1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2010 Marco Stornelli <[email protected]>
4  * Copyright (C) 2011 Kees Cook <[email protected]>
5  * Copyright (C) 2011 Google, Inc.
6  */
7 
8 #include <linux/pstore_ram.h>
9 
10 /*
11  * Choose whether access to the RAM zone requires locking or not.  If a zone
12  * can be written to from different CPUs like with ftrace for example, then
13  * PRZ_FLAG_NO_LOCK is used. For all other cases, locking is required.
14  */
15 #define PRZ_FLAG_NO_LOCK	BIT(0)
16 /*
17  * If a PRZ should only have a single-boot lifetime, this marks it as
18  * getting wiped after its contents get copied out after boot.
19  */
20 #define PRZ_FLAG_ZAP_OLD	BIT(1)
21 
22 /**
23  * struct persistent_ram_zone - Details of a persistent RAM zone (PRZ)
24  *                              used as a pstore backend
25  *
26  * @paddr:	physical address of the mapped RAM area
27  * @size:	size of mapping
28  * @label:	unique name of this PRZ
29  * @type:	frontend type for this PRZ
30  * @flags:	holds PRZ_FLAGS_* bits
31  *
32  * @buffer_lock:
33  *	locks access to @buffer "size" bytes and "start" offset
34  * @buffer:
35  *	pointer to actual RAM area managed by this PRZ
36  * @buffer_size:
37  *	bytes in @buffer->data (not including any trailing ECC bytes)
38  *
39  * @par_buffer:
40  *	pointer into @buffer->data containing ECC bytes for @buffer->data
41  * @par_header:
42  *	pointer into @buffer->data containing ECC bytes for @buffer header
43  *	(i.e. all fields up to @data)
44  * @rs_decoder:
45  *	RSLIB instance for doing ECC calculations
46  * @corrected_bytes:
47  *	ECC corrected bytes accounting since boot
48  * @bad_blocks:
49  *	ECC uncorrectable bytes accounting since boot
50  * @ecc_info:
51  *	ECC configuration details
52  *
53  * @old_log:
54  *	saved copy of @buffer->data prior to most recent wipe
55  * @old_log_size:
56  *	bytes contained in @old_log
57  *
58  */
59 struct persistent_ram_zone {
60 	phys_addr_t paddr;
61 	size_t size;
62 	void *vaddr;
63 	char *label;
64 	enum pstore_type_id type;
65 	u32 flags;
66 
67 	raw_spinlock_t buffer_lock;
68 	struct persistent_ram_buffer *buffer;
69 	size_t buffer_size;
70 
71 	char *par_buffer;
72 	char *par_header;
73 	struct rs_control *rs_decoder;
74 	int corrected_bytes;
75 	int bad_blocks;
76 	struct persistent_ram_ecc_info ecc_info;
77 
78 	char *old_log;
79 	size_t old_log_size;
80 };
81 
82 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
83 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
84 			unsigned int memtype, u32 flags, char *label);
85 void persistent_ram_free(struct persistent_ram_zone **_prz);
86 void persistent_ram_zap(struct persistent_ram_zone *prz);
87 
88 int persistent_ram_write(struct persistent_ram_zone *prz, const void *s,
89 			 unsigned int count);
90 int persistent_ram_write_user(struct persistent_ram_zone *prz,
91 			      const void __user *s, unsigned int count);
92 
93 void persistent_ram_save_old(struct persistent_ram_zone *prz);
94 size_t persistent_ram_old_size(struct persistent_ram_zone *prz);
95 void *persistent_ram_old(struct persistent_ram_zone *prz);
96 void persistent_ram_free_old(struct persistent_ram_zone *prz);
97 ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
98 	char *str, size_t len);
99