From 724a2cd70d6bc514f3715497a29213e5081d2348 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Tue, 19 Jul 2016 23:19:14 +0200
Subject: [PATCH] some code cleanups, the current version is just proof of
 concept

---
 hermit/arch/x86/loader/entry.asm | 17 ++++-------------
 hermit/arch/x86/loader/main.c    |  2 +-
 2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/hermit/arch/x86/loader/entry.asm b/hermit/arch/x86/loader/entry.asm
index 7d6325808..538cabbb2 100644
--- a/hermit/arch/x86/loader/entry.asm
+++ b/hermit/arch/x86/loader/entry.asm
@@ -201,16 +201,17 @@ L1:
 
     ; Set CR3
     mov eax, boot_pml4
+    or eax, (1 << 0)        ; set present bit
     mov cr3, eax
 
     ; Set CR4
     mov eax, cr4
     and eax, 0xfffbf9ff     ; disable SSE
-    or eax, (1 << 4)        ; enable PSE
-    or eax, (1 << 7)        ; enabel PGE
+    or eax, (1 << 7)        ; enable PGE
+    or eax, (1 << 20)       ; enable SMEP
     mov cr4, eax
 
-    ; Set CR0
+    ; Set CR0 (PM-bit is already set)
     mov eax, cr0
     and eax, ~(1 << 2)      ; disable FPU emulation
     or eax, (1 << 1)        ; enable FPU montitoring
@@ -218,7 +219,6 @@ L1:
     and eax, ~(1 << 29)     ; disable write through caching
     and eax, ~(1 << 16)	    ; allow kernel write access to read-only pages
     or eax, (1 << 31)       ; enable paging
-    or eax, (1 << 0)        ; long mode also needs PM-bit set
     mov cr0, eax
 
     ret
@@ -247,15 +247,6 @@ start64:
     call main
     jmp $
 
-;global gdt_flush
-;extern gp
-
-; This will set up our new segment registers and is declared in
-; C as 'extern void gdt_flush();'
-;gdt_flush:
-;    lgdt [gp]
-;    ret
-
 SECTION .data
 
 global mb_info:
diff --git a/hermit/arch/x86/loader/main.c b/hermit/arch/x86/loader/main.c
index 457a8d8b1..8a9dc799b 100644
--- a/hermit/arch/x86/loader/main.c
+++ b/hermit/arch/x86/loader/main.c
@@ -136,9 +136,9 @@ void main(void)
 				*((uint64_t*) (viraddr + 0x08)) = phyaddr; // physical start address
 				*((uint32_t*) (viraddr + 0x1C)) = 0; // apicid;
 				*((uint32_t*) (viraddr + 0x24)) = 1; // number of used cpus
+				*((uint32_t*) (viraddr + 0x30)) = 0; // apicid
 				*((uint64_t*) (viraddr + 0x38)) = prog_header->file_size;
 				*((uint32_t*) (viraddr + 0x60)) = 1; // numa nodes
-				*((uint32_t*) (viraddr + 0x30)) = 0; // apicid
 			}
 			break;
 		case ELF_PT_GNU_STACK:	// Indicates stack executability => nothing todo