From: Ben Gras <ben@minix3.org>
Date: Thu, 23 Apr 2009 15:11:16 +0000 (+0000)
Subject: set global flag for kernel pages, so tlb entries for kernel aren't thrown
X-Git-Tag: v3.1.4~71
X-Git-Url: http://zhaoyanbai.com/repos/Bv9ARM.ch08.html?a=commitdiff_plain;h=ef8a74130121207e7ada0a314b7298711d286508;p=minix.git

set global flag for kernel pages, so tlb entries for kernel aren't thrown
away on cr3 reload. minor optimization.
---

diff --git a/kernel/arch/i386/klib386.s b/kernel/arch/i386/klib386.s
index e91bba094..0aff6c0bd 100755
--- a/kernel/arch/i386/klib386.s
+++ b/kernel/arch/i386/klib386.s
@@ -38,6 +38,8 @@
 .define	_write_cr3	! write cr3
 .define _last_cr3
 .define	_write_cr0	! write a value in cr0
+.define	_read_cr4
+.define	_write_cr4
 
 .define	_kernel_cr3	
 
@@ -606,6 +608,31 @@ _write_cr0:
 	pop	ebp
 	ret
 
+!*===========================================================================*
+!*			      read_cr4					     *
+!*===========================================================================*
+! PUBLIC unsigned long read_cr4(void);
+_read_cr4:
+	push	ebp
+	mov	ebp, esp
+.data1	0x0f, 0x20, 0xe0 ! mov eax, cr4
+	pop	ebp
+	ret
+
+!*===========================================================================*
+!*			      write_cr4					     *
+!*===========================================================================*
+! PUBLIC void write_cr4(unsigned long value);
+_write_cr4:
+	push	ebp
+	mov	ebp, esp
+	mov	eax, 8(ebp)
+.data1	0x0f, 0x22, 0xe0 ! mov cr4, eax
+	jmp	0f
+0:
+	pop	ebp
+	ret
+
 !*===========================================================================*
 !*				write_cr3				*
 !*===========================================================================*
diff --git a/kernel/arch/i386/memory.c b/kernel/arch/i386/memory.c
index 16c6cb294..7e8456b84 100644
--- a/kernel/arch/i386/memory.c
+++ b/kernel/arch/i386/memory.c
@@ -149,10 +149,28 @@ PRIVATE void set_cr3()
 
 PRIVATE void vm_enable_paging(void)
 {
-	u32_t cr0;
+	u32_t cr0, cr4;
+
+
+	cr0= read_cr0();
+	cr4= read_cr4();
+
+	/* First clear PG and PGE flag, as PGE must be enabled after PG. */
+	write_cr0(cr0 & ~I386_CR0_PG);
+	write_cr4(cr4 & ~I386_CR4_PGE);
 
 	cr0= read_cr0();
+	cr4= read_cr4();
+
+	/* First enable paging, then enable global page flag. */
 	write_cr0(cr0 | I386_CR0_PG);
+	write_cr4(cr4 | I386_CR4_PGE);
+
+{
+	u32_t cr4v;
+	cr4v = read_cr4();
+	kprintf("cr4 = 0x%lx\n", cr4v);
+}
 }
 
 PUBLIC vir_bytes alloc_remote_segment(u32_t *selector,
diff --git a/kernel/arch/i386/proto.h b/kernel/arch/i386/proto.h
index de8de011e..b6ae9b27a 100644
--- a/kernel/arch/i386/proto.h
+++ b/kernel/arch/i386/proto.h
@@ -62,6 +62,8 @@ _PROTOTYPE( void reset, (void)                                          );
 _PROTOTYPE( void int86, (void)                     			);
 _PROTOTYPE( unsigned long read_cr0, (void)                              );
 _PROTOTYPE( void write_cr0, (unsigned long value)                       );
+_PROTOTYPE( unsigned long read_cr4, (void)                              );
+_PROTOTYPE( void write_cr4, (unsigned long value)                       );
 _PROTOTYPE( void write_cr3, (unsigned long value)                       );
 _PROTOTYPE( unsigned long read_cpu_flags, (void)                        );
 _PROTOTYPE( void phys_insb, (U16_t port, phys_bytes buf, size_t count)  );
diff --git a/servers/vm/i386/pagetable.c b/servers/vm/i386/pagetable.c
index 5c421f471..a9ad925be 100644
--- a/servers/vm/i386/pagetable.c
+++ b/servers/vm/i386/pagetable.c
@@ -785,12 +785,12 @@ PUBLIC int pt_mapkernel(pt_t *pt)
 
         /* Map in text. flags: don't write, supervisor only */
         if((r=pt_writemap(pt, KERNEL_TEXT, KERNEL_TEXT, KERNEL_TEXT_LEN,
-		I386_VM_PRESENT, 0)) != OK)
+		I386_VM_PRESENT|I386_VM_GLOBAL, 0)) != OK)
 		return r;
  
         /* Map in data. flags: read-write, supervisor only */
         if((r=pt_writemap(pt, KERNEL_DATA, KERNEL_DATA, KERNEL_DATA_LEN,
-		I386_VM_PRESENT|I386_VM_WRITE, 0)) != OK)
+		I386_VM_PRESENT|I386_VM_WRITE|I386_VM_GLOBAL, 0)) != OK)
 		return r;
 
 	return OK;
diff --git a/servers/vm/i386/pagetable.h b/servers/vm/i386/pagetable.h
index e4934c72e..b26ac9cd3 100644
--- a/servers/vm/i386/pagetable.h
+++ b/servers/vm/i386/pagetable.h
@@ -26,12 +26,13 @@ typedef struct {
 #define PTF_WRITE	I386_VM_WRITE
 #define PTF_PRESENT	I386_VM_PRESENT
 #define PTF_USER	I386_VM_USER
+#define PTF_GLOBAL	I386_VM_GLOBAL
 #define PTF_MAPALLOC	I386_VM_PTAVAIL1 /* Page allocated by pt code. */
 
 /* For arch-specific PT routines to check if no bits outside
  * the regular flags are set.
  */
-#define PTF_ALLFLAGS	(PTF_WRITE|PTF_PRESENT|PTF_USER)
+#define PTF_ALLFLAGS	(PTF_WRITE|PTF_PRESENT|PTF_USER|PTF_GLOBAL)
 
 #endif