ADD ELF SUPPORT

Cargo.lock

@@ -26,12 +26,29 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
 
+[[package]]
+name = "goblin"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4db6758c546e6f81f265638c980e5e84dfbda80cfd8e89e02f83454c8e8124bd"
+dependencies = [
+ "log",
+ "plain",
+ "scroll",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.176"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "58f929b4d672ea937a23a1ab494143d968337a5f47e56d0815df1e0890ddf174"
 
+[[package]]
+name = "log"
+version = "0.4.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
+
 [[package]]
 name = "memmap2"
 version = "0.9.8"
@@ -53,11 +70,73 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "plain"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4596b6d070b27117e987119b4dac604f3c58cfb0b191112e24771b2faeac1a6"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.103"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ee95bc4ef87b8d5ba32e8b7714ccc834865276eab0aed5c9958d00ec45f49e8"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a338cc41d27e6cc6dce6cefc13a0729dfbb81c262b1f519331575dd80ef3067f"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "scroll"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1257cd4248b4132760d6524d6dda4e053bc648c9070b960929bf50cfb1e7add"
+dependencies = [
+ "scroll_derive",
+]
+
+[[package]]
+name = "scroll_derive"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed76efe62313ab6610570951494bdaa81568026e0318eaa55f167de70eeea67d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "syn"
+version = "2.0.111"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "390cc9a294ab71bdb1aa2e99d13be9c753cd2d7bd6560c77118597410c4d2e87"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "trve"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "goblin",
  "memmap2",
  "nix",
 ]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"

Cargo.toml

@@ -5,5 +5,6 @@ edition = "2024"
 
 [dependencies]
 anyhow = "1.0.100"
+goblin = "0.10.4"
 memmap2 = "0.9.8"
 nix = { version = "0.30.1", features = ["fs"] }

echo.S

@@ -1,4 +1,4 @@
-.section .text._start
+.section .text
 .globl _start
 
 .equ UART_DATA, 0

link.ld

@@ -6,7 +6,6 @@ MEMORY {
 
 SECTIONS {
     .text : ALIGN(4) {
-        *(.text._start)
         *(.text*)
     } > RAM
 

src/execload.rs

@@ -0,0 +1,67 @@
+// Copyright (c) 2025 taitep
+// SPDX-License-Identifier: MIT
+//
+// This file is part of TRVE (https://gitea.taitep.se/taitep/trve)
+// See LICENSE file in the project root for full license text.
+
+use std::{fs, path::Path};
+
+use anyhow::{Result, bail};
+use goblin::{
+    Object,
+    elf::{
+        header::{EM_RISCV, ET_EXEC},
+        program_header::PT_LOAD,
+    },
+};
+use trve::consts::Addr;
+
+pub fn load<P: AsRef<Path>>(path: P, ram: &mut [u8], ram_start: Addr) -> Result<Addr> {
+    let buf = fs::read(path)?;
+
+    match Object::parse(&buf)? {
+        Object::Elf(elf) => {
+            if elf.header.e_type != ET_EXEC {
+                bail!("Executable type incorrect, may not be an executable or may be dynamic");
+            }
+            if elf.header.e_machine != EM_RISCV {
+                bail!("Executable architecture is not RISC-V");
+            }
+            if !elf.is_64 {
+                bail!("Executable is not 64-bit");
+            }
+            if !elf.little_endian {
+                bail!("Executable is not little-endian");
+            }
+
+            for ph in elf.program_headers {
+                if ph.p_type == PT_LOAD {
+                    let start = (ph.p_vaddr - ram_start) as usize;
+                    let end = start + ph.p_memsz as usize;
+                    let file_end = start + ph.p_filesz as usize;
+
+                    if end > ram_start as usize + ram.len() {
+                        bail!("Segment at 0x{:x} does not fit in RAM", ph.p_vaddr);
+                    }
+
+                    ram[start..file_end].copy_from_slice(
+                        &buf[ph.p_offset as usize..(ph.p_offset + ph.p_filesz) as usize],
+                    );
+
+                    ram[file_end..end].fill(0);
+                }
+            }
+
+            Ok(elf.entry)
+        }
+        Object::Unknown(_) => {
+            eprintln!("Unrecognized executable format identifier, assuming raw binary");
+            if buf.len() > ram.len() {
+                bail!("Program too large for RAM");
+            }
+            ram[..buf.len()].copy_from_slice(&buf);
+            Ok(ram_start)
+        }
+        _ => bail!("Unsupported executable format"),
+    }
+}

src/main.rs

@@ -22,25 +22,7 @@ use anyhow::{Result, bail};
 
 use crate::basic_uart::BasicUart;
 
-fn read_file_to_buffer(path: &str, buffer: &mut [u8]) -> io::Result<usize> {
+mod execload;
-    let mut file = File::open(path)?;
-    let mut total_read = 0;
-
-    while total_read < buffer.len() {
-        let n = file.read(&mut buffer[total_read..])?;
-        if n == 0 {
-            return Ok(total_read);
-        }
-        total_read += n;
-    }
-
-    let mut tmp = [0u8; 1];
-    if file.read(&mut tmp)? != 0 {
-        return Err(io::Error::other("RAM too small for file"));
-    }
-
-    Ok(total_read)
-}
 
 fn main() -> Result<()> {
     let mut ram = Ram::try_new(16 * 1024 * 1024 / 4096)?;
@@ -53,7 +35,7 @@ fn main() -> Result<()> {
         bail!("Wrong number of arguments");
     }
 
-    read_file_to_buffer(&args[1], buf)?;
+    let entry_point = execload::load(&args[1], buf, 0x8000_0000)?;
 
     let uart = BasicUart::new();
     let uart = uart.spawn_poller(Duration::from_millis(10));
@@ -76,7 +58,7 @@ fn main() -> Result<()> {
     };
 
     let mut core = Core::new(mem_cfg);
-    core.reset(0x8000_0000);
+    core.reset(entry_point);
     core.run();
 
     Ok(())