Linux Kernel  3.7.1
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mmu.h
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1 /*
2  * CRIS MMU constants and PTE layout
3  */
4 
5 #ifndef _CRIS_ARCH_MMU_H
6 #define _CRIS_ARCH_MMU_H
7 
8 /* type used in struct mm to couple an MMU context to an active mm */
9 
10 typedef struct
11 {
12  unsigned int page_id;
13 } mm_context_t;
14 
15 /* kernel memory segments */
16 
17 #define KSEG_F 0xf0000000UL
18 #define KSEG_E 0xe0000000UL
19 #define KSEG_D 0xd0000000UL
20 #define KSEG_C 0xc0000000UL
21 #define KSEG_B 0xb0000000UL
22 #define KSEG_A 0xa0000000UL
23 #define KSEG_9 0x90000000UL
24 #define KSEG_8 0x80000000UL
25 #define KSEG_7 0x70000000UL
26 #define KSEG_6 0x60000000UL
27 #define KSEG_5 0x50000000UL
28 #define KSEG_4 0x40000000UL
29 #define KSEG_3 0x30000000UL
30 #define KSEG_2 0x20000000UL
31 #define KSEG_1 0x10000000UL
32 #define KSEG_0 0x00000000UL
33 
34 /* CRIS PTE bits (see R_TLB_LO in the register description)
35  *
36  * Bit: 31 30-13 12-------4 3 2 1 0
37  * _______________________________________________________
38  * | cache |pfn | reserved | global | valid | kernel | we |
39  * |_______|____|__________|________|_______|________|_____|
40  *
41  * (pfn = physical frame number)
42  */
43 
44 /* Real HW-based PTE bits. We use some synonym names so that
45  * things become less confusing in combination with the SW-based
46  * bits further below.
47  *
48  */
49 
50 #define _PAGE_WE (1<<0) /* page is write-enabled */
51 #define _PAGE_SILENT_WRITE (1<<0) /* synonym */
52 #define _PAGE_KERNEL (1<<1) /* page is kernel only */
53 #define _PAGE_VALID (1<<2) /* page is valid */
54 #define _PAGE_SILENT_READ (1<<2) /* synonym */
55 #define _PAGE_GLOBAL (1<<3) /* global page - context is ignored */
56 #define _PAGE_NO_CACHE (1<<31) /* part of the uncached memory map */
57 
58 /* Bits the HW doesn't care about but the kernel uses them in SW */
59 
60 #define _PAGE_PRESENT (1<<4) /* page present in memory */
61 #define _PAGE_FILE (1<<5) /* set: pagecache, unset: swap (when !PRESENT) */
62 #define _PAGE_ACCESSED (1<<5) /* simulated in software using valid bit */
63 #define _PAGE_MODIFIED (1<<6) /* simulated in software using we bit */
64 #define _PAGE_READ (1<<7) /* read-enabled */
65 #define _PAGE_WRITE (1<<8) /* write-enabled */
66 
67 /* Define some higher level generic page attributes. */
68 
69 #define __READABLE (_PAGE_READ | _PAGE_SILENT_READ | _PAGE_ACCESSED)
70 #define __WRITEABLE (_PAGE_WRITE | _PAGE_SILENT_WRITE | _PAGE_MODIFIED)
71 
72 #define _PAGE_TABLE (_PAGE_PRESENT | __READABLE | __WRITEABLE)
73 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED)
74 
75 #define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_ACCESSED)
76 #define PAGE_SHARED __pgprot(_PAGE_PRESENT | __READABLE | _PAGE_WRITE | \
77  _PAGE_ACCESSED)
78 #define PAGE_COPY __pgprot(_PAGE_PRESENT | __READABLE) // | _PAGE_COW
79 #define PAGE_READONLY __pgprot(_PAGE_PRESENT | __READABLE)
80 #define PAGE_KERNEL __pgprot(_PAGE_GLOBAL | _PAGE_KERNEL | \
81  _PAGE_PRESENT | __READABLE | __WRITEABLE)
82 #define _KERNPG_TABLE (_PAGE_TABLE | _PAGE_KERNEL)
83 
84 /*
85  * CRIS can't do page protection for execute, and considers read the same.
86  * Also, write permissions imply read permissions. This is the closest we can
87  * get..
88  */
89 
90 #define __P000 PAGE_NONE
91 #define __P001 PAGE_READONLY
92 #define __P010 PAGE_COPY
93 #define __P011 PAGE_COPY
94 #define __P100 PAGE_READONLY
95 #define __P101 PAGE_READONLY
96 #define __P110 PAGE_COPY
97 #define __P111 PAGE_COPY
98 
99 #define __S000 PAGE_NONE
100 #define __S001 PAGE_READONLY
101 #define __S010 PAGE_SHARED
102 #define __S011 PAGE_SHARED
103 #define __S100 PAGE_READONLY
104 #define __S101 PAGE_READONLY
105 #define __S110 PAGE_SHARED
106 #define __S111 PAGE_SHARED
107 
108 #define PTE_FILE_MAX_BITS 26
109 
110 #endif