xref: /linux/include/xen/interface/elfnote.h (revision 52c996d3f40b40f87ef9dc80596903309682acc3)
1 /* SPDX-License-Identifier: MIT */
2 /******************************************************************************
3  * elfnote.h
4  *
5  * Definitions used for the Xen ELF notes.
6  *
7  * Copyright (c) 2006, Ian Campbell, XenSource Ltd.
8  */
9 
10 #ifndef __XEN_PUBLIC_ELFNOTE_H__
11 #define __XEN_PUBLIC_ELFNOTE_H__
12 
13 /*
14  * `incontents 200 elfnotes ELF notes
15  *
16  * The notes should live in a PT_NOTE segment and have "Xen" in the
17  * name field.
18  *
19  * Numeric types are either 4 or 8 bytes depending on the content of
20  * the desc field.
21  *
22  * LEGACY indicated the fields in the legacy __xen_guest string which
23  * this a note type replaces.
24  *
25  * String values (for non-legacy) are NULL terminated ASCII, also known
26  * as ASCIZ type.
27  *
28  * Xen only uses ELF Notes contained in x86 binaries.
29  */
30 
31 /*
32  * NAME=VALUE pair (string).
33  */
34 #define XEN_ELFNOTE_INFO           0
35 
36 /*
37  * The virtual address of the entry point (numeric).
38  *
39  * LEGACY: VIRT_ENTRY
40  */
41 #define XEN_ELFNOTE_ENTRY          1
42 
43 /* The virtual address of the hypercall transfer page (numeric).
44  *
45  * LEGACY: HYPERCALL_PAGE. (n.b. legacy value is a physical page
46  * number not a virtual address)
47  */
48 #define XEN_ELFNOTE_HYPERCALL_PAGE 2
49 
50 /* The virtual address where the kernel image should be mapped (numeric).
51  *
52  * Defaults to 0.
53  *
54  * LEGACY: VIRT_BASE
55  */
56 #define XEN_ELFNOTE_VIRT_BASE      3
57 
58 /*
59  * The offset of the ELF paddr field from the actual required
60  * pseudo-physical address (numeric).
61  *
62  * This is used to maintain backwards compatibility with older kernels
63  * which wrote __PAGE_OFFSET into that field. This field defaults to 0
64  * if not present.
65  *
66  * LEGACY: ELF_PADDR_OFFSET. (n.b. legacy default is VIRT_BASE)
67  */
68 #define XEN_ELFNOTE_PADDR_OFFSET   4
69 
70 /*
71  * The version of Xen that we work with (string).
72  *
73  * LEGACY: XEN_VER
74  */
75 #define XEN_ELFNOTE_XEN_VERSION    5
76 
77 /*
78  * The name of the guest operating system (string).
79  *
80  * LEGACY: GUEST_OS
81  */
82 #define XEN_ELFNOTE_GUEST_OS       6
83 
84 /*
85  * The version of the guest operating system (string).
86  *
87  * LEGACY: GUEST_VER
88  */
89 #define XEN_ELFNOTE_GUEST_VERSION  7
90 
91 /*
92  * The loader type (string).
93  *
94  * LEGACY: LOADER
95  */
96 #define XEN_ELFNOTE_LOADER         8
97 
98 /*
99  * The kernel supports PAE (x86/32 only, string = "yes", "no" or
100  * "bimodal").
101  *
102  * For compatibility with Xen 3.0.3 and earlier the "bimodal" setting
103  * may be given as "yes,bimodal" which will cause older Xen to treat
104  * this kernel as PAE.
105  *
106  * LEGACY: PAE (n.b. The legacy interface included a provision to
107  * indicate 'extended-cr3' support allowing L3 page tables to be
108  * placed above 4G. It is assumed that any kernel new enough to use
109  * these ELF notes will include this and therefore "yes" here is
110  * equivalent to "yes[entended-cr3]" in the __xen_guest interface.
111  */
112 #define XEN_ELFNOTE_PAE_MODE       9
113 
114 /*
115  * The features supported/required by this kernel (string).
116  *
117  * The string must consist of a list of feature names (as given in
118  * features.h, without the "XENFEAT_" prefix) separated by '|'
119  * characters. If a feature is required for the kernel to function
120  * then the feature name must be preceded by a '!' character.
121  *
122  * LEGACY: FEATURES
123  */
124 #define XEN_ELFNOTE_FEATURES      10
125 
126 /*
127  * The kernel requires the symbol table to be loaded (string = "yes" or "no")
128  * LEGACY: BSD_SYMTAB (n.b. The legacy treated the presence or absence
129  * of this string as a boolean flag rather than requiring "yes" or
130  * "no".
131  */
132 #define XEN_ELFNOTE_BSD_SYMTAB    11
133 
134 /*
135  * The lowest address the hypervisor hole can begin at (numeric).
136  *
137  * This must not be set higher than HYPERVISOR_VIRT_START. Its presence
138  * also indicates to the hypervisor that the kernel can deal with the
139  * hole starting at a higher address.
140  */
141 #define XEN_ELFNOTE_HV_START_LOW  12
142 
143 /*
144  * List of maddr_t-sized mask/value pairs describing how to recognize
145  * (non-present) L1 page table entries carrying valid MFNs (numeric).
146  */
147 #define XEN_ELFNOTE_L1_MFN_VALID  13
148 
149 /*
150  * Whether or not the guest supports cooperative suspend cancellation.
151  * This is a numeric value.
152  *
153  * Default is 0
154  */
155 #define XEN_ELFNOTE_SUSPEND_CANCEL 14
156 
157 /*
158  * The (non-default) location the initial phys-to-machine map should be
159  * placed at by the hypervisor (Dom0) or the tools (DomU).
160  * The kernel must be prepared for this mapping to be established using
161  * large pages, despite such otherwise not being available to guests. Note
162  * that these large pages may be misaligned in PFN space (they'll obviously
163  * be aligned in MFN and virtual address spaces).
164  * The kernel must also be able to handle the page table pages used for
165  * this mapping not being accessible through the initial mapping.
166  * (Only x86-64 supports this at present.)
167  */
168 #define XEN_ELFNOTE_INIT_P2M      15
169 
170 /*
171  * Whether or not the guest can deal with being passed an initrd not
172  * mapped through its initial page tables.
173  */
174 #define XEN_ELFNOTE_MOD_START_PFN 16
175 
176 /*
177  * The features supported by this kernel (numeric).
178  *
179  * Other than XEN_ELFNOTE_FEATURES on pre-4.2 Xen, this note allows a
180  * kernel to specify support for features that older hypervisors don't
181  * know about. The set of features 4.2 and newer hypervisors will
182  * consider supported by the kernel is the combination of the sets
183  * specified through this and the string note.
184  *
185  * LEGACY: FEATURES
186  */
187 #define XEN_ELFNOTE_SUPPORTED_FEATURES 17
188 
189 /*
190  * Physical entry point into the kernel.
191  *
192  * 32bit entry point into the kernel. When requested to launch the
193  * guest kernel in a HVM container, Xen will use this entry point to
194  * launch the guest in 32bit protected mode with paging disabled.
195  * Ignored otherwise.
196  */
197 #define XEN_ELFNOTE_PHYS32_ENTRY 18
198 
199 /*
200  * Physical loading constraints for PVH kernels
201  *
202  * The presence of this note indicates the kernel supports relocating itself.
203  *
204  * The note may include up to three 32bit values to place constraints on the
205  * guest physical loading addresses and alignment for a PVH kernel.  Values
206  * are read in the following order:
207  *  - a required start alignment (default 0x200000)
208  *  - a minimum address for the start of the image (default 0; see below)
209  *  - a maximum address for the last byte of the image (default 0xffffffff)
210  *
211  * When this note specifies an alignment value, it is used.  Otherwise the
212  * maximum p_align value from loadable ELF Program Headers is used, if it is
213  * greater than or equal to 4k (0x1000).  Otherwise, the default is used.
214  */
215 #define XEN_ELFNOTE_PHYS32_RELOC 19
216 
217 /*
218  * The number of the highest elfnote defined.
219  */
220 #define XEN_ELFNOTE_MAX XEN_ELFNOTE_PHYS32_RELOC
221 
222 /*
223  * System information exported through crash notes.
224  *
225  * The kexec / kdump code will create one XEN_ELFNOTE_CRASH_INFO
226  * note in case of a system crash. This note will contain various
227  * information about the system, see xen/include/xen/elfcore.h.
228  */
229 #define XEN_ELFNOTE_CRASH_INFO 0x1000001
230 
231 /*
232  * System registers exported through crash notes.
233  *
234  * The kexec / kdump code will create one XEN_ELFNOTE_CRASH_REGS
235  * note per cpu in case of a system crash. This note is architecture
236  * specific and will contain registers not saved in the "CORE" note.
237  * See xen/include/xen/elfcore.h for more information.
238  */
239 #define XEN_ELFNOTE_CRASH_REGS 0x1000002
240 
241 
242 /*
243  * xen dump-core none note.
244  * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_NONE
245  * in its dump file to indicate that the file is xen dump-core
246  * file. This note doesn't have any other information.
247  * See tools/libxc/xc_core.h for more information.
248  */
249 #define XEN_ELFNOTE_DUMPCORE_NONE               0x2000000
250 
251 /*
252  * xen dump-core header note.
253  * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_HEADER
254  * in its dump file.
255  * See tools/libxc/xc_core.h for more information.
256  */
257 #define XEN_ELFNOTE_DUMPCORE_HEADER             0x2000001
258 
259 /*
260  * xen dump-core xen version note.
261  * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_XEN_VERSION
262  * in its dump file. It contains the xen version obtained via the
263  * XENVER hypercall.
264  * See tools/libxc/xc_core.h for more information.
265  */
266 #define XEN_ELFNOTE_DUMPCORE_XEN_VERSION        0x2000002
267 
268 /*
269  * xen dump-core format version note.
270  * xm dump-core code will create one XEN_ELFNOTE_DUMPCORE_FORMAT_VERSION
271  * in its dump file. It contains a format version identifier.
272  * See tools/libxc/xc_core.h for more information.
273  */
274 #define XEN_ELFNOTE_DUMPCORE_FORMAT_VERSION     0x2000003
275 
276 #endif /* __XEN_PUBLIC_ELFNOTE_H__ */
277