1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef LINUX_CRASH_DUMP_H 3#define LINUX_CRASH_DUMP_H 4 5#include <linux/kexec.h> 6#include <linux/proc_fs.h> 7#include <linux/elf.h> 8#include <linux/pgtable.h> 9#include <uapi/linux/vmcore.h> 10 11/* For IS_ENABLED(CONFIG_CRASH_DUMP) */ 12#define ELFCORE_ADDR_MAX (-1ULL) 13#define ELFCORE_ADDR_ERR (-2ULL) 14 15extern unsigned long long elfcorehdr_addr; 16extern unsigned long long elfcorehdr_size; 17 18#ifdef CONFIG_CRASH_DUMP 19extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size); 20extern void elfcorehdr_free(unsigned long long addr); 21extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos); 22extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos); 23extern int remap_oldmem_pfn_range(struct vm_area_struct *vma, 24 unsigned long from, unsigned long pfn, 25 unsigned long size, pgprot_t prot); 26 27ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize, 28 unsigned long offset); 29ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn, 30 size_t csize, unsigned long offset); 31 32void vmcore_cleanup(void); 33 34/* Architecture code defines this if there are other possible ELF 35 * machine types, e.g. on bi-arch capable hardware. */ 36#ifndef vmcore_elf_check_arch_cross 37#define vmcore_elf_check_arch_cross(x) 0 38#endif 39 40/* 41 * Architecture code can redefine this if there are any special checks 42 * needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit 43 * only architecture, vmcore_elf64_check_arch can be set to zero. 44 */ 45#ifndef vmcore_elf32_check_arch 46#define vmcore_elf32_check_arch(x) elf_check_arch(x) 47#endif 48 49#ifndef vmcore_elf64_check_arch 50#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x)) 51#endif 52 53#ifndef is_kdump_kernel 54/* 55 * is_kdump_kernel() checks whether this kernel is booting after a panic of 56 * previous kernel or not. This is determined by checking if previous kernel 57 * has passed the elf core header address on command line. 58 * 59 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will 60 * return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic 61 * of previous kernel. 62 */ 63 64static inline bool is_kdump_kernel(void) 65{ 66 return elfcorehdr_addr != ELFCORE_ADDR_MAX; 67} 68#endif 69 70/* is_vmcore_usable() checks if the kernel is booting after a panic and 71 * the vmcore region is usable. 72 * 73 * This makes use of the fact that due to alignment -2ULL is not 74 * a valid pointer, much in the vain of IS_ERR(), except 75 * dealing directly with an unsigned long long rather than a pointer. 76 */ 77 78static inline int is_vmcore_usable(void) 79{ 80 return elfcorehdr_addr != ELFCORE_ADDR_ERR && 81 elfcorehdr_addr != ELFCORE_ADDR_MAX ? 1 : 0; 82} 83 84/* vmcore_unusable() marks the vmcore as unusable, 85 * without disturbing the logic of is_kdump_kernel() 86 */ 87 88static inline void vmcore_unusable(void) 89{ 90 elfcorehdr_addr = ELFCORE_ADDR_ERR; 91} 92 93/** 94 * struct vmcore_cb - driver callbacks for /proc/vmcore handling 95 * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when 96 * reading the vmcore. Will return "true" if it is RAM or if the 97 * callback cannot tell. If any callback returns "false", it's not 98 * RAM and the page must not be accessed; zeroes should be 99 * indicated in the vmcore instead. For example, a ballooned page 100 * contains no data and reading from such a page will cause high 101 * load in the hypervisor. 102 * @next: List head to manage registered callbacks internally; initialized by 103 * register_vmcore_cb(). 104 * 105 * vmcore callbacks allow drivers managing physical memory ranges to 106 * coordinate with vmcore handling code, for example, to prevent accessing 107 * physical memory ranges that should not be accessed when reading the vmcore, 108 * although included in the vmcore header as memory ranges to dump. 109 */ 110struct vmcore_cb { 111 bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn); 112 struct list_head next; 113}; 114extern void register_vmcore_cb(struct vmcore_cb *cb); 115extern void unregister_vmcore_cb(struct vmcore_cb *cb); 116 117#else /* !CONFIG_CRASH_DUMP */ 118static inline bool is_kdump_kernel(void) { return false; } 119#endif /* CONFIG_CRASH_DUMP */ 120 121/* Device Dump information to be filled by drivers */ 122struct vmcoredd_data { 123 char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */ 124 unsigned int size; /* Size of the dump */ 125 /* Driver's registered callback to be invoked to collect dump */ 126 int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf); 127}; 128 129#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP 130int vmcore_add_device_dump(struct vmcoredd_data *data); 131#else 132static inline int vmcore_add_device_dump(struct vmcoredd_data *data) 133{ 134 return -EOPNOTSUPP; 135} 136#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ 137 138#ifdef CONFIG_PROC_VMCORE 139ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, 140 u64 *ppos, bool encrypted); 141#else 142static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, 143 u64 *ppos, bool encrypted) 144{ 145 return -EOPNOTSUPP; 146} 147#endif /* CONFIG_PROC_VMCORE */ 148 149#endif /* LINUX_CRASHDUMP_H */ 150