 1 & 0 & 0 & NA4, exec-only & Exec-only NA4 \\
+\hline
+0x15 & 00010101 & 0 & 000 & 10 & 1 & 0 & 1 & NA4, read-exec & Read-exec NA4 \\
+\hline
+0x16 & 00010110 & 0 & 000 & 10 & 1 & 1 & 0 & NA4, write-exec & Write-exec NA4 \\
+\hline
+0x17 & 00010111 & 0 & 000 & 10 & 1 & 1 & 1 & NA4, r-w-x & R-W-X NA4 \\
+\hline
+0x18 & 00011000 & 0 & 000 & 11 & 0 & 0 & 0 & NAPOT, no perms & Unused NAPOT \\
+\hline
+0x19 & 00011001 & 0 & 000 & 11 & 0 & 0 & 1 & NAPOT, read-only & Read-only NAPOT \\
+\hline
+0x1A & 00011010 & 0 & 000 & 11 & 0 & 1 & 0 & NAPOT, write-only & Write-only NAPOT \\
+\hline
+0x1B & 00011011 & 0 & 000 & 11 & 0 & 1 & 1 & NAPOT, read-write & Read-write NAPOT \\
+\hline
+0x1C & 00011100 & 0 & 000 & 11 & 1 & 0 & 0 & NAPOT, exec-only & Exec-only NAPOT \\
+\hline
+0x1D & 00011101 & 0 & 000 & 11 & 1 & 0 & 1 & NAPOT, read-exec & Read-exec NAPOT \\
+\hline
+0x1E & 00011110 & 0 & 000 & 11 & 1 & 1 & 0 & NAPOT, write-exec & Write-exec NAPOT \\
+\hline
+0x1F & 00011111 & 0 & 000 & 11 & 1 & 1 & 1 & NAPOT, r-w-x & R-W-X NAPOT \\
+\hline
+0x20 & 00100000 & 0 & 001 & 00 & 0 & 0 & 0 & Disabled, no perms & Unused entry \\
+\hline
+0x21 & 00100001 & 0 & 001 & 00 & 0 & 0 & 1 & Disabled, read-only & Read-only mem \\
+\hline
+0x22 & 00100010 & 0 & 001 & 00 & 0 & 1 & 0 & Disabled, write-only & Write-only mem \\
+\hline
+0x23 & 00100011 & 0 & 001 & 00 & 0 & 1 & 1 & Disabled, read-write & Read-write mem \\
+\hline
+0x24 & 00100100 & 0 & 001 & 00 & 1 & 0 & 0 & Disabled, exec-only & Exec-only code \\
+\hline
+0x25 & 00100101 & 0 & 001 & 00 & 1 & 0 & 1 & Disabled, read-exec & Read-exec code \\
+\hline
+0x26 & 00100110 & 0 & 001 & 00 & 1 & 1 & 0 & Disabled, write-exec & Write-exec code \\
+\hline
+0x27 & 00100111 & 0 & 001 & 00 & 1 & 1 & 1 & Disabled, r-w-x & R-W-X code \\
+\hline
+0x28 & 00101000 & 0 & 001 & 01 & 0 & 0 & 0 & TOR, no perms & Unused TOR \\
+\hline
+0x29 & 00101001 & 0 & 001 & 01 & 0 & 0 & 1 & TOR, read-only & Read-only TOR \\
+\hline
+0x2A & 00101010 & 0 & 001 & 01 & 0 & 1 & 0 & TOR, write-only & Write-only TOR \\
+\hline
+0x2B & 00101011 & 0 & 001 & 01 & 0 & 1 & 1 & TOR, read-write & Read-write TOR \\
+\hline
+0x2C & 00101100 & 0 & 001 & 01 & 1 & 0 & 0 & TOR, exec-only & Exec-only TOR \\
+\hline
+0x2D & 00101101 & 0 & 001 & 01 & 1 & 0 & 1 & TOR, read-exec & Read-exec TOR \\
+\hline
+0x2E & 00101110 & 0 & 001 & 01 & 1 & 1 & 0 & TOR, write-exec & Write-exec TOR \\
+\hline
+0x2F & 00101111 & 0 & 001 & 01 & 1 & 1 & 1 & TOR, r-w-x & R-W-X TOR \\
+\hline
+0x30 & 00110000 & 0 & 001 & 10 & 0 & 0 & 0 & NA4, no perms & Unused NA4 \\
+\hline
+0x31 & 00110001 & 0 & 001 & 10 & 0 & 0 & 1 & NA4, read-only & Read-only NA4 \\
+\hline
+0x32 & 00110010 & 0 & 001 & 10 & 0 & 1 & 0 & NA4, write-only & Write-only NA4 \\
+\hline
+0x33 & 00110011 & 0 & 001 & 10 & 0 & 1 & 1 & NA4, read-write & Read-write NA4 \\
+\hline
+0x34 & 00110100 & 0 & 001 & 10 & 1 & 0 & 0 & NA4, exec-only & Exec-only NA4 \\
+\hline
+0x35 & 00110101 & 0 & 001 & 10 & 1 & 0 & 1 & NA4, read-exec & Read-exec NA4 \\
+\hline
+0x36 & 00110110 & 0 & 001 & 10 & 1 & 1 & 0 & NA4, write-exec & Write-exec NA4 \\
+\hline
+0x37 & 00110111 & 0 & 001 & 10 & 1 & 1 & 1 & NA4, r-w-x & R-W-X NA4 \\
+\hline
+0x38 & 00111000 & 0 & 001 & 11 & 0 & 0 & 0 & NAPOT, no perms & Unused NAPOT \\
+\hline
+0x39 & 00111001 & 0 & 001 & 11 & 0 & 0 & 1 & NAPOT, read-only & Read-only NAPOT \\
+\hline
+0x3A & 00111010 & 0 & 001 & 11 & 0 & 1 & 0 & NAPOT, write-only & Write-only NAPOT \\
+\hline
+0x3B & 00111011 & 0 & 001 & 11 & 0 & 1 & 1 & NAPOT, read-write & Read-write NAPOT \\
+\hline
+0x3C & 00111100 & 0 & 001 & 11 & 1 & 0 & 0 & NAPOT, exec-only & Exec-only NAPOT \\
+\hline
+0x3D & 00111101 & 0 & 001 & 11 & 1 & 0 & 1 & NAPOT, read-exec & Read-exec NAPOT \\
+\hline
+0x3E & 00111110 & 0 & 001 & 11 & 1 & 1 & 0 & NAPOT, write-exec & Write-exec NAPOT \\
+\hline
+0x3F & 00111111 & 0 & 001 & 11 & 1 & 1 & 1 & NAPOT, r-w-x & R-W-X NAPOT \\
+\hline
+\end{longtable}
+
+\end{document}

submissions/latifbhatti/pmp_check.py

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+import sys
+import re
+
+def parse_pmp_config(file_path):
+    with open(file_path, 'r') as file:
+        lines = file.readlines()
+        pmpcfg = [int(line.strip(), 16) & 0xFF for line in lines[:64]]
+        pmpaddr = [int(line.strip(), 16) for line in lines[64:128]]
+    return pmpcfg, pmpaddr
+
+def get_pmp_region(base, a, pmpaddr_value, pmpaddr):
+    if a == 1:
+        if base == 0:
+            prev_base = 0
+        else:
+            prev_base = (pmpaddr[base - 1])
+        region_start, region_end = prev_base, (pmpaddr_value)
+    elif a == 2:
+        region_start = (pmpaddr_value)
+        region_end = region_start + 3
+    elif a == 3:
+        n = 0
+        mask = 1
+        while (pmpaddr_value & mask) == mask:
+            n += 1
+            mask = (mask << 1) | 1
+        size = 1 << (n + 2)
+        region_start = (pmpaddr_value << 2) & ~(size - 1)
+        region_end = region_start + size - 1
+    else:
+        return None
+    return region_start, region_end
+
+def check_pmp_access(pmpcfg, pmpaddr, addr, mode, operation):
+    addr = int(addr, 16)
+    matching_index = -1
+    for i in range(0, 64, 1):
+        cfg = pmpcfg[i]
+        a = (cfg >> 3) & 0x3
+        if a == 0:
+            continue
+        region = get_pmp_region(i, a, pmpaddr[i], pmpaddr)
+        if not region:
+            continue
+        region_start, region_end = region
+        if region_start <= addr <= region_end:
+            matching_index = i            
+            break
+    cfg = pmpcfg[matching_index]
+    l = (cfg >> 7) & 0x1
+    r = (cfg >> 0) & 0x1
+    w = (cfg >> 1) & 0x1
+    x = (cfg >> 2) & 0x1
+    print("value of pmpcfg = " , hex(cfg) ,"\noperation R     = " , r,"\noperation W     = " , w,"\noperation X     = " , x)
+    if matching_index == -1:
+        if mode in ['S', 'U']:
+            return False
+        else:
+            return True
+
+    if mode == 'M':
+        if l:
+            return True
+    elif mode in ['S', 'U']:
+        if l:
+            return False
+    if operation == 'R' and not r:
+        return False
+    if operation == 'W' and not w:
+        return False
+    if operation == 'X' and not x:
+        return False
+    return True
+
+def validate_hex_address(addr):
+    return re.match(r'^0x[0-9a-fA-F]+$', addr) is not None
+
+def main():
+    if len(sys.argv) != 5:
+        print("Usage: python pmp_check.py <pmp_config_file> <physical_address> <privilege_mode> <operation>")
+        sys.exit(1)
+    if not validate_hex_address(sys.argv[2]):
+        print("Invalid physical address format. Must be in hexadecimal with a leading '0x'.")
+        sys.exit(1)
+    pmpcfg, pmpaddr = parse_pmp_config(sys.argv[1])
+    addr = sys.argv[2]
+    mode = sys.argv[3].upper()
+    operation = sys.argv[4].upper()
+    if mode not in ['M', 'S', 'U'] or operation not in ['R', 'W', 'X']:
+        print("Invalid privilege mode or operation.")
+        sys.exit(1)
+    if check_pmp_access(pmpcfg, pmpaddr, addr, mode, operation):
+        print("Access allowed.")
+    else:
+        print("Access fault.")
+
+if __name__ == "__main__":
+    main()

submissions/latifbhatti/pmp_config.txt

@@ -0,0 +1,128 @@
+0x0
+0x1
+0x2
+0x3
+0x4
+0x5
+0x6
+0x7
+0x8
+0x9
+0xA
+0xB
+0xC
+0xD
+0xE
+0xF
+0x10
+0x11
+0x12
+0x13
+0x14
+0x15
+0x16
+0x17
+0x18
+0x19
+0x1A
+0x1B
+0x1C
+0x1D
+0x1E
+0x1F
+0x20
+0x21
+0x22
+0x23
+0x24
+0x25
+0x26
+0x27
+0x28
+0x29
+0x2A
+0x2B
+0x2C
+0x2D
+0x2E
+0x2F
+0x30
+0x31
+0x32
+0x33
+0x34
+0x35
+0x36
+0x37
+0x38
+0x39
+0x3A
+0x3B
+0x3C
+0x3D
+0x3E
+0x3F
+0x100
+0x1000
+0x2000
+0x5000
+0x80000000
+0x10000000
+0x20000000
+0x70000000
+0x80000000
+0x90000000
+0xA0000000
+0xB0000000
+0xC0000000
+0xD0000000
+0xE0000000
+0xF0000000
+0x100000000
+0x110000000
+0x120000000
+0x130000000
+0x140000000
+0x150000000
+0x160000000
+0x170000000
+0x180000000
+0x190000000
+0x1A0000000
+0x1B0000000
+0x1C0000000
+0x1D0000000
+0x1E0000000
+0x1F0000000
+0x200000000
+0x210000000
+0x220000000
+0x230000000
+0x240000000
+0x250000000
+0x260000000
+0x270000000
+0x280000000
+0x290000000
+0x2A0000000
+0x2B0000000
+0x2C0000000
+0x2D0000000
+0x2E0000000
+0x2F0000000
+0x300000000
+0x310000000
+0x320000000
+0x330000000
+0x340000000
+0x350000000
+0x360000000
+0x370000000
+0x380000000
+0x390000000
+0x3A0000000
+0x3B0000000
+0x3C0000000
+0x3D0000000
+0x3E0000000
+0x3F0000000