kexec_handover.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef LINUX_KEXEC_HANDOVER_H
  3#define LINUX_KEXEC_HANDOVER_H
  4
  5#include <linux/err.h>
  6#include <linux/errno.h>
  7#include <linux/types.h>
  8
  9struct kho_scratch {
 10	phys_addr_t addr;
 11	phys_addr_t size;
 12};
 13
 14struct folio;
 15struct page;
 16
 17#define DECLARE_KHOSER_PTR(name, type) \
 18	union {                        \
 19		phys_addr_t phys;      \
 20		type ptr;              \
 21	} name
 22#define KHOSER_STORE_PTR(dest, val)               \
 23	({                                        \
 24		typeof(val) v = val;              \
 25		typecheck(typeof((dest).ptr), v); \
 26		(dest).phys = virt_to_phys(v);    \
 27	})
 28#define KHOSER_LOAD_PTR(src)                                                 \
 29	({                                                                   \
 30		typeof(src) s = src;                                         \
 31		(typeof((s).ptr))((s).phys ? phys_to_virt((s).phys) : NULL); \
 32	})
 33
 34struct kho_vmalloc_chunk;
 35struct kho_vmalloc {
 36	DECLARE_KHOSER_PTR(first, struct kho_vmalloc_chunk *);
 37	unsigned int total_pages;
 38	unsigned short flags;
 39	unsigned short order;
 40};
 41
 42#ifdef CONFIG_KEXEC_HANDOVER
 43bool kho_is_enabled(void);
 44bool is_kho_boot(void);
 45
 46int kho_preserve_folio(struct folio *folio);
 47void kho_unpreserve_folio(struct folio *folio);
 48int kho_preserve_pages(struct page *page, unsigned int nr_pages);
 49void kho_unpreserve_pages(struct page *page, unsigned int nr_pages);
 50int kho_preserve_vmalloc(void *ptr, struct kho_vmalloc *preservation);
 51void kho_unpreserve_vmalloc(struct kho_vmalloc *preservation);
 52void *kho_alloc_preserve(size_t size);
 53void kho_unpreserve_free(void *mem);
 54void kho_restore_free(void *mem);
 55struct folio *kho_restore_folio(phys_addr_t phys);
 56struct page *kho_restore_pages(phys_addr_t phys, unsigned int nr_pages);
 57void *kho_restore_vmalloc(const struct kho_vmalloc *preservation);
 58int kho_add_subtree(const char *name, void *fdt);
 59void kho_remove_subtree(void *fdt);
 60int kho_retrieve_subtree(const char *name, phys_addr_t *phys);
 61
 62void kho_memory_init(void);
 63
 64void kho_populate(phys_addr_t fdt_phys, u64 fdt_len, phys_addr_t scratch_phys,
 65		  u64 scratch_len);
 66#else
 67static inline bool kho_is_enabled(void)
 68{
 69	return false;
 70}
 71
 72static inline bool is_kho_boot(void)
 73{
 74	return false;
 75}
 76
 77static inline int kho_preserve_folio(struct folio *folio)
 78{
 79	return -EOPNOTSUPP;
 80}
 81
 82static inline void kho_unpreserve_folio(struct folio *folio) { }
 83
 84static inline int kho_preserve_pages(struct page *page, unsigned int nr_pages)
 85{
 86	return -EOPNOTSUPP;
 87}
 88
 89static inline void kho_unpreserve_pages(struct page *page, unsigned int nr_pages) { }
 90
 91static inline int kho_preserve_vmalloc(void *ptr,
 92				       struct kho_vmalloc *preservation)
 93{
 94	return -EOPNOTSUPP;
 95}
 96
 97static inline void kho_unpreserve_vmalloc(struct kho_vmalloc *preservation) { }
 98
 99static inline void *kho_alloc_preserve(size_t size)
100{
101	return ERR_PTR(-EOPNOTSUPP);
102}
103
104static inline void kho_unpreserve_free(void *mem) { }
105static inline void kho_restore_free(void *mem) { }
106
107static inline struct folio *kho_restore_folio(phys_addr_t phys)
108{
109	return NULL;
110}
111
112static inline struct page *kho_restore_pages(phys_addr_t phys,
113					     unsigned int nr_pages)
114{
115	return NULL;
116}
117
118static inline void *kho_restore_vmalloc(const struct kho_vmalloc *preservation)
119{
120	return NULL;
121}
122
123static inline int kho_add_subtree(const char *name, void *fdt)
124{
125	return -EOPNOTSUPP;
126}
127
128static inline void kho_remove_subtree(void *fdt) { }
129
130static inline int kho_retrieve_subtree(const char *name, phys_addr_t *phys)
131{
132	return -EOPNOTSUPP;
133}
134
135static inline void kho_memory_init(void) { }
136
137static inline void kho_populate(phys_addr_t fdt_phys, u64 fdt_len,
138				phys_addr_t scratch_phys, u64 scratch_len)
139{
140}
141#endif /* CONFIG_KEXEC_HANDOVER */
142
143#endif /* LINUX_KEXEC_HANDOVER_H */