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Function comments (v1)

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xamidev
2026-03-13 12:51:29 +01:00
parent 8e2a612d88
commit 8026c33639
25 changed files with 560 additions and 48 deletions
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54
src/mem/paging/paging.c
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@@ -24,17 +24,41 @@ If we use 1GB huge pages: PML4 -> PDPT -> 1gb pages
4KB (regular size): PML4 -> PDPT -> PD -> PT -> 4kb pages
*/
/*
* load_cr3 - Load a new value into the CR3 register
* @value: the value to load
*
* This function is used to load the physical address
* of the root page table (PML4), to switch the paging
* structures the CPU sees and uses.
*/
void load_cr3(uint64_t value) {
asm volatile ("mov %0, %%cr3" :: "r"(value) : "memory");
}
// To flush TLB
/*
* invlpg - Invalidates a Translation Lookaside Buffer entry
* @addr: page memory address
*
* This function is used to flush at least the TLB entrie(s)
* for the page that contains the <addr> address.
*/
static inline void invlpg(void *addr)
{
asm volatile("invlpg (%0)" :: "r"(addr) : "memory");
}
// Allocates a 512-entry 64bit page table/directory/whatever (zeroed)
/*
* alloc_page_table - Page table allocation
*
* This function allocates enough memory for a 512-entry
* 64-bit page table, for any level (PML4/3/2).
*
* Memory allocated here is zeroed.
*
* Return:
* <virt> - Pointer to allocated page table
*/
static uint64_t* alloc_page_table()
{
uint64_t* virt = (uint64_t*)PHYS_TO_VIRT(pmm_alloc());
@@ -49,10 +73,19 @@ static uint64_t* alloc_page_table()
__attribute__((aligned(4096)))
uint64_t *kernel_pml4;
// Map a page, taking virt and phys address. This will go through the paging structures
// beginning at the given root table, translate the virtual address in indexes in
// page table/directories, and then mapping the correct page table entry with the
// given physical address + flags
/*
* paging_map_page - Mapping a memory page
* @root_table: Address of the PML4
* @virt: Virtual address
* @phys: Physical address
* @flags: Flags to set on page
*
* This function maps the physical address <phys> to the virtual
* address <virt>, using the paging structures beginning at
* <root_table>. <flags> can be set according to the PTE_FLAGS enum.
*
* If a page table/directory entry is not present yet, it creates it.
*/
void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_t flags)
{
virt = PAGE_ALIGN_DOWN(virt);
@@ -102,6 +135,15 @@ void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_
uint64_t kernel_phys_base;
uint64_t kernel_virt_base;
/*
* paging_init - Paging initialization
* @boot_ctx: Boot context structure
*
* This function initializes new paging structures, to replace
* the ones given by the bootloader.
*
* It maps the kernel, the HHDM space, and the framebuffer.
*/
void paging_init(struct boot_context boot_ctx)
{
// We should map the kernel, GDT, IDT, stack, framebuffer.