linux_kernel/include/linux/kexec.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef LINUX_KEXEC_H
#define LINUX_KEXEC_H

#define IND_DESTINATION_BIT 0
#define IND_INDIRECTION_BIT 1
#define IND_DONE_BIT        2
#define IND_SOURCE_BIT      3

#define IND_DESTINATION  (1 << IND_DESTINATION_BIT)
#define IND_INDIRECTION  (1 << IND_INDIRECTION_BIT)
#define IND_DONE         (1 << IND_DONE_BIT)
#define IND_SOURCE       (1 << IND_SOURCE_BIT)
#define IND_FLAGS (IND_DESTINATION | IND_INDIRECTION | IND_DONE | IND_SOURCE)

#if !defined(__ASSEMBLY__)

#include <linux/crash_core.h>
#include <asm/io.h>

#include <uapi/linux/kexec.h>

#ifdef CONFIG_KEXEC_CORE
#include <linux/list.h>
#include <linux/compat.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <asm/kexec.h>

/* Verify architecture specific macros are defined */

#ifndef KEXEC_SOURCE_MEMORY_LIMIT
#error KEXEC_SOURCE_MEMORY_LIMIT not defined
#endif

#ifndef KEXEC_DESTINATION_MEMORY_LIMIT
#error KEXEC_DESTINATION_MEMORY_LIMIT not defined
#endif

#ifndef KEXEC_CONTROL_MEMORY_LIMIT
#error KEXEC_CONTROL_MEMORY_LIMIT not defined
#endif

#ifndef KEXEC_CONTROL_MEMORY_GFP
#define KEXEC_CONTROL_MEMORY_GFP (GFP_KERNEL | __GFP_NORETRY)
#endif

#ifndef KEXEC_CONTROL_PAGE_SIZE
#error KEXEC_CONTROL_PAGE_SIZE not defined
#endif

#ifndef KEXEC_ARCH
#error KEXEC_ARCH not defined
#endif

#ifndef KEXEC_CRASH_CONTROL_MEMORY_LIMIT
#define KEXEC_CRASH_CONTROL_MEMORY_LIMIT KEXEC_CONTROL_MEMORY_LIMIT
#endif

#ifndef KEXEC_CRASH_MEM_ALIGN
#define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
#endif

#define KEXEC_CORE_NOTE_NAME	CRASH_CORE_NOTE_NAME

/*
 * This structure is used to hold the arguments that are used when loading
 * kernel binaries.
 */

typedef unsigned long kimage_entry_t;

struct kexec_segment {
	/*
	 * This pointer can point to user memory if kexec_load() system
	 * call is used or will point to kernel memory if
	 * kexec_file_load() system call is used.
	 *
	 * Use ->buf when expecting to deal with user memory and use ->kbuf
	 * when expecting to deal with kernel memory.
	 */
	union {
		void __user *buf;
		void *kbuf;
	};
	size_t bufsz;
	unsigned long mem;
	size_t memsz;
};

#ifdef CONFIG_COMPAT
struct compat_kexec_segment {
	compat_uptr_t buf;
	compat_size_t bufsz;
	compat_ulong_t mem;	/* User space sees this as a (void *) ... */
	compat_size_t memsz;
};
#endif

#ifdef CONFIG_KEXEC_FILE
struct purgatory_info {
	/*
	 * Pointer to elf header at the beginning of kexec_purgatory.
	 * Note: kexec_purgatory is read only
	 */
	const Elf_Ehdr *ehdr;
	/*
	 * Temporary, modifiable buffer for sechdrs used for relocation.
	 * This memory can be freed post image load.
	 */
	Elf_Shdr *sechdrs;
	/*
	 * Temporary, modifiable buffer for stripped purgatory used for
	 * relocation. This memory can be freed post image load.
	 */
	void *purgatory_buf;
};

struct kimage;

typedef int (kexec_probe_t)(const char *kernel_buf, unsigned long kernel_size);
typedef void *(kexec_load_t)(struct kimage *image, char *kernel_buf,
			     unsigned long kernel_len, char *initrd,
			     unsigned long initrd_len, char *cmdline,
			     unsigned long cmdline_len);
typedef int (kexec_cleanup_t)(void *loader_data);

#ifdef CONFIG_KEXEC_VERIFY_SIG
typedef int (kexec_verify_sig_t)(const char *kernel_buf,
				 unsigned long kernel_len);
#endif

struct kexec_file_ops {
	kexec_probe_t *probe;
	kexec_load_t *load;
	kexec_cleanup_t *cleanup;
#ifdef CONFIG_KEXEC_VERIFY_SIG
	kexec_verify_sig_t *verify_sig;
#endif
};

extern const struct kexec_file_ops * const kexec_file_loaders[];

int kexec_image_probe_default(struct kimage *image, void *buf,
			      unsigned long buf_len);

/**
 * struct kexec_buf - parameters for finding a place for a buffer in memory
 * @image:	kexec image in which memory to search.
 * @buffer:	Contents which will be copied to the allocated memory.
 * @bufsz:	Size of @buffer.
 * @mem:	On return will have address of the buffer in memory.
 * @memsz:	Size for the buffer in memory.
 * @buf_align:	Minimum alignment needed.
 * @buf_min:	The buffer can't be placed below this address.
 * @buf_max:	The buffer can't be placed above this address.
 * @top_down:	Allocate from top of memory.
 */
struct kexec_buf {
	struct kimage *image;
	void *buffer;
	unsigned long bufsz;
	unsigned long mem;
	unsigned long memsz;
	unsigned long buf_align;
	unsigned long buf_min;
	unsigned long buf_max;
	bool top_down;
};

int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf);
int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
				   void *buf, unsigned int size,
				   bool get_value);
void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name);

int __weak arch_kexec_apply_relocations_add(struct purgatory_info *pi,
					    Elf_Shdr *section,
					    const Elf_Shdr *relsec,
					    const Elf_Shdr *symtab);
int __weak arch_kexec_apply_relocations(struct purgatory_info *pi,
					Elf_Shdr *section,
					const Elf_Shdr *relsec,
					const Elf_Shdr *symtab);

int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
			       int (*func)(struct resource *, void *));
extern int kexec_add_buffer(struct kexec_buf *kbuf);
int kexec_locate_mem_hole(struct kexec_buf *kbuf);

/* Alignment required for elf header segment */
#define ELF_CORE_HEADER_ALIGN   4096

struct crash_mem_range {
	u64 start, end;
};

struct crash_mem {
	unsigned int max_nr_ranges;
	unsigned int nr_ranges;
	struct crash_mem_range ranges[0];
};

extern int crash_exclude_mem_range(struct crash_mem *mem,
				   unsigned long long mstart,
				   unsigned long long mend);
extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
				       void **addr, unsigned long *sz);
#endif /* CONFIG_KEXEC_FILE */

struct kimage {
	kimage_entry_t head;
	kimage_entry_t *entry;
	kimage_entry_t *last_entry;

	unsigned long start;
	struct page *control_code_page;
	struct page *swap_page;
	void *vmcoreinfo_data_copy; /* locates in the crash memory */

	unsigned long nr_segments;
	struct kexec_segment segment[KEXEC_SEGMENT_MAX];

	struct list_head control_pages;
	struct list_head dest_pages;
	struct list_head unusable_pages;

	/* Address of next control page to allocate for crash kernels. */
	unsigned long control_page;

	/* Flags to indicate special processing */
	unsigned int type : 1;
#define KEXEC_TYPE_DEFAULT 0
#define KEXEC_TYPE_CRASH   1
	unsigned int preserve_context : 1;
	/* If set, we are using file mode kexec syscall */
	unsigned int file_mode:1;

#ifdef ARCH_HAS_KIMAGE_ARCH
	struct kimage_arch arch;
#endif

#ifdef CONFIG_KEXEC_FILE
	/* Additional fields for file based kexec syscall */
	void *kernel_buf;
	unsigned long kernel_buf_len;

	void *initrd_buf;
	unsigned long initrd_buf_len;

	char *cmdline_buf;
	unsigned long cmdline_buf_len;

	/* File operations provided by image loader */
	const struct kexec_file_ops *fops;

	/* Image loader handling the kernel can store a pointer here */
	void *image_loader_data;

	/* Information for loading purgatory */
	struct purgatory_info purgatory_info;
#endif
};

/* kexec interface functions */
extern void machine_kexec(struct kimage *image);
extern int machine_kexec_prepare(struct kimage *image);
extern void machine_kexec_cleanup(struct kimage *image);
extern int kernel_kexec(void);
extern struct page *kimage_alloc_control_pages(struct kimage *image,
						unsigned int order);
extern void __crash_kexec(struct pt_regs *);
extern void crash_kexec(struct pt_regs *);
int kexec_should_crash(struct task_struct *);
int kexec_crash_loaded(void);
void crash_save_cpu(struct pt_regs *regs, int cpu);
extern int kimage_crash_copy_vmcoreinfo(struct kimage *image);

extern struct kimage *kexec_image;
extern struct kimage *kexec_crash_image;
extern int kexec_load_disabled;

#ifndef kexec_flush_icache_page
#define kexec_flush_icache_page(page)
#endif

/* List of defined/legal kexec flags */
#ifndef CONFIG_KEXEC_JUMP
#define KEXEC_FLAGS    KEXEC_ON_CRASH
#else
#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT)
#endif

/* List of defined/legal kexec file flags */
#define KEXEC_FILE_FLAGS	(KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \
				 KEXEC_FILE_NO_INITRAMFS)

/* Location of a reserved region to hold the crash kernel.
 */
extern struct resource crashk_res;
extern struct resource crashk_low_res;
extern note_buf_t __percpu *crash_notes;

/* flag to track if kexec reboot is in progress */
extern bool kexec_in_progress;

int crash_shrink_memory(unsigned long new_size);
size_t crash_get_memory_size(void);
void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);

void arch_kexec_protect_crashkres(void);
void arch_kexec_unprotect_crashkres(void);

#ifndef page_to_boot_pfn
static inline unsigned long page_to_boot_pfn(struct page *page)
{
	return page_to_pfn(page);
}
#endif

#ifndef boot_pfn_to_page
static inline struct page *boot_pfn_to_page(unsigned long boot_pfn)
{
	return pfn_to_page(boot_pfn);
}
#endif

#ifndef phys_to_boot_phys
static inline unsigned long phys_to_boot_phys(phys_addr_t phys)
{
	return phys;
}
#endif

#ifndef boot_phys_to_phys
static inline phys_addr_t boot_phys_to_phys(unsigned long boot_phys)
{
	return boot_phys;
}
#endif

static inline unsigned long virt_to_boot_phys(void *addr)
{
	return phys_to_boot_phys(__pa((unsigned long)addr));
}

static inline void *boot_phys_to_virt(unsigned long entry)
{
	return phys_to_virt(boot_phys_to_phys(entry));
}

#ifndef arch_kexec_post_alloc_pages
static inline int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp) { return 0; }
#endif

#ifndef arch_kexec_pre_free_pages
static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) { }
#endif

#else /* !CONFIG_KEXEC_CORE */
struct pt_regs;
struct task_struct;
static inline void __crash_kexec(struct pt_regs *regs) { }
static inline void crash_kexec(struct pt_regs *regs) { }
static inline int kexec_should_crash(struct task_struct *p) { return 0; }
static inline int kexec_crash_loaded(void) { return 0; }
#define kexec_in_progress false
#endif /* CONFIG_KEXEC_CORE */

#endif /* !defined(__ASSEBMLY__) */

#endif /* LINUX_KEXEC_H */