memory.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Based on arch/arm/include/asm/memory.h
 *
 * Copyright (C) 2000-2002 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * 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 <linux/sizes.h>

/*
 * 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

/*
 * VMEMMAP_SIZE - allows the whole linear region to be covered by
 *                a struct page array
 *
 * If we are configured with a 52-bit kernel VA then our VMEMMAP_SIZE
 * neads to cover the memory region from the beginning of the 52-bit
 * PAGE_OFFSET all the way to VA_START for 48-bit. This allows us to
 * keep a constant PAGE_OFFSET and "fallback" to using the higher end
 * of the VMEMMAP where 52-bit support is not available in hardware.
 */
#define VMEMMAP_SIZE ((_VA_START(VA_BITS_MIN) - PAGE_OFFSET) \
			>> (PAGE_SHIFT - 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.
 */
#define VA_BITS			(CONFIG_ARM64_VA_BITS)
#define _PAGE_OFFSET(va)	(-(UL(1) << (va)))
#define PAGE_OFFSET		(_PAGE_OFFSET(VA_BITS))
#define KIMAGE_VADDR		(MODULES_END)
#define BPF_JIT_REGION_START	(KASAN_SHADOW_END)
#define BPF_JIT_REGION_SIZE	(SZ_128M)
#define BPF_JIT_REGION_END	(BPF_JIT_REGION_START + BPF_JIT_REGION_SIZE)
#define MODULES_END		(MODULES_VADDR + MODULES_VSIZE)
#define MODULES_VADDR		(BPF_JIT_REGION_END)
#define MODULES_VSIZE		(SZ_128M)
#define VMEMMAP_START		(-VMEMMAP_SIZE - SZ_2M)
#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)
#if VA_BITS > 48
#define VA_BITS_MIN		(48)
#else
#define VA_BITS_MIN		(VA_BITS)
#endif
#define _VA_START(va)		(-(UL(1) << ((va) - 1)))

#define KERNEL_START      _text
#define KERNEL_END        _end

#ifdef CONFIG_ARM64_VA_BITS_52
#define MAX_USER_VA_BITS	52
#else
#define MAX_USER_VA_BITS	VA_BITS
#endif

/*
 * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual
 * address space for the shadow region respectively. They can bloat the stack
 * significantly, so double the (minimum) stack size when they are in use.
 */
#ifdef CONFIG_KASAN
#define KASAN_SHADOW_OFFSET	_AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
#define KASAN_SHADOW_END	((UL(1) << (64 - KASAN_SHADOW_SCALE_SHIFT)) \
					+ KASAN_SHADOW_OFFSET)
#define KASAN_THREAD_SHIFT	1
#else
#define KASAN_THREAD_SHIFT	0
#define KASAN_SHADOW_END	(_VA_START(VA_BITS_MIN))
#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

/*
 * Memory types for Stage-2 translation when ID_AA64MMFR2_EL1.FWB is 0001
 * Stage-2 enforces Normal-WB and Device-nGnRE
 */
#define MT_S2_FWB_NORMAL	6
#define MT_S2_FWB_DEVICE_nGnRE	1

#ifdef CONFIG_ARM64_4K_PAGES
#define IOREMAP_MAX_ORDER	(PUD_SHIFT)
#else
#define IOREMAP_MAX_ORDER	(PMD_SHIFT)
#endif

#ifndef __ASSEMBLY__
extern u64			vabits_actual;
#define VA_START		(_VA_START(vabits_actual))

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

extern s64			physvirt_offset;
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;
}

/*
 * 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)

/*
 * When dealing with data aborts, watchpoints, or instruction traps we may end
 * up with a tagged userland pointer. Clear the tag to get a sane pointer to
 * pass on to access_ok(), for instance.
 */
#define untagged_addr(addr)	\
	((__typeof__(addr))sign_extend64((u64)(addr), 55))

#ifdef CONFIG_KASAN_SW_TAGS
#define __tag_shifted(tag)	((u64)(tag) << 56)
#define __tag_reset(addr)	untagged_addr(addr)
#define __tag_get(addr)		(__u8)((u64)(addr) >> 56)
#else
#define __tag_shifted(tag)	0UL
#define __tag_reset(addr)	(addr)
#define __tag_get(addr)		0
#endif

static inline const void *__tag_set(const void *addr, u8 tag)
{
	u64 __addr = (u64)addr & ~__tag_shifted(0xff);
	return (const void *)(__addr | __tag_shifted(tag));
}

/*
 * 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 at the bottom of the virtual address
 * space. Testing the top bit for the start of the region is a
 * sufficient check and avoids having to worry about the tag.
 */
#define __is_lm_address(addr)	(!(((u64)addr) & BIT(vabits_actual - 1)))

#define __lm_to_phys(addr)	(((addr) + physvirt_offset))
#define __kimg_to_phys(addr)	((addr) - kimage_voffset)

#define __virt_to_phys_nodebug(x) ({					\
	phys_addr_t __x = (phys_addr_t)(__tag_reset(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) - physvirt_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));
}

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

/*
 * 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)

#if !defined(CONFIG_SPARSEMEM_VMEMMAP) || defined(CONFIG_DEBUG_VIRTUAL)
#define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
#else
#define page_to_virt(x)	({						\
	__typeof__(x) __page = x;					\
	u64 __idx = ((u64)__page - VMEMMAP_START) / sizeof(struct page);\
	u64 __addr = PAGE_OFFSET + (__idx * PAGE_SIZE);			\
	(void *)__tag_set((const void *)__addr, page_kasan_tag(__page));\
})

#define virt_to_page(x)	({						\
	u64 __idx = (__tag_reset((u64)x) - PAGE_OFFSET) / PAGE_SIZE;	\
	u64 __addr = VMEMMAP_START + (__idx * sizeof(struct page));	\
	(struct page *)__addr;						\
})
#endif

#define virt_addr_valid(addr)	({					\
	__typeof__(addr) __addr = addr;					\
	__is_lm_address(__addr) && pfn_valid(virt_to_pfn(__addr));	\
})

#endif

/*
 * Given that the GIC architecture permits ITS implementations that can only be
 * configured with a LPI table address once, GICv3 systems with many CPUs may
 * end up reserving a lot of different regions after a kexec for their LPI
 * tables (one per CPU), as we are forced to reuse the same memory after kexec
 * (and thus reserve it persistently with EFI beforehand)
 */
#if defined(CONFIG_EFI) && defined(CONFIG_ARM_GIC_V3_ITS)
# define INIT_MEMBLOCK_RESERVED_REGIONS	(INIT_MEMBLOCK_REGIONS + NR_CPUS + 1)
#endif

#include <asm-generic/memory_model.h>

#endif