terrible hack to not overwrite mboot data

4 files changed, 58 insertions, 11 deletions

diff --git a/kernel/include/comus/mboot.h b/kernel/include/comus/mboot.h
index aba3e4e..bed29f1 100644
--- a/kernel/include/comus/mboot.h
+++ b/kernel/include/comus/mboot.h
@@ -47,4 +47,14 @@ EFI_HANDLE mboot_get_efi_hdl(void);
  */
 void *mboot_get_initrd(size_t *len);
 
+/**
+ * Returns the physical pointer to the loaded init ram disk with size given by len
+ */
+void *mboot_get_initrd_phys(size_t *len);
+
+/**
+ * Gets the end of the mboot pointer
+ */
+void *mboot_end(void);
+
 #endif /* mboot.h */
diff --git a/kernel/mboot/mboot.c b/kernel/mboot/mboot.c
index e4547e7..8163f04 100644
--- a/kernel/mboot/mboot.c
+++ b/kernel/mboot/mboot.c
@@ -5,6 +5,8 @@
 
 static volatile void *mboot = NULL;
 
+extern char kernel_end[];
+
 void mboot_init(long magic, volatile void *ptr)
 {
 	if (magic != MULTIBOOT2_BOOTLOADER_MAGIC)
@@ -12,6 +14,23 @@ void mboot_init(long magic, volatile void *ptr)
 	mboot = ptr;
 }
 
+void *mboot_end(void)
+{
+	if (mboot == NULL)
+		return NULL;
+
+	struct multiboot *info = (struct multiboot *)mboot;
+	uintptr_t mboot_end, initrd_end;
+	size_t initrd_len;
+
+	mboot_end = (uintptr_t)info + info->total_size;
+	initrd_end = (uintptr_t)mboot_get_initrd_phys(&initrd_len);
+	if (initrd_end)
+		initrd_end += initrd_len;
+
+	return (void *)MAX(mboot_end, initrd_end);
+}
+
 void *locate_mboot_table(uint32_t type)
 {
 	if (mboot == NULL)
diff --git a/kernel/mboot/module.c b/kernel/mboot/module.c
index bf15eca..03c5147 100644
--- a/kernel/mboot/module.c
+++ b/kernel/mboot/module.c
@@ -1,4 +1,4 @@
-#include "comus/memory.h"
+#include <comus/memory.h>
 #include <comus/mboot.h>
 
 #include "mboot.h"
@@ -16,7 +16,7 @@ struct multiboot_tag_module {
 static void *mapped_addr = NULL;
 size_t initrd_len;
 
-void *mboot_get_initrd(size_t *len)
+void *mboot_get_initrd_phys(size_t *len)
 {
 	struct multiboot_tag_module *mod;
 	void *tag, *phys;
@@ -36,11 +36,21 @@ void *mboot_get_initrd(size_t *len)
 	phys = (void *)(uintptr_t)mod->mod_start;
 	initrd_len = mod->mod_end - mod->mod_start;
 
+	*len = initrd_len;
+	return phys;
+}
+
+void *mboot_get_initrd(size_t *len)
+{
+	// get phys
+	void *phys = mboot_get_initrd_phys(len);
+	if (phys == NULL)
+		return NULL;
+
 	// map addr
 	mapped_addr = kmapaddr(phys, NULL, initrd_len, F_PRESENT | F_WRITEABLE);
 	if (mapped_addr == NULL)
 		return NULL;
 
-	*len = initrd_len;
 	return mapped_addr;
 }
diff --git a/kernel/memory/physalloc.c b/kernel/memory/physalloc.c
index 47522b8..7551c75 100644
--- a/kernel/memory/physalloc.c
+++ b/kernel/memory/physalloc.c
@@ -1,12 +1,14 @@
-#include "lib/kio.h"
 #include <lib.h>
 #include <comus/memory.h>
 #include <comus/asm.h>
+#include <comus/mboot.h>
+#include <stdint.h>
 
 #include "physalloc.h"
 
 extern char kernel_start[];
 extern char kernel_end[];
+static void *kernel_real_end = NULL;
 
 // between memory_start and kernel_start will be the bitmap
 static uintptr_t memory_start = 0;
@@ -30,16 +32,17 @@ static int n_pages(const struct memory_segment *m)
 	return (m->len + PAGE_SIZE - 1) / PAGE_SIZE;
 }
 
-static void *page_at(int i)
+static void *page_at(size_t i)
 {
-	int cur_page = 0;
+	size_t cur_page = 0;
+	const struct memory_segment *m = page_start;
 	for (uint64_t idx = 0; idx < segment_count; idx++) {
-		const struct memory_segment *m = page_start;
-		int pages = n_pages(m);
+		size_t pages = n_pages(m);
 		if (i - cur_page < pages) {
 			return (void *)(m->addr + (PAGE_SIZE * (i - cur_page)));
 		}
 		cur_page += pages;
+		m++;
 	}
 	return NULL;
 }
@@ -48,8 +51,8 @@ static long page_idx(void *page)
 {
 	uintptr_t addr = (uintptr_t)page;
 	int cur_page = 0;
+	const struct memory_segment *m = page_start;
 	for (uint64_t idx = 0; idx < segment_count; idx++) {
-		const struct memory_segment *m = page_start;
 		if (addr < m->addr) {
 			return -1;
 		}
@@ -57,6 +60,7 @@ static long page_idx(void *page)
 			return cur_page + ((addr - m->addr) / PAGE_SIZE);
 		}
 		cur_page += n_pages(m);
+		m++;
 	}
 	return -1;
 }
@@ -211,7 +215,7 @@ static struct memory_segment clamp_segment(const struct memory_segment *segment)
 	if (memory_start)
 		start = memory_start;
 	else
-		start = (uintptr_t)kernel_end;
+		start = (uintptr_t)kernel_real_end;
 
 	if (segment->addr < start) {
 		addr = start;
@@ -243,6 +247,10 @@ void physalloc_init(struct memory_map *map)
 
 	segment_count = 0;
 
+	kernel_real_end = mboot_end();
+	if ((char *)kernel_real_end < kernel_end)
+		kernel_real_end = kernel_end;
+
 	for (uint32_t i = 0; i < map->entry_count; i++) {
 		struct memory_segment *segment = &map->entries[i];
 
@@ -256,7 +264,7 @@ void physalloc_init(struct memory_map *map)
 
 	long bitmap_pages = (page_count / 64 / PAGE_SIZE) + 1;
 	long bitmap_size = bitmap_pages * PAGE_SIZE;
-	bitmap = (uint64_t *)page_align((uintptr_t)kernel_end);
+	bitmap = (uint64_t *)page_align((uintptr_t)kernel_real_end);
 
 	long page_area_size = segment_count * sizeof(struct memory_segment);
 	char *page_area_addr = (char *)bitmap + bitmap_size;