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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef LINUX_CRASH_DUMP_H
#define LINUX_CRASH_DUMP_H
#include <linux/kexec.h>
#include <linux/proc_fs.h>
#include <linux/elf.h>
#include <linux/pgtable.h>
#include <uapi/linux/vmcore.h>
/* For IS_ENABLED(CONFIG_CRASH_DUMP) */
#define ELFCORE_ADDR_MAX (-1ULL)
#define ELFCORE_ADDR_ERR (-2ULL)
extern unsigned long long elfcorehdr_addr;
extern unsigned long long elfcorehdr_size;
#ifdef CONFIG_CRASH_DUMP
extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
extern void elfcorehdr_free(unsigned long long addr);
extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
unsigned long from, unsigned long pfn,
unsigned long size, pgprot_t prot);
ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize,
unsigned long offset);
ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
size_t csize, unsigned long offset);
void vmcore_cleanup(void);
/* Architecture code defines this if there are other possible ELF
* machine types, e.g. on bi-arch capable hardware. */
#ifndef vmcore_elf_check_arch_cross
#define vmcore_elf_check_arch_cross(x) 0
#endif
/*
* Architecture code can redefine this if there are any special checks
* needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit
* only architecture, vmcore_elf64_check_arch can be set to zero.
*/
#ifndef vmcore_elf32_check_arch
#define vmcore_elf32_check_arch(x) elf_check_arch(x)
#endif
#ifndef vmcore_elf64_check_arch
#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
#endif
/*
* is_kdump_kernel() checks whether this kernel is booting after a panic of
* previous kernel or not. This is determined by checking if previous kernel
* has passed the elf core header address on command line.
*
* This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
* return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic
* of previous kernel.
*/
static inline bool is_kdump_kernel(void)
{
return elfcorehdr_addr != ELFCORE_ADDR_MAX;
}
/* is_vmcore_usable() checks if the kernel is booting after a panic and
* the vmcore region is usable.
*
* This makes use of the fact that due to alignment -2ULL is not
* a valid pointer, much in the vain of IS_ERR(), except
* dealing directly with an unsigned long long rather than a pointer.
*/
static inline int is_vmcore_usable(void)
{
return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
}
/* vmcore_unusable() marks the vmcore as unusable,
* without disturbing the logic of is_kdump_kernel()
*/
static inline void vmcore_unusable(void)
{
if (is_kdump_kernel())
elfcorehdr_addr = ELFCORE_ADDR_ERR;
}
/**
* struct vmcore_cb - driver callbacks for /proc/vmcore handling
* @pfn_is_ram: check whether a PFN really is RAM and should be accessed when
* reading the vmcore. Will return "true" if it is RAM or if the
* callback cannot tell. If any callback returns "false", it's not
* RAM and the page must not be accessed; zeroes should be
* indicated in the vmcore instead. For example, a ballooned page
* contains no data and reading from such a page will cause high
* load in the hypervisor.
* @next: List head to manage registered callbacks internally; initialized by
* register_vmcore_cb().
*
* vmcore callbacks allow drivers managing physical memory ranges to
* coordinate with vmcore handling code, for example, to prevent accessing
* physical memory ranges that should not be accessed when reading the vmcore,
* although included in the vmcore header as memory ranges to dump.
*/
struct vmcore_cb {
bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn);
struct list_head next;
};
extern void register_vmcore_cb(struct vmcore_cb *cb);
extern void unregister_vmcore_cb(struct vmcore_cb *cb);
#else /* !CONFIG_CRASH_DUMP */
static inline bool is_kdump_kernel(void) { return false; }
#endif /* CONFIG_CRASH_DUMP */
/* Device Dump information to be filled by drivers */
struct vmcoredd_data {
char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
unsigned int size; /* Size of the dump */
/* Driver's registered callback to be invoked to collect dump */
int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
};
#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
int vmcore_add_device_dump(struct vmcoredd_data *data);
#else
static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
#ifdef CONFIG_PROC_VMCORE
ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
u64 *ppos, bool encrypted);
#else
static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
u64 *ppos, bool encrypted)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_PROC_VMCORE */
#endif /* LINUX_CRASHDUMP_H */
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