1 /****************************************************************************** 2 * kexec.h - Public portion 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a copy 5 * of this software and associated documentation files (the "Software"), to 6 * deal in the Software without restriction, including without limitation the 7 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 8 * sell copies of the Software, and to permit persons to whom the Software is 9 * furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be included in 12 * all copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 19 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 20 * DEALINGS IN THE SOFTWARE. 21 * 22 * Xen port written by: 23 * - Simon 'Horms' Horman <horms@verge.net.au> 24 * - Magnus Damm <magnus@valinux.co.jp> 25 */ 26 27 #ifndef _XEN_PUBLIC_KEXEC_H 28 #define _XEN_PUBLIC_KEXEC_H 29 30 31 /* This file describes the Kexec / Kdump hypercall interface for Xen. 32 * 33 * Kexec under vanilla Linux allows a user to reboot the physical machine 34 * into a new user-specified kernel. The Xen port extends this idea 35 * to allow rebooting of the machine from dom0. When kexec for dom0 36 * is used to reboot, both the hypervisor and the domains get replaced 37 * with some other kernel. It is possible to kexec between vanilla 38 * Linux and Xen and back again. Xen to Xen works well too. 39 * 40 * The hypercall interface for kexec can be divided into three main 41 * types of hypercall operations: 42 * 43 * 1) Range information: 44 * This is used by the dom0 kernel to ask the hypervisor about various 45 * address information. This information is needed to allow kexec-tools 46 * to fill in the ELF headers for /proc/vmcore properly. 47 * 48 * 2) Load and unload of images: 49 * There are no big surprises here, the kexec binary from kexec-tools 50 * runs in userspace in dom0. The tool loads/unloads data into the 51 * dom0 kernel such as new kernel, initramfs and hypervisor. When 52 * loaded the dom0 kernel performs a load hypercall operation, and 53 * before releasing all page references the dom0 kernel calls unload. 54 * 55 * 3) Kexec operation: 56 * This is used to start a previously loaded kernel. 57 */ 58 59 #include "xen.h" 60 61 #if defined(__i386__) || defined(__x86_64__) 62 #define KEXEC_XEN_NO_PAGES 17 63 #endif 64 65 /* 66 * Prototype for this hypercall is: 67 * int kexec_op(int cmd, void *args) 68 * @cmd == KEXEC_CMD_... 69 * KEXEC operation to perform 70 * @args == Operation-specific extra arguments (NULL if none). 71 */ 72 73 /* 74 * Kexec supports two types of operation: 75 * - kexec into a regular kernel, very similar to a standard reboot 76 * - KEXEC_TYPE_DEFAULT is used to specify this type 77 * - kexec into a special "crash kernel", aka kexec-on-panic 78 * - KEXEC_TYPE_CRASH is used to specify this type 79 * - parts of our system may be broken at kexec-on-panic time 80 * - the code should be kept as simple and self-contained as possible 81 */ 82 83 #define KEXEC_TYPE_DEFAULT 0 84 #define KEXEC_TYPE_CRASH 1 85 86 87 /* The kexec implementation for Xen allows the user to load two 88 * types of kernels, KEXEC_TYPE_DEFAULT and KEXEC_TYPE_CRASH. 89 * All data needed for a kexec reboot is kept in one xen_kexec_image_t 90 * per "instance". The data mainly consists of machine address lists to pages 91 * together with destination addresses. The data in xen_kexec_image_t 92 * is passed to the "code page" which is one page of code that performs 93 * the final relocations before jumping to the new kernel. 94 */ 95 96 typedef struct xen_kexec_image { 97 #if defined(__i386__) || defined(__x86_64__) 98 unsigned long page_list[KEXEC_XEN_NO_PAGES]; 99 #endif 100 unsigned long indirection_page; 101 unsigned long start_address; 102 } xen_kexec_image_t; 103 104 /* 105 * Perform kexec having previously loaded a kexec or kdump kernel 106 * as appropriate. 107 * type == KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH [in] 108 * 109 * Control is transferred to the image entry point with the host in 110 * the following state. 111 * 112 * - The image may be executed on any PCPU and all other PCPUs are 113 * stopped. 114 * 115 * - Local interrupts are disabled. 116 * 117 * - Register values are undefined. 118 * 119 * - The image segments have writeable 1:1 virtual to machine 120 * mappings. The location of any page tables is undefined and these 121 * page table frames are not be mapped. 122 */ 123 #define KEXEC_CMD_kexec 0 124 typedef struct xen_kexec_exec { 125 int type; 126 } xen_kexec_exec_t; 127 128 /* 129 * Load/Unload kernel image for kexec or kdump. 130 * type == KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH [in] 131 * image == relocation information for kexec (ignored for unload) [in] 132 */ 133 #define KEXEC_CMD_kexec_load_v1 1 /* obsolete since 0x00040400 */ 134 #define KEXEC_CMD_kexec_unload_v1 2 /* obsolete since 0x00040400 */ 135 typedef struct xen_kexec_load_v1 { 136 int type; 137 xen_kexec_image_t image; 138 } xen_kexec_load_v1_t; 139 140 #define KEXEC_RANGE_MA_CRASH 0 /* machine address and size of crash area */ 141 #define KEXEC_RANGE_MA_XEN 1 /* machine address and size of Xen itself */ 142 #define KEXEC_RANGE_MA_CPU 2 /* machine address and size of a CPU note */ 143 #define KEXEC_RANGE_MA_XENHEAP 3 /* machine address and size of xenheap 144 * Note that although this is adjacent 145 * to Xen it exists in a separate EFI 146 * region on ia64, and thus needs to be 147 * inserted into iomem_machine separately */ 148 #define KEXEC_RANGE_MA_BOOT_PARAM 4 /* Obsolete: machine address and size of 149 * the ia64_boot_param */ 150 #define KEXEC_RANGE_MA_EFI_MEMMAP 5 /* machine address and size of 151 * of the EFI Memory Map */ 152 #define KEXEC_RANGE_MA_VMCOREINFO 6 /* machine address and size of vmcoreinfo */ 153 154 /* 155 * Find the address and size of certain memory areas 156 * range == KEXEC_RANGE_... [in] 157 * nr == physical CPU number (starting from 0) if KEXEC_RANGE_MA_CPU [in] 158 * size == number of bytes reserved in window [out] 159 * start == address of the first byte in the window [out] 160 */ 161 #define KEXEC_CMD_kexec_get_range 3 162 typedef struct xen_kexec_range { 163 int range; 164 int nr; 165 unsigned long size; 166 unsigned long start; 167 } xen_kexec_range_t; 168 169 #if __XEN_INTERFACE_VERSION__ >= 0x00040400 170 /* 171 * A contiguous chunk of a kexec image and it's destination machine 172 * address. 173 */ 174 typedef struct xen_kexec_segment { 175 union { 176 XEN_GUEST_HANDLE(const_void) h; 177 uint64_t _pad; 178 } buf; 179 uint64_t buf_size; 180 uint64_t dest_maddr; 181 uint64_t dest_size; 182 } xen_kexec_segment_t; 183 DEFINE_XEN_GUEST_HANDLE(xen_kexec_segment_t); 184 185 /* 186 * Load a kexec image into memory. 187 * 188 * For KEXEC_TYPE_DEFAULT images, the segments may be anywhere in RAM. 189 * The image is relocated prior to being executed. 190 * 191 * For KEXEC_TYPE_CRASH images, each segment of the image must reside 192 * in the memory region reserved for kexec (KEXEC_RANGE_MA_CRASH) and 193 * the entry point must be within the image. The caller is responsible 194 * for ensuring that multiple images do not overlap. 195 * 196 * All image segments will be loaded to their destination machine 197 * addresses prior to being executed. The trailing portion of any 198 * segments with a source buffer (from dest_maddr + buf_size to 199 * dest_maddr + dest_size) will be zeroed. 200 * 201 * Segments with no source buffer will be accessible to the image when 202 * it is executed. 203 */ 204 205 #define KEXEC_CMD_kexec_load 4 206 typedef struct xen_kexec_load { 207 uint8_t type; /* One of KEXEC_TYPE_* */ 208 uint8_t _pad; 209 uint16_t arch; /* ELF machine type (EM_*). */ 210 uint32_t nr_segments; 211 union { 212 XEN_GUEST_HANDLE(xen_kexec_segment_t) h; 213 uint64_t _pad; 214 } segments; 215 uint64_t entry_maddr; /* image entry point machine address. */ 216 } xen_kexec_load_t; 217 DEFINE_XEN_GUEST_HANDLE(xen_kexec_load_t); 218 219 /* 220 * Unload a kexec image. 221 * 222 * Type must be one of KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH. 223 */ 224 #define KEXEC_CMD_kexec_unload 5 225 typedef struct xen_kexec_unload { 226 uint8_t type; 227 } xen_kexec_unload_t; 228 DEFINE_XEN_GUEST_HANDLE(xen_kexec_unload_t); 229 230 /* 231 * Figure out whether we have an image loaded. A return value of 232 * zero indicates no image loaded. A return value of one 233 * indicates an image is loaded. A negative return value 234 * indicates an error. 235 * 236 * Type must be one of KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH. 237 */ 238 #define KEXEC_CMD_kexec_status 6 239 typedef struct xen_kexec_status { 240 uint8_t type; 241 } xen_kexec_status_t; 242 DEFINE_XEN_GUEST_HANDLE(xen_kexec_status_t); 243 244 #else /* __XEN_INTERFACE_VERSION__ < 0x00040400 */ 245 246 #define KEXEC_CMD_kexec_load KEXEC_CMD_kexec_load_v1 247 #define KEXEC_CMD_kexec_unload KEXEC_CMD_kexec_unload_v1 248 #define xen_kexec_load xen_kexec_load_v1 249 #define xen_kexec_load_t xen_kexec_load_v1_t 250 251 #endif 252 253 #endif /* _XEN_PUBLIC_KEXEC_H */ 254 255 /* 256 * Local variables: 257 * mode: C 258 * c-file-style: "BSD" 259 * c-basic-offset: 4 260 * tab-width: 4 261 * indent-tabs-mode: nil 262 * End: 263 */ 264