From d1ff7bcc91886626dc9060ec5fb67ee102ab7c1d Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Mon, 11 Mar 2024 21:30:31 -0400
Subject: usermode capable kernel with logging syscall

---
 boot/limine/limine.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 boot/limine/limine.c

(limited to 'boot/limine/limine.c')

diff --git a/boot/limine/limine.c b/boot/limine/limine.c
new file mode 100644
index 0000000..7cc50d0
--- /dev/null
+++ b/boot/limine/limine.c
@@ -0,0 +1,89 @@
+#include "limine.h"
+#include "boot/boot.h"
+
+static char s_kernel_stack[KERNEL_INITIAL_STACK_WIDTH];
+
+struct MemoryMap boot_memorymap;
+
+struct BootModule boot_modules[BOOT_MODULE_MAX_ENTRIES];
+struct BootModule boot_kernel_file;
+size_t boot_module_count = 0;
+
+uintptr_t boot_kernel_physical_address;
+void *boot_kernel_initial_stack_base = &s_kernel_stack;
+const char *boot_kernel_cmdline = NULL;
+
+struct limine_memmap_request s_mmap_request = {
+    .id = LIMINE_MEMMAP_REQUEST
+};
+struct limine_kernel_address_request s_kaddr_request = {
+    .id = LIMINE_KERNEL_ADDRESS_REQUEST
+};
+struct limine_kernel_file_request s_kfile_request = {
+    .id = LIMINE_KERNEL_FILE_REQUEST
+};
+struct limine_module_request s_module_request = {
+    .id = LIMINE_MODULE_REQUEST
+};
+
+static void
+s_load_memorymap(void)
+{
+    struct limine_memmap_response *response = s_mmap_request.response;
+    if(response == NULL) return;
+    boot_memorymap.count = response->entry_count;
+    for(size_t i = 0; i < response->entry_count; i++) {
+        struct limine_memmap_entry *e = response->entries[i];
+        struct MemoryMapEntry *bme = &boot_memorymap.entries[i];
+
+        bme->base = e->base;
+        bme->length = e->length;
+        bme->usable = e->type == LIMINE_MEMMAP_USABLE ||
+                      e->type == LIMINE_MEMMAP_ACPI_RECLAIMABLE ||
+                      e->type == LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE;
+    }
+}
+
+static void
+s_load_modules(void)
+{
+    struct limine_module_response *response = s_module_request.response;
+    if(response->module_count > 4) response->module_count = 4;
+    boot_module_count = response->module_count;
+    for(size_t i = 0; i < response->module_count; i++) {
+        boot_modules[i] = (struct BootModule){
+            .path = response->modules[i]->path,
+            .cmdline = response->modules[i]->cmdline,
+            .size = response->modules[i]->size,
+            .addr = (uintptr_t)response->modules[i]->address
+        };
+    }
+}
+
+static void
+s_load_kernel_file(void)
+{
+    struct limine_kernel_file_response *response = s_kfile_request.response;
+    boot_kernel_file = (struct BootModule) {
+        .path = response->kernel_file->path,
+        .cmdline = response->kernel_file->cmdline,
+        .size = response->kernel_file->size,
+        .addr = (uintptr_t)response->kernel_file->address
+    };
+    boot_kernel_cmdline = response->kernel_file->cmdline;
+}
+
+void _start(void)
+{
+    boot_kernel_physical_address = s_kaddr_request.response->physical_base;
+    s_load_memorymap();
+    
+    s_load_kernel_file();
+    s_load_modules();
+
+    char *kernel_stack_entry = s_kernel_stack + (KERNEL_INITIAL_STACK_WIDTH - 1);
+    __asm__ volatile("movq %0, %%rsp":: "r"(kernel_stack_entry));
+
+    extern void kernel_main(void);
+    kernel_main();
+}
-- 
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