phys_addr_t size;
};
+struct kho_vmalloc;
+
struct folio;
struct page;
-#define DECLARE_KHOSER_PTR(name, type) \
- union { \
- phys_addr_t phys; \
- type ptr; \
- } name
-#define KHOSER_STORE_PTR(dest, val) \
- ({ \
- typeof(val) v = val; \
- typecheck(typeof((dest).ptr), v); \
- (dest).phys = virt_to_phys(v); \
- })
-#define KHOSER_LOAD_PTR(src) \
- ({ \
- typeof(src) s = src; \
- (typeof((s).ptr))((s).phys ? phys_to_virt((s).phys) : NULL); \
- })
-
-struct kho_vmalloc_chunk;
-struct kho_vmalloc {
- DECLARE_KHOSER_PTR(first, struct kho_vmalloc_chunk *);
- unsigned int total_pages;
- unsigned short flags;
- unsigned short order;
-};
-
#ifdef CONFIG_KEXEC_HANDOVER
bool kho_is_enabled(void);
bool is_kho_boot(void);
#ifndef _LINUX_KHO_ABI_KEXEC_HANDOVER_H
#define _LINUX_KHO_ABI_KEXEC_HANDOVER_H
+#include <linux/types.h>
+
/**
* DOC: Kexec Handover ABI
*
/* The FDT property for sub-FDTs. */
#define KHO_FDT_SUB_TREE_PROP_NAME "fdt"
+/**
+ * DOC: Kexec Handover ABI for vmalloc Preservation
+ *
+ * The Kexec Handover ABI for preserving vmalloc'ed memory is defined by
+ * a set of structures and helper macros. The layout of these structures is a
+ * stable contract between kernels and is versioned by the KHO_FDT_COMPATIBLE
+ * string.
+ *
+ * The preservation is managed through a main descriptor &struct kho_vmalloc,
+ * which points to a linked list of &struct kho_vmalloc_chunk structures. These
+ * chunks contain the physical addresses of the preserved pages, allowing the
+ * next kernel to reconstruct the vmalloc area with the same content and layout.
+ * Helper macros are also defined for storing and loading pointers within
+ * these structures.
+ */
+
+/* Helper macro to define a union for a serializable pointer. */
+#define DECLARE_KHOSER_PTR(name, type) \
+ union { \
+ u64 phys; \
+ type ptr; \
+ } name
+
+/* Stores the physical address of a serializable pointer. */
+#define KHOSER_STORE_PTR(dest, val) \
+ ({ \
+ typeof(val) v = val; \
+ typecheck(typeof((dest).ptr), v); \
+ (dest).phys = virt_to_phys(v); \
+ })
+
+/* Loads the stored physical address back to a pointer. */
+#define KHOSER_LOAD_PTR(src) \
+ ({ \
+ typeof(src) s = src; \
+ (typeof((s).ptr))((s).phys ? phys_to_virt((s).phys) : NULL); \
+ })
+
+/*
+ * This header is embedded at the beginning of each `kho_vmalloc_chunk`
+ * and contains a pointer to the next chunk in the linked list,
+ * stored as a physical address for handover.
+ */
+struct kho_vmalloc_hdr {
+ DECLARE_KHOSER_PTR(next, struct kho_vmalloc_chunk *);
+};
+
+#define KHO_VMALLOC_SIZE \
+ ((PAGE_SIZE - sizeof(struct kho_vmalloc_hdr)) / \
+ sizeof(u64))
+
+/*
+ * Each chunk is a single page and is part of a linked list that describes
+ * a preserved vmalloc area. It contains the header with the link to the next
+ * chunk and a zero terminated array of physical addresses of the pages that
+ * make up the preserved vmalloc area.
+ */
+struct kho_vmalloc_chunk {
+ struct kho_vmalloc_hdr hdr;
+ u64 phys[KHO_VMALLOC_SIZE];
+};
+
+static_assert(sizeof(struct kho_vmalloc_chunk) == PAGE_SIZE);
+
+/*
+ * Describes a preserved vmalloc memory area, including the
+ * total number of pages, allocation flags, page order, and a pointer to the
+ * first chunk of physical page addresses.
+ */
+struct kho_vmalloc {
+ DECLARE_KHOSER_PTR(first, struct kho_vmalloc_chunk *);
+ unsigned int total_pages;
+ unsigned short flags;
+ unsigned short order;
+};
+
#endif /* _LINUX_KHO_ABI_KEXEC_HANDOVER_H */
}
EXPORT_SYMBOL_GPL(kho_unpreserve_pages);
-struct kho_vmalloc_hdr {
- DECLARE_KHOSER_PTR(next, struct kho_vmalloc_chunk *);
-};
-
-#define KHO_VMALLOC_SIZE \
- ((PAGE_SIZE - sizeof(struct kho_vmalloc_hdr)) / \
- sizeof(phys_addr_t))
-
-struct kho_vmalloc_chunk {
- struct kho_vmalloc_hdr hdr;
- phys_addr_t phys[KHO_VMALLOC_SIZE];
-};
-
-static_assert(sizeof(struct kho_vmalloc_chunk) == PAGE_SIZE);
-
/* vmalloc flags KHO supports */
#define KHO_VMALLOC_SUPPORTED_FLAGS (VM_ALLOC | VM_ALLOW_HUGE_VMAP)
projects / thirdparty / kernel / linux.git / commitdiff
