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Core kernel infrastructure: - Multiboot2 boot with GRUB, long mode setup, higher-half kernel - Serial port output for debugging - Unified boot info abstraction for future UEFI support Memory management: - Physical frame allocator with bitmap tracking - Page table manipulation via recursive mapping (PML4[510]) - Support for 4KB, 2MB, and 1GB page mappings - TLB invalidation and proper NXE support Build system: - Cargo-based build with custom x86_64 target - Makefile for QEMU and Bochs testing - GRUB ISO generation for multiboot2 boot
6 lines
1.4 KiB
Markdown
6 lines
1.4 KiB
Markdown
The XOmB exokernel multiplexes hardware resources mostly through the use of the virtual memory system. So, a hardware resource might be memory mapped into a certain memory range and then that memory range is, when access is granted, mapped into the virtual address space of a process.
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This means that the kernel needs to allocate memory pages in order to allocate the page table entries. So, it maintains the data structure responsible for keeping track of free pages of physical memory. Applications may request specific physical pages to be allocated. Applications may create resources which are represented by page table entries... in our case, the kernel is a PML4, a process is a PML3, and thus a resource is either a PML2 (PD) or a first-level page table (PT). An application or library OS (libOS) can do this by asking the kernel to allocate a resource with a particular physical page to be used as its relative page table root.
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The kernel should be somewhat aware of hardware memory mapped ranges and allocate resources for those that can be securely provisioned when asked by a user application via a library OS. The kernel does not create those resources itself, however, or have any logic that is specific to any hardware except what it needs for debugging itself. An 'init' process will eventually exist that will allocate some of those initial resources that it can pass off to driving libOSes and applications that run later.
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