From b2547584ec8bf9723cd5e49697130506b5a65ca6 Mon Sep 17 00:00:00 2001
From: Johann Rudloff <johann.rudloff@googlemail.com>
Date: Fri, 12 Dec 2014 20:06:41 +0100
Subject: [PATCH] Minor improvements, dont hardcode memory map base address.

---
 boot1.asm            |  5 +----
 boot2.c              |  2 +-
 entry.asm            | 10 ++++++----
 include/sys/memory.h |  4 +++-
 kernel.c             | 10 +++++-----
 kmem.c               | 17 +++++++----------
 6 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/boot1.asm b/boot1.asm
index 0c5cbfc..89e4b92 100644
--- a/boot1.asm
+++ b/boot1.asm
@@ -107,10 +107,7 @@ protected_main:
   mov eax, 0x8000
   mov esp, eax
 
-  call boot2_main
-  .idle:
-  hlt
-  jmp .idle
+  jmp boot2_main
 
 ; pread_sector(unit32_t lba, uint8_t *dest)
 %define DRIVE_PORT_BASE 0x01f0
diff --git a/boot2.c b/boot2.c
index a8b2715..64cae7b 100644
--- a/boot2.c
+++ b/boot2.c
@@ -78,7 +78,7 @@ void boot2_main(void) {
     fs_inode_read_block(&fs, &ino_kernel, i, dst);
     dst += fs.block_size;
   }
-  asm volatile ("ljmp $0x08,$0x100000" : : );
+  asm volatile ("pushl $0x1000\nljmp $0x08,$0x100000" : : );
 }
 
 static void
diff --git a/entry.asm b/entry.asm
index 7667725..b49b36d 100644
--- a/entry.asm
+++ b/entry.asm
@@ -4,16 +4,14 @@ extern kernel_main
 %include "assym.asm"
 
 start:
+  mov ebx, [esp]
   mov ax, 0x10
   mov ss, ax
   mov esp, 0x200000 ; this gives us 2MiB - kernel_size of stack
 
+  push ebx
   call kernel_main
 
-  .hang:
-  hlt
-  jmp .hang
-
 %define USER_CS 0x1b
 %define USER_DS 0x23
 
@@ -21,8 +19,12 @@ global proc_switch
 proc_switch:
   mov ebp, [esp + 4] ; struct proc*
 
+  mov ebx, cr3
   mov eax, PROC_PD(ebp)
+  cmp eax, ebx
+  je .have_cr3 ; CR3 is already set, no need to flush TLB
   mov cr3, eax
+.have_cr3:
 
   mov ebp, PROC_PCB(ebp)
 
diff --git a/include/sys/memory.h b/include/sys/memory.h
index 036ca2f..bcc0388 100644
--- a/include/sys/memory.h
+++ b/include/sys/memory.h
@@ -5,6 +5,8 @@
 
 #define alloca(size) __builtin_alloca(size)
 
+struct memory_map_entry;
+
 void *kmalloc(size_t size);
 void *kmalloc_align(size_t alignment, size_t size);
 void kfree(void *p);
@@ -18,6 +20,6 @@ static inline void *memset(void *b, int c, size_t len) {
   return b;
 }
 
-void kmem_init(void);
+void kmem_init(uint32_t memory_map_entry_count, struct memory_map_entry *entries);
 
 #endif /* _MEMORY_H_ */
diff --git a/kernel.c b/kernel.c
index 285f280..1a26490 100644
--- a/kernel.c
+++ b/kernel.c
@@ -45,18 +45,18 @@ static void setup_tss(void);
 
 static struct proc *launch(const char *binary, uint32_t mem);
 
-void kernel_main() {
+void kernel_main(void *meminfo) {
   kprint("kernel main entered\n");
   console_init(&global_console);
+  console_clear(&global_console);
+  console_print(&global_console, "xos kernel loaded\n");
+
   setup_gdt();
 
-  kmem_init();
+  kmem_init(*(uint32_t *)meminfo, meminfo + 4);
   paging_init();
 
 
-  console_clear(&global_console);
-  console_print(&global_console, "xos kernel loaded\n");
-
   setup_idt();
 
   struct proc *proc1 = launch("/init", 0x70000000);
diff --git a/kmem.c b/kmem.c
index 6ffd7ab..c0683bd 100644
--- a/kmem.c
+++ b/kmem.c
@@ -9,7 +9,7 @@
 #define KMEM_ARENA_START 0x200000
 #define KMEM_ARENA_END 0x400000
 
-struct detect_mmap_info {
+struct memory_map_entry {
   uint32_t base_low;
   uint32_t base_high;
   uint32_t length_low;
@@ -28,10 +28,10 @@ struct free_info {
 
 static struct kmem kmem_state;
 
-void kmem_detect(void);
+void kmem_detect(uint32_t count, struct memory_map_entry *mmap);
 
-void kmem_init(void) {
-  kmem_detect();
+void kmem_init(uint32_t memory_map_entry_count, struct memory_map_entry *entries) {
+  kmem_detect(memory_map_entry_count, entries);
 
   // begin with the last page
   void *page = (void *)(KMEM_ARENA_END - PAGE_SIZE);
@@ -50,12 +50,9 @@ void kmem_init(void) {
 }
 
 void
-kmem_detect(void) {
-  uint32_t mmap_count = *(uint32_t *)0x1000;
-  struct detect_mmap_info *mmap = (struct detect_mmap_info *)(0x1000 + 4);
-  khexprint("mmap count", mmap_count);
-  khexprint("mmap size", sizeof(struct detect_mmap_info));
-  for (int i=0; i<mmap_count; ++i) {
+kmem_detect(uint32_t count, struct memory_map_entry *mmap) {
+  khexprint("mmap count", count);
+  for (int i=0; i<count; ++i) {
     khexprint("=========== mmap entry", i);
     khexprint("base_low", mmap[i].base_low);
     khexprint("base_high", mmap[i].base_high);
-- 
2.34.2