cregit-Linux how code gets into the kernel

Release 4.14 arch/arm64/include/asm/memory.h

/*
 * Based on arch/arm/include/asm/memory.h
 *
 * Copyright (C) 2000-2002 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Note: this file should not be included by non-asm/.h files
 */
#ifndef __ASM_MEMORY_H

#define __ASM_MEMORY_H

#include <linux/compiler.h>
#include <linux/const.h>
#include <linux/types.h>
#include <asm/bug.h>
#include <asm/page-def.h>
#include <asm/sizes.h>

/*
 * Allow for constants defined here to be used from assembly code
 * by prepending the UL suffix only with actual C code compilation.
 */

#define UL(x) _AC(x, UL)

/*
 * Size of the PCI I/O space. This must remain a power of two so that
 * IO_SPACE_LIMIT acts as a mask for the low bits of I/O addresses.
 */

#define PCI_IO_SIZE		SZ_16M

/*
 * Log2 of the upper bound of the size of a struct page. Used for sizing
 * the vmemmap region only, does not affect actual memory footprint.
 * We don't use sizeof(struct page) directly since taking its size here
 * requires its definition to be available at this point in the inclusion
 * chain, and it may not be a power of 2 in the first place.
 */

#define STRUCT_PAGE_MAX_SHIFT	6

/*
 * VMEMMAP_SIZE - allows the whole linear region to be covered by
 *                a struct page array
 */

#define VMEMMAP_SIZE (UL(1) << (VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT))

/*
 * PAGE_OFFSET - the virtual address of the start of the linear map (top
 *               (VA_BITS - 1))
 * KIMAGE_VADDR - the virtual address of the start of the kernel image
 * VA_BITS - the maximum number of bits for virtual addresses.
 * VA_START - the first kernel virtual address.
 * TASK_SIZE - the maximum size of a user space task.
 * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area.
 */

#define VA_BITS			(CONFIG_ARM64_VA_BITS)

#define VA_START		(UL(0xffffffffffffffff) - \
        (UL(1) << VA_BITS) + 1)

#define PAGE_OFFSET		(UL(0xffffffffffffffff) - \
        (UL(1) << (VA_BITS - 1)) + 1)

#define KIMAGE_VADDR		(MODULES_END)

#define MODULES_END		(MODULES_VADDR + MODULES_VSIZE)

#define MODULES_VADDR		(VA_START + KASAN_SHADOW_SIZE)

#define MODULES_VSIZE		(SZ_128M)

#define VMEMMAP_START		(PAGE_OFFSET - VMEMMAP_SIZE)

#define PCI_IO_END		(VMEMMAP_START - SZ_2M)

#define PCI_IO_START		(PCI_IO_END - PCI_IO_SIZE)

#define FIXADDR_TOP		(PCI_IO_START - SZ_2M)

#define TASK_SIZE_64		(UL(1) << VA_BITS)

#ifdef CONFIG_COMPAT

#define TASK_SIZE_32		UL(0x100000000)

#define TASK_SIZE		(test_thread_flag(TIF_32BIT) ? \
                                TASK_SIZE_32 : TASK_SIZE_64)

#define TASK_SIZE_OF(tsk)	(test_tsk_thread_flag(tsk, TIF_32BIT) ? \
                                TASK_SIZE_32 : TASK_SIZE_64)
#else

#define TASK_SIZE		TASK_SIZE_64
#endif /* CONFIG_COMPAT */


#define TASK_UNMAPPED_BASE	(PAGE_ALIGN(TASK_SIZE / 4))


#define KERNEL_START      _text

#define KERNEL_END        _end

/*
 * KASAN requires 1/8th of the kernel virtual address space for the shadow
 * region. KASAN can bloat the stack significantly, so double the (minimum)
 * stack size when KASAN is in use.
 */
#ifdef CONFIG_KASAN

#define KASAN_SHADOW_SIZE	(UL(1) << (VA_BITS - 3))

#define KASAN_THREAD_SHIFT	1
#else

#define KASAN_SHADOW_SIZE	(0)

#define KASAN_THREAD_SHIFT	0
#endif


#define MIN_THREAD_SHIFT	(14 + KASAN_THREAD_SHIFT)

/*
 * VMAP'd stacks are allocated at page granularity, so we must ensure that such
 * stacks are a multiple of page size.
 */
#if defined(CONFIG_VMAP_STACK) && (MIN_THREAD_SHIFT < PAGE_SHIFT)

#define THREAD_SHIFT		PAGE_SHIFT
#else

#define THREAD_SHIFT		MIN_THREAD_SHIFT
#endif

#if THREAD_SHIFT >= PAGE_SHIFT

#define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)
#endif


#define THREAD_SIZE		(UL(1) << THREAD_SHIFT)

/*
 * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
 * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
 * assembly.
 */
#ifdef CONFIG_VMAP_STACK

#define THREAD_ALIGN		(2 * THREAD_SIZE)
#else

#define THREAD_ALIGN		THREAD_SIZE
#endif


#define IRQ_STACK_SIZE		THREAD_SIZE


#define OVERFLOW_STACK_SIZE	SZ_4K

/*
 * Alignment of kernel segments (e.g. .text, .data).
 */
#if defined(CONFIG_DEBUG_ALIGN_RODATA)
/*
 *  4 KB granule:   1 level 2 entry
 * 16 KB granule: 128 level 3 entries, with contiguous bit
 * 64 KB granule:  32 level 3 entries, with contiguous bit
 */

#define SEGMENT_ALIGN			SZ_2M
#else
/*
 *  4 KB granule:  16 level 3 entries, with contiguous bit
 * 16 KB granule:   4 level 3 entries, without contiguous bit
 * 64 KB granule:   1 level 3 entry
 */

#define SEGMENT_ALIGN			SZ_64K
#endif

/*
 * Memory types available.
 */

#define MT_DEVICE_nGnRnE	0

#define MT_DEVICE_nGnRE		1

#define MT_DEVICE_GRE		2

#define MT_NORMAL_NC		3

#define MT_NORMAL		4

#define MT_NORMAL_WT		5

/*
 * Memory types for Stage-2 translation
 */

#define MT_S2_NORMAL		0xf

#define MT_S2_DEVICE_nGnRE	0x1

#ifdef CONFIG_ARM64_4K_PAGES

#define IOREMAP_MAX_ORDER	(PUD_SHIFT)
#else

#define IOREMAP_MAX_ORDER	(PMD_SHIFT)
#endif

#ifdef CONFIG_BLK_DEV_INITRD

#define __early_init_dt_declare_initrd(__start, __end)			\
	do {                                                            \
                initrd_start = (__start);                               \
                initrd_end = (__end);                                   \
        } while (0)
#endif

#ifndef __ASSEMBLY__

#include <linux/bitops.h>
#include <linux/mmdebug.h>

extern s64			memstart_addr;
/* PHYS_OFFSET - the physical address of the start of memory. */

#define PHYS_OFFSET		({ VM_BUG_ON(memstart_addr & 1); memstart_addr; })

/* the virtual base of the kernel image (minus TEXT_OFFSET) */
extern u64			kimage_vaddr;

/* the offset between the kernel virtual and physical mappings */
extern u64			kimage_voffset;


static inline unsigned long kaslr_offset(void) { return kimage_vaddr - KIMAGE_VADDR; }

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/* * Allow all memory at the discovery stage. We will clip it later. */ #define MIN_MEMBLOCK_ADDR 0 #define MAX_MEMBLOCK_ADDR U64_MAX /* * PFNs are used to describe any physical page; this means * PFN 0 == physical address 0. * * This is the PFN of the first RAM page in the kernel * direct-mapped view. We assume this is the first page * of RAM in the mem_map as well. */ #define PHYS_PFN_OFFSET (PHYS_OFFSET >> PAGE_SHIFT) /* * Physical vs virtual RAM address space conversion. These are * private definitions which should NOT be used outside memory.h * files. Use virt_to_phys/phys_to_virt/__pa/__va instead. */ /* * The linear kernel range starts in the middle of the virtual adddress * space. Testing the top bit for the start of the region is a * sufficient check. */ #define __is_lm_address(addr) (!!((addr) & BIT(VA_BITS - 1))) #define __lm_to_phys(addr) (((addr) & ~PAGE_OFFSET) + PHYS_OFFSET) #define __kimg_to_phys(addr) ((addr) - kimage_voffset) #define __virt_to_phys_nodebug(x) ({ \ phys_addr_t __x = (phys_addr_t)(x); \ __is_lm_address(__x) ? __lm_to_phys(__x) : \ __kimg_to_phys(__x); \ }) #define __pa_symbol_nodebug(x) __kimg_to_phys((phys_addr_t)(x)) #ifdef CONFIG_DEBUG_VIRTUAL extern phys_addr_t __virt_to_phys(unsigned long x); extern phys_addr_t __phys_addr_symbol(unsigned long x); #else #define __virt_to_phys(x) __virt_to_phys_nodebug(x) #define __phys_addr_symbol(x) __pa_symbol_nodebug(x) #endif #define __phys_to_virt(x) ((unsigned long)((x) - PHYS_OFFSET) | PAGE_OFFSET) #define __phys_to_kimg(x) ((unsigned long)((x) + kimage_voffset)) /* * Convert a page to/from a physical address */ #define page_to_phys(page) (__pfn_to_phys(page_to_pfn(page))) #define phys_to_page(phys) (pfn_to_page(__phys_to_pfn(phys))) /* * Note: Drivers should NOT use these. They are the wrong * translation for translating DMA addresses. Use the driver * DMA support - see dma-mapping.h. */ #define virt_to_phys virt_to_phys
static inline phys_addr_t virt_to_phys(const volatile void *x) { return __virt_to_phys((unsigned long)(x)); }

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#define phys_to_virt phys_to_virt
static inline void *phys_to_virt(phys_addr_t x) { return (void *)(__phys_to_virt(x)); }

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/* * Drivers should NOT use these either. */ #define __pa(x) __virt_to_phys((unsigned long)(x)) #define __pa_symbol(x) __phys_addr_symbol(RELOC_HIDE((unsigned long)(x), 0)) #define __pa_nodebug(x) __virt_to_phys_nodebug((unsigned long)(x)) #define __va(x) ((void *)__phys_to_virt((phys_addr_t)(x))) #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) #define virt_to_pfn(x) __phys_to_pfn(__virt_to_phys((unsigned long)(x))) #define sym_to_pfn(x) __phys_to_pfn(__pa_symbol(x)) /* * virt_to_page(k) convert a _valid_ virtual address to struct page * * virt_addr_valid(k) indicates whether a virtual address is valid */ #define ARCH_PFN_OFFSET ((unsigned long)PHYS_PFN_OFFSET) #ifndef CONFIG_SPARSEMEM_VMEMMAP #define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT) #define _virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) #else #define __virt_to_pgoff(kaddr) (((u64)(kaddr) & ~PAGE_OFFSET) / PAGE_SIZE * sizeof(struct page)) #define __page_to_voff(kaddr) (((u64)(kaddr) & ~VMEMMAP_START) * PAGE_SIZE / sizeof(struct page)) #define page_to_virt(page) ((void *)((__page_to_voff(page)) | PAGE_OFFSET)) #define virt_to_page(vaddr) ((struct page *)((__virt_to_pgoff(vaddr)) | VMEMMAP_START)) #define _virt_addr_valid(kaddr) pfn_valid((((u64)(kaddr) & ~PAGE_OFFSET) \ + PHYS_OFFSET) >> PAGE_SHIFT) #endif #endif #define _virt_addr_is_linear(kaddr) (((u64)(kaddr)) >= PAGE_OFFSET) #define virt_addr_valid(kaddr) (_virt_addr_is_linear(kaddr) && \ _virt_addr_valid(kaddr)) #include <asm-generic/memory_model.h> #endif

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