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Use 4 KiB pages with 2-level paging (dir & tables)

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This commit is contained in:
Alex Kotov 2021-12-20 09:20:34 +05:00
parent f82698edad
commit 18deba7396
Signed by: kotovalexarian
GPG key ID: 553C0EBBEB5D5F08
1 changed files with 31 additions and 12 deletions
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43
kernel/paging.c
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@ -27,7 +27,7 @@ void paging_enable()
cr4 = kernaux_arch_i386_read_cr4(); cr4 = kernaux_arch_i386_read_cr4();
// Our page table contains 4MB entries. // Our page table contains 4MB entries.
cr4 |= KERNAUX_ARCH_I386_CR4_PSE; // cr4 |= KERNAUX_ARCH_I386_CR4_PSE;
kernaux_arch_i386_write_cr4(cr4); kernaux_arch_i386_write_cr4(cr4);
@ -49,8 +49,8 @@ void paging_clear(struct Paging *const paging)
void paging_identity(struct Paging *const paging) void paging_identity(struct Paging *const paging)
{ {
for (size_t i = 0; i < PAGE_DIR_LENGTH; ++i) { for (size_t i = 0; i < (1024 * 1024); ++i) {
const size_t addr = i * PAGE_BIG_SIZE; const size_t addr = i * (4 * 1024);
mapping(paging, addr, addr); mapping(paging, addr, addr);
} }
} }
@ -59,8 +59,8 @@ void paging_mapkernel(
struct Paging *const paging, struct Paging *const paging,
const struct Kernel_Info *const kinfo const struct Kernel_Info *const kinfo
) { ) {
assert(!(kinfo->kernel_phys_base % PAGE_BIG_SIZE), "Kernel physical address is not aligned."); assert(!(kinfo->kernel_phys_base % (4 * 1024)), "Kernel physical address is not aligned.");
assert(!(kinfo->kernel_virt_base % PAGE_BIG_SIZE), "Kernel virtual address is not aligned."); assert(!(kinfo->kernel_virt_base % (4 * 1024)), "Kernel virtual address is not aligned.");
size_t phys = kinfo->kernel_phys_base; size_t phys = kinfo->kernel_phys_base;
size_t virt = kinfo->kernel_virt_base; size_t virt = kinfo->kernel_virt_base;
@ -69,9 +69,9 @@ void paging_mapkernel(
while (mapped < kinfo->kernel_size) { while (mapped < kinfo->kernel_size) {
mapping(paging, virt, phys); mapping(paging, virt, phys);
phys += PAGE_BIG_SIZE; phys += (4 * 1024);
virt += PAGE_BIG_SIZE; virt += (4 * 1024);
mapped += PAGE_BIG_SIZE; mapped += (4 * 1024);
} }
} }
@ -82,14 +82,20 @@ void mapping(
) { ) {
KERNAUX_NOTNULL_RETURN(paging); KERNAUX_NOTNULL_RETURN(paging);
const size_t pde_index = virt / PAGE_BIG_SIZE; const size_t pde_index = (virt >> 22);
struct KernAux_Arch_I386_PDE *const pde = &paging->page_dir.pdes[pde_index]; const size_t pte_index = (virt >> 12) & 0x3ff;
struct KernAux_Arch_I386_PageDir *const page_dir = &paging->page_dir;
struct KernAux_Arch_I386_PageTable *const page_table = &paging->page_tables[pde_index];
struct KernAux_Arch_I386_PDE *const pde = &page_dir->pdes[pde_index];
struct KernAux_Arch_I386_PTE *const pte = &page_table->ptes[pte_index];
if (!pde->present) { if (!pde->present) {
pde->addr = PAGE_DIR_ADDR(phys); pde->addr = ((size_t)page_table) >> 12;
pde->available1 = 0; pde->available1 = 0;
pde->page_size = 1; pde->page_size = 0;
pde->available0 = 0; pde->available0 = 0;
pde->accessed = 0; pde->accessed = 0;
pde->cache_disabled = 0; pde->cache_disabled = 0;
@ -98,4 +104,17 @@ void mapping(
pde->writable = 1; pde->writable = 1;
pde->present = 1; pde->present = 1;
} }
pte->addr = phys >> 12;
pte->available = 1;
pte->global = 1;
pte->attr_table = 0;
pte->dirty = 0;
pte->accessed = 0;
pte->cache_disabled = 0;
pte->write_through = 0;
pte->user = 0;
pte->writable = 1;
pte->present = 1;
} }