RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-04 18:17:36 +00:00
Code Issues Activity Actions

Kernel: Implement OffsetDiskDevice to prepare for partition support

Browse source 
This implements a passthrough disk driver that translates the read/write
block addresses by a fixed offset. This could form the basis of MBR
partition support if we were to parse the MBR table at boot and create that
OffsetDiskDevice dynamically, rather than seeking to a fixed offset.

This also introduces a dependency in the form of grub. You'll need to have
32-bit grub binaries installed to build the project now.

As a bonus, divorcing Serenity from qemu's kernel loading means we can now
*technically* boot on real hardware. It just... doesn't get very far yet.
If you write the `_disk_image` file to an IDE hard drive and boot it in a
machine that supports all the basic PC hardware, it *will* start loading
the kernel.
This commit is contained in:
Conrad Pankoff 2019-06-02 18:58:59 +10:00 • committed by Andreas Kling
parent 5e1c7cb32c
commit 6f43f81fb4
8 changed files with 220 additions and 66 deletions
Download patch file Download diff file Expand all files Collapse all files

9
Kernel/init.cpp
View file

@ -6,6 +6,7 @@
#include "Process.h"
#include "PIC.h"
#include <Kernel/Devices/IDEDiskDevice.h>
#include <Kernel/Devices/OffsetDiskDevice.h>
#include "KSyms.h"
#include <Kernel/Devices/NullDevice.h>
#include <Kernel/Devices/ZeroDevice.h>
@ -57,6 +58,11 @@ VFS* vfs;
}
#endif
// TODO: delete this magic number. this block offset corresponds to a
// partition that starts at 32k into an MBR disk. this value is also specified
// in sync.sh, but should ideally be read from the MBR header at startup.
#define PARTITION_OFFSET 62
[[noreturn]] static void init_stage2()
{
Syscall::initialize();
@ -66,7 +72,8 @@ VFS* vfs;
auto dev_random = make<RandomDevice>();
auto dev_ptmx = make<PTYMultiplexer>();
auto dev_hd0 = IDEDiskDevice::create();
auto e2fs = Ext2FS::create(dev_hd0.copy_ref());
auto dev_hd0p1 = OffsetDiskDevice::create(dev_hd0.copy_ref(), PARTITION_OFFSET);
auto e2fs = Ext2FS::create(dev_hd0p1.copy_ref());
e2fs->initialize();
vfs->mount_root(e2fs.copy_ref());