Code-base clean-up and refactoring (#47)

[lunaix-os.git] / lunaix-os / arch / x86 / includes / asm / mm_defs.h

diff --git a/lunaix-os/arch/x86/includes/asm/mm_defs.h b/lunaix-os/arch/x86/includes/asm/mm_defs.h
new file mode 100644 (file)
index 0000000..40804d0
--- /dev/null
+++ b/lunaix-os/arch/x86/includes/asm/mm_defs.h
@@ -0,0 +1,40 @@
+#ifndef __LUNAIX_MM_DEFS_H
+#define __LUNAIX_MM_DEFS_H
+
+#include "mempart.h"
+#include "pagetable.h"
+
+/*
+    Regardless architecture we need to draw the line very carefully, and must 
+    take the size of VM into account. In general, we aims to achieve 
+    "sufficiently large" of memory for kernel
+
+    In terms of x86_32:
+        * #768~1022 PTEs of PD      (0x00000000c0000000, ~1GiB)
+    
+    In light of upcomming x86_64 support (for Level 4&5 Paging):
+        * #510 entry of PML4        (0x0000ff0000000000, ~512GiB)
+        * #510 entry of PML5        (0x01fe000000000000, ~256TiB)
+    
+
+    KERNEL_RESIDENT  -  a high-mem region, kernel should be
+    KSTACK_PAGES     -  kernel stack, pages allocated to
+    KEXEC_RSVD       -  page reserved for kernel images
+*/
+
+#ifdef CONFIG_ARCH_X86_64
+#   define KSTACK_PAGES            4
+#   define KEXEC_RSVD              32
+#else
+#   define KSTACK_PAGES            2
+#   define KEXEC_RSVD              16
+#endif
+
+#define KSTACK_SIZE             (KSTACK_PAGES * PAGE_SIZE)
+
+#define kernel_addr(addr)       ((addr) >= KERNEL_RESIDENT || (addr) < USR_EXEC)
+
+#define to_kphysical(k_va)      ((ptr_t)(k_va) - KERNEL_IMG)
+#define to_kvirtual(k_pa)       ((ptr_t)(k_pa) + KERNEL_IMG)
+
+#endif /* __LUNAIX_MM_DEFS_H */