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 #ifndef VMA_ITERATOR 12 #define VMA_ITERATOR(name, mm, addr) \ 13 struct mm_struct *name = mm 14 #define for_each_vma(vmi, vma) \ 15 for (vma = vmi->mmap; vma; vma = vma->vm_next) 16 #endif 17 18 #define for_each_mte_vma(vmi, vma) \ 19 if (system_supports_mte()) \ 20 for_each_vma(vmi, vma) \ 21 if (vma->vm_flags & VM_MTE) 22 23 static unsigned long mte_vma_tag_dump_size(struct vm_area_struct *vma) 24 { 25 if (vma->vm_flags & VM_DONTDUMP) 26 return 0; 27 28 return vma_pages(vma) * MTE_PAGE_TAG_STORAGE; 29 } 30 31 /* Derived from dump_user_range(); start/end must be page-aligned */ 32 static int mte_dump_tag_range(struct coredump_params *cprm, 33 unsigned long start, unsigned long end) 34 { 35 unsigned long addr; 36 37 for (addr = start; addr < end; addr += PAGE_SIZE) { 38 char tags[MTE_PAGE_TAG_STORAGE]; 39 struct page *page = get_dump_page(addr); 40 41 /* 42 * get_dump_page() returns NULL when encountering an empty 43 * page table entry that would otherwise have been filled with 44 * the zero page. Skip the equivalent tag dump which would 45 * have been all zeros. 46 */ 47 if (!page) { 48 dump_skip(cprm, MTE_PAGE_TAG_STORAGE); 49 continue; 50 } 51 52 /* 53 * Pages mapped in user space as !pte_access_permitted() (e.g. 54 * PROT_EXEC only) may not have the PG_mte_tagged flag set. 55 */ 56 if (!test_bit(PG_mte_tagged, &page->flags)) { 57 put_page(page); 58 dump_skip(cprm, MTE_PAGE_TAG_STORAGE); 59 continue; 60 } 61 62 mte_save_page_tags(page_address(page), tags); 63 put_page(page); 64 if (!dump_emit(cprm, tags, MTE_PAGE_TAG_STORAGE)) 65 return 0; 66 } 67 68 return 1; 69 } 70 71 Elf_Half elf_core_extra_phdrs(void) 72 { 73 struct vm_area_struct *vma; 74 int vma_count = 0; 75 VMA_ITERATOR(vmi, current->mm, 0); 76 77 for_each_mte_vma(vmi, vma) 78 vma_count++; 79 80 return vma_count; 81 } 82 83 int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset) 84 { 85 struct vm_area_struct *vma; 86 VMA_ITERATOR(vmi, current->mm, 0); 87 88 for_each_mte_vma(vmi, vma) { 89 struct elf_phdr phdr; 90 91 phdr.p_type = PT_ARM_MEMTAG_MTE; 92 phdr.p_offset = offset; 93 phdr.p_vaddr = vma->vm_start; 94 phdr.p_paddr = 0; 95 phdr.p_filesz = mte_vma_tag_dump_size(vma); 96 phdr.p_memsz = vma->vm_end - vma->vm_start; 97 offset += phdr.p_filesz; 98 phdr.p_flags = 0; 99 phdr.p_align = 0; 100 101 if (!dump_emit(cprm, &phdr, sizeof(phdr))) 102 return 0; 103 } 104 105 return 1; 106 } 107 108 size_t elf_core_extra_data_size(void) 109 { 110 struct vm_area_struct *vma; 111 size_t data_size = 0; 112 VMA_ITERATOR(vmi, current->mm, 0); 113 114 for_each_mte_vma(vmi, vma) 115 data_size += mte_vma_tag_dump_size(vma); 116 117 return data_size; 118 } 119 120 int elf_core_write_extra_data(struct coredump_params *cprm) 121 { 122 struct vm_area_struct *vma; 123 VMA_ITERATOR(vmi, current->mm, 0); 124 125 for_each_mte_vma(vmi, vma) { 126 if (vma->vm_flags & VM_DONTDUMP) 127 continue; 128 129 if (!mte_dump_tag_range(cprm, vma->vm_start, vma->vm_end)) 130 return 0; 131 } 132 133 return 1; 134 } 135