kernel / arch / arm64 / include / asm / 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/const.h>
#include <linux/sizes.h>
#include <asm/page-def.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
 * needs to cover the memory region from the beginning of the 52-bit
 * PAGE_OFFSET all the way to PAGE_END 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_RANGE	(_PAGE_END(VA_BITS_MIN) - PAGE_OFFSET)
#define VMEMMAP_SIZE	((VMEMMAP_RANGE >> PAGE_SHIFT) * sizeof(struct page))

/*
 * PAGE_OFFSET - the virtual address of the start of the linear map, at the
 *               start of the TTBR1 address space.
 * PAGE_END - the end of the linear map, where all other kernel mappings begin.
 * KIMAGE_VADDR - the virtual address of the start of the kernel image.
 * VA_BITS - the maximum number of bits for virtual addresses.
 */
#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 MODULES_END		(MODULES_VADDR + MODULES_VSIZE)
#define MODULES_VADDR		(_PAGE_END(VA_BITS_MIN))
#define MODULES_VSIZE		(SZ_2G)
#define VMEMMAP_START		(VMEMMAP_END - VMEMMAP_SIZE)
#define VMEMMAP_END		(-UL(SZ_1G))
#define PCI_IO_START		(VMEMMAP_END + SZ_8M)
#define PCI_IO_END		(PCI_IO_START + PCI_IO_SIZE)
#define FIXADDR_TOP		(-UL(SZ_8M))

#if VA_BITS > 48
#ifdef CONFIG_ARM64_16K_PAGES
#define VA_BITS_MIN		(47)
#else
#define VA_BITS_MIN		(48)
#endif
#else
#define VA_BITS_MIN		(VA_BITS)
#endif

#define _PAGE_END(va)		(-(UL(1) << ((va) - 1)))

#define KERNEL_START		_text
#define KERNEL_END		_end

/*
 * Generic and Software Tag-Based KASAN modes require 1/8th and 1/16th of the
 * kernel virtual address space for storing the shadow memory respectively.
 *
 * The mapping between a virtual memory address and its corresponding shadow
 * memory address is defined based on the formula:
 *
 *     shadow_addr = (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET
 *
 * where KASAN_SHADOW_SCALE_SHIFT is the order of the number of bits that map
 * to a single shadow byte and KASAN_SHADOW_OFFSET is a constant that offsets
 * the mapping. Note that KASAN_SHADOW_OFFSET does not point to the start of
 * the shadow memory region.
 *
 * Based on this mapping, we define two constants:
 *
 *     KASAN_SHADOW_START: the start of the shadow memory region;
 *     KASAN_SHADOW_END: the end of the shadow memory region.
 *
 * KASAN_SHADOW_END is defined first as the shadow address that corresponds to
 * the upper bound of possible virtual kernel memory addresses UL(1) << 64
 * according to the mapping formula.
 *
 * KASAN_SHADOW_START is defined second based on KASAN_SHADOW_END. The shadow
 * memory start must map to the lowest possible kernel virtual memory address
 * and thus it depends on the actual bitness of the address space.
 *
 * As KASAN inserts redzones between stack variables, this increases the stack
 * memory usage significantly. Thus, we double the (minimum) stack size.
 */
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
#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_SHADOW_START(va)	(KASAN_SHADOW_END - (UL(1) << ((va) - KASAN_SHADOW_SCALE_SHIFT)))
#define KASAN_SHADOW_START	_KASAN_SHADOW_START(vabits_actual)
#define PAGE_END		KASAN_SHADOW_START
#define KASAN_THREAD_SHIFT	1
#else
#define KASAN_THREAD_SHIFT	0
#define PAGE_END		(_PAGE_END(VA_BITS_MIN))
#endif /* CONFIG_KASAN */

#define DIRECT_MAP_PHYSMEM_END	__pa(PAGE_END - 1)

#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 (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.
 */
#define THREAD_ALIGN		(2 * THREAD_SIZE)

#define IRQ_STACK_SIZE		THREAD_SIZE

#define OVERFLOW_STACK_SIZE	SZ_4K

#define NVHE_STACK_SHIFT       PAGE_SHIFT
#define NVHE_STACK_SIZE        (UL(1) << NVHE_STACK_SHIFT)

/*
 * With the minimum frame size of [x29, x30], exactly half the combined
 * sizes of the hyp and overflow stacks is the maximum size needed to
 * save the unwinded stacktrace; plus an additional entry to delimit the
 * end.
 */
#define NVHE_STACKTRACE_SIZE	((OVERFLOW_STACK_SIZE + NVHE_STACK_SIZE) / 2 + sizeof(long))

/*
 * Alignment of kernel segments (e.g. .text, .data).
 *
 *  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

/*
 * Memory types available.
 *
 * IMPORTANT: MT_NORMAL must be index 0 since vm_get_page_prot() may 'or' in
 *	      the MT_NORMAL_TAGGED memory type for PROT_MTE mappings. Note
 *	      that protection_map[] only contains MT_NORMAL attributes.
 */
#define MT_NORMAL		0
#define MT_NORMAL_TAGGED	1
#define MT_NORMAL_NC		2
#define MT_DEVICE_nGnRnE	3
#define MT_DEVICE_nGnRE		4

/*
 * Memory types for Stage-2 translation
 */
#define MT_S2_NORMAL		0xf
#define MT_S2_NORMAL_NC		0x5
#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_NORMAL_NC	5
#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

/*
 *  Open-coded (swapper_pg_dir - reserved_pg_dir) as this cannot be calculated
 *  until link time.
 */
#define RESERVED_SWAPPER_OFFSET	(PAGE_SIZE)

/*
 *  Open-coded (swapper_pg_dir - tramp_pg_dir) as this cannot be calculated
 *  until link time.
 */
#define TRAMP_SWAPPER_OFFSET	(2 * PAGE_SIZE)

#ifndef __ASSEMBLER__

#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/mmdebug.h>
#include <linux/types.h>
#include <asm/boot.h>
#include <asm/bug.h>
#include <asm/sections.h>
#include <asm/sysreg.h>

static inline u64 __pure read_tcr(void)
{
	u64  tcr;

	// read_sysreg() uses asm volatile, so avoid it here
	asm("mrs %0, tcr_el1" : "=r"(tcr));
	return tcr;
}

#if VA_BITS > 48
// For reasons of #include hell, we can't use TCR_T1SZ_OFFSET/TCR_T1SZ_MASK here
#define vabits_actual		(64 - ((read_tcr() >> 16) & 63))
#else
#define vabits_actual		((u64)VA_BITS)
#endif

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

static inline unsigned long kaslr_offset(void)
{
	return (u64)&_text - KIMAGE_VADDR;
}

#ifdef CONFIG_RANDOMIZE_BASE
void kaslr_init(void);
static inline bool kaslr_enabled(void)
{
	extern bool __kaslr_is_enabled;
	return __kaslr_is_enabled;
}
#else
static inline void kaslr_init(void) { }
static inline bool kaslr_enabled(void) { return false; }
#endif

/*
 * 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)	\
	((__force __typeof__(addr))sign_extend64((__force u64)(addr), 55))

#define untagged_addr(addr)	({					\
	u64 __addr = (__force u64)(addr);					\
	__addr &= __untagged_addr(__addr);				\
	(__force __typeof__(addr))__addr;				\
})

#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_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 /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */

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));
}

#ifdef CONFIG_KASAN_HW_TAGS
#define arch_enable_tag_checks_sync()		mte_enable_kernel_sync()
#define arch_enable_tag_checks_async()		mte_enable_kernel_async()
#define arch_enable_tag_checks_asymm()		mte_enable_kernel_asymm()
#define arch_enable_tag_checks_write_only()	mte_enable_kernel_store_only()
#define arch_suppress_tag_checks_start()	mte_enable_tco()
#define arch_suppress_tag_checks_stop()		mte_disable_tco()
#define arch_force_async_tag_fault()		mte_check_tfsr_exit()
#define arch_get_random_tag()			mte_get_random_tag()
#define arch_get_mem_tag(addr)			mte_get_mem_tag(addr)
#define arch_set_mem_tag_range(addr, size, tag, init)	\
			mte_set_mem_tag_range((addr), (size), (tag), (init))
#endif /* CONFIG_KASAN_HW_TAGS */

/*
 * 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.
 */


/*
 * Check whether an arbitrary address is within the linear map, which
 * lives in the [PAGE_OFFSET, PAGE_END) interval at the bottom of the
 * kernel's TTBR1 address range.
 */
#define __is_lm_address(addr)	(((u64)(addr) - PAGE_OFFSET) < (PAGE_END - PAGE_OFFSET))

#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)(__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 /* CONFIG_DEBUG_VIRTUAL */

#define __phys_to_virt(x)	((unsigned long)((x) - PHYS_OFFSET) | PAGE_OFFSET)
#define __phys_to_kimg(x)	((unsigned long)((x) + kimage_voffset))

/*
 * 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));
}

/* Needed already here for resolving __phys_to_pfn() in virt_to_pfn() */
#include <asm-generic/memory_model.h>

static inline unsigned long virt_to_pfn(const void *kaddr)
{
	return __phys_to_pfn(virt_to_phys(kaddr));
}

/*
 * 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 sym_to_pfn(x)		__phys_to_pfn(__pa_symbol(x))

/*
 *  virt_to_page(x)	convert a _valid_ virtual address to struct page *
 *  virt_addr_valid(x)	indicates whether a virtual address is valid
 */

#if defined(CONFIG_DEBUG_VIRTUAL)
#define page_to_virt(x)	({						\
	__typeof__(x) __page = x;					\
	void *__addr = __va(page_to_phys(__page));			\
	(void *)__tag_set((const void *)__addr, page_kasan_tag(__page));\
})
#define virt_to_page(x)		pfn_to_page(virt_to_pfn(x))
#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 /* CONFIG_DEBUG_VIRTUAL */

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

void dump_mem_limit(void);
#endif /* !__ASSEMBLER__ */

/*
 * 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

/*
 * memory regions which marked with flag MEMBLOCK_NOMAP(for example, the memory
 * of the EFI_UNUSABLE_MEMORY type) may divide a continuous memory block into
 * multiple parts. As a result, the number of memory regions is large.
 */
#ifdef CONFIG_EFI
#define INIT_MEMBLOCK_MEMORY_REGIONS	(INIT_MEMBLOCK_REGIONS * 8)
#endif


#endif /* __ASM_MEMORY_H */