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 | |
31 | for (addr = start; addr < start + len; addr += PAGE_SIZE) { |
32 | struct page *page = get_dump_page(addr); |
33 | |
34 | /* |
35 | * get_dump_page() returns NULL when encountering an empty |
36 | * page table entry that would otherwise have been filled with |
37 | * the zero page. Skip the equivalent tag dump which would |
38 | * have been all zeros. |
39 | */ |
40 | if (!page) { |
41 | dump_skip(cprm, nr: MTE_PAGE_TAG_STORAGE); |
42 | continue; |
43 | } |
44 | |
45 | /* |
46 | * Pages mapped in user space as !pte_access_permitted() (e.g. |
47 | * PROT_EXEC only) may not have the PG_mte_tagged flag set. |
48 | */ |
49 | if (!page_mte_tagged(page)) { |
50 | put_page(page); |
51 | dump_skip(cprm, nr: MTE_PAGE_TAG_STORAGE); |
52 | continue; |
53 | } |
54 | |
55 | if (!tags) { |
56 | tags = mte_allocate_tag_storage(); |
57 | if (!tags) { |
58 | put_page(page); |
59 | ret = 0; |
60 | break; |
61 | } |
62 | } |
63 | |
64 | mte_save_page_tags(page_address(page), tags); |
65 | put_page(page); |
66 | if (!dump_emit(cprm, addr: tags, nr: MTE_PAGE_TAG_STORAGE)) { |
67 | ret = 0; |
68 | break; |
69 | } |
70 | } |
71 | |
72 | if (tags) |
73 | mte_free_tag_storage(tags); |
74 | |
75 | return ret; |
76 | } |
77 | |
78 | Elf_Half (struct coredump_params *cprm) |
79 | { |
80 | int i; |
81 | struct core_vma_metadata *m; |
82 | int vma_count = 0; |
83 | |
84 | for_each_mte_vma(cprm, i, m) |
85 | vma_count++; |
86 | |
87 | return vma_count; |
88 | } |
89 | |
90 | int (struct coredump_params *cprm, loff_t offset) |
91 | { |
92 | int i; |
93 | struct core_vma_metadata *m; |
94 | |
95 | for_each_mte_vma(cprm, i, m) { |
96 | struct elf_phdr phdr; |
97 | |
98 | phdr.p_type = PT_AARCH64_MEMTAG_MTE; |
99 | phdr.p_offset = offset; |
100 | phdr.p_vaddr = m->start; |
101 | phdr.p_paddr = 0; |
102 | phdr.p_filesz = mte_vma_tag_dump_size(m); |
103 | phdr.p_memsz = m->end - m->start; |
104 | offset += phdr.p_filesz; |
105 | phdr.p_flags = 0; |
106 | phdr.p_align = 0; |
107 | |
108 | if (!dump_emit(cprm, addr: &phdr, nr: sizeof(phdr))) |
109 | return 0; |
110 | } |
111 | |
112 | return 1; |
113 | } |
114 | |
115 | size_t (struct coredump_params *cprm) |
116 | { |
117 | int i; |
118 | struct core_vma_metadata *m; |
119 | size_t data_size = 0; |
120 | |
121 | for_each_mte_vma(cprm, i, m) |
122 | data_size += mte_vma_tag_dump_size(m); |
123 | |
124 | return data_size; |
125 | } |
126 | |
127 | int (struct coredump_params *cprm) |
128 | { |
129 | int i; |
130 | struct core_vma_metadata *m; |
131 | |
132 | for_each_mte_vma(cprm, i, m) { |
133 | if (!mte_dump_tag_range(cprm, start: m->start, len: m->dump_size)) |
134 | return 0; |
135 | } |
136 | |
137 | return 1; |
138 | } |
139 | |