1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 #ifndef _ASM_POWERPC_PAGE_H
3 #define _ASM_POWERPC_PAGE_H
4
5 /*
6 * Copyright (C) 2001,2005 IBM Corporation.
7 */
8
9 #ifndef __ASSEMBLY__
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #else
13 #include <asm/types.h>
14 #endif
15 #include <asm/asm-const.h>
16
17 /*
18 * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
19 * on PPC44x and 4K/16K on 8xx). For PPC64 we support either 4K or 64K software
20 * page size. When using 64K pages however, whether we are really supporting
21 * 64K pages in HW or not is irrelevant to those definitions.
22 */
23 #define PAGE_SHIFT CONFIG_PPC_PAGE_SHIFT
24 #define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT)
25
26 #ifndef __ASSEMBLY__
27 #ifndef CONFIG_HUGETLB_PAGE
28 #define HPAGE_SHIFT PAGE_SHIFT
29 #elif defined(CONFIG_PPC_BOOK3S_64)
30 extern unsigned int hpage_shift;
31 #define HPAGE_SHIFT hpage_shift
32 #elif defined(CONFIG_PPC_8xx)
33 #define HPAGE_SHIFT 19 /* 512k pages */
34 #elif defined(CONFIG_PPC_FSL_BOOK3E)
35 #define HPAGE_SHIFT 22 /* 4M pages */
36 #endif
37 #define HPAGE_SIZE ((1UL) << HPAGE_SHIFT)
38 #define HPAGE_MASK (~(HPAGE_SIZE - 1))
39 #define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
40 #define HUGE_MAX_HSTATE (MMU_PAGE_COUNT-1)
41 #endif
42
43 /*
44 * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
45 * assign PAGE_MASK to a larger type it gets extended the way we want
46 * (i.e. with 1s in the high bits)
47 */
48 #define PAGE_MASK (~((1 << PAGE_SHIFT) - 1))
49
50 /*
51 * KERNELBASE is the virtual address of the start of the kernel, it's often
52 * the same as PAGE_OFFSET, but _might not be_.
53 *
54 * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
55 *
56 * PAGE_OFFSET is the virtual address of the start of lowmem.
57 *
58 * PHYSICAL_START is the physical address of the start of the kernel.
59 *
60 * MEMORY_START is the physical address of the start of lowmem.
61 *
62 * KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
63 * ppc32 and based on how they are set we determine MEMORY_START.
64 *
65 * For the linear mapping the following equation should be true:
66 * KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
67 *
68 * Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
69 *
70 * There are two ways to determine a physical address from a virtual one:
71 * va = pa + PAGE_OFFSET - MEMORY_START
72 * va = pa + KERNELBASE - PHYSICAL_START
73 *
74 * If you want to know something's offset from the start of the kernel you
75 * should subtract KERNELBASE.
76 *
77 * If you want to test if something's a kernel address, use is_kernel_addr().
78 */
79
80 #define KERNELBASE ASM_CONST(CONFIG_KERNEL_START)
81 #define PAGE_OFFSET ASM_CONST(CONFIG_PAGE_OFFSET)
82 #define LOAD_OFFSET ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
83
84 #if defined(CONFIG_NONSTATIC_KERNEL)
85 #ifndef __ASSEMBLY__
86
87 extern phys_addr_t memstart_addr;
88 extern phys_addr_t kernstart_addr;
89
90 #if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
91 extern long long virt_phys_offset;
92 #endif
93
94 #endif /* __ASSEMBLY__ */
95 #define PHYSICAL_START kernstart_addr
96
97 #else /* !CONFIG_NONSTATIC_KERNEL */
98 #define PHYSICAL_START ASM_CONST(CONFIG_PHYSICAL_START)
99 #endif
100
101 /* See Description below for VIRT_PHYS_OFFSET */
102 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
103 #ifdef CONFIG_RELOCATABLE
104 #define VIRT_PHYS_OFFSET virt_phys_offset
105 #else
106 #define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
107 #endif
108 #endif
109
110 #ifdef CONFIG_PPC64
111 #define MEMORY_START 0UL
112 #elif defined(CONFIG_NONSTATIC_KERNEL)
113 #define MEMORY_START memstart_addr
114 #else
115 #define MEMORY_START (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
116 #endif
117
118 #ifdef CONFIG_FLATMEM
119 #define ARCH_PFN_OFFSET ((unsigned long)(MEMORY_START >> PAGE_SHIFT))
120 #ifndef __ASSEMBLY__
121 extern unsigned long max_mapnr;
pfn_valid(unsigned long pfn)122 static inline bool pfn_valid(unsigned long pfn)
123 {
124 unsigned long min_pfn = ARCH_PFN_OFFSET;
125
126 return pfn >= min_pfn && pfn < max_mapnr;
127 }
128 #endif
129 #endif
130
131 #define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
132 #define virt_to_page(kaddr) pfn_to_page(virt_to_pfn(kaddr))
133 #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
134
135 #define virt_addr_valid(kaddr) pfn_valid(virt_to_pfn(kaddr))
136
137 /*
138 * On Book-E parts we need __va to parse the device tree and we can't
139 * determine MEMORY_START until then. However we can determine PHYSICAL_START
140 * from information at hand (program counter, TLB lookup).
141 *
142 * On BookE with RELOCATABLE && PPC32
143 *
144 * With RELOCATABLE && PPC32, we support loading the kernel at any physical
145 * address without any restriction on the page alignment.
146 *
147 * We find the runtime address of _stext and relocate ourselves based on
148 * the following calculation:
149 *
150 * virtual_base = ALIGN_DOWN(KERNELBASE,256M) +
151 * MODULO(_stext.run,256M)
152 * and create the following mapping:
153 *
154 * ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M)
155 *
156 * When we process relocations, we cannot depend on the
157 * existing equation for the __va()/__pa() translations:
158 *
159 * __va(x) = (x) - PHYSICAL_START + KERNELBASE
160 *
161 * Where:
162 * PHYSICAL_START = kernstart_addr = Physical address of _stext
163 * KERNELBASE = Compiled virtual address of _stext.
164 *
165 * This formula holds true iff, kernel load address is TLB page aligned.
166 *
167 * In our case, we need to also account for the shift in the kernel Virtual
168 * address.
169 *
170 * E.g.,
171 *
172 * Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET).
173 * In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
174 *
175 * Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
176 * = 0xbc100000 , which is wrong.
177 *
178 * Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000
179 * according to our mapping.
180 *
181 * Hence we use the following formula to get the translations right:
182 *
183 * __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ]
184 *
185 * Where :
186 * PHYSICAL_START = dynamic load address.(kernstart_addr variable)
187 * Effective KERNELBASE = virtual_base =
188 * = ALIGN_DOWN(KERNELBASE,256M) +
189 * MODULO(PHYSICAL_START,256M)
190 *
191 * To make the cost of __va() / __pa() more light weight, we introduce
192 * a new variable virt_phys_offset, which will hold :
193 *
194 * virt_phys_offset = Effective KERNELBASE - PHYSICAL_START
195 * = ALIGN_DOWN(KERNELBASE,256M) -
196 * ALIGN_DOWN(PHYSICALSTART,256M)
197 *
198 * Hence :
199 *
200 * __va(x) = x - PHYSICAL_START + Effective KERNELBASE
201 * = x + virt_phys_offset
202 *
203 * and
204 * __pa(x) = x + PHYSICAL_START - Effective KERNELBASE
205 * = x - virt_phys_offset
206 *
207 * On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use
208 * the other definitions for __va & __pa.
209 */
210 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
211 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
212 #define __pa(x) ((phys_addr_t)(unsigned long)(x) - VIRT_PHYS_OFFSET)
213 #else
214 #ifdef CONFIG_PPC64
215 /*
216 * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
217 * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit.
218 * This also results in better code generation.
219 */
220 #define __va(x) \
221 ({ \
222 VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET); \
223 (void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET); \
224 })
225
226 #define __pa(x) \
227 ({ \
228 VIRTUAL_BUG_ON((unsigned long)(x) < PAGE_OFFSET); \
229 (unsigned long)(x) & 0x0fffffffffffffffUL; \
230 })
231
232 #else /* 32-bit, non book E */
233 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
234 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
235 #endif
236 #endif
237
238 /*
239 * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
240 * and needs to be executable. This means the whole heap ends
241 * up being executable.
242 */
243 #define VM_DATA_DEFAULT_FLAGS32 VM_DATA_FLAGS_TSK_EXEC
244 #define VM_DATA_DEFAULT_FLAGS64 VM_DATA_FLAGS_NON_EXEC
245
246 #ifdef __powerpc64__
247 #include <asm/page_64.h>
248 #else
249 #include <asm/page_32.h>
250 #endif
251
252 /*
253 * Don't compare things with KERNELBASE or PAGE_OFFSET to test for
254 * "kernelness", use is_kernel_addr() - it should do what you want.
255 */
256 #ifdef CONFIG_PPC_BOOK3E_64
257 #define is_kernel_addr(x) ((x) >= 0x8000000000000000ul)
258 #elif defined(CONFIG_PPC_BOOK3S_64)
259 #define is_kernel_addr(x) ((x) >= PAGE_OFFSET)
260 #else
261 #define is_kernel_addr(x) ((x) >= TASK_SIZE)
262 #endif
263
264 #ifndef CONFIG_PPC_BOOK3S_64
265 /*
266 * Use the top bit of the higher-level page table entries to indicate whether
267 * the entries we point to contain hugepages. This works because we know that
268 * the page tables live in kernel space. If we ever decide to support having
269 * page tables at arbitrary addresses, this breaks and will have to change.
270 */
271 #ifdef CONFIG_PPC64
272 #define PD_HUGE 0x8000000000000000UL
273 #else
274 #define PD_HUGE 0x80000000
275 #endif
276
277 #else /* CONFIG_PPC_BOOK3S_64 */
278 /*
279 * Book3S 64 stores real addresses in the hugepd entries to
280 * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE.
281 */
282 #define HUGEPD_ADDR_MASK (0x0ffffffffffffffful & ~HUGEPD_SHIFT_MASK)
283 #endif /* CONFIG_PPC_BOOK3S_64 */
284
285 /*
286 * Some number of bits at the level of the page table that points to
287 * a hugepte are used to encode the size. This masks those bits.
288 * On 8xx, HW assistance requires 4k alignment for the hugepte.
289 */
290 #ifdef CONFIG_PPC_8xx
291 #define HUGEPD_SHIFT_MASK 0xfff
292 #else
293 #define HUGEPD_SHIFT_MASK 0x3f
294 #endif
295
296 #ifndef __ASSEMBLY__
297
298 #ifdef CONFIG_PPC_BOOK3S_64
299 #include <asm/pgtable-be-types.h>
300 #else
301 #include <asm/pgtable-types.h>
302 #endif
303
304
305 #ifndef CONFIG_HUGETLB_PAGE
306 #define is_hugepd(pdep) (0)
307 #define pgd_huge(pgd) (0)
308 #endif /* CONFIG_HUGETLB_PAGE */
309
310 struct page;
311 extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
312 extern void copy_user_page(void *to, void *from, unsigned long vaddr,
313 struct page *p);
314 extern int devmem_is_allowed(unsigned long pfn);
315
316 #ifdef CONFIG_PPC_SMLPAR
317 void arch_free_page(struct page *page, int order);
318 #define HAVE_ARCH_FREE_PAGE
319 #endif
320
321 struct vm_area_struct;
322
323 extern unsigned long kernstart_virt_addr;
324
kaslr_offset(void)325 static inline unsigned long kaslr_offset(void)
326 {
327 return kernstart_virt_addr - KERNELBASE;
328 }
329
330 #include <asm-generic/memory_model.h>
331 #endif /* __ASSEMBLY__ */
332 #include <asm/slice.h>
333
334 #endif /* _ASM_POWERPC_PAGE_H */
335
