cregit-Linux how code gets into the kernel

Release 4.18 arch/powerpc/include/asm/page.h

#ifndef _ASM_POWERPC_PAGE_H

#define _ASM_POWERPC_PAGE_H

/*
 * Copyright (C) 2001,2005 IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/kernel.h>
#else
#include <asm/types.h>
#endif
#include <asm/asm-compat.h>
#include <asm/kdump.h>

/*
 * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
 * on PPC44x). For PPC64 we support either 4K or 64K software
 * page size. When using 64K pages however, whether we are really supporting
 * 64K pages in HW or not is irrelevant to those definitions.
 */
#if defined(CONFIG_PPC_256K_PAGES)

#define PAGE_SHIFT		18
#elif defined(CONFIG_PPC_64K_PAGES)

#define PAGE_SHIFT		16
#elif defined(CONFIG_PPC_16K_PAGES)

#define PAGE_SHIFT		14
#else

#define PAGE_SHIFT		12
#endif


#define PAGE_SIZE		(ASM_CONST(1) << PAGE_SHIFT)

#ifndef __ASSEMBLY__
#ifdef CONFIG_HUGETLB_PAGE
extern bool hugetlb_disabled;
extern unsigned int HPAGE_SHIFT;
#else

#define HPAGE_SHIFT PAGE_SHIFT
#endif

#define HPAGE_SIZE		((1UL) << HPAGE_SHIFT)

#define HPAGE_MASK		(~(HPAGE_SIZE - 1))

#define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)

#define HUGE_MAX_HSTATE		(MMU_PAGE_COUNT-1)
#endif

/*
 * Subtle: (1 << PAGE_SHIFT) is an int, not an unsigned long. So if we
 * assign PAGE_MASK to a larger type it gets extended the way we want
 * (i.e. with 1s in the high bits)
 */

#define PAGE_MASK      (~((1 << PAGE_SHIFT) - 1))

/*
 * KERNELBASE is the virtual address of the start of the kernel, it's often
 * the same as PAGE_OFFSET, but _might not be_.
 *
 * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
 *
 * PAGE_OFFSET is the virtual address of the start of lowmem.
 *
 * PHYSICAL_START is the physical address of the start of the kernel.
 *
 * MEMORY_START is the physical address of the start of lowmem.
 *
 * KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
 * ppc32 and based on how they are set we determine MEMORY_START.
 *
 * For the linear mapping the following equation should be true:
 * KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
 *
 * Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
 *
 * There are two ways to determine a physical address from a virtual one:
 * va = pa + PAGE_OFFSET - MEMORY_START
 * va = pa + KERNELBASE - PHYSICAL_START
 *
 * If you want to know something's offset from the start of the kernel you
 * should subtract KERNELBASE.
 *
 * If you want to test if something's a kernel address, use is_kernel_addr().
 */


#define KERNELBASE      ASM_CONST(CONFIG_KERNEL_START)

#define PAGE_OFFSET	ASM_CONST(CONFIG_PAGE_OFFSET)

#define LOAD_OFFSET	ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))

#if defined(CONFIG_NONSTATIC_KERNEL)
#ifndef __ASSEMBLY__

extern phys_addr_t memstart_addr;
extern phys_addr_t kernstart_addr;

#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
extern long long virt_phys_offset;
#endif

#endif /* __ASSEMBLY__ */

#define PHYSICAL_START	kernstart_addr

#else	/* !CONFIG_NONSTATIC_KERNEL */

#define PHYSICAL_START	ASM_CONST(CONFIG_PHYSICAL_START)
#endif

/* See Description below for VIRT_PHYS_OFFSET */
#if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
#ifdef CONFIG_RELOCATABLE

#define VIRT_PHYS_OFFSET virt_phys_offset
#else

#define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
#endif
#endif

#ifdef CONFIG_PPC64

#define MEMORY_START	0UL
#elif defined(CONFIG_NONSTATIC_KERNEL)

#define MEMORY_START	memstart_addr
#else

#define MEMORY_START	(PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
#endif

#ifdef CONFIG_FLATMEM

#define ARCH_PFN_OFFSET		((unsigned long)(MEMORY_START >> PAGE_SHIFT))
#ifndef __ASSEMBLY__
extern unsigned long max_mapnr;

static inline bool pfn_valid(unsigned long pfn) { unsigned long min_pfn = ARCH_PFN_OFFSET; return pfn >= min_pfn && pfn < max_mapnr; }

Contributors

PersonTokensPropCommitsCommitProp
Mathieu Malaterre2284.62%150.00%
Michael Ellerman415.38%150.00%
Total26100.00%2100.00%

#endif #endif #define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT) #define virt_to_page(kaddr) pfn_to_page(virt_to_pfn(kaddr)) #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) #ifdef CONFIG_PPC_BOOK3S_64 /* * On hash the vmalloc and other regions alias to the kernel region when passed * through __pa(), which virt_to_pfn() uses. That means virt_addr_valid() can * return true for some vmalloc addresses, which is incorrect. So explicitly * check that the address is in the kernel region. */ #define virt_addr_valid(kaddr) (REGION_ID(kaddr) == KERNEL_REGION_ID && \ pfn_valid(virt_to_pfn(kaddr))) #else #define virt_addr_valid(kaddr) pfn_valid(virt_to_pfn(kaddr)) #endif /* * On Book-E parts we need __va to parse the device tree and we can't * determine MEMORY_START until then. However we can determine PHYSICAL_START * from information at hand (program counter, TLB lookup). * * On BookE with RELOCATABLE && PPC32 * * With RELOCATABLE && PPC32, we support loading the kernel at any physical * address without any restriction on the page alignment. * * We find the runtime address of _stext and relocate ourselves based on * the following calculation: * * virtual_base = ALIGN_DOWN(KERNELBASE,256M) + * MODULO(_stext.run,256M) * and create the following mapping: * * ALIGN_DOWN(_stext.run,256M) => ALIGN_DOWN(KERNELBASE,256M) * * When we process relocations, we cannot depend on the * existing equation for the __va()/__pa() translations: * * __va(x) = (x) - PHYSICAL_START + KERNELBASE * * Where: * PHYSICAL_START = kernstart_addr = Physical address of _stext * KERNELBASE = Compiled virtual address of _stext. * * This formula holds true iff, kernel load address is TLB page aligned. * * In our case, we need to also account for the shift in the kernel Virtual * address. * * E.g., * * Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as PAGE_OFFSET). * In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M * * Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000 * = 0xbc100000 , which is wrong. * * Rather, it should be : 0xc0000000 + 0x100000 = 0xc0100000 * according to our mapping. * * Hence we use the following formula to get the translations right: * * __va(x) = (x) - [ PHYSICAL_START - Effective KERNELBASE ] * * Where : * PHYSICAL_START = dynamic load address.(kernstart_addr variable) * Effective KERNELBASE = virtual_base = * = ALIGN_DOWN(KERNELBASE,256M) + * MODULO(PHYSICAL_START,256M) * * To make the cost of __va() / __pa() more light weight, we introduce * a new variable virt_phys_offset, which will hold : * * virt_phys_offset = Effective KERNELBASE - PHYSICAL_START * = ALIGN_DOWN(KERNELBASE,256M) - * ALIGN_DOWN(PHYSICALSTART,256M) * * Hence : * * __va(x) = x - PHYSICAL_START + Effective KERNELBASE * = x + virt_phys_offset * * and * __pa(x) = x + PHYSICAL_START - Effective KERNELBASE * = x - virt_phys_offset * * On non-Book-E PPC64 PAGE_OFFSET and MEMORY_START are constants so use * the other definitions for __va & __pa. */ #if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE) #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET)) #define __pa(x) ((unsigned long)(x) - VIRT_PHYS_OFFSET) #else #ifdef CONFIG_PPC64 /* * gcc miscompiles (unsigned long)(&static_var) - PAGE_OFFSET * with -mcmodel=medium, so we use & and | instead of - and + on 64-bit. */ #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET)) #define __pa(x) ((unsigned long)(x) & 0x0fffffffffffffffUL) #else /* 32-bit, non book E */ #define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + PAGE_OFFSET - MEMORY_START)) #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START) #endif #endif /* * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI, * and needs to be executable. This means the whole heap ends * up being executable. */ #define VM_DATA_DEFAULT_FLAGS32 \ (((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0) | \ VM_READ | VM_WRITE | \ VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC) #define VM_DATA_DEFAULT_FLAGS64 (VM_READ | VM_WRITE | \ VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC) #ifdef __powerpc64__ #include <asm/page_64.h> #else #include <asm/page_32.h> #endif /* align addr on a size boundary - adjust address up/down if needed */ #define _ALIGN_UP(addr, size) __ALIGN_KERNEL(addr, size) #define _ALIGN_DOWN(addr, size) ((addr)&(~((typeof(addr))(size)-1))) /* align addr on a size boundary - adjust address up if needed */ #define _ALIGN(addr,size) _ALIGN_UP(addr,size) /* * Don't compare things with KERNELBASE or PAGE_OFFSET to test for * "kernelness", use is_kernel_addr() - it should do what you want. */ #ifdef CONFIG_PPC_BOOK3E_64 #define is_kernel_addr(x) ((x) >= 0x8000000000000000ul) #else #define is_kernel_addr(x) ((x) >= PAGE_OFFSET) #endif #ifndef CONFIG_PPC_BOOK3S_64 /* * Use the top bit of the higher-level page table entries to indicate whether * the entries we point to contain hugepages. This works because we know that * the page tables live in kernel space. If we ever decide to support having * page tables at arbitrary addresses, this breaks and will have to change. */ #ifdef CONFIG_PPC64 #define PD_HUGE 0x8000000000000000 #else #define PD_HUGE 0x80000000 #endif #else /* CONFIG_PPC_BOOK3S_64 */ /* * Book3S 64 stores real addresses in the hugepd entries to * avoid overlaps with _PAGE_PRESENT and _PAGE_PTE. */ #define HUGEPD_ADDR_MASK (0x0ffffffffffffffful & ~HUGEPD_SHIFT_MASK) #endif /* CONFIG_PPC_BOOK3S_64 */ /* * Some number of bits at the level of the page table that points to * a hugepte are used to encode the size. This masks those bits. */ #define HUGEPD_SHIFT_MASK 0x3f #ifndef __ASSEMBLY__ #ifdef CONFIG_PPC_BOOK3S_64 #include <asm/pgtable-be-types.h> #else #include <asm/pgtable-types.h> #endif #ifndef CONFIG_HUGETLB_PAGE #define is_hugepd(pdep) (0) #define pgd_huge(pgd) (0) #endif /* CONFIG_HUGETLB_PAGE */ struct page; extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg); extern void copy_user_page(void *to, void *from, unsigned long vaddr, struct page *p); extern int page_is_ram(unsigned long pfn); extern int devmem_is_allowed(unsigned long pfn); #ifdef CONFIG_PPC_SMLPAR void arch_free_page(struct page *page, int order); #define HAVE_ARCH_FREE_PAGE #endif struct vm_area_struct; #ifdef CONFIG_PPC_BOOK3S_64 /* * For BOOK3s 64 with 4k and 64K linux page size * we want to use pointers, because the page table * actually store pfn */ typedef pte_t *pgtable_t; #else #if defined(CONFIG_PPC_64K_PAGES) && defined(CONFIG_PPC64) typedef pte_t *pgtable_t; #else typedef struct page *pgtable_t; #endif #endif #include <asm-generic/memory_model.h> #endif /* __ASSEMBLY__ */ #include <asm/slice.h> #endif /* _ASM_POWERPC_PAGE_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman20730.85%49.52%
Kumar Gala7210.73%49.52%
Aneesh Kumar K.V669.84%921.43%
Becky Bruce588.64%12.38%
Paul Mackerras527.75%37.14%
Mathieu Malaterre324.77%12.38%
Suzuki K. Poulose284.17%24.76%
Scott Wood253.73%24.76%
Robert Jennings202.98%12.38%
Benjamin Herrenschmidt172.53%24.76%
Ilya Yanok152.24%12.38%
Yuri Tikhonov121.79%12.38%
Kevin Hao121.79%12.38%
Alistair Popple101.49%12.38%
David Gibson101.49%12.38%
Sukadev Bhattiprolu91.34%12.38%
Stephen Rothwell71.04%12.38%
Martin Schwidefsky60.89%12.38%
Hari Bathini40.60%12.38%
Christophe Leroy30.45%12.38%
Kamezawa Hiroyuki30.45%12.38%
Denys Vlasenko20.30%12.38%
Vaishnavi Bhat10.15%12.38%
Total671100.00%42100.00%
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