From 82e9f02aef1ea1a6588234ee58e3625e3561005f Mon Sep 17 00:00:00 2001 From: Aleksa Vuckovic Date: Thu, 8 Sep 2022 14:37:47 +0200 Subject: higher half in x86_64 kernel is now located at -2GB heap blocks are aligned on block size paging will allocate new page tables on heap --- kernel/src/mem/heap.c | 23 ++++++++++--------- kernel/src/mem/paging.c | 55 +++++++++++++++++++++------------------------ kernel/src/mem/paging_asm.S | 4 ++-- 3 files changed, 40 insertions(+), 42 deletions(-) (limited to 'kernel/src/mem') diff --git a/kernel/src/mem/heap.c b/kernel/src/mem/heap.c index 229933b..e37e003 100644 --- a/kernel/src/mem/heap.c +++ b/kernel/src/mem/heap.c @@ -34,12 +34,12 @@ void kheap_add_block(kheap_t* kheap, uint64_t addr, uint32_t size, uint32_t bsiz bm[i] = 0; } - bcnt = upper_div(bcnt, bsize); - for (size_t i = 0; i < bcnt; i++) { + uint32_t bcnt_used = upper_div((bcnt + (uint32_t)sizeof(kheapblock_t)), bsize); + for (size_t i = 0; i < bcnt_used; i++) { bm[i] = 5; } - kheapblock->used = bcnt; + kheapblock->used = bcnt_used; } void* kheap_alloc(kheap_t* kheap, uint32_t size) @@ -52,6 +52,13 @@ void* kheap_alloc(kheap_t* kheap, uint32_t size) continue; } + // use heap with bsize 4096 just for that block size + bool ind1 = ((size % 4096) == 0); + bool ind2 = (kheapblock->bsize == 4096); + if (ind1 + ind2 == 1) { + continue; + } + uint32_t bcnt = kheapblock->size / kheapblock->bsize; uint32_t bneed = upper_div(size, kheapblock->bsize); uint8_t* bm = (uint8_t*)&kheapblock[1]; @@ -81,7 +88,7 @@ void* kheap_alloc(kheap_t* kheap, uint32_t size) kheapblock->used += bneed; - return (void*)(i * kheapblock->bsize + (uintptr_t)&kheapblock[1]); + return (void*)(i * kheapblock->bsize + (uintptr_t)&kheapblock[0]); } } printf("Error: there is no remaining memory in kheap\n"); @@ -118,10 +125,6 @@ void kheap_free(kheap_t* kheap, void* pointer) void init_heap() { kheap_init(&main_kheap); - - // allocate pages for kheap - for (size_t i = 0; i < upper_div(HEAP_SIZE, PAGE_SIZE); i++) - map_addr(HEAP_VMEM_ADDR + i * PAGE_SIZE, HEAP_PMEM_ADDR + i * PAGE_SIZE, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE); - - kheap_add_block(&main_kheap, HEAP_VMEM_ADDR, HEAP_SIZE, HEAP_BLOCK_SIZE); + kheap_add_block(&main_kheap, HEAP1_VMEM_ADDR, HEAP1_SIZE, HEAP1_BLOCK_SIZE); + kheap_add_block(&main_kheap, HEAP2_VMEM_ADDR, HEAP2_SIZE, HEAP2_BLOCK_SIZE); } diff --git a/kernel/src/mem/paging.c b/kernel/src/mem/paging.c index 19a2c3a..f714f66 100644 --- a/kernel/src/mem/paging.c +++ b/kernel/src/mem/paging.c @@ -1,17 +1,15 @@ #include #include +#include #include -#include +#include void load_pt_lvl4(uint64_t*); __attribute__((aligned(4096))) uint64_t page_table_lvl4[512]; __attribute__((aligned(4096))) uint64_t page_table_lvl3[512]; -__attribute__((aligned(4096))) uint64_t page_table_lvl2_0[512]; -__attribute__((aligned(4096))) uint64_t page_table_lvl2_1[512]; -__attribute__((aligned(4096))) uint64_t page_table_lvl2_2[512]; -__attribute__((aligned(4096))) uint64_t page_table_lvl2_3[512]; +__attribute__((aligned(4096))) uint64_t page_table_lvl2[512]; void map_addr(uint64_t virt, uint64_t phys, uint32_t flags) { @@ -24,38 +22,35 @@ void map_addr(uint64_t virt, uint64_t phys, uint32_t flags) size_t pt_lvl2_i = (virt >> 21) % 0x200; // 2mb entry // size_t pt_lvl1_i = (virt >> 12) % 0x200; // 4kb entry - // first 4gb - if (pt_lvl4_i == 0) { - switch(pt_lvl3_i) { - case 0: - page_table_lvl2_0[pt_lvl2_i] = phys | flags; - break; - case 1: - page_table_lvl2_1[pt_lvl2_i] = phys | flags; - break; - case 2: - page_table_lvl2_2[pt_lvl2_i] = phys | flags; - break; - case 3: - page_table_lvl2_3[pt_lvl2_i] = phys | flags; - break; - } + uint64_t* pt_lvl3 = (uint64_t*)(page_table_lvl4[pt_lvl4_i] + KERNEL_VMA); + if (!((uint64_t)pt_lvl3 & FLAG_PRESENT)) { + pt_lvl3 = (uint64_t*)kalloc(4096); + page_table_lvl4[pt_lvl4_i] = ((uint64_t)pt_lvl3 - KERNEL_VMA) | flags; + } else { + pt_lvl3 = (uint64_t*)((uint64_t)pt_lvl3 - (uint64_t)pt_lvl3 % 4096); } + + uint64_t* pt_lvl2 = (uint64_t*)(pt_lvl3[pt_lvl3_i] + KERNEL_VMA); + if (!((uint64_t)pt_lvl2 & FLAG_PRESENT)) { + pt_lvl2 = (uint64_t*)kalloc(4096); + pt_lvl3[pt_lvl3_i] = ((uint64_t)pt_lvl2 - KERNEL_VMA) | flags; + } else { + pt_lvl2 -= (uint64_t)pt_lvl2 % 4096; + } + + pt_lvl2[pt_lvl2_i] = virt | flags; } void init_paging(void) { - page_table_lvl4[0] = (uint64_t)page_table_lvl3 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER - KERNEL_VMA; - page_table_lvl3[0] = (uint64_t)page_table_lvl2_0 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER - KERNEL_VMA; - page_table_lvl3[1] = (uint64_t)page_table_lvl2_1 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER - KERNEL_VMA; - page_table_lvl3[2] = (uint64_t)page_table_lvl2_2 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER - KERNEL_VMA; - page_table_lvl3[3] = (uint64_t)page_table_lvl2_3 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER - KERNEL_VMA; - - // higher half map first 6mb - for (size_t i = 0; i < 3; i++) { - map_addr(KERNEL_VMA + PAGE_SIZE * i, 0x00000000 + PAGE_SIZE * i, FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER + FLAG_HUGE); + page_table_lvl4[511] = (uint64_t)page_table_lvl3 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER - KERNEL_VMA; + page_table_lvl3[510] = (uint64_t)page_table_lvl2 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER - KERNEL_VMA; + // 16mb kernel + 32mb heap + for (size_t i = 0; i < 24; i++) { + page_table_lvl2[i] = (uint64_t)0x0 + PAGE_SIZE * i + FLAG_PRESENT + FLAG_WRITABLE + FLAG_USER + FLAG_HUGE; } + load_pt_lvl4(page_table_lvl4); } diff --git a/kernel/src/mem/paging_asm.S b/kernel/src/mem/paging_asm.S index c7e11f3..e7c7814 100644 --- a/kernel/src/mem/paging_asm.S +++ b/kernel/src/mem/paging_asm.S @@ -1,6 +1,6 @@ .section .text -.set KERNEL_VMA, 0xc0000000 +.set KERNEL_VMA, 0xffffffff80000000 .global load_pt_lvl4 load_pt_lvl4: @@ -8,7 +8,7 @@ load_pt_lvl4: mov %rsp, %rbp push %r12 - mov $KERNEL_VMA, %r12 + movabs $KERNEL_VMA, %r12 sub %r12, %rdi mov %rdi, %cr3 pop %r12 -- cgit v1.2.3