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