Remove ROM from platform

ceno_emul/src/lib.rs

@@ -4,7 +4,7 @@ mod addr;
 pub use addr::*;
 
 mod platform;
-pub use platform::{CENO_PLATFORM, Platform};
+pub use platform::{CENO_PLATFORM, MOCK_BASE, MOCK_ENTRY_POINT, Platform};
 
 mod tracer;
 pub use tracer::{Change, MemOp, ReadOp, StepRecord, Tracer, WriteOp};

ceno_emul/src/platform.rs

@@ -9,7 +9,6 @@ use crate::addr::{Addr, RegIdx};
 /// - codes of environment calls.
 #[derive(Clone, Debug)]
 pub struct Platform {
-    pub rom: Range<Addr>,
     pub prog_data: BTreeSet<Addr>,
     pub stack: Range<Addr>,
     pub heap: Range<Addr>,
@@ -20,7 +19,6 @@ pub struct Platform {
 }
 
 pub const CENO_PLATFORM: Platform = Platform {
-    rom: 0x2000_0000..0x3000_0000,
     prog_data: BTreeSet::new(),
     stack: 0xB0000000..0xC0000000,
     heap: 0x8000_0000..0xFFFF_0000,
@@ -29,13 +27,11 @@ pub const CENO_PLATFORM: Platform = Platform {
     unsafe_ecall_nop: false,
 };
 
+pub const MOCK_ENTRY_POINT: Addr = 0x2000_0000;
+pub const MOCK_BASE: Addr = 0x2000_0000;
+
 impl Platform {
     // Virtual memory layout.
-
-    pub fn is_rom(&self, addr: Addr) -> bool {
-        self.rom.contains(&addr)
-    }
-
     pub fn is_prog_data(&self, addr: Addr) -> bool {
         self.prog_data.contains(&(addr & !0x3))
     }
@@ -63,14 +59,7 @@ impl Platform {
         (vma >> 8) as RegIdx
     }
 
-    // Startup.
-
-    pub const fn pc_base(&self) -> Addr {
-        self.rom.start
-    }
-
     // Permissions.
-
     pub fn can_read(&self, addr: Addr) -> bool {
         self.can_write(addr)
     }
@@ -110,22 +99,16 @@ impl Platform {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{VMState, WORD_SIZE};
+    use crate::VMState;
 
     #[test]
     fn test_no_overlap() {
         let p = CENO_PLATFORM;
-        // ROM and RAM do not overlap.
-        assert!(!p.is_rom(p.heap.start));
-        assert!(!p.is_rom(p.heap.end - WORD_SIZE as Addr));
-        assert!(!p.is_ram(p.rom.start));
-        assert!(!p.is_ram(p.rom.end - WORD_SIZE as Addr));
-        // Registers do not overlap with ROM or RAM.
+        // Registers do not overlap with RAM.
         for reg in [
             Platform::register_vma(0),
             Platform::register_vma(VMState::REG_COUNT - 1),
         ] {
-            assert!(!p.is_rom(reg));
             assert!(!p.is_ram(reg));
         }
     }

ceno_emul/tests/test_vm_trace.rs

@@ -6,15 +6,15 @@ use std::{
 };
 
 use ceno_emul::{
-    CENO_PLATFORM, Cycle, EmuContext, InsnKind, Instruction, Platform, Program, StepRecord, Tracer,
-    VMState, WordAddr, encode_rv32,
+    CENO_PLATFORM, Cycle, EmuContext, InsnKind, Instruction, MOCK_BASE, MOCK_ENTRY_POINT, Platform,
+    Program, StepRecord, Tracer, VMState, WordAddr, encode_rv32,
 };
 
 #[test]
 fn test_vm_trace() -> Result<()> {
     let program = Program::new(
-        CENO_PLATFORM.pc_base(),
-        CENO_PLATFORM.pc_base(),
+        MOCK_ENTRY_POINT,
+        MOCK_BASE,
         program_fibonacci_20(),
         Default::default(),
     );
@@ -40,12 +40,7 @@ fn test_vm_trace() -> Result<()> {
 
 #[test]
 fn test_empty_program() -> Result<()> {
-    let empty_program = Program::new(
-        CENO_PLATFORM.pc_base(),
-        CENO_PLATFORM.pc_base(),
-        vec![],
-        BTreeMap::new(),
-    );
+    let empty_program = Program::new(MOCK_ENTRY_POINT, MOCK_BASE, vec![], BTreeMap::new());
     let mut ctx = VMState::new(CENO_PLATFORM, Arc::new(empty_program));
     let res = run(&mut ctx);
     assert!(matches!(res, Err(e) if e.to_string().contains("InstructionAccessFault")),);

ceno_zkvm/examples/riscv_opcodes.rs

@@ -13,8 +13,8 @@ use clap::Parser;
 use ceno_emul::{
     CENO_PLATFORM, EmuContext,
     InsnKind::{ADD, ADDI, BLTU, ECALL, LW},
-    Instruction, Platform, Program, StepRecord, Tracer, VMState, Word, WordAddr, encode_rv32,
-    encode_rv32u,
+    Instruction, MOCK_BASE, MOCK_ENTRY_POINT, Platform, Program, StepRecord, Tracer, VMState, Word,
+    WordAddr, encode_rv32, encode_rv32u,
 };
 use ceno_zkvm::{
     scheme::{PublicValues, constants::MAX_NUM_VARIABLES, verifier::ZKVMVerifier},
@@ -71,8 +71,8 @@ fn main() {
     let program_size = program_code.len();
 
     let program = Program::new(
-        CENO_PLATFORM.pc_base(),
-        CENO_PLATFORM.pc_base(),
+        MOCK_ENTRY_POINT,
+        MOCK_BASE,
         program_code,
         Default::default(),
     );

ceno_zkvm/src/e2e.rs

@@ -201,8 +201,6 @@ pub fn setup_platform(
     };
 
     Platform {
-        rom: program.base_address
-            ..program.base_address + (program.instructions.len() * WORD_SIZE) as u32,
         prog_data,
         stack,
         heap,

ceno_zkvm/src/scheme/mock_prover.rs

@@ -17,7 +17,7 @@ use crate::{
 };
 use ark_std::test_rng;
 use base64::{Engine, engine::general_purpose::STANDARD_NO_PAD};
-use ceno_emul::{ByteAddr, CENO_PLATFORM, Platform, Program};
+use ceno_emul::{ByteAddr, CENO_PLATFORM, MOCK_BASE, MOCK_ENTRY_POINT, Program};
 use ff::Field;
 use ff_ext::ExtensionField;
 use generic_static::StaticTypeMap;
@@ -38,19 +38,7 @@ use strum::IntoEnumIterator;
 
 const MAX_CONSTRAINT_DEGREE: usize = 2;
 const MOCK_PROGRAM_SIZE: usize = 32;
-pub const MOCK_PC_START: ByteAddr = ByteAddr({
-    // This needs to be a static, because otherwise the compiler complains
-    // that 'the destructor for [Platform] cannot be evaluated in constants'
-    // The `static` keyword means that we keep exactly one copy of the variable
-    // around per process, and never deallocate it.  Thus never having to call
-    // the destructor.
-    //
-    // At least conceptually.  In practice with anything beyond -O0, the optimizer
-    // will inline and fold constants and replace `MOCK_PC_START` with
-    // a simple number.
-    static CENO_PLATFORM: Platform = ceno_emul::CENO_PLATFORM;
-    CENO_PLATFORM.pc_base()
-});
+pub const MOCK_PC_START: ByteAddr = ByteAddr(MOCK_BASE);
 
 #[allow(clippy::enum_variant_names)]
 #[derive(Debug, Clone)]
@@ -427,8 +415,8 @@ impl<'a, E: ExtensionField + Hash> MockProver<E> {
         lkm: Option<LkMultiplicity>,
     ) -> Result<(), Vec<MockProverError<E>>> {
         let program = Program::new(
-            CENO_PLATFORM.pc_base(),
-            CENO_PLATFORM.pc_base(),
+            MOCK_ENTRY_POINT,
+            MOCK_BASE,
             input_programs.to_vec(),
             Default::default(),
         );

ceno_zkvm/src/scheme/tests.rs

@@ -4,7 +4,7 @@ use ark_std::test_rng;
 use ceno_emul::{
     CENO_PLATFORM,
     InsnKind::{ADD, ECALL},
-    Platform, Program, StepRecord, VMState, encode_rv32,
+    MOCK_BASE, MOCK_ENTRY_POINT, Platform, Program, StepRecord, VMState, encode_rv32,
 };
 use ff::Field;
 use ff_ext::ExtensionField;
@@ -201,8 +201,8 @@ fn test_single_add_instance_e2e() {
 
     // set up program
     let program = Program::new(
-        CENO_PLATFORM.pc_base(),
-        CENO_PLATFORM.pc_base(),
+        MOCK_ENTRY_POINT,
+        MOCK_BASE,
         PROGRAM_CODE.to_vec(),
         Default::default(),
     );