1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_POWERPC_NOHASH_32_PTE_8xx_H
3 #define _ASM_POWERPC_NOHASH_32_PTE_8xx_H
4 #ifdef __KERNEL__
5
6 /*
7 * The PowerPC MPC8xx uses a TLB with hardware assisted, software tablewalk.
8 * We also use the two level tables, but we can put the real bits in them
9 * needed for the TLB and tablewalk. These definitions require Mx_CTR.PPM = 0,
10 * Mx_CTR.PPCS = 0, and MD_CTR.TWAM = 1. The level 2 descriptor has
11 * additional page protection (when Mx_CTR.PPCS = 1) that allows TLB hit
12 * based upon user/super access. The TLB does not have accessed nor write
13 * protect. We assume that if the TLB get loaded with an entry it is
14 * accessed, and overload the changed bit for write protect. We use
15 * two bits in the software pte that are supposed to be set to zero in
16 * the TLB entry (24 and 25) for these indicators. Although the level 1
17 * descriptor contains the guarded and writethrough/copyback bits, we can
18 * set these at the page level since they get copied from the Mx_TWC
19 * register when the TLB entry is loaded. We will use bit 27 for guard, since
20 * that is where it exists in the MD_TWC, and bit 26 for writethrough.
21 * These will get masked from the level 2 descriptor at TLB load time, and
22 * copied to the MD_TWC before it gets loaded.
23 * Large page sizes added. We currently support two sizes, 4K and 8M.
24 * This also allows a TLB hander optimization because we can directly
25 * load the PMD into MD_TWC. The 8M pages are only used for kernel
26 * mapping of well known areas. The PMD (PGD) entries contain control
27 * flags in addition to the address, so care must be taken that the
28 * software no longer assumes these are only pointers.
29 */
30
31 /* Definitions for 8xx embedded chips. */
32 #define _PAGE_PRESENT 0x0001 /* V: Page is valid */
33 #define _PAGE_NO_CACHE 0x0002 /* CI: cache inhibit */
34 #define _PAGE_SH 0x0004 /* SH: No ASID (context) compare */
35 #define _PAGE_SPS 0x0008 /* SPS: Small Page Size (1 if 16k, 512k or 8M)*/
36 #define _PAGE_DIRTY 0x0100 /* C: page changed */
37
38 /* These 4 software bits must be masked out when the L2 entry is loaded
39 * into the TLB.
40 */
41 #define _PAGE_GUARDED 0x0010 /* Copied to L1 G entry in DTLB */
42 #define _PAGE_SPECIAL 0x0020 /* SW entry */
43 #define _PAGE_EXEC 0x0040 /* Copied to PP (bit 21) in ITLB */
44 #define _PAGE_ACCESSED 0x0080 /* software: page referenced */
45
46 #define _PAGE_NA 0x0200 /* Supervisor NA, User no access */
47 #define _PAGE_RO 0x0600 /* Supervisor RO, User no access */
48
49 /* cache related flags non existing on 8xx */
50 #define _PAGE_COHERENT 0
51 #define _PAGE_WRITETHRU 0
52
53 #define _PAGE_KERNEL_RO (_PAGE_SH | _PAGE_RO)
54 #define _PAGE_KERNEL_ROX (_PAGE_SH | _PAGE_RO | _PAGE_EXEC)
55 #define _PAGE_KERNEL_RW (_PAGE_SH | _PAGE_DIRTY)
56 #define _PAGE_KERNEL_RWX (_PAGE_SH | _PAGE_DIRTY | _PAGE_EXEC)
57
58 #define _PMD_PRESENT 0x0001
59 #define _PMD_PRESENT_MASK _PMD_PRESENT
60 #define _PMD_BAD 0x0fd0
61 #define _PMD_PAGE_MASK 0x000c
62 #define _PMD_PAGE_8M 0x000c
63 #define _PMD_PAGE_512K 0x0004
64 #define _PMD_USER 0x0020 /* APG 1 */
65
66 #define _PTE_NONE_MASK 0
67
68 #ifdef CONFIG_PPC_16K_PAGES
69 #define _PAGE_PSIZE _PAGE_SPS
70 #else
71 #define _PAGE_PSIZE 0
72 #endif
73
74 #define _PAGE_BASE_NC (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)
75 #define _PAGE_BASE (_PAGE_BASE_NC)
76
77 /* Permission masks used to generate the __P and __S table */
78 #define PAGE_NONE __pgprot(_PAGE_BASE | _PAGE_NA)
79 #define PAGE_SHARED __pgprot(_PAGE_BASE)
80 #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_EXEC)
81 #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_RO)
82 #define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_RO | _PAGE_EXEC)
83 #define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_RO)
84 #define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_RO | _PAGE_EXEC)
85
86 #ifndef __ASSEMBLY__
pte_wrprotect(pte_t pte)87 static inline pte_t pte_wrprotect(pte_t pte)
88 {
89 return __pte(pte_val(pte) | _PAGE_RO);
90 }
91
92 #define pte_wrprotect pte_wrprotect
93
pte_read(pte_t pte)94 static inline int pte_read(pte_t pte)
95 {
96 return (pte_val(pte) & _PAGE_RO) != _PAGE_NA;
97 }
98
99 #define pte_read pte_read
100
pte_write(pte_t pte)101 static inline int pte_write(pte_t pte)
102 {
103 return !(pte_val(pte) & _PAGE_RO);
104 }
105
106 #define pte_write pte_write
107
pte_mkwrite(pte_t pte)108 static inline pte_t pte_mkwrite(pte_t pte)
109 {
110 return __pte(pte_val(pte) & ~_PAGE_RO);
111 }
112
113 #define pte_mkwrite pte_mkwrite
114
pte_user(pte_t pte)115 static inline bool pte_user(pte_t pte)
116 {
117 return !(pte_val(pte) & _PAGE_SH);
118 }
119
120 #define pte_user pte_user
121
pte_mkprivileged(pte_t pte)122 static inline pte_t pte_mkprivileged(pte_t pte)
123 {
124 return __pte(pte_val(pte) | _PAGE_SH);
125 }
126
127 #define pte_mkprivileged pte_mkprivileged
128
pte_mkuser(pte_t pte)129 static inline pte_t pte_mkuser(pte_t pte)
130 {
131 return __pte(pte_val(pte) & ~_PAGE_SH);
132 }
133
134 #define pte_mkuser pte_mkuser
135
pte_mkhuge(pte_t pte)136 static inline pte_t pte_mkhuge(pte_t pte)
137 {
138 return __pte(pte_val(pte) | _PAGE_SPS);
139 }
140
141 #define pte_mkhuge pte_mkhuge
142 #endif
143
144 #endif /* __KERNEL__ */
145 #endif /* _ASM_POWERPC_NOHASH_32_PTE_8xx_H */
146