1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | |
3 | #include <linux/coredump.h> |
4 | #include <linux/elfcore.h> |
5 | #include <linux/kernel.h> |
6 | #include <linux/mm.h> |
7 | |
8 | #include <asm/cpufeature.h> |
9 | #include <asm/mte.h> |
10 | |
11 | #define for_each_mte_vma(cprm, i, m) \ |
12 | if (system_supports_mte()) \ |
13 | for (i = 0, m = cprm->vma_meta; \ |
14 | i < cprm->vma_count; \ |
15 | i++, m = cprm->vma_meta + i) \ |
16 | if (m->flags & VM_MTE) |
17 | |
18 | static unsigned long mte_vma_tag_dump_size(struct core_vma_metadata *m) |
19 | { |
20 | return (m->dump_size >> PAGE_SHIFT) * MTE_PAGE_TAG_STORAGE; |
21 | } |
22 | |
23 | /* Derived from dump_user_range(); start/end must be page-aligned */ |
24 | static int mte_dump_tag_range(struct coredump_params *cprm, |
25 | unsigned long start, unsigned long len) |
26 | { |
27 | int ret = 1; |
28 | unsigned long addr; |
29 | void *tags = NULL; |
30 | int locked = 0; |
31 | |
32 | for (addr = start; addr < start + len; addr += PAGE_SIZE) { |
33 | struct page *page = get_dump_page(addr, locked: &locked); |
34 | |
35 | /* |
36 | * get_dump_page() returns NULL when encountering an empty |
37 | * page table entry that would otherwise have been filled with |
38 | * the zero page. Skip the equivalent tag dump which would |
39 | * have been all zeros. |
40 | */ |
41 | if (!page) { |
42 | dump_skip(cprm, nr: MTE_PAGE_TAG_STORAGE); |
43 | continue; |
44 | } |
45 | |
46 | /* |
47 | * Pages mapped in user space as !pte_access_permitted() (e.g. |
48 | * PROT_EXEC only) may not have the PG_mte_tagged flag set. |
49 | */ |
50 | if (!page_mte_tagged(page)) { |
51 | put_page(page); |
52 | dump_skip(cprm, nr: MTE_PAGE_TAG_STORAGE); |
53 | continue; |
54 | } |
55 | |
56 | if (!tags) { |
57 | tags = mte_allocate_tag_storage(); |
58 | if (!tags) { |
59 | put_page(page); |
60 | ret = 0; |
61 | break; |
62 | } |
63 | } |
64 | |
65 | mte_save_page_tags(page_address(page), tags); |
66 | put_page(page); |
67 | if (!dump_emit(cprm, addr: tags, nr: MTE_PAGE_TAG_STORAGE)) { |
68 | ret = 0; |
69 | break; |
70 | } |
71 | } |
72 | |
73 | if (tags) |
74 | mte_free_tag_storage(tags); |
75 | |
76 | return ret; |
77 | } |
78 | |
79 | Elf_Half (struct coredump_params *cprm) |
80 | { |
81 | int i; |
82 | struct core_vma_metadata *m; |
83 | int vma_count = 0; |
84 | |
85 | for_each_mte_vma(cprm, i, m) |
86 | vma_count++; |
87 | |
88 | return vma_count; |
89 | } |
90 | |
91 | int (struct coredump_params *cprm, loff_t offset) |
92 | { |
93 | int i; |
94 | struct core_vma_metadata *m; |
95 | |
96 | for_each_mte_vma(cprm, i, m) { |
97 | struct elf_phdr phdr; |
98 | |
99 | phdr.p_type = PT_AARCH64_MEMTAG_MTE; |
100 | phdr.p_offset = offset; |
101 | phdr.p_vaddr = m->start; |
102 | phdr.p_paddr = 0; |
103 | phdr.p_filesz = mte_vma_tag_dump_size(m); |
104 | phdr.p_memsz = m->end - m->start; |
105 | offset += phdr.p_filesz; |
106 | phdr.p_flags = 0; |
107 | phdr.p_align = 0; |
108 | |
109 | if (!dump_emit(cprm, addr: &phdr, nr: sizeof(phdr))) |
110 | return 0; |
111 | } |
112 | |
113 | return 1; |
114 | } |
115 | |
116 | size_t (struct coredump_params *cprm) |
117 | { |
118 | int i; |
119 | struct core_vma_metadata *m; |
120 | size_t data_size = 0; |
121 | |
122 | for_each_mte_vma(cprm, i, m) |
123 | data_size += mte_vma_tag_dump_size(m); |
124 | |
125 | return data_size; |
126 | } |
127 | |
128 | int (struct coredump_params *cprm) |
129 | { |
130 | int i; |
131 | struct core_vma_metadata *m; |
132 | |
133 | for_each_mte_vma(cprm, i, m) { |
134 | if (!mte_dump_tag_range(cprm, start: m->start, len: m->dump_size)) |
135 | return 0; |
136 | } |
137 | |
138 | return 1; |
139 | } |
140 | |