xref: /linux/arch/powerpc/include/asm/page.h (revision fcc79e1714e8c2b8e216dc3149812edd37884eef)
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 #include <linux/bug.h>
13 #else
14 #include <asm/types.h>
15 #endif
16 #include <asm/asm-const.h>
17 
18 /*
19  * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
20  * on PPC44x and 4K/16K on 8xx). For PPC64 we support either 4K or 64K software
21  * page size. When using 64K pages however, whether we are really supporting
22  * 64K pages in HW or not is irrelevant to those definitions.
23  */
24 #include <vdso/page.h>
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_E500)
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  * KERNELBASE is the virtual address of the start of the kernel, it's often
45  * the same as PAGE_OFFSET, but _might not be_.
46  *
47  * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
48  *
49  * PAGE_OFFSET is the virtual address of the start of lowmem.
50  *
51  * PHYSICAL_START is the physical address of the start of the kernel.
52  *
53  * MEMORY_START is the physical address of the start of lowmem.
54  *
55  * KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
56  * ppc32 and based on how they are set we determine MEMORY_START.
57  *
58  * For the linear mapping the following equation should be true:
59  * KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
60  *
61  * Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
62  *
63  * There are two ways to determine a physical address from a virtual one:
64  * va = pa + PAGE_OFFSET - MEMORY_START
65  * va = pa + KERNELBASE - PHYSICAL_START
66  *
67  * If you want to know something's offset from the start of the kernel you
68  * should subtract KERNELBASE.
69  *
70  * If you want to test if something's a kernel address, use is_kernel_addr().
71  */
72 
73 #define KERNELBASE      ASM_CONST(CONFIG_KERNEL_START)
74 #define PAGE_OFFSET	ASM_CONST(CONFIG_PAGE_OFFSET)
75 #define LOAD_OFFSET	ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
76 
77 #if defined(CONFIG_NONSTATIC_KERNEL)
78 #ifndef __ASSEMBLY__
79 
80 extern phys_addr_t memstart_addr;
81 extern phys_addr_t kernstart_addr;
82 
83 #if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
84 extern long long virt_phys_offset;
85 #endif
86 
87 #endif /* __ASSEMBLY__ */
88 #define PHYSICAL_START	kernstart_addr
89 
90 #else	/* !CONFIG_NONSTATIC_KERNEL */
91 #define PHYSICAL_START	ASM_CONST(CONFIG_PHYSICAL_START)
92 #endif
93 
94 /* See Description below for VIRT_PHYS_OFFSET */
95 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
96 #ifdef CONFIG_RELOCATABLE
97 #define VIRT_PHYS_OFFSET virt_phys_offset
98 #else
99 #define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
100 #endif
101 #endif
102 
103 #ifdef CONFIG_PPC64
104 #define MEMORY_START	0UL
105 #elif defined(CONFIG_NONSTATIC_KERNEL)
106 #define MEMORY_START	memstart_addr
107 #else
108 #define MEMORY_START	(PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
109 #endif
110 
111 #ifdef CONFIG_FLATMEM
112 #define ARCH_PFN_OFFSET		((unsigned long)(MEMORY_START >> PAGE_SHIFT))
113 #endif
114 
115 /*
116  * On Book-E parts we need __va to parse the device tree and we can't
117  * determine MEMORY_START until then.  However we can determine PHYSICAL_START
118  * from information at hand (program counter, TLB lookup).
119  *
120  * On BookE with RELOCATABLE && PPC32
121  *
122  *   With RELOCATABLE && PPC32,  we support loading the kernel at any physical
123  *   address without any restriction on the page alignment.
124  *
125  *   We find the runtime address of _stext and relocate ourselves based on
126  *   the following calculation:
127  *
128  *  	  virtual_base = ALIGN_DOWN(KERNELBASE,256M) +
129  *  				MODULO(_stext.run,256M)
130  *   and create the following mapping:
131  *
132  * 	  ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M)
133  *
134  *   When we process relocations, we cannot depend on the
135  *   existing equation for the __va()/__pa() translations:
136  *
137  * 	   __va(x) = (x)  - PHYSICAL_START + KERNELBASE
138  *
139  *   Where:
140  *   	 PHYSICAL_START = kernstart_addr = Physical address of _stext
141  *  	 KERNELBASE = Compiled virtual address of _stext.
142  *
143  *   This formula holds true iff, kernel load address is TLB page aligned.
144  *
145  *   In our case, we need to also account for the shift in the kernel Virtual
146  *   address.
147  *
148  *   E.g.,
149  *
150  *   Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET).
151  *   In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M
152  *
153  *   Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
154  *                 = 0xbc100000 , which is wrong.
155  *
156  *   Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000
157  *      	according to our mapping.
158  *
159  *   Hence we use the following formula to get the translations right:
160  *
161  * 	  __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ]
162  *
163  * 	  Where :
164  * 		PHYSICAL_START = dynamic load address.(kernstart_addr variable)
165  * 		Effective KERNELBASE = virtual_base =
166  * 				     = ALIGN_DOWN(KERNELBASE,256M) +
167  * 						MODULO(PHYSICAL_START,256M)
168  *
169  * 	To make the cost of __va() / __pa() more light weight, we introduce
170  * 	a new variable virt_phys_offset, which will hold :
171  *
172  * 	virt_phys_offset = Effective KERNELBASE - PHYSICAL_START
173  * 			 = ALIGN_DOWN(KERNELBASE,256M) -
174  * 			 	ALIGN_DOWN(PHYSICALSTART,256M)
175  *
176  * 	Hence :
177  *
178  * 	__va(x) = x - PHYSICAL_START + Effective KERNELBASE
179  * 		= x + virt_phys_offset
180  *
181  * 		and
182  * 	__pa(x) = x + PHYSICAL_START - Effective KERNELBASE
183  * 		= x - virt_phys_offset
184  *
185  * On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use
186  * the other definitions for __va & __pa.
187  */
188 #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
189 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))
190 #define __pa(x) ((phys_addr_t)(unsigned long)(x) - VIRT_PHYS_OFFSET)
191 #else
192 #ifdef CONFIG_PPC64
193 
194 #define VIRTUAL_WARN_ON(x)	WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && (x))
195 
196 /*
197  * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET
198  * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit.
199  * This also results in better code generation.
200  */
201 #define __va(x)								\
202 ({									\
203 	VIRTUAL_WARN_ON((unsigned long)(x) >= PAGE_OFFSET);		\
204 	(void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);	\
205 })
206 
207 #define __pa(x)								\
208 ({									\
209 	VIRTUAL_WARN_ON((unsigned long)(x) < PAGE_OFFSET);		\
210 	(unsigned long)(x) & 0x0fffffffffffffffUL;			\
211 })
212 
213 #else /* 32-bit, non book E */
214 #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START))
215 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
216 #endif
217 #endif
218 
219 #ifndef __ASSEMBLY__
220 static inline unsigned long virt_to_pfn(const void *kaddr)
221 {
222 	return __pa(kaddr) >> PAGE_SHIFT;
223 }
224 
225 static inline const void *pfn_to_kaddr(unsigned long pfn)
226 {
227 	return __va(pfn << PAGE_SHIFT);
228 }
229 #endif
230 
231 #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
232 #define virt_addr_valid(vaddr)	({					\
233 	unsigned long _addr = (unsigned long)vaddr;			\
234 	_addr >= PAGE_OFFSET && _addr < (unsigned long)high_memory &&	\
235 	pfn_valid(virt_to_pfn((void *)_addr));				\
236 })
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 __ASSEMBLY__
265 
266 #ifdef CONFIG_PPC_BOOK3S_64
267 #include <asm/pgtable-be-types.h>
268 #else
269 #include <asm/pgtable-types.h>
270 #endif
271 
272 struct page;
273 extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
274 extern void copy_user_page(void *to, void *from, unsigned long vaddr,
275 		struct page *p);
276 extern int devmem_is_allowed(unsigned long pfn);
277 
278 #ifdef CONFIG_PPC_SMLPAR
279 void arch_free_page(struct page *page, int order);
280 #define HAVE_ARCH_FREE_PAGE
281 #endif
282 
283 struct vm_area_struct;
284 
285 extern unsigned long kernstart_virt_addr;
286 
287 static inline unsigned long kaslr_offset(void)
288 {
289 	return kernstart_virt_addr - KERNELBASE;
290 }
291 
292 #include <asm-generic/memory_model.h>
293 #endif /* __ASSEMBLY__ */
294 
295 #endif /* _ASM_POWERPC_PAGE_H */
296