Fixed ELF loading again, memory management needs to be redone properly

Brewfile

@@ -10,6 +10,8 @@ brew "make"
 brew "gptfdisk"
 brew "xorriso"
 brew "qemu"
+brew "llvm"
+brew "lld"
 brew "util-linux" if OS.mac?
 brew "gsed" if OS.mac?
 

boot/arch/x86_64/common/mm/paging.c

@@ -28,45 +28,55 @@
 /* https://github.com/KevinAlavik/nekonix/blob/main/kernel/src/mm/vmm.c */
 /* Thanks, Kevin <3 */
 
-void map_pages(pagetable *pm, uintptr_t virt, uintptr_t phys, size_t size, uint64_t flags)
-{
-    for (size_t i = 0; i < ROUND_UP(size, PAGE_SIZE); i += PAGE_SIZE) {
-        map_page(pm, virt + i, phys + i, flags);
-    }
-}
-
-void map_page(pagetable *pm, uintptr_t virt, uintptr_t phys, uint64_t flags)
+static void _map(pagetable *pm, uintptr_t virt, uintptr_t phys, uint64_t flags)
 {
     uint64_t pml1_idx = (virt >> 12) & 0x1ff;
     uint64_t pml2_idx = (virt >> 21) & 0x1ff;
     uint64_t pml3_idx = (virt >> 30) & 0x1ff;
     uint64_t pml4_idx = (virt >> 39) & 0x1ff;
 
+    flags |= VMM_PRESENT;
+    
     if (!(pm->entries[pml4_idx] & 1)) {
         void *pml4 = mem_alloc(PAGE_SIZE);
         memset(pml4, 0, sizeof(pagetable));
-        pm->entries[pml4_idx] = (uint64_t)pml4 | VMM_PRESENT | VMM_WRITABLE | VMM_USER;
+        pm->entries[pml4_idx] = (uint64_t)pml4 | VMM_PRESENT | VMM_WRITABLE;
     }
 
     pagetable *pml3_table = (pagetable *)(pm->entries[pml4_idx] & 0x000FFFFFFFFFF000);
     if (!(pml3_table->entries[pml3_idx] & 1)) {
         void *pml3 = mem_alloc(PAGE_SIZE);
         memset(pml3, 0, sizeof(pagetable));
-        pml3_table->entries[pml3_idx] = (uint64_t)pml3 | VMM_PRESENT | VMM_WRITABLE | VMM_USER;
+        pml3_table->entries[pml3_idx] = (uint64_t)pml3 | VMM_PRESENT | VMM_WRITABLE;
     }
 
     pagetable *pml2_table = (pagetable *)(pml3_table->entries[pml3_idx] & 0x000FFFFFFFFFF000);
     if (!(pml2_table->entries[pml2_idx] & 1)) {
         void *pml2 = mem_alloc(PAGE_SIZE);
         memset(pml2, 0, sizeof(pagetable));
-        pml2_table->entries[pml2_idx] = (uint64_t)pml2 | VMM_PRESENT | VMM_WRITABLE | VMM_USER;
+        pml2_table->entries[pml2_idx] = (uint64_t)pml2 | VMM_PRESENT | VMM_WRITABLE;
     }
 
     pagetable *pml1_table = (pagetable *)(pml2_table->entries[pml2_idx] & 0x000FFFFFFFFFF000);
-    if (!(pml1_table->entries[pml1_idx] & 1)) {
-        pml1_table->entries[pml1_idx] = (phys | 0x000FFFFFFFFFF000) | flags;
+    if ((pml1_table->entries[pml1_idx] & 1)) {
+        debug("_map(): Remapping present page\n");
     }
 
+    pml1_table->entries[pml1_idx] = (phys & 0x000FFFFFFFFFF000) | flags;
+}
+
+void map_pages(pagetable *pm, uintptr_t virt, uintptr_t phys, size_t size, uint64_t flags)
+{
+    for (size_t i = 0; i < ROUND_UP(size, PAGE_SIZE); i += PAGE_SIZE) {
+        _map(pm, virt + i, phys + i, flags);
+    }
+
+    debug("map_pages(): Mapped 0x%llx-0x%llx -> 0x%llx-0x%llx\n", phys, phys + (size * PAGE_SIZE), virt, virt + (size * PAGE_SIZE));
+}
+
+void map_page(pagetable *pm, uintptr_t virt, uintptr_t phys, uint64_t flags)
+{
+   _map(pm, virt, phys, flags);
 	debug("map_page(): Mapped 0x%llx -> 0x%llx\n", phys, virt);
 }
 
@@ -77,6 +87,7 @@ pagetable *create_pagemap()
         debug("create_pagemap(): Failed to allocate memory for a new pm.\n");
         return NULL;
     }
+    pm = (pagetable *)ROUND_UP((uint64_t)pm, PAGE_SIZE);
     memset(pm, 0, sizeof(pagetable));
 
     debug("create_pagemap(): Created new pm at 0x%llx\n", (uint64_t)pm);

boot/arch/x86_64/common/proto/aurix_handoff.S

@@ -2,10 +2,23 @@
 .globl _aurix_handoff_end
 .globl aurix_handoff
 
+_aurix_handoff_start:
 aurix_handoff:
 	cli
 	movq %rsi, %rsp
-_aurix_handoff_start:
+.section _aurix_handoff
 	movq %rdi, %cr3
-	jmpq *%rdx
+	xor %rax, %rax
+	xor %rbx, %rbx
+	xor %rcx, %rcx
+	xor %rdi, %rdi
+	xor %r8, %r8
+	xor %r9, %r9
+	xor %r10, %r10
+	xor %r11, %r11
+	xor %r12, %r12
+	xor %r13, %r13
+	xor %r14, %r14
+	xor %r15, %r15
+	callq *%rdx
 _aurix_handoff_end:

boot/common/loader/elf.c

@@ -66,20 +66,20 @@ uintptr_t elf64_load(char *data, pagetable *pagemap)
         if (!(ph[i].p_flags & PF_X))
             flags |= VMM_NX;
     
-        debug("elf64_load(): phys=0x%llx, virt=0x%llx, size=%lu\n", ph[i].p_paddr, ph[i].p_vaddr, ph[i].p_filesz);
-        
         uint64_t phys = (uint64_t)mem_alloc(ph[i].p_memsz);
         if (!phys) {
             debug("elf64_load(): Out of memory\n");
             return 0;
         }
         
+        debug("elf64_load(): phys=0x%llx, virt=0x%llx, size=%lu\n", phys, ph[i].p_vaddr, ph[i].p_filesz);
+
         map_page(pagemap, ph[i].p_vaddr, phys, flags);
         memcpy((void*)ph[i].p_vaddr - lowest, data + ph[i].p_offset, ph[i].p_filesz);
     }
 
     debug("elf64_load(): ELF loaded successfully, entry: 0x%llx\n", header->e_entry);
-    return (uintptr_t)((uint8_t *)data + (header->e_entry - lowest));
+    return (uintptr_t)((uint8_t *)data + header->e_entry);
 }
 
 uintptr_t elf_load(char *data, pagetable *pagemap)

boot/common/proto/aurix.c

@@ -23,6 +23,9 @@
 #include <mm/vmm.h>
 #include <vfs/vfs.h>
 #include <print.h>
+#include <axboot.h>
+#include <efi.h>
+#include <efilib.h>
 
 extern __attribute__((noreturn)) void aurix_handoff(void *pagemap, void *stack, uint64_t entry, void *params);
 extern char _aurix_handoff_start[], _aurix_handoff_end[];
@@ -35,13 +38,15 @@ void aurix_load(char *kernel)
 
 	// TODO: Do something with the kernel :p
 	pagetable *pm = create_pagemap();
+	// __asm__ volatile("mov %%cr3, %0" : "=r"(pm));
 	if (!pm) {
 		debug("aurix_load(): Failed to create kernel pagemap! Halting...\n");
 		// TODO: Halt
 		while (1);
 	}
 
-	map_pages(pm, (uintptr_t)_aurix_handoff_start, (uintptr_t)_aurix_handoff_start, (uint64_t)_aurix_handoff_end - (uint64_t)_aurix_handoff_start, VMM_PRESENT | VMM_USER | VMM_WRITABLE);
+	map_pages(pm, (uintptr_t)pm, (uintptr_t)pm, PAGE_SIZE, VMM_WRITABLE);
+	map_pages(pm, (uintptr_t)_aurix_handoff_start, (uintptr_t)_aurix_handoff_start, (uint64_t)_aurix_handoff_end - (uint64_t)_aurix_handoff_start, 0);
 	
 	void *stack = mem_alloc(16*1024); // 16 KiB stack should be well more than enough
 	if (!stack) {
@@ -49,6 +54,8 @@ void aurix_load(char *kernel)
 		while (1);
 	}
 
+	map_pages(pm, (uintptr_t)stack, (uintptr_t)stack, 16*1024, VMM_WRITABLE | VMM_NX);
+
 	void *kernel_entry = (void *)elf_load(kbuf, pm);
 	if (!kernel_entry) {
 		debug("aurix_load(): Failed to load '%s'! Halting...\n", kernel);
@@ -60,10 +67,14 @@ void aurix_load(char *kernel)
 
 	debug("aurix_load(): Handoff state: pm=0x%llx, stack=0x%llx, kernel_entry=0x%llx\n", pm, stack, kernel_entry);
 
-	aurix_handoff(pm, (void *)((uint8_t)stack + 16*1024), (uint64_t)kernel_entry, (void *)parameters);
+	// this triggers a #GP ????
+	// aurix_handoff(pm, stack, (uint64_t)kernel_entry, (void *)parameters);
+	// __builtin_unreachable();
 
-	// __asm__ volatile("movq %[pml4], %%cr3\n" :: [pml4]"r"(pm) : "memory");
+	__asm__ volatile("movq %[pml4], %%cr3\n"
+					"movq %[stack], %%rsp\n"
+					"callq *%[entry]\n"
+					:: [pml4]"r"(pm), [stack]"r"(stack), [entry]"r"(kernel_entry) : "memory");
 	// __asm__ volatile("callq *%[entry]\n"
 	// 				:: [entry]"r"(kernel_entry));
-
 }

kernel/Makefile

@@ -55,7 +55,7 @@ KERNEL_CFLAGS := $(foreach d, $(INCLUDE_DIRS), -I$d) \
 KERNEL_LDFLAGS := -Tarch/$(ARCH)/linker.ld \
 				-nostdlib \
 				-static \
-				#-no-pie
+				-no-pie
 
 ifeq ($(BUILD_TYPE),debug)
 KERNEL_CFLAGS += -O0 -g3

kernel/arch/x86_64/linker.ld

@@ -32,7 +32,7 @@ PHDRS
 SECTIONS
 {
 	/* TODO: 0xffffffff80000000 */
-	. = 0xffffffff80000000;
+	. = 0x1000;
 
 	_linker_start_text = .;
 

kernel/kinit.c

@@ -31,4 +31,6 @@ void _start(void)
 		__asm__ volatile("wfe");
 #endif
 	}
+
+	__builtin_unreachable();
 }

machine/riscv32/qemu.mk

@@ -0,0 +1 @@
+QEMU_MACHINE_FLAGS := -M virt -bios default -nographic