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(tsk, vma) \
12 if (system_supports_mte()) \
13 for (vma = tsk->mm->mmap; vma; vma = vma->vm_next) \
14 if (vma->vm_flags & VM_MTE)
15
mte_vma_tag_dump_size(struct vm_area_struct * vma)16 static unsigned long mte_vma_tag_dump_size(struct vm_area_struct *vma)
17 {
18 if (vma->vm_flags & VM_DONTDUMP)
19 return 0;
20
21 return vma_pages(vma) * MTE_PAGE_TAG_STORAGE;
22 }
23
24 /* Derived from dump_user_range(); start/end must be page-aligned */
mte_dump_tag_range(struct coredump_params * cprm,unsigned long start,unsigned long end)25 static int mte_dump_tag_range(struct coredump_params *cprm,
26 unsigned long start, unsigned long end)
27 {
28 int ret = 1;
29 unsigned long addr;
30 void *tags = NULL;
31
32 for (addr = start; addr < end; addr += PAGE_SIZE) {
33 struct page *page = get_dump_page(addr);
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, 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 (!test_bit(PG_mte_tagged, &page->flags)) {
51 put_page(page);
52 dump_skip(cprm, 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, tags, 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
elf_core_extra_phdrs(struct coredump_params * cprm)79 Elf_Half elf_core_extra_phdrs(struct coredump_params *cprm)
80 {
81 struct vm_area_struct *vma;
82 int vma_count = 0;
83
84 for_each_mte_vma(current, vma)
85 vma_count++;
86
87 return vma_count;
88 }
89
elf_core_write_extra_phdrs(struct coredump_params * cprm,loff_t offset)90 int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset)
91 {
92 struct vm_area_struct *vma;
93
94 for_each_mte_vma(current, vma) {
95 struct elf_phdr phdr;
96
97 phdr.p_type = PT_AARCH64_MEMTAG_MTE;
98 phdr.p_offset = offset;
99 phdr.p_vaddr = vma->vm_start;
100 phdr.p_paddr = 0;
101 phdr.p_filesz = mte_vma_tag_dump_size(vma);
102 phdr.p_memsz = vma->vm_end - vma->vm_start;
103 offset += phdr.p_filesz;
104 phdr.p_flags = 0;
105 phdr.p_align = 0;
106
107 if (!dump_emit(cprm, &phdr, sizeof(phdr)))
108 return 0;
109 }
110
111 return 1;
112 }
113
elf_core_extra_data_size(struct coredump_params * cprm)114 size_t elf_core_extra_data_size(struct coredump_params *cprm)
115 {
116 struct vm_area_struct *vma;
117 size_t data_size = 0;
118
119 for_each_mte_vma(current, vma)
120 data_size += mte_vma_tag_dump_size(vma);
121
122 return data_size;
123 }
124
elf_core_write_extra_data(struct coredump_params * cprm)125 int elf_core_write_extra_data(struct coredump_params *cprm)
126 {
127 struct vm_area_struct *vma;
128
129 for_each_mte_vma(current, vma) {
130 if (vma->vm_flags & VM_DONTDUMP)
131 continue;
132
133 if (!mte_dump_tag_range(cprm, vma->vm_start, vma->vm_end))
134 return 0;
135 }
136
137 return 1;
138 }
139