sad: death of panicless *+ smth

Give in in favor of str and utf8 with perfect valid state and panic
bailout everywhere in std.

Define some more Boot Info Format tags.

.cargo/config.toml

@@ -1,5 +1,5 @@
 [build]
-target = ".cargo/target-i386.json"
+target = ".cargo/target-protected-i386.json"
 
 [unstable]
 build-std = ["core", "compiler_builtins"]

.cargo/linker-multiboot.ld

@@ -1,4 +1,4 @@
-ENTRY(start)
+ENTRY(start_stub)
 
 SECTIONS {
     . = 1M;

Cargo.lock

@@ -2,6 +2,12 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "ascii"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d92bec98840b8f03a5ff5413de5293bfcd8bf96467cf5452609f939ec6f5de16"
+
 [[package]]
 name = "bios"
 version = "0.1.0"
@@ -10,5 +16,6 @@ version = "0.1.0"
 name = "oxide"
 version = "0.1.0"
 dependencies = [
+ "ascii",
  "bios",
 ]

Cargo.toml

@@ -6,18 +6,9 @@ members = ["deps/bios", "members/oxide"]
 bios = { path = "deps/bios" }
 
 [profile.release]
-opt-level = "z"
 codegen-units = 1
 lto = "fat"
 panic = "abort"
 
 [profile.dev]
 panic = "abort"
-
-[profile.release.package.microloader-mbr]
-codegen-units = 1
-opt-level = "z"
-
-[profile.release.package.microloader-vba]
-codegen-units = 1
-opt-level = "z"

Makefile

@@ -7,9 +7,11 @@ RUST_DEP := Cargo.toml Cargo.lock $(shell find .cargo -type f) $(shell find deps
 
 KERNELFILE = $(OXIDE_MULTIBOOT)
 $(KERNELFILE): $(shell find members/oxide -type f) $(RUST_DEP)
-	cargo b -r --target=.cargo/target-protected-i386.json --package oxide
+	cargo b -r --package oxide
 
 BOOTLOADER ?= grub
+# Must not contain '/' with current limitations
+CMDLINE ?=
 include mk/make_bootloader/$(BOOTLOADER).mk
 
 .PHONY: clean \
@@ -24,6 +26,6 @@ run-bootloader-qemu-nographic: $(OUTIMG)
 	qemu-system-x86_64 -nographic -drive format=raw,file=$(OUTIMG)
 # one day qemu will support multiboot2
 run-qemu: $(KERNELFILE)
-	qemu-system-x86_64 -kernel $(KERNELFILE)
+	qemu-system-x86_64 -kernel $(KERNELFILE) -append $(CMDLINE)
 run-qemu-nographic: $(KERNELFILE)
-	qemu-system-x86_64 -nographic -kernel $(KERNELFILE)
+	qemu-system-x86_64 -nographic -kernel $(KERNELFILE) -append $(CMDLINE)

extra/grub_iso.cfg

@@ -2,6 +2,6 @@ set timeout=2
 set default=0
 
 menuentry "OxideOS" {
-    multiboot2 /boot/kernel.bin
+    multiboot2 /boot/kernel.bin $args
     boot
 }

members/oxide/Cargo.toml

@@ -10,4 +10,5 @@ test = false
 bench = false
 
 [dependencies]
+ascii = { version = "1.1.0", default-features = false }
 bios = { workspace = true }

members/oxide/src/main.rs

@@ -2,36 +2,48 @@
 #![no_main]
 #![deny(clippy::float_arithmetic)]
 #![feature(
+    arbitrary_self_types,
+    arbitrary_self_types_pointers,
+    associated_type_defaults,
+    const_convert,
     const_range,
     const_trait_impl,
-    const_convert,
+    decl_macro,
     generic_const_exprs,
-    associated_type_defaults
+    ptr_metadata
 )]
 
 /// Triggers a linker failure if this reaches that phase
 #[panic_handler]
 fn panic(_info: &PanicInfo) -> ! {
-    unsafe extern "C" {
-        static __PANIC_HANDLER_WAS_LINKED__DO_NOT_DEFINE: extern "C" fn() -> !;
-    }
+    // 2026-02-21: Officially the end of panicless OxideOS, did you know `Debug for str` has panic
+    // code paths :pensive:. At least compile ones, maybe runtime impossible but still not compiled
+    // away.
+    unsafe { asm!("ud2", "hlt", options(noreturn)) };
 
-    unsafe { __PANIC_HANDLER_WAS_LINKED__DO_NOT_DEFINE() };
+    // unsafe extern "C" {
+    //     static __PANIC_HANDLER_WAS_LINKED__DO_NOT_DEFINE: extern "C" fn() -> !;
+    // }
+
+    // unsafe { __PANIC_HANDLER_WAS_LINKED__DO_NOT_DEFINE() };
 }
 
-use core::{arch::asm, hint::black_box, panic::PanicInfo};
+use core::{arch::asm, fmt::Write as _, hint::black_box, panic::PanicInfo};
 
-use crate::vga::{ColorNibble, VgaBuffer, VgaColor};
+use crate::{
+    multiboot2::bif,
+    vga::{ColorNibble, VgaBuffer, VgaColor},
+};
 
 pub mod multiboot2;
+pub mod start_stub;
 pub mod vga;
 
 #[used]
 #[unsafe(link_section = ".multiboot2_header")]
 static HEADER: multiboot2::Header = multiboot2::Header::new();
 
-#[unsafe(no_mangle)]
-fn start() -> ! {
+extern "C" fn start(boot_info: &bif::FixedPart) -> ! {
     let mut vga = unsafe { VgaBuffer::<vga::text_modes::VGAText2>::new_uninitialized() };
 
     vga.write_at(0, 1, b'H');
@@ -42,12 +54,51 @@ fn start() -> ! {
     vt.set_color(VgaColor::new(ColorNibble::BLUE, ColorNibble::GREEN));
     vt.put_at(10, 5);
     vt.slide();
-    vt.write(b"testinggg");
-    // loop {
-    //     for x in b'a'..b'z' {
-    //         vt.write(&[x]);
-    //     }
+    vt.write(b"testinggg\ntags:\n");
+
+    let tags = bif::TagsIter::new(boot_info);
+    for tag in tags {
+        sleep_short();
+
+        let _ = write!(&mut vt, "{}: ", tag.typ());
+        let Some(tag) = tag.tag() else {
+            vt.write(b"unknown tag\n");
+            continue;
+        };
+
+        // this single line pulls like half of the fmt module which means ~ 7.5KiB of BS
+        let _ = writeln!(&mut vt, "{tag:?}");
+
+        // tbh I prefer these, I need to like, write u8 chars, on the TTY level like I really care
+        // about writting binary, still need to differenciate a slice of u8's and a asciistr,
+        // AsciiChar looks innteresting in std and could make astr = [AsciiChar], the thing I don't
+        // like is that disply is straight up against non-utf8 output, so I'd have to make my own
+        // raw-display?? but then Im going all against rust, no Display or Derive std macros
+        // either...
+        //
+        // match tag {
+        //     bif::TagTagged::BootCommandLine(_) => vt.write(b"BootCommandLine\n"),
+        //     bif::TagTagged::BasicMemoryInformation(_) => vt.write(b"BasicMemoryInformation\n"),
+        //     bif::TagTagged::BIOSBootDevice(_) => vt.write(b"BIOSBootDevice\n"),
+        //     bif::TagTagged::Terminate(_) => vt.write(b"Terminate\n"),
+        //     bif::TagTagged::BootLoaderName(_) => vt.write(b"BootLoaderName\n"),
+        //     bif::TagTagged::ImageLoadBasePhyAddr(_) => vt.write(b"ImageLoadBasePhyAddr\n"),
         // }
+        //
+        //
+        // Somebody else, body else, body elseeee, e- e- e- elsee
+        //
+        // I don't know what to do, 'cause when you are around then I'm aaaaaalll over youuuu
+        //
+        // I always think about it, I can't play it coooool
+        //
+        // Blazing in your heeeeell, he- he- he- heeeellllll~
+        //
+    }
+
+    for _ in 0..=30 {
+        sleep_short();
+    }
 
     for _ in 0..=5 {
         sleep_short();
@@ -63,6 +114,7 @@ fn start() -> ! {
 fn sleep_short() {
     let mut n = 0_u64;
     while n < 100_000_000 {
+        #[allow(clippy::unit_arg)]
         black_box(n += 1);
     }
 }

members/oxide/src/multiboot2.rs

@@ -39,4 +39,218 @@ impl Default for Header {
 #[derive(Clone, Copy, PartialEq, Eq)]
 pub enum HeaderArchitecture {
     ProtectedI386 = 0,
+    MIPS32 = 4,
+}
+
+pub mod bif {
+    //! # Boot Information Format
+    //!
+    //! <https://www.gnu.org/software/grub/manual/multiboot2/multiboot.html>
+
+    use core::ptr;
+
+    pub trait TagType {
+        const ID: u32 = 4;
+    }
+
+    pub mod types {
+        use ascii::AsciiStr;
+
+        macro tagset($taggedvis:vis $taggedname:ident { $( $typname:ident ($typn:expr) { $($typprop:ident : $typpropty:ty),* $(,)? } ),* $(,)? }) {
+            $(
+                #[repr(C)]
+                #[derive(Debug)]
+                pub struct $typname { $(pub $typprop: $typpropty),* }
+
+                impl super::TagType for $typname {
+                    const ID: u32 = $typn;
+                }
+            )*
+
+            #[derive(Debug)]
+            $taggedvis enum $taggedname<'a> {
+                $( $typname(&'a $typname) ),*
+            }
+        }
+
+        // All these AsciiStr are actually CStr's
+        tagset! { pub TagTagged {
+            Terminate(0) {},
+            BootCommandLine(1) {
+                string: AsciiStr,
+            },
+            BootLoaderName(2) {
+                string: AsciiStr,
+            },
+            BasicMemoryInformation(4) {
+                mem_lower: u32,
+                mem_upper: u32,
+            },
+            BIOSBootDevice(5) {
+                biosdev: u32,
+                partition: u32,
+                sub_partition: u32,
+            },
+            MemoryMap(6) {
+                entry_size: u32,
+                entry_version: u32,
+                entries: [u8], // "varies"?
+            },
+            FramebufferInfo(8) {
+                 addr: u64,
+                 pitch: u32,
+                 width: u32,
+                 height: u32,
+                 bpp: u8,
+                 typ: u8,
+                 _reserved: u8,
+                 color_info: [u8],
+            },
+            ELFSymbols(9) {
+                num: u16,
+                entsize: u16,
+                shndx: u16,
+                _reserved: u16,
+                section_headers: [u8], // "varies"?
+            },
+            APMTable(10) {
+                version: u16,
+                cseg: u16,
+                offset: u32,
+                cseg_16: u16,
+                dseg: u16,
+                flags: u16,
+                cseg_len: u16,
+                cseg_16_len: u16,
+                dseg_len: u16,
+            },
+            ACPIoldRSDP(14) {
+                rsdpv1_old: [u8],
+            },
+            ImageLoadBasePhyAddr(21) {
+                load_base_addr: u32,
+            },
+        }}
+    }
+
+    pub use types::TagTagged;
+
+    #[repr(C)]
+    pub struct TagHead {
+        typ: u32,
+        size: u32,
+        __end: (),
+    }
+
+    impl TagHead {
+        pub fn typ(&self) -> u32 {
+            self.typ
+        }
+
+        pub fn size(&self) -> u32 {
+            self.size
+        }
+
+        pub fn aligned8_size(&self) -> u32 {
+            (self.size + 7) & !7
+        }
+
+        /// Gets the reference of the next laying in memory tag, considering this one's size.
+        ///
+        /// # Safety
+        ///
+        /// Assumes there's a contiguous one in memory.
+        pub unsafe fn next(&self) -> &Self {
+            unsafe { &*ptr::from_ref(self).byte_add(self.aligned8_size() as usize) }
+        }
+
+        pub fn tag<'a>(&self) -> Option<TagTagged<'a>> {
+            let typ = self.typ;
+            let size = self.size;
+
+            let contents_addr = ptr::addr_of!(self.__end).cast::<()>();
+
+            macro typ_match(match $var:ident { $($name:ident)* } fat { $($fatname:ident)* }) {
+                match $var {
+                    $(
+                        types::$name::ID => Some(TagTagged::$name(unsafe {
+                            &*core::ptr::from_raw_parts::<types::$name>(
+                                contents_addr,
+                                (),
+                            )
+                        }))
+                    ),*,
+                    $(
+                        types::$fatname::ID => Some(TagTagged::$fatname(unsafe {
+                            &*core::ptr::from_raw_parts::<types::$fatname>(
+                                contents_addr,
+                                size as usize - core::mem::size_of::<Self>(),
+                            )
+                        }))
+                    ),*,
+                    _ => None,
+                }
+            }
+
+            typ_match!(match typ {
+                Terminate
+                BasicMemoryInformation
+                BIOSBootDevice
+                APMTable
+                ImageLoadBasePhyAddr
+            } fat {
+                BootCommandLine
+                BootLoaderName
+                MemoryMap
+                FramebufferInfo
+                ELFSymbols
+                ACPIoldRSDP
+            })
+        }
+    }
+
+    // ---
+
+    /// Represents the fixed part of the BIF
+    #[repr(C, align(8))]
+    pub struct FixedPart {
+        pub total_size: u32,
+        _reserved: u32,
+        __end: (),
+    }
+
+    /// Iterator for the tags of a [`FixedPart`]
+    pub struct TagsIter<'a> {
+        rem_size: u32,
+        next_ref: &'a TagHead,
+    }
+
+    impl<'a> TagsIter<'a> {
+        pub fn new(fixed: &FixedPart) -> Self {
+            let rem_size = fixed.total_size - core::mem::size_of::<FixedPart>() as u32;
+            let next_ptr = unsafe { &*core::ptr::addr_of!(fixed.__end).cast() };
+
+            Self {
+                rem_size,
+                next_ref: next_ptr,
+            }
+        }
+    }
+
+    impl<'a> Iterator for TagsIter<'a> {
+        type Item = &'a TagHead;
+
+        fn next(&mut self) -> Option<&'a TagHead> {
+            if self.rem_size > 0 {
+                let this_ref = self.next_ref;
+                self.rem_size -= this_ref.aligned8_size();
+                // SAFETY: if there were no tags left we'd reach rem_size and not use this referece
+                // any further
+                self.next_ref = unsafe { this_ref.next() };
+                Some(this_ref)
+            } else {
+                None
+            }
+        }
+    }
 }

members/oxide/src/start_stub.rs

@@ -0,0 +1,16 @@
+//! <https://www.gnu.org/software/grub/manual/multiboot2/multiboot.html>
+
+use core::arch::naked_asm;
+
+#[cfg(target_arch = "x86")]
+#[unsafe(no_mangle)]
+#[unsafe(naked)]
+unsafe extern "C" fn start_stub() -> ! {
+    // In cdecl, protected i386, the first argument is passed in the stack
+
+    // Sadly need to call bcs stack expectations, I wanna make a extern natural compiled thing for
+    // this.
+
+    const _: extern "C" fn(&crate::multiboot2::bif::FixedPart) -> ! = crate::start;
+    naked_asm!("push ebx", "call {}", sym crate::start);
+}

members/oxide/src/vga/mod.rs

@@ -54,7 +54,7 @@ impl<M: TextMode> VgaBuffer<M> {
     where
         [[(u8, u8); M::WIDTH as usize]; M::HEIGHT as usize]:,
     {
-        unsafe { core::mem::transmute(Self::VGA_ADDR) }
+        unsafe { &mut *Self::VGA_ADDR.cast() }
     }
 }
 

members/oxide/src/vga/vt.rs

@@ -1,3 +1,5 @@
+use core::fmt::Write;
+
 use crate::vga::{ColorNibble, TextMode, VgaBuffer, VgaColor};
 
 pub struct Writer<M: TextMode> {
@@ -20,7 +22,7 @@ where
 
     pub fn carry(&mut self) {
         self.pos.0 = 0;
-        if self.pos.1 >= M::HEIGHT {
+        if self.pos.1 + 1 >= M::HEIGHT {
             self.slide();
         } else {
             self.pos.1 += 1;
@@ -28,7 +30,7 @@ where
     }
 
     pub fn next_cell(&mut self) {
-        if self.pos.0 >= M::WIDTH {
+        if self.pos.0 + 1 >= M::WIDTH {
             self.carry();
         } else {
             self.pos.0 += 1;
@@ -94,3 +96,13 @@ where
         }
     }
 }
+
+impl<M: TextMode> Write for Writer<M>
+where
+    [[(u8, u8); M::WIDTH as usize]; M::HEIGHT as usize]:,
+{
+    fn write_str(&mut self, s: &str) -> core::fmt::Result {
+        self.write(s.as_bytes());
+        Ok(())
+    }
+}

mk/make_bootloader/grub.mk

@@ -6,4 +6,5 @@ $(OUTIMG): $(KERNELFILE) $(GRUB_CFG)
 	mkdir -p $(GRUB_DIR)/boot/grub
 	cp $(KERNELFILE) $(GRUB_DIR)/boot/kernel.bin
 	cp $(GRUB_CFG) $(GRUB_DIR)/boot/grub/grub.cfg
+	sed -i 's/$$args/$(CMDLINE)/' $(GRUB_DIR)/boot/grub/grub.cfg
 	grub-mkrescue -o $@ $(GRUB_DIR)