Add syscall handler, still work in progress

Add elf files

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
+    }
+}