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 15 extern unsigned long long elfcorehdr_addr; 16 extern unsigned long long elfcorehdr_size; 17 18 #ifdef CONFIG_CRASH_DUMP 19 extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size); 20 extern void elfcorehdr_free(unsigned long long addr); 21 extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos); 22 extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos); 23 extern 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 27 ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize, 28 unsigned long offset); 29 ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn, 30 size_t csize, unsigned long offset); 31 32 void 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 /* 54 * is_kdump_kernel() checks whether this kernel is booting after a panic of 55 * previous kernel or not. This is determined by checking if previous kernel 56 * has passed the elf core header address on command line. 57 * 58 * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will 59 * return true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic 60 * of previous kernel. 61 */ 62 63 static inline bool is_kdump_kernel(void) 64 { 65 return elfcorehdr_addr != ELFCORE_ADDR_MAX; 66 } 67 68 /* is_vmcore_usable() checks if the kernel is booting after a panic and 69 * the vmcore region is usable. 70 * 71 * This makes use of the fact that due to alignment -2ULL is not 72 * a valid pointer, much in the vain of IS_ERR(), except 73 * dealing directly with an unsigned long long rather than a pointer. 74 */ 75 76 static inline int is_vmcore_usable(void) 77 { 78 return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0; 79 } 80 81 /* vmcore_unusable() marks the vmcore as unusable, 82 * without disturbing the logic of is_kdump_kernel() 83 */ 84 85 static inline void vmcore_unusable(void) 86 { 87 if (is_kdump_kernel()) 88 elfcorehdr_addr = ELFCORE_ADDR_ERR; 89 } 90 91 /** 92 * struct vmcore_cb - driver callbacks for /proc/vmcore handling 93 * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when 94 * reading the vmcore. Will return "true" if it is RAM or if the 95 * callback cannot tell. If any callback returns "false", it's not 96 * RAM and the page must not be accessed; zeroes should be 97 * indicated in the vmcore instead. For example, a ballooned page 98 * contains no data and reading from such a page will cause high 99 * load in the hypervisor. 100 * @next: List head to manage registered callbacks internally; initialized by 101 * register_vmcore_cb(). 102 * 103 * vmcore callbacks allow drivers managing physical memory ranges to 104 * coordinate with vmcore handling code, for example, to prevent accessing 105 * physical memory ranges that should not be accessed when reading the vmcore, 106 * although included in the vmcore header as memory ranges to dump. 107 */ 108 struct vmcore_cb { 109 bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn); 110 struct list_head next; 111 }; 112 extern void register_vmcore_cb(struct vmcore_cb *cb); 113 extern void unregister_vmcore_cb(struct vmcore_cb *cb); 114 115 #else /* !CONFIG_CRASH_DUMP */ 116 static inline bool is_kdump_kernel(void) { return false; } 117 #endif /* CONFIG_CRASH_DUMP */ 118 119 /* Device Dump information to be filled by drivers */ 120 struct vmcoredd_data { 121 char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */ 122 unsigned int size; /* Size of the dump */ 123 /* Driver's registered callback to be invoked to collect dump */ 124 int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf); 125 }; 126 127 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP 128 int vmcore_add_device_dump(struct vmcoredd_data *data); 129 #else 130 static inline int vmcore_add_device_dump(struct vmcoredd_data *data) 131 { 132 return -EOPNOTSUPP; 133 } 134 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ 135 136 #ifdef CONFIG_PROC_VMCORE 137 ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, 138 u64 *ppos, bool encrypted); 139 #else 140 static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, 141 u64 *ppos, bool encrypted) 142 { 143 return -EOPNOTSUPP; 144 } 145 #endif /* CONFIG_PROC_VMCORE */ 146 147 #endif /* LINUX_CRASHDUMP_H */ 148