boot: separate BIOS from UEFI
boot/bios/ now holds the MBR, the El Torito stub and the real-mode stage 2; boot/uefi/ is empty and documented. Separate directories rather than #ifdefs, because the two share almost nothing. A BIOS loader lives in 16-bit real mode, reaches the firmware through software interrupts, and walks itself up into long mode. A UEFI loader is a 64-bit PE that the firmware has already placed in long mode with paging on, calling services through a table of function pointers. What they do share is the hand-off contract, which boot/README.md now writes down: ELF segments placed, long mode, a 24-byte-entry memory map at E820_MAP_ADDR, framebuffer geometry at VBE_INFO_ADDR. That contract is the point of documenting it now. UEFI's GetMemoryMap returns EFI_MEMORY_DESCRIPTORs, and the right move is to translate them into the entries kernel/arch/x86_64/e820.c already parses rather than teach the kernel a second format. Build output paths under $(BUILD)/boot are unchanged; only sources moved.
This commit is contained in:
Nexoniarz
parent
8a4ac03ea9
commit
08a1a9033a
19 changed files with 125 additions and 33 deletions
|
|
@ -16,7 +16,7 @@ one group. Verified rendering correctly on 2026-08-08.
|
|||
counter-intuitive part and it is a timing fact, not a preference: the kernel does
|
||||
not reach `vga_init()` until roughly the last 300ms of a ~2.8s boot, so a
|
||||
kernel-drawn logo appeared for about one frame before `console_takeover()` wiped
|
||||
it. Drawn from `splash()` in `boot/stage2main.c` it is up for the whole boot.
|
||||
it. Drawn from `splash()` in `boot/bios/stage2main.c` it is up for the whole boot.
|
||||
`kernel/dev/vga.c` keeps the same drawing code against the same mask
|
||||
(`vga_draw_logo`, `vga_logo_centered`) for things that want the mark *after*
|
||||
boot — the crash screen, eventually `schinit`. Don't "fix" the duplication by
|
||||
|
|
@ -35,7 +35,7 @@ for the one rule. 4 bits rather than 8 because the header is included by the
|
|||
**`STAGE2_SECTORS` was encoded in five places, not the three `docs/layout.md`
|
||||
claimed.** Raising it 24 → 48 to fit the 8 KiB mask proved it: the `dd seek=25`
|
||||
offset stayed behind and the kernel got written straight over stage2's tail.
|
||||
The five were `boot/bootasm.S`, `boot/stage2main.c`, the `dd seek=`, and *twice*
|
||||
The five were `boot/bios/bootasm.S`, `boot/bios/stage2main.c`, the `dd seek=`, and *twice*
|
||||
inside `tools/mkiso.sh` (its size assertion and `-boot-load-size`). It now lives
|
||||
only in the root Makefile, which passes `-DSTAGE2_SECTORS` and exports it to
|
||||
mkiso; the `#define`s left in the boot sources are `#ifndef` fallbacks. Hard
|
||||
|
|
|
|||
|
|
@ -18,7 +18,7 @@ protected mode before it reads the kernel. That rules out both El Torito
|
|||
emulation modes (hard-disk emulation exists only through the BIOS) and floppy
|
||||
emulation (2.88 MB cap). So:
|
||||
|
||||
- `boot/cdboot.S` — a separate stage 1 for optical media. `tools/mkiso.sh`
|
||||
- `boot/bios/cdboot.S` — a separate stage 1 for optical media. `tools/mkiso.sh`
|
||||
passes `-boot-load-size 25`, so the BIOS loads cdboot *and* all 24 sectors of
|
||||
stage2 before anything of ours runs, putting stage2 at 0x7E00 exactly where
|
||||
`bootasm.S` would have. cdboot only records the medium and jumps.
|
||||
|
|
|
|||
22
Makefile
22
Makefile
|
|
@ -383,10 +383,10 @@ qemu-iso: schos.iso
|
|||
# splash, and loads the kernel — not size-constrained the same way, just
|
||||
# padded out to a fixed STAGE2_SECTORS*512 bytes so the kernel's starting
|
||||
# sector on disk is predictable (kept in sync with STAGE2_SECTORS in
|
||||
# boot/bootasm.S and boot/stage2main.c).
|
||||
# boot/bios/bootasm.S and boot/bios/stage2main.c).
|
||||
# -----------------------------------------------------------------------
|
||||
# STAGE2_SECTORS used to be written out three times -- here, in boot/bootasm.S
|
||||
# and in boot/stage2main.c -- and docs/layout.md carried a warning about keeping
|
||||
# STAGE2_SECTORS used to be written out three times -- here, in boot/bios/bootasm.S
|
||||
# and in boot/bios/stage2main.c -- and docs/layout.md carried a warning about keeping
|
||||
# them in step. They are now all fed from this one variable via -D, so the
|
||||
# warning describes a problem that can no longer happen. Both C/asm files keep
|
||||
# an #ifndef fallback purely so they still read sensibly on their own.
|
||||
|
|
@ -405,9 +405,9 @@ STAGE2_DEF = -DSTAGE2_SECTORS=$(STAGE2_SECTORS)
|
|||
# that make carried on and padstage2.pl received nonsense.
|
||||
STAGE2_BYTES = $$(( $(STAGE2_SECTORS) * 512 ))
|
||||
|
||||
$(BUILD)/boot/bootblock: boot/bootasm.S
|
||||
$(BUILD)/boot/bootblock: boot/bios/bootasm.S
|
||||
@mkdir -p $(BUILD)/boot
|
||||
$(CC32) $(STAGE2_DEF) -fno-builtin -fno-pic -nostdinc -I./include -c boot/bootasm.S -o $(BUILD)/boot/bootasm.o
|
||||
$(CC32) $(STAGE2_DEF) -fno-builtin -fno-pic -nostdinc -I./include -c boot/bios/bootasm.S -o $(BUILD)/boot/bootasm.o
|
||||
$(LD) -m elf_i386 -nostdlib $(LD_LOWBASE) -n -N -e start -Ttext 0x7C00 \
|
||||
-o $(BUILD)/boot/bootblocktmp.o $(BUILD)/boot/bootasm.o
|
||||
$(OBJCOPY) -S -O binary -j .text $(BUILD)/boot/bootblocktmp.o $(BUILD)/boot/bootblock
|
||||
|
|
@ -415,19 +415,19 @@ $(BUILD)/boot/bootblock: boot/bootasm.S
|
|||
|
||||
# Stage 1 for optical media. Same job as bootblock, far less of it: El Torito
|
||||
# has already loaded stage2 alongside this sector by the time it runs, so it
|
||||
# only records that we came from a CD and jumps. See boot/cdboot.S.
|
||||
$(BUILD)/boot/cdboot: boot/cdboot.S
|
||||
# only records that we came from a CD and jumps. See boot/bios/cdboot.S.
|
||||
$(BUILD)/boot/cdboot: boot/bios/cdboot.S
|
||||
@mkdir -p $(BUILD)/boot
|
||||
$(CC32) -fno-builtin -fno-pic -nostdinc -I./include -c boot/cdboot.S -o $(BUILD)/boot/cdbootasm.o
|
||||
$(CC32) -fno-builtin -fno-pic -nostdinc -I./include -c boot/bios/cdboot.S -o $(BUILD)/boot/cdbootasm.o
|
||||
$(LD) -m elf_i386 -nostdlib $(LD_LOWBASE) -n -N -e start -Ttext 0x7C00 \
|
||||
-o $(BUILD)/boot/cdboottmp.o $(BUILD)/boot/cdbootasm.o
|
||||
$(OBJCOPY) -S -O binary -j .text $(BUILD)/boot/cdboottmp.o $@
|
||||
./tools/sign.pl $@
|
||||
|
||||
$(BUILD)/boot/stage2: boot/stage2.S boot/stage2main.c include/logo.h
|
||||
$(BUILD)/boot/stage2: boot/bios/stage2.S boot/bios/stage2main.c include/logo.h
|
||||
@mkdir -p $(BUILD)/boot
|
||||
$(CC32) $(STAGE2_DEF) -fno-builtin -fno-pic -nostdinc -I./include -c boot/stage2.S -o $(BUILD)/boot/stage2asm.o
|
||||
$(CC32) $(STAGE2_DEF) -fno-builtin -fno-pic -O -nostdinc -I./include -c boot/stage2main.c -o $(BUILD)/boot/stage2main.o
|
||||
$(CC32) $(STAGE2_DEF) -fno-builtin -fno-pic -nostdinc -I./include -c boot/bios/stage2.S -o $(BUILD)/boot/stage2asm.o
|
||||
$(CC32) $(STAGE2_DEF) -fno-builtin -fno-pic -O -nostdinc -I./include -c boot/bios/stage2main.c -o $(BUILD)/boot/stage2main.o
|
||||
$(LD) -m elf_i386 -nostdlib $(LD_LOWBASE) -n -N -e stage2start -Ttext 0x7E00 \
|
||||
-o $(BUILD)/boot/stage2tmp.o $(BUILD)/boot/stage2asm.o $(BUILD)/boot/stage2main.o
|
||||
$(OBJCOPY) -S -O binary -j .text -j .rodata -j .data $(BUILD)/boot/stage2tmp.o $(BUILD)/boot/stage2
|
||||
|
|
|
|||
64
boot/README.md
Normal file
64
boot/README.md
Normal file
|
|
@ -0,0 +1,64 @@
|
|||
<!-- SPDX-License-Identifier: Apache-2.0 -->
|
||||
# Booting SchOS
|
||||
|
||||
Two firmware paths, kept apart on purpose:
|
||||
|
||||
```
|
||||
boot/
|
||||
bios/ legacy BIOS: MBR, El Torito CD stub, real-mode stage 2
|
||||
uefi/ UEFI application (not written yet)
|
||||
```
|
||||
|
||||
They are separate directories rather than `#ifdef`s in one because they share
|
||||
almost nothing. A BIOS loader lives in 16-bit real mode, talks to the firmware
|
||||
through software interrupts, and has to walk itself up into long mode. A UEFI
|
||||
loader is a 64-bit PE executable that the firmware has *already* placed in long
|
||||
mode with paging on, and it asks for services by calling through a table of
|
||||
function pointers. The only things genuinely in common are the logo bitmap, the
|
||||
menu's appearance, and the hand-off contract below.
|
||||
|
||||
## What the loader must hand the kernel
|
||||
|
||||
Whichever path runs, the kernel expects the same things. This is the contract;
|
||||
a second loader is correct exactly when it satisfies it.
|
||||
|
||||
| | Where | Notes |
|
||||
|---|---|---|
|
||||
| Kernel image | loaded per its ELF program headers | entry at `entry64` |
|
||||
| CPU state | long mode, paging on, interrupts off | BIOS path builds this itself |
|
||||
| Memory map | `E820_MAP_ADDR`, 24-byte entries, count at `E820_COUNT_ADDR` | `kernel/arch/x86_64/e820.c` reads it |
|
||||
| Framebuffer | `VBE_INFO_ADDR` | address, pitch, width, height, depth |
|
||||
| Verbose flag | `BOOT_VERBOSE_FLAG_ADDR` | set by the F8 menu |
|
||||
|
||||
The addresses are defined once, in `include/memlayout.h` and
|
||||
`boot/bios/stage2main.c`. A UEFI loader must fill the same structures — the
|
||||
kernel does not care which firmware produced them, and that is what keeps the
|
||||
split cheap.
|
||||
|
||||
`e820.c` reads a *BIOS* memory map. UEFI hands out a different structure
|
||||
(`EFI_MEMORY_DESCRIPTOR`, from `GetMemoryMap`), so the UEFI loader has to
|
||||
translate it into the same 24-byte entries rather than inventing a second
|
||||
format for the kernel to learn.
|
||||
|
||||
## The BIOS path today
|
||||
|
||||
1. **`bios/bootasm.S`** — the literal MBR sector. Signed to 512 bytes by
|
||||
`tools/sign.pl`, loads stage 2 from LBA 1 and jumps.
|
||||
2. **`bios/cdboot.S`** — the same job for optical media, as an El Torito
|
||||
no-emulation image. Separate because the loader never uses INT 13h and so
|
||||
needs a real ATAPI read.
|
||||
3. **`bios/stage2.S`** — collects the E820 map, sets a VBE mode, enters
|
||||
protected mode.
|
||||
4. **`bios/stage2main.c`** — the boot menu and splash, then loads the kernel
|
||||
and enters long mode.
|
||||
|
||||
`STAGE2_SECTORS` is defined **once**, in the Makefile, and passed to both the
|
||||
assembler and the `dd` that writes the image. It used to be written out by hand
|
||||
in five places and silently truncated the loader when they disagreed.
|
||||
|
||||
## Why UEFI is worth doing
|
||||
|
||||
Everything since roughly 2012 boots UEFI by default, and Secure Boot machines
|
||||
will not run the BIOS path at all without firmware settings most people never
|
||||
touch. The BIOS loader stays regardless: it is what QEMU's default machine and
|
||||
older hardware use, and it costs nothing to keep once the two are separated.
|
||||
|
|
@ -46,7 +46,7 @@ _Static_assert(0x7E00 + STAGE2_SECTORS * 512 <= 0x10000,
|
|||
// kind of thing that turns into one later.
|
||||
#define BOOT_VERBOSE_FLAG_ADDR (VBE_INFO_ADDR + 0x100)
|
||||
|
||||
// Set by boot/cdboot.S when we were booted from optical media. One byte past
|
||||
// Set by boot/bios/cdboot.S when we were booted from optical media. One byte past
|
||||
// the verbose flag, for the same reason that one sits where it does: clear of
|
||||
// the 256-byte VBE mode info block at VBE_INFO_ADDR.
|
||||
#define BOOT_MEDIA_FLAG_ADDR (VBE_INFO_ADDR + 0x101)
|
||||
28
boot/uefi/README.md
Normal file
28
boot/uefi/README.md
Normal file
|
|
@ -0,0 +1,28 @@
|
|||
<!-- SPDX-License-Identifier: Apache-2.0 -->
|
||||
# UEFI loader
|
||||
|
||||
Not written yet. This directory exists so the BIOS path could be moved into
|
||||
`boot/bios/` without pretending the split was hypothetical.
|
||||
|
||||
See `../README.md` for the hand-off contract a loader has to satisfy. The
|
||||
short version: the kernel wants long mode with paging on, its ELF segments
|
||||
placed, a 24-byte-entry E820-shaped memory map, and framebuffer geometry — and
|
||||
it does not care which firmware produced them.
|
||||
|
||||
What this will need, in rough order:
|
||||
|
||||
1. A PE/COFF target. clang can emit one directly
|
||||
(`--target=x86_64-unknown-windows -fuse-ld=lld-link`), so no new toolchain:
|
||||
the same LLVM install already builds every other target here.
|
||||
2. The handful of UEFI structures actually used — the system table, boot
|
||||
services, `LOADED_IMAGE`, `SIMPLE_FILE_SYSTEM`, `GRAPHICS_OUTPUT`. Written
|
||||
from the specification rather than by importing gnu-efi or EDK II, which is
|
||||
both a licence question and a large dependency for something this small.
|
||||
3. `GetMemoryMap` translated into the same 24-byte entries `e820.c` already
|
||||
parses. Not a second format for the kernel to learn.
|
||||
4. `ExitBootServices` before touching the memory it described.
|
||||
5. Graphics Output Protocol for the framebuffer, filling the same
|
||||
`VBE_INFO_ADDR` structure the BIOS path fills.
|
||||
|
||||
The image goes at `EFI/BOOT/BOOTX64.EFI` on a FAT ESP, which also means the
|
||||
ISO gains an El Torito EFI entry alongside the BIOS one it already has.
|
||||
|
|
@ -142,14 +142,14 @@ no room to add so much as a print statement.
|
|||
|
||||
Split into two stages, the standard way real bootloaders solve this:
|
||||
|
||||
- **Stage 1** (`boot/bootasm.S`, still the literal MBR sector, still
|
||||
- **Stage 1** (`boot/bios/bootasm.S`, still the literal MBR sector, still
|
||||
≤510 bytes) does exactly one thing: raw IDE PIO (LBA28) reads
|
||||
`STAGE2_SECTORS` (16) sectors starting at disk sector 1 into memory at
|
||||
`0x7E00`, then jumps there. Nothing else fits, nothing else is needed.
|
||||
(Caught a real bug writing this: `outb $0x1F7,%al`-style immediates
|
||||
silently truncate to 8 bits — ports 0x1F2-0x1F7 are all > 0xFF and need
|
||||
the `%dx` register form, or you're hitting the wrong I/O port entirely.)
|
||||
- **Stage 2** (`boot/stage2.S` + `boot/stage2main.c`, loaded at `0x7E00`,
|
||||
- **Stage 2** (`boot/bios/stage2.S` + `boot/bios/stage2main.c`, loaded at `0x7E00`,
|
||||
occupies disk sectors 1-16) does everything stage 1 used to skip straight
|
||||
to, plus a boot banner (BIOS teletype, real mode, before the VBE mode
|
||||
switch — note this only reaches the video device, not serial, so it
|
||||
|
|
@ -287,7 +287,7 @@ across a long `ls`-heavy session to see what's actually climbing.
|
|||
|
||||
## 6. Boot speed
|
||||
|
||||
Two cheap, real wins in `boot/stage2main.c`, no functional changes:
|
||||
Two cheap, real wins in `boot/bios/stage2main.c`, no functional changes:
|
||||
|
||||
- `progress_tick()` (called once per 512-byte disk sector) used to trigger
|
||||
a full progress-bar redraw — border plus fill, a few thousand pixel
|
||||
|
|
|
|||
|
|
@ -155,7 +155,7 @@ blob's build location and those symbol names change; update the Makefile to
|
|||
match or the kernel fails to link.
|
||||
|
||||
**`STAGE2_SECTORS` now lives in exactly one place: the root `Makefile`.** It used
|
||||
to be written out by hand in five — `boot/bootasm.S`, `boot/stage2main.c`'s
|
||||
to be written out by hand in five — `boot/bios/bootasm.S`, `boot/bios/stage2main.c`'s
|
||||
`readseg()`, the `dd ... seek=` offset, and twice more inside `tools/posix/mkiso.sh`
|
||||
(its stage2 size assertion and `-boot-load-size`). This note used to warn you to
|
||||
keep three of them in step and did not know about the other two.
|
||||
|
|
@ -170,6 +170,6 @@ Makefile always wins.
|
|||
|
||||
Two things still fail the build rather than silently misbooting, and should stay
|
||||
that way: `tools/padstage2.pl` errors if stage2 overflows its budget instead of
|
||||
truncating it, and `boot/stage2main.c` static-asserts that stage2 cannot reach
|
||||
truncating it, and `boot/bios/stage2main.c` static-asserts that stage2 cannot reach
|
||||
the multiboot kernel-search buffer at `0x10000` — which puts the hard ceiling at
|
||||
65 sectors, since stage2 loads at `0x7E00`.
|
||||
|
|
|
|||
|
|
@ -354,7 +354,7 @@ stops being extendable: it is 16-bit real mode, INT 10h VBE, and PIO ATA, none
|
|||
of which exist on a UEFI-only machine. The realistic shape is a *second*
|
||||
loader — an EFI application that gets the framebuffer from GOP, the memory map
|
||||
from `GetMemoryMap()`, loads the kernel off a FAT ESP, and enters at the same
|
||||
place `boot/stage2main.c` does — rather than a port of the existing one. Worth
|
||||
place `boot/bios/stage2main.c` does — rather than a port of the existing one. Worth
|
||||
noting that the splash work just done survives that transition: it is a mask, a
|
||||
palette and a layout, none of which care how the pixels were found. What does
|
||||
not survive is every assumption in `stage2main.c` about where things live in low
|
||||
|
|
@ -465,9 +465,9 @@ does not. Measured 2026-08-08: boots at 224M and above, triple faults at 192M
|
|||
and below. Nothing is actually being *used* — the requirement is entirely
|
||||
fictional.
|
||||
|
||||
**The fix is already half-built.** `boot/stage2.S` collects a full E820 memory
|
||||
**The fix is already half-built.** `boot/bios/stage2.S` collects a full E820 memory
|
||||
map in real mode and leaves it at `VBE_INFO_ADDR + 0x200` (count) and `+ 0x208`
|
||||
(24-byte entries); `boot/stage2main.c` already parses it to print detected RAM.
|
||||
(24-byte entries); `boot/bios/stage2main.c` already parses it to print detected RAM.
|
||||
**The kernel never reads it.** So: have `main()` take the top of the highest
|
||||
usable E820 region instead of the constant, clamp it to what the direct map
|
||||
covers, and keep `PHYSTOP` only as a fallback for the case where the firmware
|
||||
|
|
|
|||
|
|
@ -7,7 +7,7 @@
|
|||
// solid logo. Whoever draws it picks the colour, so the palette stays in
|
||||
// include/theme.h and can change without regenerating anything.
|
||||
//
|
||||
// Two pixels per byte, high nibble first. Included by boot/stage2main.c
|
||||
// Two pixels per byte, high nibble first. Included by boot/bios/stage2main.c
|
||||
// as well as kernel/dev/vga.c, and stage2 must fit below the 0x10000
|
||||
// kernel-search buffer -- hence 4 bits rather than 8.
|
||||
|
||||
|
|
|
|||
|
|
@ -13,7 +13,7 @@
|
|||
// Boot, console and shell share SCH_BG/SCH_FG. The panic screen keeps the
|
||||
// full-bleed purple entirely to itself, which is what makes it mean something.
|
||||
//
|
||||
// Included by boot/stage2main.c (freestanding, pre-kernel), kernel/dev/vga.c,
|
||||
// Included by boot/bios/stage2main.c (freestanding, pre-kernel), kernel/dev/vga.c,
|
||||
// kernel/core/console.c and kernel/core/panic.c. Plain #defines only — no
|
||||
// types, no code — because stage2 is compiled 32-bit against a different
|
||||
// world than the kernel.
|
||||
|
|
|
|||
|
|
@ -7,7 +7,7 @@
|
|||
// every byte above 224 MB is invisible. Measured before this file existed:
|
||||
// SchOS booted at 224 MB and triple faulted at 192 MB, for no reason at all.
|
||||
//
|
||||
// The firmware has known the answer the whole time. boot/stage2.S asks it with
|
||||
// The firmware has known the answer the whole time. boot/bios/stage2.S asks it with
|
||||
// INT 0x15 / E820 in real mode -- the same interface Linux's boot stub and GRUB
|
||||
// use -- and leaves the result in low memory. stage2main.c already parses it to
|
||||
// print detected RAM on the splash. The kernel simply never read it.
|
||||
|
|
@ -23,7 +23,7 @@
|
|||
uint64 phystop = PHYSTOP_FALLBACK;
|
||||
|
||||
// Where stage2 left the map. Must match E820_COUNT_ADDR / E820_MAP_ADDR in
|
||||
// boot/stage2main.c, which are themselves relative to VBE_INFO_ADDR.
|
||||
// boot/bios/stage2main.c, which are themselves relative to VBE_INFO_ADDR.
|
||||
#define E820_COUNT_ADDR (0x30000 + 0x200)
|
||||
#define E820_MAP_ADDR (0x30000 + 0x208)
|
||||
|
||||
|
|
|
|||
|
|
@ -12,12 +12,12 @@ static void startothers(void);
|
|||
static void mpmain(void) __attribute__((noreturn));
|
||||
extern char end[]; // first address after kernel loaded from ELF file
|
||||
|
||||
// Set by stage2main.c (boot/stage2main.c, BOOT_VERBOSE_FLAG_ADDR) when the
|
||||
// Set by stage2main.c (boot/bios/stage2main.c, BOOT_VERBOSE_FLAG_ADDR) when the
|
||||
// user picks "Boot SchOS (verbose)" from the F8 boot menu; read once here,
|
||||
// before anything else, so subsystem init can log its own steps.
|
||||
int boot_verbose;
|
||||
|
||||
// Must match BOOT_VERBOSE_FLAG_ADDR in boot/stage2main.c exactly: just past
|
||||
// Must match BOOT_VERBOSE_FLAG_ADDR in boot/bios/stage2main.c exactly: just past
|
||||
// the VBE info block, not 0x7000 (startothers() below uses that address for
|
||||
// the AP boot trampoline).
|
||||
#define BOOT_VERBOSE_FLAG_ADDR (0x30000 + 0x100)
|
||||
|
|
|
|||
|
|
@ -39,7 +39,7 @@ vga_set_bg(uint32 color)
|
|||
vga_bg = color;
|
||||
}
|
||||
|
||||
// Written by boot/stage2.S's VBE call and read by boot/stage2main.c under
|
||||
// Written by boot/bios/stage2.S's VBE call and read by boot/bios/stage2main.c under
|
||||
// the same name (VBE_INFO_ADDR) — not 0x9000, since stage2's own code now
|
||||
// runs up to nearly 0x9000 once the boot-menu/progress-bar logic is
|
||||
// included, which would otherwise clobber a mode info block placed there.
|
||||
|
|
@ -391,7 +391,7 @@ vga_text_at(int x, int y, const char *s, uint32 color)
|
|||
// --- Logo ------------------------------------------------------------------
|
||||
//
|
||||
// The boot splash's logo is drawn by the *loader*, not here -- see splash() in
|
||||
// boot/stage2main.c. It has to be, because the kernel does not reach vga_init()
|
||||
// boot/bios/stage2main.c. It has to be, because the kernel does not reach vga_init()
|
||||
// until roughly the last 300ms of a 2.8s boot: drawing it here put the logo on
|
||||
// screen for one frame before console_takeover() wiped it, which is worse than
|
||||
// not having one.
|
||||
|
|
|
|||
|
|
@ -22,7 +22,7 @@
|
|||
# is that stage2main.c reads the kernel back with ATAPI instead of ATA.
|
||||
#
|
||||
# STAGE2_SECTORS comes from the environment, set by the Makefile, because this
|
||||
# same number also lives in boot/bootasm.S, boot/stage2main.c and the dd offsets
|
||||
# same number also lives in boot/bios/bootasm.S, boot/bios/stage2main.c and the dd offsets
|
||||
# in schos.img's recipe. It was previously written out by hand in three
|
||||
# separate spots in this file alone, and raising it for the boot logo is what
|
||||
# turned that from a latent hazard into a broken image.
|
||||
|
|
|
|||
|
|
@ -468,7 +468,7 @@ if ($gens.Count -ge 2 -and
|
|||
|
||||
if ($Fb) {
|
||||
Expect 'id\s+schosfb' 'FBIOGET_FSCREENINFO identifies the device'
|
||||
# 800x600 is what boot/stage2.S asks VBE for. Asserting the numbers rather
|
||||
# 800x600 is what boot/bios/stage2.S asks VBE for. Asserting the numbers rather
|
||||
# than just "the ioctl returned" is the point: the old code path returned
|
||||
# success with an untouched buffer, i.e. a 0x0 screen.
|
||||
Expect '(?m)^xres\s+800' 'the reported width is the mode actually set'
|
||||
|
|
|
|||
Loading…
Reference in a new issue