page.h

  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 __ASSEMBLER__
 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 __ASSEMBLER__
 27#ifndef CONFIG_HUGETLB_PAGE
 28#define HPAGE_SHIFT PAGE_SHIFT
 29#elif defined(CONFIG_PPC_BOOK3S_64)
 30extern 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 __ASSEMBLER__
 79
 80extern phys_addr_t memstart_addr;
 81extern phys_addr_t kernstart_addr;
 82
 83#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
 84extern long long virt_phys_offset;
 85#endif
 86
 87#endif /* __ASSEMBLER__ */
 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 __ASSEMBLER__
220static inline unsigned long virt_to_pfn(const void *kaddr)
221{
222	return __pa(kaddr) >> PAGE_SHIFT;
223}
224
225static 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 __ASSEMBLER__
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
272struct page;
273extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
274extern void copy_user_page(void *to, void *from, unsigned long vaddr,
275		struct page *p);
276extern int devmem_is_allowed(unsigned long pfn);
277
278#ifdef CONFIG_PPC_SMLPAR
279void arch_free_page(struct page *page, int order);
280#define HAVE_ARCH_FREE_PAGE
281#endif
282
283struct vm_area_struct;
284
285extern unsigned long kernstart_virt_addr;
286
287static inline unsigned long kaslr_offset(void)
288{
289	return kernstart_virt_addr - KERNELBASE;
290}
291
292#include <asm-generic/memory_model.h>
293#endif /* __ASSEMBLER__ */
294
295#endif /* _ASM_POWERPC_PAGE_H */