Emulate PinePhone with Unicorn Emulator

Read the articles...

We're porting a new operating system (Apache NuttX RTOS) to Pine64 PinePhone. And I wondered...

To make PinePhone testing easier...

Can we emulate Arm64 PinePhone with Unicorn Emulator?

Let's find out! We'll call the Unicorn Emulator in Rust (instead of C).

(Because I'm too old to write meticulous C... But I'm OK to get nagged by Rust Compiler if I miss something!)

We begin by emulating simple Arm64 Machine Code...

Emulate Arm64 Machine Code

Suppose we wish to emulate some Arm64 Machine Code...

pinephone-emulator/src/main.rs

Lines 7 to 8 in bc5643d

    
           0xab, 0x05, 0x00, 0xb8,  // str w11, [x13], #0 
        
           0xaf, 0x05, 0x40, 0x38,  // ldrb w15, [x13], #0

Here's our Rust Program that calls Unicorn Emulator to emulate the Arm64 Machine Code...

pinephone-emulator/src/main.rs

Lines 1 to 55 in bc5643d

    
           use unicorn_engine::{Unicorn, RegisterARM64}; 
        
           use unicorn_engine::unicorn_const::{Arch, Mode, Permission}; 
        
           fn main() { 
        
               // Arm64 Code 
        
               let arm64_code: Vec<u8> = vec![ 
        
                   0xab, 0x05, 0x00, 0xb8,  // str w11, [x13], #0 
        
                   0xaf, 0x05, 0x40, 0x38,  // ldrb w15, [x13], #0 
        
               ]; 
        
               // Initialize emulator in ARM64 mode 
        
               let mut unicorn = Unicorn::new( 
        
                   Arch::ARM64, 
        
                   Mode::LITTLE_ENDIAN 
        
               ).expect("failed to initialize Unicorn instance"); 
        
               let emu = &mut unicorn; 
        
               // memory address where emulation starts 
        
               const ADDRESS: u64 = 0x10000; 
        
               // map 2MB memory for this emulation 
        
               emu.mem_map( 
        
                   ADDRESS, 
        
                   2 * 1024 * 1024, 
        
                   Permission::ALL 
        
               ).expect("failed to map code page"); 
        
               // write machine code to be emulated to memory 
        
               emu.mem_write( 
        
                   ADDRESS,  
        
                   &arm64_code 
        
               ).expect("failed to write instructions"); 
        
               // Register Values 
        
               const X11: u64 = 0x12345678;    // X11 register 
        
               const X13: u64 = 0x10000 + 0x8; // X13 register 
        
               const X15: u64 = 0x33;          // X15 register 
        
               // initialize machine registers 
        
               emu.reg_write(RegisterARM64::X11, X11) 
        
                   .expect("failed to set X11"); 
        
               emu.reg_write(RegisterARM64::X13, X13) 
        
                   .expect("failed to set X13"); 
        
               emu.reg_write(RegisterARM64::X15, X15) 
        
                   .expect("failed to set X15"); 
        
               let _ = emu.emu_start( 
        
                   ADDRESS, 
        
                   ADDRESS + arm64_code.len() as u64, 
        
                   0, // Previously: 10 * SECOND_SCALE, 
        
                   0  // Previously: 1000 
        
               ); 
        
               assert_eq!(emu.reg_read(RegisterARM64::X15), Ok(0x78)); 
        
           }

We add unicorn-engine to Cargo.toml...

pinephone-emulator/Cargo.toml

Lines 8 to 9 in bc5643d

    
           [dependencies] 
        
           unicorn-engine = "2.0.0"

And we run our Rust Program...

→ cargo run --verbose
  Fresh cc v1.0.79
  Fresh cmake v0.1.49
  Fresh pkg-config v0.3.26
  Fresh bitflags v1.3.2
  Fresh libc v0.2.139
  Fresh unicorn-engine v2.0.1
  Fresh pinephone-emulator v0.1.0
Finished dev [unoptimized + debuginfo] target(s) in 0.08s
  Running `target/debug/pinephone-emulator`

Our Rust Program works OK for emulating Arm64 Memory and Arm64 Registers.

Let's talk about Arm64 Memory-Mapped Input / Output...

Memory Access Hook for Arm64 Emulation

How will we emulate Arm64 Memory-Mapped Input / Output?

Unicorn Emulator lets us attach hooks to Emulate Memory Access.

Here's a Hook Function for Memory Access...

pinephone-emulator/src/main.rs

Lines 83 to 95 in 3655ac2

    
           // Hook Function for Memory Access. 
        
           // Called once for every Arm64 Memory Access. 
        
           fn hook_memory( 
        
               _: &mut Unicorn<()>,  // Emulator 
        
               mem_type: MemType,    // Read or Write Access 
        
               address: u64,  // Accessed Address 
        
               size: usize,   // Number of bytes accessed 
        
               value: i64     // Read / Write Value 
        
           ) -> bool { 
        
               // TODO: Simulate Memory-Mapped Input/Output (UART Controller) 
        
               println!("hook_memory: mem_type={:?}, address={:#x}, size={:?}, value={:#x}", mem_type, address, size, value); 
        
               true 
        
           }

Our Hook Function prints all Read / Write Access to Emulated Arm64 Memory.

(Return value is unused)

This is how we attach the Hook Function to the Unicorn Emulator...

pinephone-emulator/src/main.rs

Lines 59 to 74 in 3655ac2

    
           // Add Hook for Arm64 Memory Access 
        
           let _ = emu.add_mem_hook( 
        
               HookType::MEM_ALL,  
        
               0, 
        
               u64::MAX, 
        
               hook_memory 
        
           ).expect("failed to add memory hook"); 
        
           // Emulate machine code in infinite time (last param = 0), 
        
           // or when all code has completed 
        
           let _ = emu.emu_start( 
        
               ADDRESS, 
        
               ADDRESS + arm64_code.len() as u64, 
        
               0, // Previously: 10 * SECOND_SCALE, 
        
               0  // Previously: 1000 
        
           );

When we run our Rust Program, we see the Read and Write Memory Accesses made by our Emulated Arm64 Code...

hook_memory: 
  mem_type=WRITE, 
  address=0x10008, 
  size=4, 
  value=0x12345678

hook_memory: 
  mem_type=READ, 
  address=0x10008, 
  size=1, 
  value=0x0

This Memory Access Hook Function will be helpful when we emulate Memory-Mapped Input/Output on PinePhone.

(Like for the Allwinner A64 UART Controller)

Unicorn Emulator allows Code Execution Hooks too...

Code Execution Hook for Arm64 Emulation

Can we intercept every Arm64 Instruction that will be emulated?

Yep we can call Unicorn Emulator to add a Code Execution Hook.

Here's a sample Hook Function that will be called for every Arm64 Instruction...

pinephone-emulator/src/main.rs

Lines 108 to 117 in 3655ac2

    
           // Hook Function for Code Emulation. 
        
           // Called once for each Arm64 Instruction. 
        
           fn hook_code( 
        
               _: &mut Unicorn<()>,  // Emulator 
        
               address: u64,  // Instruction Address 
        
               size: u32      // Instruction Size 
        
           ) { 
        
               // TODO: Handle special Arm64 Instructions 
        
               println!("hook_code: address={:#x}, size={:?}", address, size); 
        
           }

And this is how we call Unicorn Emulator to add the above Hook Function...

pinephone-emulator/src/main.rs

Lines 52 to 57 in 3655ac2

    
           // Add Hook for emulating each Arm64 Instruction 
        
           let _ = emu.add_code_hook( 
        
               ADDRESS,  // Begin Address 
        
               ADDRESS + arm64_code.len() as u64,  // End Address 
        
               hook_code  // Hook Function for Code Emulation 
        
           ).expect("failed to add code hook");

When we run our Rust Program, we see the Address of every Arm64 Instruction emulated (and its size)...

hook_code:
  address=0x10000,
  size=4

hook_code:
  address=0x10004,
  size=4

We might use this to emulate special Arm64 Instructions.

If we don't need to intercept every single instruction, try the Block Execution Hook...

Block Execution Hook for Arm64 Emulation

Is there something that works like a Code Execution Hook...

But doesn't stop at every single Arm64 Instruction?

Yep Unicorn Emulator supports Block Execution Hooks.

This Hook Function will be called once when executing a Block of Arm64 Instructions...

pinephone-emulator/src/main.rs

Lines 97 to 106 in 3655ac2

    
           // Hook Function for Block Emulation. 
        
           // Called once for each Basic Block of Arm64 Instructions. 
        
           fn hook_block( 
        
               _: &mut Unicorn<()>,  // Emulator 
        
               address: u64,  // Block Address 
        
               size: u32      // Block Size 
        
           ) { 
        
               // TODO: Trace the flow of emulated code 
        
               println!("hook_block: address={:#x}, size={:?}", address, size); 
        
           }

This is how we add the Block Execution Hook...

pinephone-emulator/src/main.rs

Lines 48 to 50 in 3655ac2

    
           // Add Hook for emulating each Basic Block of Arm64 Instructions 
        
           let _ = emu.add_block_hook(hook_block) 
        
               .expect("failed to add block hook");

When we run the Rust Program, we see that that the Block Size is 8...

hook_block:
  address=0x10000,
  size=8

Which means that Unicorn Emulator calls our Hook Function only once for the entire Block of 2 Arm64 Instructions.

This Block Execution Hook will be super helpful for monitoring the Execution Flow of our emulated code.

Let's talk about the Block...

What is a Block of Arm64 Instructions?

What exactly is a Block of Arm64 Instructions?

When we run this code from Apache NuttX RTOS (that handles UART Output)...

SECTION_FUNC(text, up_lowputc)
  ldr   x15, =UART0_BASE_ADDRESS
  400801f0:	580000cf 	ldr	x15, 40080208 <up_lowputc+0x18>
nuttx/arch/arm64/src/chip/a64_lowputc.S:89
  early_uart_ready x15, w2
  400801f4:	794029e2 	ldrh	w2, [x15, #20]
  400801f8:	721b005f 	tst	w2, #0x20
  400801fc:	54ffffc0 	b.eq	400801f4 <up_lowputc+0x4>  // b.none
nuttx/arch/arm64/src/chip/a64_lowputc.S:90
  early_uart_transmit x15, w0
  40080200:	390001e0 	strb	w0, [x15]
nuttx/arch/arm64/src/chip/a64_lowputc.S:91
  ret
  40080204:	d65f03c0 	ret

(Arm64 Disassembly)

(Source Code)

We observe that Unicorm Emulator treats 400801f0 to 400801fc as a Block of Arm64 Instructins...

hook_block:  address=0x400801f0, size=16
hook_code:   address=0x400801f0, size=4
hook_code:   address=0x400801f4, size=4
hook_code:   address=0x400801f4, size=4
hook_code:   address=0x400801f8, size=4
hook_code:   address=0x400801fc, size=4

hook_block:  address=0x400801f4, size=12
hook_code:   address=0x400801f4, size=4
hook_code:   address=0x400801f8, size=4
hook_code:   address=0x400801fc, size=4

hook_block:  address=0x400801f4, size=12
hook_code:   address=0x400801f4, size=4
hook_code:   address=0x400801f8, size=4
hook_code:   address=0x400801fc, size=4

(Source)

The Block ends at 400801fc because there's an Arm64 Branch Instruction b.eq.

From this we deduce that Unicorn Emulator treats a sequence of Arm64 Instructions as a Block, until it sees a Branch Instruction. (Including function calls)

Unmapped Memory in Unicorn Emulator

What happens when Unicorn Emulator tries to access memory that isn't mapped?

Unicorn Emulator will call our Memory Access Hook with mem_type set to READ_UNMAPPED...

hook_memory:
  address=0x01c28014,
  size=2,
  mem_type=READ_UNMAPPED,
  value=0x0

(Source)

The log above says that address 0x01c2 8014 is unmapped.

This is how we map the memory...

pinephone-emulator/src/main.rs

Lines 26 to 32 in cd03095

    
           // Map 16 MB at 0x0100 0000 for Memory-Mapped I/O by Allwinner A64 Peripherals 
        
           // https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/hardware/a64_memorymap.h#L33-L51 
        
           emu.mem_map( 
        
               0x0100_0000,       // Address 
        
               16 * 1024 * 1024,  // Size 
        
               Permission::READ | Permission::WRITE  // Read and Write Access 
        
           ).expect("failed to map memory mapped I/O");

(See the NuttX Memory Map)

Can we map Memory Regions during emulation?

Yep we may use a Memory Access Hook to map memory regions on the fly. (See this)

Run Apache NuttX RTOS in Unicorn Emulator

Let's run Apache NuttX RTOS in Unicorn Emulator!

We have compiled Apache NuttX RTOS for PinePhone into an Arm64 Binary Image nuttx.bin.

This is how we load the NuttX Binary Image into Unicorn...

pinephone-emulator/src/main.rs

Lines 6 to 40 in aa24d1c

    
           // Arm64 Memory Address where emulation starts 
        
           const ADDRESS: u64 = 0x4008_0000; 
        
           // Arm64 Machine Code for the above address 
        
           let arm64_code = include_bytes!("../nuttx/nuttx.bin"); 
        
           // Initialize emulator in Arm64 mode 
        
           let mut unicorn = Unicorn::new( 
        
               Arch::ARM64, 
        
               Mode::LITTLE_ENDIAN 
        
           ).expect("failed to initialize Unicorn instance"); 
        
           let emu = &mut unicorn; 
        
           // Map 128 MB Executable Memory at 0x4000 0000 for Arm64 Machine Code 
        
           // https://github.com/apache/nuttx/blob/master/arch/arm64/include/a64/chip.h#L44-L52 
        
           emu.mem_map( 
        
               0x4000_0000,        // Address 
        
               128 * 1024 * 1024,  // Size 
        
               Permission::ALL     // Read, Write and Execute Access 
        
           ).expect("failed to map code page"); 
        
           // Map 512 MB Read/Write Memory at 0x0000 0000 for 
        
           // Memory-Mapped I/O by Allwinner A64 Peripherals 
        
           // https://github.com/apache/nuttx/blob/master/arch/arm64/include/a64/chip.h#L44-L52 
        
           emu.mem_map( 
        
               0x0000_0000,        // Address 
        
               512 * 1024 * 1024,  // Size 
        
               Permission::READ | Permission::WRITE  // Read and Write Access 
        
           ).expect("failed to map memory mapped I/O"); 
        
           // Write Arm64 Machine Code to emulated Executable Memory 
        
           emu.mem_write( 
        
               ADDRESS,  
        
               arm64_code 
        
           ).expect("failed to write instructions");

In our Rust Program above, we mapped 2 Memory Regions for NuttX...

Map 128 MB Executable Memory at 0x4000 0000 for Arm64 Machine Code
Map 512 MB Read/Write Memory at 0x0000 0000 for Memory-Mapped I/O by Allwinner A64 Peripherals

This is based on the NuttX Memory Map for PinePhone.

When we run this, Unicorn Emulator loops forever. Let's find out why...

Unicorn Emulator Waits Forever for UART Controller Ready

Here's the output when we run NuttX RTOS in Unicorn Emulator...

hook_memory: address=0x01c28014, size=2, mem_type=READ, value=0x0
hook_code:   address=0x400801f8, size=4
hook_code:   address=0x400801fc, size=4
hook_block:  address=0x400801f4, size=12
hook_code:   address=0x400801f4, size=4

hook_memory: address=0x01c28014, size=2, mem_type=READ, value=0x0
hook_code:   address=0x400801f8, size=4
hook_code:   address=0x400801fc, size=4
hook_block:  address=0x400801f4, size=12
hook_code:   address=0x400801f4, size=4

hook_memory: address=0x01c28014, size=2, mem_type=READ, value=0x0
hook_code:   address=0x400801f8, size=4
hook_code:   address=0x400801fc, size=4
hook_block:  address=0x400801f4, size=12
hook_code:   address=0x400801f4, size=4
...

(Source)

The above log shows that Unicorn Emulator loops forever at address 0x4008 01f4, while reading the data from address 0x01c2 8014.

Let's check the NuttX Arm64 Code at address 0x4008 01f4...

SECTION_FUNC(text, up_lowputc)
  ldr   x15, =UART0_BASE_ADDRESS
  400801f0:	580000cf 	ldr	x15, 40080208 <up_lowputc+0x18>
nuttx/arch/arm64/src/chip/a64_lowputc.S:89
  early_uart_ready x15, w2
  400801f4:	794029e2 	ldrh	w2, [x15, #20]
  400801f8:	721b005f 	tst	w2, #0x20
  400801fc:	54ffffc0 	b.eq	400801f4 <up_lowputc+0x4>  // b.none
nuttx/arch/arm64/src/chip/a64_lowputc.S:90
  early_uart_transmit x15, w0
  40080200:	390001e0 	strb	w0, [x15]
nuttx/arch/arm64/src/chip/a64_lowputc.S:91
  ret
  40080204:	d65f03c0 	ret

(Arm64 Disassembly)

Which comes from this NuttX Source Code...

/* Wait for A64 UART to be ready to transmit
 * xb: Register that contains the UART Base Address
 * wt: Scratch register number
 */
.macro early_uart_ready xb, wt
1:
  ldrh  \wt, [\xb, #0x14]      /* UART_LSR (Line Status Register) */
  tst   \wt, #0x20             /* Check THRE (TX Holding Register Empty) */
  b.eq  1b                     /* Wait for the UART to be ready (THRE=1) */
.endm

(Source Code)

This code waits for the UART Controller to be ready (before printing UART Output), by checking the value at 0x01c2 8014. The code is explained here...

"Wait for UART Ready"

What is 0x01c2 8014?

According to the Allwinner A64 Doc...

"Wait To Transmit"

0x01c2 8014 is the UART Line Status Register (UART_LSR) at Offset 0x14.

Bit 5 needs to be set to 1 to indicate that the UART Transmit FIFO is ready.

We emulate the UART Ready Bit like so...

pinephone-emulator/src/main.rs

Lines 42 to 49 in 4d78876

    
           // Allwinner A64 UART Line Status Register (UART_LSR) at Offset 0x14. 
        
           // To indicate that the UART Transmit FIFO is ready: 
        
           // Set Bit 5 to 1. 
        
           // https://lupyuen.github.io/articles/serial#wait-to-transmit 
        
           emu.mem_write( 
        
               0x01c2_8014,  // UART Register Address 
        
               &[0b10_0000]  // UART Register Value 
        
           ).expect("failed to set UART_LSR");

And Unicorn Emulator stops looping! It continues execution to memset() (to init the BSS Section to 0)...

hook_block:  address=0x40089328, size=8
hook_memory: address=0x400b6a52, size=1, mem_type=WRITE, value=0x0
hook_block:  address=0x40089328, size=8
hook_memory: address=0x400b6a53, size=1, mem_type=WRITE, value=0x0
hook_block:  address=0x40089328, size=8
hook_memory: address=0x400b6a54, size=1, mem_type=WRITE, value=0x0
...

(Source)

But we don't see any UART Output. Let's print the UART Output...

Emulate UART Output in Unicorn Emulator

How do we print the UART Output?

According to the Allwinner A64 Doc...

"Transmit UART"

NuttX RTOS will write the UART Output to the UART Transmit Holding Register (THR) at 0x01c2 8000.

In our Memory Access Hook, let's intercept all writes to 0x01c2 8000 and dump the characters written to UART Output...

pinephone-emulator/src/main.rs

Lines 89 to 111 in aa6dd98

    
           // Hook Function for Memory Access. 
        
           // Called once for every Arm64 Memory Access. 
        
           fn hook_memory( 
        
               _: &mut Unicorn<()>,  // Emulator 
        
               mem_type: MemType,    // Read or Write Access 
        
               address: u64,  // Accessed Address 
        
               size: usize,   // Number of bytes accessed 
        
               value: i64     // Read / Write Value 
        
           ) -> bool { 
        
               // Ignore RAM access, we only intercept Memory-Mapped Input / Output 
        
               if address >= 0x4000_0000 { return true; } 
        
               println!("hook_memory: address={:#010x}, size={:?}, mem_type={:?}, value={:#x}", address, size, mem_type, value); 
        
               // If writing to UART Transmit Holding Register (THR): 
        
               // Print the output 
        
               // https://lupyuen.github.io/articles/serial#transmit-uart 
        
               if address == 0x01c2_8000 { 
        
                   println!("uart output: {:?}", value as u8 as char); 
        
               } 
        
               // Always return true, value is unused by caller 
        
               true 
        
           }

When we run this, we see a long chain of UART Output...

→ cargo run | grep uart
uart output: '-'
uart output: ' '
uart output: 'R'
uart output: 'e'
uart output: 'a'
uart output: 'd'
uart output: 'y'
...

(Source)

Which reads as...

- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize

(Similar to this)

Yep NuttX RTOS is booting on Unicorn Emulator! But Unicorn Emulator halts while booting NuttX...

Unicorn Emulator Halts in NuttX MMU

Unicorn Emulator halts with an Arm64 Exception at address 4008 0EF8...

hook_block:  address=0x40080cec, size=16
hook_code:   address=0x40080cec, size=4
hook_memory: address=0x400c3f90, size=8, mem_type=READ, value=0x0
hook_memory: address=0x400c3f98, size=8, mem_type=READ, value=0x0
hook_code:   address=0x40080cf0, size=4
hook_memory: address=0x400c3fa0, size=8, mem_type=READ, value=0x0
hook_code:   address=0x40080cf4, size=4
hook_memory: address=0x400c3f80, size=8, mem_type=READ, value=0x0
hook_memory: address=0x400c3f88, size=8, mem_type=READ, value=0x0
hook_code:   address=0x40080cf8, size=4
hook_block:  address=0x40080eb0, size=12
hook_code:   address=0x40080eb0, size=4
hook_code:   address=0x40080eb4, size=4
hook_code:   address=0x40080eb8, size=4
hook_block:  address=0x40080ebc, size=16
hook_code:   address=0x40080ebc, size=4
hook_code:   address=0x40080ec0, size=4
hook_code:   address=0x40080ec4, size=4
hook_code:   address=0x40080ec8, size=4
hook_block:  address=0x40080ecc, size=16
hook_code:   address=0x40080ecc, size=4
hook_code:   address=0x40080ed0, size=4
hook_code:   address=0x40080ed4, size=4
hook_code:   address=0x40080ed8, size=4
hook_block:  address=0x40080edc, size=12
hook_code:   address=0x40080edc, size=4
hook_code:   address=0x40080ee0, size=4
hook_code:   address=0x40080ee4, size=4
hook_block:  address=0x40080ee8, size=4
hook_code:   address=0x40080ee8, size=4
hook_block:  address=0x40080eec, size=16
hook_code:   address=0x40080eec, size=4
hook_code:   address=0x40080ef0, size=4
hook_code:   address=0x40080ef4, size=4
hook_code:   address=0x40080ef8, size=4
err=Err(EXCEPTION)

(See the Complete Log)

Unicorn Emulator halts at the NuttX MMU (EL1) code at 0x4008 0ef8...

nuttx/arch/arm64/src/common/arm64_mmu.c:544
  write_sysreg((value | SCTLR_M_BIT | SCTLR_C_BIT), sctlr_el1);
    40080ef0:	d28000a1 	mov	x1, #0x5                   	// #5
    40080ef4:	aa010000 	orr	x0, x0, x1
    40080ef8:	d5181000 	msr	sctlr_el1, x0

Why did MSR fail with an Exception?

Here's the context...

enable_mmu_el1():
nuttx/arch/arm64/src/common/arm64_mmu.c:533
  write_sysreg(MEMORY_ATTRIBUTES, mair_el1);
    40080ebc:	d2808000 	mov	x0, #0x400                 	// #1024
    40080ec0:	f2a88180 	movk	x0, #0x440c, lsl #16
    40080ec4:	f2c01fe0 	movk	x0, #0xff, lsl #32
    40080ec8:	d518a200 	msr	mair_el1, x0
nuttx/arch/arm64/src/common/arm64_mmu.c:534
  write_sysreg(get_tcr(1), tcr_el1);
    40080ecc:	d286a380 	mov	x0, #0x351c                	// #13596
    40080ed0:	f2a01000 	movk	x0, #0x80, lsl #16
    40080ed4:	f2c00020 	movk	x0, #0x1, lsl #32
    40080ed8:	d5182040 	msr	tcr_el1, x0
nuttx/arch/arm64/src/common/arm64_mmu.c:535
  write_sysreg(((uint64_t)base_xlat_table), ttbr0_el1);
    40080edc:	d00001a0 	adrp	x0, 400b6000 <g_uart1port>
    40080ee0:	91200000 	add	x0, x0, #0x800
    40080ee4:	d5182000 	msr	ttbr0_el1, x0
arm64_isb():
nuttx/arch/arm64/src/common/barriers.h:58
  __asm__ volatile ("isb" : : : "memory");
    40080ee8:	d5033fdf 	isb
enable_mmu_el1():
nuttx/arch/arm64/src/common/arm64_mmu.c:543
  value = read_sysreg(sctlr_el1);
    40080eec:	d5381000 	mrs	x0, sctlr_el1
nuttx/arch/arm64/src/common/arm64_mmu.c:544
  write_sysreg((value | SCTLR_M_BIT | SCTLR_C_BIT), sctlr_el1);
    40080ef0:	d28000a1 	mov	x1, #0x5                   	// #5
    40080ef4:	aa010000 	orr	x0, x0, x1
    40080ef8:	d5181000 	msr	sctlr_el1, x0
arm64_isb():
nuttx/arch/arm64/src/common/barriers.h:58
    40080efc:	d5033fdf 	isb

Which comes from this NuttX Source Code: arm64_mmu.c

// Enable the MMU and data cache:
// Read from System Control Register EL1
value = read_sysreg(sctlr_el1);

// Write to System Control Register EL1
write_sysreg(  // Write to System Register...
  value | SCTLR_M_BIT | SCTLR_C_BIT,  // Enable Address Translation and Caching
  sctlr_el1    // System Control Register EL1
);

Let's dump the Arm64 Exception...

Dump the Arm64 Exception

To find out the cause of the Arm64 Exception, let's dump the Exception Syndrome Register (ESR).

But this won't work...

pinephone-emulator/src/main.rs

Lines 86 to 91 in 1cbfa48

    
           println!("err={:?}", err); 
        
           println!("CP_REG={:?}", emu.reg_read(RegisterARM64::CP_REG)); 
        
           println!("ESR_EL0={:?}", emu.reg_read(RegisterARM64::ESR_EL0)); 
        
           println!("ESR_EL1={:?}", emu.reg_read(RegisterARM64::ESR_EL1)); 
        
           println!("ESR_EL2={:?}", emu.reg_read(RegisterARM64::ESR_EL2)); 
        
           println!("ESR_EL3={:?}", emu.reg_read(RegisterARM64::ESR_EL3));

Because ESR_EL is no longer supported and CP_REG can't be read in Rust...

err=Err(EXCEPTION)
CP_REG=Err(ARG)
ESR_EL0=Ok(0)
ESR_EL1=Ok(0)
ESR_EL2=Ok(0)
ESR_EL3=Ok(0)

(See the Complete Log)

CP_REG can't be read in Rust because Unicorn needs a pointer to uc_arm64_cp_reg...

static uc_err reg_read(CPUARMState *env, unsigned int regid, void *value) {
  ...
  case UC_ARM64_REG_CP_REG:
      ret = read_cp_reg(env, (uc_arm64_cp_reg *)value);
      break;

(Source)

Which isn't supported by the Rust Bindings.

(Works in Python though)

So instead we set a breakpoint at arm64_reg_read() (pic below) in...

.cargo/registry/src/github.com-1ecc6299db9ec823/unicorn-engine-2.0.1/qemu/target/arm/unicorn_aarch64.c

(arm64_reg_read() calls reg_read() in unicorn_aarch64.c)

Which shows the Exception as...

env.exception = {
  syndrome: 0x8600 003f, 
  fsr: 5, 
  vaddress: 0x400c 3fff,
  target_el: 1
}

Let's study the Arm64 Exception...

Arm64 MMU Exception

Earlier we saw this Arm64 Exception in Unicorn Emulator...

env.exception = {
  syndrome: 0x8600 003f, 
  fsr: 5, 
  vaddress: 0x400c 3fff,
  target_el: 1
}

TODO: What is address 0x400c 3fff?

What is Syndrome 0x8600 003f?

Bits 26-31 of Syndrome = 0b100001, which means...

0b100001: Instruction Abort taken without a change in Exception level.

Used for MMU faults generated by instruction accesses and synchronous External aborts, including synchronous parity or ECC errors. Not used for debug-related exceptions.

(Source)

What is FSR 5?

FSR 5 means...

0b00101: Translation Fault (in) Section

(Source)

Why the MMU Fault?

Unicorn Emulator triggers the exception when NuttX writes to SCTLR_EL1...

  /* Enable the MMU and data cache */
  value = read_sysreg(sctlr_el1);
  write_sysreg((value | SCTLR_M_BIT | SCTLR_C_BIT), sctlr_el1);

(Source)

The above code sets these flags in SCTLR_EL1 (System Control Register EL1)...

SCTLR_M_BIT (Bit 0): Enable Address Translation for EL0 and EL1 Stage 1
SCTLR_C_BIT (Bit 2): Enable Caching for EL0 and EL1 Stage 1

(More about SCTLR_EL1)

TODO: Why did the Address Translation (or Caching) fail?

TODO: Should we skip the MMU Update to SCTLR_EL1? Since we don't use MMU?

Debug the Unicorn Emulator

To troubleshoot the Arm64 MMU Exception...

Can we use a debugger to step through Unicorn Emulator?

Yes but it gets messy.

To trace the exception in the debugger. Look for...

$HOME/.cargo/registry/src/github.com-1ecc6299db9ec823/unicorn-engine-2.0.1/qemu/target/arm/translate-a64.c

Set a breakpoint in aarch64_tr_translate_insn()

Which calls disas_b_exc_sys()
Which calls disas_system()
Which calls handle_sys() to handle system instructions

To inspect the Emulator Settings, set a breakpoint at cpu_aarch64_init() in...

$HOME/.cargo/registry/src/github.com-1ecc6299db9ec823/unicorn-engine-2.0.1/qemu/target/arm/cpu64.c

TODO: Check that the CPU Setting is correct for PinePhone. (CPU Model should be Cortex-A53)

Map Address to Function with ELF File

Read the article...

"(Clickable) Call Graph for Apache NuttX Real-Time Operating System"

Our Block Execution Hook now prints the Function Name and the Filename...

hook_block:  
  address=0x40080eb0, 
  size=12, 
  setup_page_tables, 
  arch/arm64/src/common/arm64_mmu.c:516:25

hook_block:  
  address=0x40080eec, 
  size=16, 
  enable_mmu_el1, 
  arch/arm64/src/common/arm64_mmu.c:543:11

err=Err(EXCEPTION)

(Source)

Our Hook Function looks up the Address in the DWARF Debug Symbols of the NuttX ELF File.

This is explained here...

"Map Address to Function with ELF File"

Call Graph for Apache NuttX RTOS

To troubleshoot the Apache NuttX MMU Fault on Unicorn Emulator, we auto-generated this Call Graph...

(To see the NuttX Source Code: Right-click the Node and select "Open Link")

  flowchart TD
  START --> arm64_head
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L104" "arch/arm64/src/common/arm64_head.S " _blank
  a64_lowputc --> arm64_head
  click a64_lowputc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_lowputc.S#L58" "arch/arm64/src/a64/a64_lowputc.S " _blank
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L177" "arch/arm64/src/common/arm64_head.S " _blank
  a64_lowputc --> arm64_head
  click a64_lowputc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_lowputc.S#L87" "arch/arm64/src/a64/a64_lowputc.S " _blank
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  a64_lowputc --> arm64_head
  click a64_lowputc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_lowputc.S#L87" "arch/arm64/src/a64/a64_lowputc.S " _blank
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  a64_lowputc --> arm64_head
  click a64_lowputc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_lowputc.S#L87" "arch/arm64/src/a64/a64_lowputc.S " _blank
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  a64_lowputc --> arm64_head
  click a64_lowputc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_lowputc.S#L87" "arch/arm64/src/a64/a64_lowputc.S " _blank
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  a64_lowputc --> arm64_head
  click a64_lowputc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_lowputc.S#L87" "arch/arm64/src/a64/a64_lowputc.S " _blank
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  a64_lowputc --> arm64_head
  click a64_lowputc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_lowputc.S#L87" "arch/arm64/src/a64/a64_lowputc.S " _blank
  arm64_head --> a64_lowputc
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  arm64_head --> arm64_boot_el1_init
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  arm64_boot_el1_init --> arm64_isb
  click arm64_boot_el1_init href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_boot.c#L137" "arch/arm64/src/common/arm64_boot.c " _blank
  arm64_isb --> arm64_boot_el1_init
  click arm64_isb href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/barriers.h#L57" "arch/arm64/src/common/barriers.h " _blank
  arm64_boot_el1_init --> arm64_isb
  click arm64_boot_el1_init href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_boot.c#L145" "arch/arm64/src/common/arm64_boot.c " _blank
  arm64_isb --> arm64_boot_el1_init
  click arm64_isb href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/barriers.h#L57" "arch/arm64/src/common/barriers.h " _blank
  arm64_head --> arm64_boot_primary_c_routine
  click arm64_head href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_head.S#L298" "arch/arm64/src/common/arm64_head.S " _blank
  arm64_boot_primary_c_routine --> memset
  click arm64_boot_primary_c_routine href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_boot.c#L180" "arch/arm64/src/common/arm64_boot.c " _blank
  memset --> arm64_boot_primary_c_routine
  click memset href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/libs/libc/string/lib_memset.c#L168" "libs/libc/string/lib_memset.c " _blank
  arm64_boot_primary_c_routine --> arm64_chip_boot
  click arm64_boot_primary_c_routine href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_boot.c#L181" "arch/arm64/src/common/arm64_boot.c " _blank
  arm64_chip_boot --> arm64_mmu_init
  click arm64_chip_boot href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/a64/a64_boot.c#L81" "arch/arm64/src/a64/a64_boot.c " _blank
  arm64_mmu_init --> setup_page_tables
  click arm64_mmu_init href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L583" "arch/arm64/src/common/arm64_mmu.c " _blank
  setup_page_tables --> init_xlat_tables
  click setup_page_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L490" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> calculate_pte_index
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L417" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> init_xlat_tables
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L246" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> pte_desc_type
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  pte_desc_type --> new_prealloc_table
  click pte_desc_type href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L234" "arch/arm64/src/common/arm64_mmu.c " _blank
  new_prealloc_table --> init_xlat_tables
  click new_prealloc_table href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L378" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> calculate_pte_index
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L437" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> pte_desc_type
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L246" "arch/arm64/src/common/arm64_mmu.c " _blank
  pte_desc_type --> calculate_pte_index
  click pte_desc_type href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L234" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> init_xlat_tables
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L247" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  set_pte_block_desc --> init_xlat_tables
  click set_pte_block_desc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L293" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> calculate_pte_index
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L456" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> init_xlat_tables
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L246" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> pte_desc_type
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  pte_desc_type --> init_xlat_tables
  click pte_desc_type href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L234" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> calculate_pte_index
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L472" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> pte_desc_type
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L246" "arch/arm64/src/common/arm64_mmu.c " _blank
  pte_desc_type --> calculate_pte_index
  click pte_desc_type href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L234" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> init_xlat_tables
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L247" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> calculate_pte_index
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L456" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> pte_desc_type
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> calculate_pte_index
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L472" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> pte_desc_type
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L246" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> pte_desc_type
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  calculate_pte_index --> pte_desc_type
  click calculate_pte_index href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L246" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> set_pte_block_desc
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L447" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> setup_page_tables
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L456" "arch/arm64/src/common/arm64_mmu.c " _blank
  pte_desc_type --> new_prealloc_table
  click pte_desc_type href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L234" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> setup_page_tables
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L456" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> new_prealloc_table
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L472" "arch/arm64/src/common/arm64_mmu.c " _blank
  new_prealloc_table --> split_pte_block_desc
  click new_prealloc_table href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L378" "arch/arm64/src/common/arm64_mmu.c " _blank
  split_pte_block_desc --> set_pte_table_desc
  click split_pte_block_desc href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L401" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> setup_page_tables
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L456" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> setup_page_tables
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L456" "arch/arm64/src/common/arm64_mmu.c " _blank
  init_xlat_tables --> setup_page_tables
  click init_xlat_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L456" "arch/arm64/src/common/arm64_mmu.c " _blank
  setup_page_tables --> enable_mmu_el1
  click setup_page_tables href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L515" "arch/arm64/src/common/arm64_mmu.c " _blank
  enable_mmu_el1 --> arm64_isb
  click enable_mmu_el1 href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L532" "arch/arm64/src/common/arm64_mmu.c " _blank
  arm64_isb --> enable_mmu_el1
  click arm64_isb href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/barriers.h#L57" "arch/arm64/src/common/barriers.h " _blank
  enable_mmu_el1 --> ***_HALT_***
  click enable_mmu_el1 href "https://github.com/apache/nuttx/blob/0f20888a0ececc5dc7419d57a01ac508ac3ace5b/arch/arm64/src/common/arm64_mmu.c#L542" "arch/arm64/src/common/arm64_mmu.c " _blank

We generated the Call Graph with this command...

cargo run | grep call_graph | cut -c 12-

(cut command removes columns 1 to 11)

Which produces this Mermaid Flowchart...

→ cargo run | grep call_graph | cut -c 12- 
  flowchart TD
  arm64_boot_el1_init --> arm64_isb
  click arm64_boot_el1_init href "https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_boot.c#L137" "arch/arm64/src/common/arm64_boot.c "
  arm64_isb --> arm64_boot_el1_init
  click arm64_isb href "https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/barriers.h#L57" "arch/arm64/src/common/barriers.h "
  arm64_boot_el1_init --> arm64_isb
  click arm64_boot_el1_init href "https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_boot.c#L145" "arch/arm64/src/common/arm64_boot.c "
  arm64_isb --> arm64_boot_el1_init
  ...
  setup_page_tables --> enable_mmu_el1
  click setup_page_tables href "https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_mmu.c#L515" "arch/arm64/src/common/arm64_mmu.c "
  enable_mmu_el1 --> arm64_isb
  click enable_mmu_el1 href "https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_mmu.c#L532" "arch/arm64/src/common/arm64_mmu.c "
  arm64_isb --> enable_mmu_el1
  click arm64_isb href "https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/barriers.h#L57" "arch/arm64/src/common/barriers.h "
  enable_mmu_el1 --> ***_HALT_***
  click enable_mmu_el1 href "https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_mmu.c#L542" "arch/arm64/src/common/arm64_mmu.c "

(Source)

The Call Graph is generated by our Block Execution Hook like so...

pinephone-emulator/src/main.rs

Lines 130 to 159 in b23c1d2

    
           /// Hook Function for Block Emulation. 
        
           /// Called once for each Basic Block of Arm64 Instructions. 
        
           fn hook_block( 
        
               _: &mut Unicorn<()>,  // Emulator 
        
               address: u64,  // Block Address 
        
               size: u32      // Block Size 
        
           ) { 
        
               // Ignore the memset() loop. TODO: Read the ELF Symbol Table to get address of memset(). 
        
               if address >= 0x4008_9328 && address <= 0x4008_933c { return; } 
        
               print!("hook_block:  address={:#010x}, size={:02}", address, size); 
        
               // Print the Function Name 
        
               let function = map_address_to_function(address); 
        
               if let Some(ref name) = function { 
        
                   print!(", {}", name); 
        
               } 
        
               // Print the Source Filename 
        
               let loc = map_address_to_location(address); 
        
               if let Some((ref file, line, col)) = loc { 
        
                   let file = file.clone().unwrap_or("".to_string()); 
        
                   let line = line.unwrap_or(0); 
        
                   let col = col.unwrap_or(0); 
        
                   print!(", {}:{}:{}", file, line, col); 
        
               } 
        
               println!(); 
        
               // Print the Call Graph 
        
               call_graph(address, size, function, loc); 
        
           }

call_graph prints the Call Graph by looking up the Block Address in the ELF Context...

pinephone-emulator/src/main.rs

Lines 224 to 265 in b23c1d2

    
           /// Print the Mermaid Call Graph for this Function Call: 
        
           /// cargo run | grep call_graph | cut -c 12- 
        
           fn call_graph( 
        
               _address: u64,  // Code Address 
        
               _size: u32,     // Size of Code Block 
        
               function: Option<String>,  // Function Name 
        
               loc: Option<(        // Source Location 
        
                   Option<String>,  // Filename 
        
                   Option<u32>,     // Line 
        
                   Option<u32>      // Column 
        
               )> 
        
           ) { 
        
               // Get the Function Name 
        
               let Some(fname) = function 
        
                   else { return; }; 
        
               // Unsafe because `LAST_FNAME` is a Static Mutable 
        
               unsafe { 
        
                   // Skip if we are still in the same Function 
        
                   static mut LAST_FNAME: String = String::new(); 
        
                   static mut LAST_LOC: Option<(Option<String>, Option<u32>, Option<u32>)> = None; 
        
                   if fname.eq(&LAST_FNAME) { return; } 
        
                   // If this function has not been shown too often... 
        
                   if can_show_function(&fname) { 
        
                       // Print the Call Flow 
        
                       if LAST_FNAME.is_empty() {             
        
                           println!("call_graph:  flowchart TD");  // Top-Down Flowchart 
        
                       } else { 
        
                           // URL looks like https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_mmu.c#L541 
        
                           let (file, line, _) = LAST_LOC.clone().unwrap_or((Some("".to_string()), None, None)); 
        
                           let file = file.unwrap_or("".to_string()); 
        
                           let line = line.unwrap_or(1) - 1; 
        
                           let url = format!("https://github.com/apache/nuttx/blob/master/{file}#L{line}"); 
        
                           println!("call_graph:  {LAST_FNAME} --> {fname}"); 
        
                           println!("call_graph:  click {LAST_FNAME} href \"{url}\" \"{file} \""); 
        
                       } 
        
                   } 
        
                   LAST_FNAME = fname; 
        
                   LAST_LOC = loc; 
        
               } 
        
           }

We map the Block Address to Function Name and Source File in map_address_to_function and map_address_to_location...

pinephone-emulator/src/main.rs

Lines 175 to 222 in b23c1d2

    
           /// Map the Arm64 Code Address to the Function Name by looking up the ELF Context 
        
           fn map_address_to_function( 
        
               address: u64       // Code Address 
        
           ) -> Option<String> {  // Function Name 
        
               // Lookup the Arm64 Code Address in the ELF Context 
        
               let context = ELF_CONTEXT.context.borrow(); 
        
               let mut frames = context.find_frames(address) 
        
                   .expect("failed to find frames"); 
        
               // Return the Function Name 
        
               if let Some(frame) = frames.next().unwrap() { 
        
                   if let Some(func) = frame.function { 
        
                       if let Ok(name) = func.raw_name() { 
        
                           let s = String::from(name); 
        
                           return Some(s); 
        
                       } 
        
                   }     
        
               } 
        
               None 
        
           } 
        
           /// Map the Arm64 Code Address to the Source Filename, Line and Column 
        
           fn map_address_to_location( 
        
               address: u64     // Code Address 
        
           ) -> Option<(        // Returns... 
        
               Option<String>,  // Filename 
        
               Option<u32>,     // Line 
        
               Option<u32>      // Column 
        
           )> { 
        
               // Lookup the Arm64 Code Address in the ELF Context 
        
               let context = ELF_CONTEXT.context.borrow(); 
        
               let loc = context.find_location(address) 
        
                   .expect("failed to find location"); 
        
               // Return the Filename, Line and Column 
        
               if let Some(loc) = loc { 
        
                   if let Some(file) = loc.file { 
        
                       let s = String::from(file) 
        
                           .replace("/private/tmp/nuttx/nuttx/", "") 
        
                           .replace("arch/arm64/src/chip", "arch/arm64/src/a64");  // TODO: Handle other chips 
        
                       Some((Some(s), loc.line, loc.column)) 
        
                   } else { 
        
                       Some((None, loc.line, loc.column)) 
        
                   } 
        
               } else { 
        
                   None 
        
               } 
        
           }

ELF_CONTEXT is explained here...

"(Clickable) Call Graph for Apache NuttX Real-Time Operating System"

Other Emulators

What about emulating popular operating systems: Linux / macOS / Windows / Android?

Check out the Qiling Binary Emulation Framework...

qilingframework/qiling

How about other hardware platforms: STM32 Blue Pill and ESP32?

Check out QEMU...

TODO

TODO: Emulate Input Interupts from UART Controller

TODO: Emulate Apache NuttX NSH Shell with UART Controller

TODO: Select Arm Cortex-A53 as CPU

TODO: Emulate Multiple CPUs

TODO: Emulate Arm64 Memory Protection

TODO: Emulate Arm64 Generic Interrupt Controller version 2

TODO: Read the Symbol Table in NuttX ELF File to match the addresses received by Block Execution Hook

TODO: Emulate PinePhone's Allwinner A64 Display Engine. How to render the emulated graphics: Use Web Browser + WebAssembly + Unicorn.js? Will framebuffer emulation be slow?

Name		Name	Last commit message	Last commit date
Latest commit History 161 Commits
.github		.github
nuttx		nuttx
src		src
.gitignore		.gitignore
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE		LICENSE
README.md		README.md

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Repository files navigation

Emulate PinePhone with Unicorn Emulator

Emulate Arm64 Machine Code

Memory Access Hook for Arm64 Emulation

Code Execution Hook for Arm64 Emulation

Block Execution Hook for Arm64 Emulation

What is a Block of Arm64 Instructions?

Unmapped Memory in Unicorn Emulator

Run Apache NuttX RTOS in Unicorn Emulator

Unicorn Emulator Waits Forever for UART Controller Ready

Emulate UART Output in Unicorn Emulator

Unicorn Emulator Halts in NuttX MMU

Dump the Arm64 Exception

Arm64 MMU Exception

Debug the Unicorn Emulator

Map Address to Function with ELF File

Call Graph for Apache NuttX RTOS

Other Emulators

TODO

About

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Languages

	0xab, 0x05, 0x00, 0xb8, // str w11, [x13], #0
	0xaf, 0x05, 0x40, 0x38, // ldrb w15, [x13], #0

	use unicorn_engine::{Unicorn, RegisterARM64};
	use unicorn_engine::unicorn_const::{Arch, Mode, Permission};

	fn main() {
	// Arm64 Code
	let arm64_code: Vec<u8> = vec![
	0xab, 0x05, 0x00, 0xb8, // str w11, [x13], #0
	0xaf, 0x05, 0x40, 0x38, // ldrb w15, [x13], #0
	];

	// Initialize emulator in ARM64 mode
	let mut unicorn = Unicorn::new(
	Arch::ARM64,
	Mode::LITTLE_ENDIAN
	).expect("failed to initialize Unicorn instance");
	let emu = &mut unicorn;

	// memory address where emulation starts
	const ADDRESS: u64 = 0x10000;

	// map 2MB memory for this emulation
	emu.mem_map(
	ADDRESS,
	2 * 1024 * 1024,
	Permission::ALL
	).expect("failed to map code page");

	// write machine code to be emulated to memory
	emu.mem_write(
	ADDRESS,
	&arm64_code
	).expect("failed to write instructions");

	// Register Values
	const X11: u64 = 0x12345678; // X11 register
	const X13: u64 = 0x10000 + 0x8; // X13 register
	const X15: u64 = 0x33; // X15 register

	// initialize machine registers
	emu.reg_write(RegisterARM64::X11, X11)
	.expect("failed to set X11");
	emu.reg_write(RegisterARM64::X13, X13)
	.expect("failed to set X13");
	emu.reg_write(RegisterARM64::X15, X15)
	.expect("failed to set X15");

	let _ = emu.emu_start(
	ADDRESS,
	ADDRESS + arm64_code.len() as u64,
	0, // Previously: 10 * SECOND_SCALE,
	0 // Previously: 1000
	);

	assert_eq!(emu.reg_read(RegisterARM64::X15), Ok(0x78));
	}

	// Hook Function for Memory Access.
	// Called once for every Arm64 Memory Access.
	fn hook_memory(
	_: &mut Unicorn<()>, // Emulator
	mem_type: MemType, // Read or Write Access
	address: u64, // Accessed Address
	size: usize, // Number of bytes accessed
	value: i64 // Read / Write Value
	) -> bool {
	// TODO: Simulate Memory-Mapped Input/Output (UART Controller)
	println!("hook_memory: mem_type={:?}, address={:#x}, size={:?}, value={:#x}", mem_type, address, size, value);
	true
	}

	// Add Hook for Arm64 Memory Access
	let _ = emu.add_mem_hook(
	HookType::MEM_ALL,
	0,
	u64::MAX,
	hook_memory
	).expect("failed to add memory hook");

	// Emulate machine code in infinite time (last param = 0),
	// or when all code has completed
	let _ = emu.emu_start(
	ADDRESS,
	ADDRESS + arm64_code.len() as u64,
	0, // Previously: 10 * SECOND_SCALE,
	0 // Previously: 1000
	);

	// Hook Function for Code Emulation.
	// Called once for each Arm64 Instruction.
	fn hook_code(
	_: &mut Unicorn<()>, // Emulator
	address: u64, // Instruction Address
	size: u32 // Instruction Size
	) {
	// TODO: Handle special Arm64 Instructions
	println!("hook_code: address={:#x}, size={:?}", address, size);
	}

	// Add Hook for emulating each Arm64 Instruction
	let _ = emu.add_code_hook(
	ADDRESS, // Begin Address
	ADDRESS + arm64_code.len() as u64, // End Address
	hook_code // Hook Function for Code Emulation
	).expect("failed to add code hook");

	// Hook Function for Block Emulation.
	// Called once for each Basic Block of Arm64 Instructions.
	fn hook_block(
	_: &mut Unicorn<()>, // Emulator
	address: u64, // Block Address
	size: u32 // Block Size
	) {
	// TODO: Trace the flow of emulated code
	println!("hook_block: address={:#x}, size={:?}", address, size);
	}

	// Add Hook for emulating each Basic Block of Arm64 Instructions
	let _ = emu.add_block_hook(hook_block)
	.expect("failed to add block hook");

	// Map 16 MB at 0x0100 0000 for Memory-Mapped I/O by Allwinner A64 Peripherals
	// https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/hardware/a64_memorymap.h#L33-L51
	emu.mem_map(
	0x0100_0000, // Address
	16 * 1024 * 1024, // Size
	Permission::READ \| Permission::WRITE // Read and Write Access
	).expect("failed to map memory mapped I/O");

	// Arm64 Memory Address where emulation starts
	const ADDRESS: u64 = 0x4008_0000;

	// Arm64 Machine Code for the above address
	let arm64_code = include_bytes!("../nuttx/nuttx.bin");

	// Initialize emulator in Arm64 mode
	let mut unicorn = Unicorn::new(
	Arch::ARM64,
	Mode::LITTLE_ENDIAN
	).expect("failed to initialize Unicorn instance");
	let emu = &mut unicorn;

	// Map 128 MB Executable Memory at 0x4000 0000 for Arm64 Machine Code
	// https://github.com/apache/nuttx/blob/master/arch/arm64/include/a64/chip.h#L44-L52
	emu.mem_map(
	0x4000_0000, // Address
	128 * 1024 * 1024, // Size
	Permission::ALL // Read, Write and Execute Access
	).expect("failed to map code page");

	// Map 512 MB Read/Write Memory at 0x0000 0000 for
	// Memory-Mapped I/O by Allwinner A64 Peripherals
	// https://github.com/apache/nuttx/blob/master/arch/arm64/include/a64/chip.h#L44-L52
	emu.mem_map(
	0x0000_0000, // Address
	512 * 1024 * 1024, // Size
	Permission::READ \| Permission::WRITE // Read and Write Access
	).expect("failed to map memory mapped I/O");

	// Write Arm64 Machine Code to emulated Executable Memory
	emu.mem_write(
	ADDRESS,
	arm64_code
	).expect("failed to write instructions");

	// Allwinner A64 UART Line Status Register (UART_LSR) at Offset 0x14.
	// To indicate that the UART Transmit FIFO is ready:
	// Set Bit 5 to 1.
	// https://lupyuen.github.io/articles/serial#wait-to-transmit
	emu.mem_write(
	0x01c2_8014, // UART Register Address
	&[0b10_0000] // UART Register Value
	).expect("failed to set UART_LSR");

	println!("err={:?}", err);
	println!("CP_REG={:?}", emu.reg_read(RegisterARM64::CP_REG));
	println!("ESR_EL0={:?}", emu.reg_read(RegisterARM64::ESR_EL0));
	println!("ESR_EL1={:?}", emu.reg_read(RegisterARM64::ESR_EL1));
	println!("ESR_EL2={:?}", emu.reg_read(RegisterARM64::ESR_EL2));
	println!("ESR_EL3={:?}", emu.reg_read(RegisterARM64::ESR_EL3));

	/// Hook Function for Block Emulation.
	/// Called once for each Basic Block of Arm64 Instructions.
	fn hook_block(
	_: &mut Unicorn<()>, // Emulator
	address: u64, // Block Address
	size: u32 // Block Size
	) {
	// Ignore the memset() loop. TODO: Read the ELF Symbol Table to get address of memset().
	if address >= 0x4008_9328 && address <= 0x4008_933c { return; }
	print!("hook_block: address={:#010x}, size={:02}", address, size);

	// Print the Function Name
	let function = map_address_to_function(address);
	if let Some(ref name) = function {
	print!(", {}", name);
	}

	// Print the Source Filename
	let loc = map_address_to_location(address);
	if let Some((ref file, line, col)) = loc {
	let file = file.clone().unwrap_or("".to_string());
	let line = line.unwrap_or(0);
	let col = col.unwrap_or(0);
	print!(", {}:{}:{}", file, line, col);
	}
	println!();

	// Print the Call Graph
	call_graph(address, size, function, loc);
	}

	/// Print the Mermaid Call Graph for this Function Call:
	/// cargo run \| grep call_graph \| cut -c 12-
	fn call_graph(
	_address: u64, // Code Address
	_size: u32, // Size of Code Block
	function: Option<String>, // Function Name
	loc: Option<( // Source Location
	Option<String>, // Filename
	Option<u32>, // Line
	Option<u32> // Column
	)>
	) {
	// Get the Function Name
	let Some(fname) = function
	else { return; };

	// Unsafe because `LAST_FNAME` is a Static Mutable
	unsafe {
	// Skip if we are still in the same Function
	static mut LAST_FNAME: String = String::new();
	static mut LAST_LOC: Option<(Option<String>, Option<u32>, Option<u32>)> = None;
	if fname.eq(&LAST_FNAME) { return; }

	// If this function has not been shown too often...
	if can_show_function(&fname) {
	// Print the Call Flow
	if LAST_FNAME.is_empty() {
	println!("call_graph: flowchart TD"); // Top-Down Flowchart
	} else {
	// URL looks like https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_mmu.c#L541
	let (file, line, _) = LAST_LOC.clone().unwrap_or((Some("".to_string()), None, None));
	let file = file.unwrap_or("".to_string());
	let line = line.unwrap_or(1) - 1;
	let url = format!("https://github.com/apache/nuttx/blob/master/{file}#L{line}");
	println!("call_graph: {LAST_FNAME} --> {fname}");
	println!("call_graph: click {LAST_FNAME} href \"{url}\" \"{file} \"");
	}
	}
	LAST_FNAME = fname;
	LAST_LOC = loc;
	}
	}

	/// Map the Arm64 Code Address to the Function Name by looking up the ELF Context
	fn map_address_to_function(
	address: u64 // Code Address
	) -> Option<String> { // Function Name
	// Lookup the Arm64 Code Address in the ELF Context
	let context = ELF_CONTEXT.context.borrow();
	let mut frames = context.find_frames(address)
	.expect("failed to find frames");

	// Return the Function Name
	if let Some(frame) = frames.next().unwrap() {
	if let Some(func) = frame.function {
	if let Ok(name) = func.raw_name() {
	let s = String::from(name);
	return Some(s);
	}
	}
	}
	None
	}

	/// Map the Arm64 Code Address to the Source Filename, Line and Column
	fn map_address_to_location(
	address: u64 // Code Address
	) -> Option<( // Returns...
	Option<String>, // Filename
	Option<u32>, // Line
	Option<u32> // Column
	)> {
	// Lookup the Arm64 Code Address in the ELF Context
	let context = ELF_CONTEXT.context.borrow();
	let loc = context.find_location(address)
	.expect("failed to find location");

	// Return the Filename, Line and Column
	if let Some(loc) = loc {
	if let Some(file) = loc.file {
	let s = String::from(file)
	.replace("/private/tmp/nuttx/nuttx/", "")
	.replace("arch/arm64/src/chip", "arch/arm64/src/a64"); // TODO: Handle other chips
	Some((Some(s), loc.line, loc.column))
	} else {
	Some((None, loc.line, loc.column))
	}
	} else {
	None
	}
	}

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lupyuen/pinephone-emulator

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Emulate PinePhone with Unicorn Emulator

Emulate Arm64 Machine Code

Memory Access Hook for Arm64 Emulation

Code Execution Hook for Arm64 Emulation

Block Execution Hook for Arm64 Emulation

What is a Block of Arm64 Instructions?

Unmapped Memory in Unicorn Emulator

Run Apache NuttX RTOS in Unicorn Emulator

Unicorn Emulator Waits Forever for UART Controller Ready

Emulate UART Output in Unicorn Emulator

Unicorn Emulator Halts in NuttX MMU

Dump the Arm64 Exception

Arm64 MMU Exception

Debug the Unicorn Emulator

Map Address to Function with ELF File

Call Graph for Apache NuttX RTOS

Other Emulators

TODO

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