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 extern ssize_t copy_oldmem_page(unsigned long, char *, size_t, 28 unsigned long, int); 29 extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, 30 size_t csize, unsigned long offset, 31 int userbuf); 32 33 void vmcore_cleanup(void); 34 35 /* Architecture code defines this if there are other possible ELF 36 * machine types, e.g. on bi-arch capable hardware. */ 37 #ifndef vmcore_elf_check_arch_cross 38 #define vmcore_elf_check_arch_cross(x) 0 39 #endif 40 41 /* 42 * Architecture code can redefine this if there are any special checks 43 * needed for 32-bit ELF or 64-bit ELF vmcores. In case of 32-bit 44 * only architecture, vmcore_elf64_check_arch can be set to zero. 45 */ 46 #ifndef vmcore_elf32_check_arch 47 #define vmcore_elf32_check_arch(x) elf_check_arch(x) 48 #endif 49 50 #ifndef vmcore_elf64_check_arch 51 #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x)) 52 #endif 53 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 64 static inline bool is_kdump_kernel(void) 65 { 66 return elfcorehdr_addr != ELFCORE_ADDR_MAX; 67 } 68 69 /* is_vmcore_usable() checks if the kernel is booting after a panic and 70 * the vmcore region is usable. 71 * 72 * This makes use of the fact that due to alignment -2ULL is not 73 * a valid pointer, much in the vain of IS_ERR(), except 74 * dealing directly with an unsigned long long rather than a pointer. 75 */ 76 77 static inline int is_vmcore_usable(void) 78 { 79 return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0; 80 } 81 82 /* vmcore_unusable() marks the vmcore as unusable, 83 * without disturbing the logic of is_kdump_kernel() 84 */ 85 86 static inline void vmcore_unusable(void) 87 { 88 if (is_kdump_kernel()) 89 elfcorehdr_addr = ELFCORE_ADDR_ERR; 90 } 91 92 /** 93 * struct vmcore_cb - driver callbacks for /proc/vmcore handling 94 * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when 95 * reading the vmcore. Will return "true" if it is RAM or if the 96 * callback cannot tell. If any callback returns "false", it's not 97 * RAM and the page must not be accessed; zeroes should be 98 * indicated in the vmcore instead. For example, a ballooned page 99 * contains no data and reading from such a page will cause high 100 * load in the hypervisor. 101 * @next: List head to manage registered callbacks internally; initialized by 102 * register_vmcore_cb(). 103 * 104 * vmcore callbacks allow drivers managing physical memory ranges to 105 * coordinate with vmcore handling code, for example, to prevent accessing 106 * physical memory ranges that should not be accessed when reading the vmcore, 107 * although included in the vmcore header as memory ranges to dump. 108 */ 109 struct vmcore_cb { 110 bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn); 111 struct list_head next; 112 }; 113 extern void register_vmcore_cb(struct vmcore_cb *cb); 114 extern void unregister_vmcore_cb(struct vmcore_cb *cb); 115 116 #else /* !CONFIG_CRASH_DUMP */ 117 static inline bool is_kdump_kernel(void) { return false; } 118 #endif /* CONFIG_CRASH_DUMP */ 119 120 /* Device Dump information to be filled by drivers */ 121 struct vmcoredd_data { 122 char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */ 123 unsigned int size; /* Size of the dump */ 124 /* Driver's registered callback to be invoked to collect dump */ 125 int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf); 126 }; 127 128 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP 129 int vmcore_add_device_dump(struct vmcoredd_data *data); 130 #else 131 static inline int vmcore_add_device_dump(struct vmcoredd_data *data) 132 { 133 return -EOPNOTSUPP; 134 } 135 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ 136 137 #ifdef CONFIG_PROC_VMCORE 138 ssize_t read_from_oldmem(char *buf, size_t count, 139 u64 *ppos, int userbuf, 140 bool encrypted); 141 #else 142 static inline ssize_t read_from_oldmem(char *buf, size_t count, 143 u64 *ppos, int userbuf, 144 bool encrypted) 145 { 146 return -EOPNOTSUPP; 147 } 148 #endif /* CONFIG_PROC_VMCORE */ 149 150 #endif /* LINUX_CRASHDUMP_H */ 151