Commit 2b5f9408 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

[PATCH] document unused pte bits on i386

From: Rusty Russell <rusty@rustcorp.com.au>

From:  Ed L Cashin <ecashin@uga.edu>

This small patch documents that bits 9, 10, and 11 are unused by the Linux
kernel.  The IA-32 Intel Architecture Software Developer's Manual says that
these bits are available for programmer use.
parent b4ecf1b0
...@@ -107,6 +107,9 @@ void paging_init(void); ...@@ -107,6 +107,9 @@ void paging_init(void);
#define _PAGE_BIT_DIRTY 6 #define _PAGE_BIT_DIRTY 6
#define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page, Pentium+, if present.. */ #define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page, Pentium+, if present.. */
#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */ #define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
#define _PAGE_BIT_UNUSED1 9 /* available for programmer */
#define _PAGE_BIT_UNUSED2 10
#define _PAGE_BIT_UNUSED3 11
#define _PAGE_PRESENT 0x001 #define _PAGE_PRESENT 0x001
#define _PAGE_RW 0x002 #define _PAGE_RW 0x002
...@@ -117,6 +120,9 @@ void paging_init(void); ...@@ -117,6 +120,9 @@ void paging_init(void);
#define _PAGE_DIRTY 0x040 #define _PAGE_DIRTY 0x040
#define _PAGE_PSE 0x080 /* 4 MB (or 2MB) page, Pentium+, if present.. */ #define _PAGE_PSE 0x080 /* 4 MB (or 2MB) page, Pentium+, if present.. */
#define _PAGE_GLOBAL 0x100 /* Global TLB entry PPro+ */ #define _PAGE_GLOBAL 0x100 /* Global TLB entry PPro+ */
#define _PAGE_UNUSED1 0x200 /* available for programmer */
#define _PAGE_UNUSED2 0x400
#define _PAGE_UNUSED3 0x800
#define _PAGE_FILE 0x040 /* set:pagecache unset:swap */ #define _PAGE_FILE 0x040 /* set:pagecache unset:swap */
#define _PAGE_PROTNONE 0x080 /* If not present */ #define _PAGE_PROTNONE 0x080 /* If not present */
......
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