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

3 files changed, 40 insertions, 42 deletions

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 <types.h>
 #include <paging.h>
 
+#include <heap.h>
 #include <libk/stdio.h>
-#include <debug.h>
+#include <kernel_vma.h>
 
 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