feat: introduce HOT! executable format and Ring 3 process isolation (v0.5.2)

- Implement custom 'HOT!' binary format and Rust-based elf2hot converter.
- Upgrade kernel loader with segment-based loading and BSS zeroing.
- Refactor scheduler for Ring 3 IRET frames and fix CS/SS selector swap.
- Add user stack allocation (0x70000000) and linker scripts for binary cleanup.

tools/elf2hot/Cargo.lock

@@ -0,0 +1,88 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "elf2hot"
+version = "0.1.0"
+dependencies = [
+ "goblin",
+]
+
+[[package]]
+name = "goblin"
+version = "0.10.4"
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+checksum = "4db6758c546e6f81f265638c980e5e84dfbda80cfd8e89e02f83454c8e8124bd"
+dependencies = [
+ "log",
+ "plain",
+ "scroll",
+]
+
+[[package]]
+name = "log"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
+
+[[package]]
+name = "plain"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4596b6d070b27117e987119b4dac604f3c58cfb0b191112e24771b2faeac1a6"
+
+[[package]]
+name = "proc-macro2"
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+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
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+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "scroll"
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+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 = "2.0.114"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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tools/elf2hot/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "elf2hot"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+goblin = "0.10.4"

tools/elf2hot/src/main.rs

@@ -0,0 +1,98 @@
+use goblin::elf::program_header::PT_LOAD;
+use std::env;
+use std::fs::File;
+use std::io::{Read, Write};
+
+#[repr(C, packed)]
+#[derive(Default, Debug)]
+struct HotHeader {
+    magic: u32,
+    version: u8,
+    reserved_pad: [u8; 3],
+    entry_point: u64,
+    segments_count: u64,
+    reserved: u64,
+}
+
+#[repr(C, packed)]
+#[derive(Default, Debug, Clone, Copy)]
+struct HotSegment {
+    stype: u64,
+    vaddr: u64,
+    offset: u64, 
+    filesz: u64,
+    memsz: u64,
+}
+
+const HOT_MAGIC: u32 = 0x21544F48; // "HOT!"
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let args: Vec<String> = env::args().collect();
+    if args.len() < 3 {
+        println!("Usage: elf2hot <input_elf> <output_hot>");
+        return Ok(());
+    }
+
+    let input_path = &args[1];
+    let output_path = &args[2];
+
+    let mut f = File::open(input_path)?;
+    let mut buffer = Vec::new();
+    f.read_to_end(&mut buffer)?;
+
+    let elf = goblin::elf::Elf::parse(&buffer)?;
+    
+    let mut hot_segments = Vec::new();
+    let mut segment_data = Vec::new();
+
+    let mut current_offset = std::mem::size_of::<HotHeader>() as u64;
+
+    let load_segments: Vec<_> = elf.program_headers.iter()
+        .filter(|ph| ph.p_type == PT_LOAD)
+        .collect();
+    
+    current_offset += (load_segments.len() * std::mem::size_of::<HotSegment>()) as u64;
+
+    for ph in load_segments {
+        let is_code = ph.is_executable();
+        
+        let data = &buffer[ph.p_offset as usize..(ph.p_offset + ph.p_filesz) as usize];
+        segment_data.push(data);
+
+        hot_segments.push(HotSegment {
+            stype: if is_code { 1 } else { 2 },
+            vaddr: ph.p_vaddr,
+            offset: current_offset,
+            filesz: ph.p_filesz,
+            memsz: ph.p_memsz,
+        });
+
+        current_offset += ph.p_filesz;
+    }
+
+    let header = HotHeader {
+        magic: HOT_MAGIC,
+        version: 1,
+        entry_point: elf.entry,
+        segments_count: hot_segments.len() as u64,
+        ..Default::default()
+    };
+
+    let mut out = File::create(output_path)?;
+
+    let header_bytes: [u8; std::mem::size_of::<HotHeader>()] = unsafe { std::mem::transmute(header) };
+    out.write_all(&header_bytes)?;
+
+    for seg in hot_segments {
+        let seg_bytes: [u8; std::mem::size_of::<HotSegment>()] = unsafe { std::mem::transmute(seg) };
+        out.write_all(&seg_bytes)?;
+    }
+
+    for data in segment_data {
+        out.write_all(data)?;
+    }
+
+    println!("Successfully converted {} to {}!", input_path, output_path);
+    println!("Entry point: 0x{:X}", elf.entry);
+    Ok(())
+}