Add syscall handler, still work in progress

Add elf files

arch/x86_64/src/acpi/madt.rs

@@ -85,7 +85,7 @@ pub enum MadtEntry {
     InvalidIoApic(usize),
     IntSrcOverride(&'static MadtIntSrcOverride),
     InvalidIntSrcOverride(usize),
-    Unknown
+    Unknown(u8)
 }
 
 pub struct MadtIter {
@@ -117,7 +117,7 @@ impl Iterator for MadtIter {
                     } else {
                         MadtEntry::InvalidIntSrcOverride(entry_len)
                     },
-                    _ => MadtEntry::Unknown
+                    _ => MadtEntry::Unknown(entry_type)
                 };
 
                 self.i += entry_len;

arch/x86_64/src/elf.rs

@@ -0,0 +1,92 @@
+pub const ELF_CLASS: u8 = 2;
+pub type ElfAddr = u64;
+pub type ElfOff = u64;
+pub type ElfHalf = u16;
+pub type ElfWord = u32;
+pub type ElfXword = u64;
+
+/// An ELF header
+#[repr(packed)]
+#[derive(Debug)]
+pub struct ElfHeader {
+    /// The "magic number" (4 bytes)
+    pub magic: [u8; 4],
+    /// 64 or 32 bit?
+    pub class: u8,
+    /// Little (1) or big endianness (2)?
+    pub endian: u8,
+    /// The ELF version (set to 1 for default)
+    pub ver: u8,
+    /// Operating system ABI (0x03 for Linux)
+    pub abi: [u8; 2],
+    /// Unused
+    pub pad: [u8; 7],
+    /// Specify whether the object is relocatable, executable, shared, or core (in order).
+    pub _type: ElfHalf,
+    /// Instruction set archcitecture
+    pub machine: ElfHalf,
+    /// Second version
+    pub ver_2: ElfWord,
+    /// The ELF entry
+    pub entry: ElfAddr,
+    /// The program header table offset
+    pub ph_off: ElfOff,
+    /// The section header table offset
+    pub sh_off: ElfOff,
+    /// The flags set
+    pub flags: ElfWord,
+    /// The header table length
+    pub h_len: ElfHalf,
+    /// The program header table entry length
+    pub ph_ent_len: ElfHalf,
+    /// The program head table length
+    pub ph_len: ElfHalf,
+    /// The section header table entry length
+    pub sh_ent_len: ElfHalf,
+    /// The section header table length
+    pub sh_len: ElfHalf,
+    /// The section header table string index
+    pub sh_str_index: ElfHalf,
+}
+
+/// An ELF segment
+#[repr(packed)]
+#[derive(Debug)]
+pub struct ElfSegment {
+    pub _type: ElfWord,
+    pub flags: ElfWord,
+    pub off: ElfOff,
+    pub vaddr: ElfAddr,
+    pub paddr: ElfAddr,
+    pub file_len: ElfXword,
+    pub mem_len: ElfXword,
+    pub align: ElfXword,
+}
+
+/// An ELF section
+#[repr(packed)]
+#[derive(Debug)]
+pub struct ElfSection {
+    pub name: ElfWord,
+    pub _type: ElfWord,
+    pub flags: ElfXword,
+    pub addr: ElfAddr,
+    pub off: ElfOff,
+    pub len: ElfXword,
+    pub link: ElfWord,
+    pub info: ElfWord,
+    pub addr_align: ElfXword,
+    pub ent_len: ElfXword,
+}
+
+/// An ELF symbol
+#[repr(packed)]
+#[derive(Debug)]
+pub struct ElfSymbol {
+    pub name: ElfWord,
+    pub info: u8,
+    pub other: u8,
+    pub sh_index: ElfHalf,
+    pub value: ElfAddr,
+    pub size: ElfXword,
+}

arch/x86_64/src/idt.rs

@@ -20,6 +20,7 @@ pub unsafe fn init() {
         entry.set_flags(IDT_PRESENT | IDT_RING_0 | IDT_INTERRUPT);
         entry.set_offset(8, blank as usize);
     }
+    IDT[0x80].set_offset(8, syscall as usize);
     IDTR.set_slice(&IDT);
 
     init_ap();
@@ -54,6 +55,29 @@ interrupt_error!(page_fault, {
     }
 });
 
+#[naked]
+pub unsafe extern fn syscall() {
+    extern {
+        fn syscall(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize) -> usize;
+    }
+
+    let a;
+    let b;
+    let c;
+    let d;
+    let e;
+    let f;
+    asm!("" : "={rax}"(a), "={rbx}"(b), "={rcx}"(c), "={rdx}"(d), "={rsi}"(e), "={rdi}"(f)
+        : : : "intel", "volatile");
+
+    let a = syscall(a, b, c, d, e, f);
+
+    asm!("" : : "{rax}"(a) : : "intel", "volatile");
+
+    // Pop scratch registers, error code, and return
+    asm!("iretq" : : : : "intel", "volatile");
+}
+
 bitflags! {
     pub flags IdtFlags: u8 {
         const IDT_PRESENT = 1 << 7,

arch/x86_64/src/lib.rs

@@ -119,6 +119,9 @@ macro_rules! interrupt_error {
 /// ACPI table parsing
 pub mod acpi;
 
+/// ELF file handling
+pub mod elf;
+
 /// Memcpy, memmove, etc.
 pub mod externs;
 

arch/x86_64/src/start.rs

@@ -27,7 +27,7 @@ extern {
     /// Kernel main function
     fn kmain() -> !;
     /// Kernel main for APs
-    fn kmain_ap() -> !;
+    fn kmain_ap(id: usize) -> !;
 }
 
 /// The entry to Rust, all things must be initialized
@@ -88,8 +88,6 @@ pub unsafe extern fn kstart() -> ! {
         }
 
         BSP_READY.store(true, Ordering::SeqCst);
-
-        print!("BSP\n");
     }
 
     kmain();
@@ -115,7 +113,5 @@ pub unsafe extern fn kstart_ap(stack_start: usize, stack_end: usize) -> ! {
         asm!("pause" : : : : "intel", "volatile");
     }
 
-    print!("{}", ::core::str::from_utf8_unchecked(&[b'A', b'P', b' ', ap_number as u8 + b'0', b'\n']));
-
-    kmain_ap();
+    kmain_ap(ap_number);
 }

bootloader/x86/harddrive.asm

@@ -17,5 +17,3 @@ kernel_file:
 .end:
 .length equ kernel_file.end - kernel_file
 .length_sectors equ .length / 512
-
-times 1024*1024-($-$$) db 0

bootloader/x86/kernel.ld

@@ -1,16 +1,14 @@
 ENTRY(kstart)
 OUTPUT_FORMAT(elf64-x86-64)
 
-KERNEL_OFFSET = 0;
+KERNEL_OFFSET = 0x100000;
 
 SECTIONS {
-    . = 0x100000;
+    . = KERNEL_OFFSET;
 
     . += SIZEOF_HEADERS;
     . = ALIGN(4096);
 
-	. += KERNEL_OFFSET;
-
     .text : AT(ADDR(.text) - KERNEL_OFFSET) {
         __text_start = .;
         *(.text*)

kernel/elf.rs

@@ -0,0 +1,120 @@
+//! ELF executables
+
+use collections::{String, Vec};
+
+use core::{mem, ptr, str, slice};
+
+pub use arch::elf::*;
+
+/// An ELF executable
+pub struct Elf<'a> {
+    pub data: &'a [u8],
+}
+
+impl<'a> Elf<'a> {
+    /// Create a ELF executable from data
+    pub fn from(data: &'a [u8]) -> Result<Elf<'a>, String> {
+        if data.len() < mem::size_of::<ElfHeader>() {
+            Err(format!("Elf: Not enough data: {} < {}", data.len(), mem::size_of::<ElfHeader>()))
+        } else if &data[..4] != b"\x7FELF" {
+            Err(format!("Elf: Invalid magic: {:?} != {:?}", &data[..4], b"\x7FELF"))
+        } else if data.get(4) != Some(&ELF_CLASS) {
+            Err(format!("Elf: Invalid architecture: {:?} != {:?}", data.get(4), Some(&ELF_CLASS)))
+        } else {
+            Ok(Elf { data: data })
+        }
+    }
+
+    pub unsafe fn load_segments(&self) -> Vec<ElfSegment> {
+        let mut segments = Vec::new();
+
+        let header = &*(self.data.as_ptr() as usize as *const ElfHeader);
+
+        for i in 0..header.ph_len {
+            let segment = ptr::read((self.data.as_ptr() as usize + header.ph_off as usize + i as usize * header.ph_ent_len as usize) as *const ElfSegment);
+
+            if segment._type == 1 || segment._type == 7 {
+                segments.push(segment);
+            }
+        }
+
+        segments
+    }
+
+    /// Get the entry field of the header
+    pub unsafe fn entry(&self) -> usize {
+        let header = &*(self.data.as_ptr() as usize as *const ElfHeader);
+        header.entry as usize
+    }
+
+    /// ELF symbol
+    pub unsafe fn symbol(&self, name: &str) -> usize {
+        let header = &*(self.data.as_ptr() as usize as *const ElfHeader);
+
+        let sh_str_section =
+            &*((self.data.as_ptr() as usize + header.sh_off as usize +
+                header.sh_str_index as usize *
+                header.sh_ent_len as usize) as *const ElfSection);
+
+        let mut sym_section = &*((self.data.as_ptr() as usize + header.sh_off as usize) as *const ElfSection);
+
+        let mut str_section = &*((self.data.as_ptr() as usize + header.sh_off as usize) as *const ElfSection);
+
+        for i in 0..header.sh_len {
+            let section =
+                &*((self.data.as_ptr() as usize + header.sh_off as usize +
+                    i as usize *
+                    header.sh_ent_len as usize) as *const ElfSection);
+
+            let section_name_ptr =
+                (self.data.as_ptr() as usize + sh_str_section.off as usize + section.name as usize) as *const u8;
+            let mut section_name_len = 0;
+            for j in 0..4096 {
+                section_name_len = j;
+                if ptr::read(section_name_ptr.offset(j)) == 0 {
+                    break;
+                }
+            }
+            let section_name =
+                str::from_utf8_unchecked(slice::from_raw_parts(section_name_ptr,
+                                                               section_name_len as usize));
+
+            if section_name == ".symtab" {
+                sym_section = section;
+            } else if section_name == ".strtab" {
+                str_section = section;
+            }
+        }
+
+        if sym_section.off > 0 && str_section.off > 0 {
+            if sym_section.ent_len > 0 {
+                let len = sym_section.len / sym_section.ent_len;
+                for i in 0..len {
+                    let symbol = &*((self.data.as_ptr() as usize + sym_section.off as usize + i as usize * sym_section.ent_len as usize) as *const ElfSymbol);
+
+                    let symbol_name_ptr =
+                        (self.data.as_ptr() as usize + str_section.off as usize +
+                         symbol.name as usize) as *const u8;
+                    let mut symbol_name_len = 0;
+                    for j in 0..4096 {
+                        symbol_name_len = j;
+                        if ptr::read(symbol_name_ptr.offset(j)) == 0 {
+                            break;
+                        }
+                    }
+                    let symbol_name = str::from_utf8_unchecked(slice::from_raw_parts(symbol_name_ptr, symbol_name_len as usize));
+
+                    if name == symbol_name {
+                        return symbol.value as usize;
+                    }
+                }
+            } else {
+                print!("No sym_section ent len\n");
+            }
+        } else {
+            print!("No sym_section or str_section\n");
+        }
+
+        0
+    }
+}

kernel/lib.rs

@@ -65,6 +65,7 @@
 //! In this case, it is recommended to add one page, 4096 bytes, to the buffer and retry.
 
 #![feature(alloc)]
+#![feature(asm)]
 #![feature(collections)]
 #![feature(const_fn)]
 #![feature(drop_types_in_const)]
@@ -94,6 +95,9 @@ extern crate spin;
 /// Context management
 pub mod context;
 
+/// ELF file parsing
+pub mod elf;
+
 /// Schemes, filesystem handlers
 pub mod scheme;
 
@@ -106,16 +110,18 @@ pub mod tests;
 
 #[no_mangle]
 pub extern fn kmain() {
+    print!("{}", format!("BSP\n"));
+
     loop {
         unsafe { interrupt::enable_and_halt(); }
-        print!("INT BSP\n");
     }
 }
 
 #[no_mangle]
-pub extern fn kmain_ap() {
+pub extern fn kmain_ap(id: usize) {
+    print!("{}", format!("ASP {}\n", id));
+
     loop {
         unsafe { interrupt::enable_and_halt() }
-        print!("INT AP\n");
     }
 }

kernel/syscall/mod.rs

@@ -106,3 +106,11 @@ pub fn handle(a: usize, b: usize, c: usize, d: usize, e: usize, _f: usize) -> ::
         Call::Unknown => Err(Error::NoCall)
     }.map_err(|err| err.into())
 }
+
+#[no_mangle]
+pub extern fn syscall(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize) -> usize {
+    match handle(a, b, c, d, e, f) {
+        Ok(value) => value,
+        Err(value) => !value
+    }
+}

x86_64-unknown-redox.json

@@ -16,7 +16,7 @@
     "code-model": "kernel",
     "disable-redzone": true,
     "eliminate-frame-pointer": false,
-    "exe-suffix": ".bin",
+    "exe-suffix": "",
     "has-rpath": false,
     "no-compiler-rt": true,
     "no-default-libraries": true,