linux/arch/arm64/kernel/elfcore.c

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// SPDX-License-Identifier: GPL-2.0-only
#include <linux/coredump.h>
#include <linux/elfcore.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/cpufeature.h>
#include <asm/mte.h>
#define for_each_mte_vma(tsk, vma) \
if (system_supports_mte()) \
for (vma = tsk->mm->mmap; vma; vma = vma->vm_next) \
if (vma->vm_flags & VM_MTE)
static unsigned long mte_vma_tag_dump_size(struct vm_area_struct *vma)
{
if (vma->vm_flags & VM_DONTDUMP)
return 0;
return vma_pages(vma) * MTE_PAGE_TAG_STORAGE;
}
/* Derived from dump_user_range(); start/end must be page-aligned */
static int mte_dump_tag_range(struct coredump_params *cprm,
unsigned long start, unsigned long end)
{
int ret = 1;
unsigned long addr;
void *tags = NULL;
for (addr = start; addr < end; addr += PAGE_SIZE) {
struct page *page = get_dump_page(addr);
/*
* get_dump_page() returns NULL when encountering an empty
* page table entry that would otherwise have been filled with
* the zero page. Skip the equivalent tag dump which would
* have been all zeros.
*/
if (!page) {
dump_skip(cprm, MTE_PAGE_TAG_STORAGE);
continue;
}
/*
* Pages mapped in user space as !pte_access_permitted() (e.g.
* PROT_EXEC only) may not have the PG_mte_tagged flag set.
*/
if (!test_bit(PG_mte_tagged, &page->flags)) {
put_page(page);
dump_skip(cprm, MTE_PAGE_TAG_STORAGE);
continue;
}
if (!tags) {
tags = mte_allocate_tag_storage();
if (!tags) {
put_page(page);
ret = 0;
break;
}
}
mte_save_page_tags(page_address(page), tags);
put_page(page);
if (!dump_emit(cprm, tags, MTE_PAGE_TAG_STORAGE)) {
mte_free_tag_storage(tags);
ret = 0;
break;
}
}
if (tags)
mte_free_tag_storage(tags);
return ret;
}
Elf_Half elf_core_extra_phdrs(void)
{
struct vm_area_struct *vma;
int vma_count = 0;
for_each_mte_vma(current, vma)
vma_count++;
return vma_count;
}
int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset)
{
struct vm_area_struct *vma;
for_each_mte_vma(current, vma) {
struct elf_phdr phdr;
phdr.p_type = PT_AARCH64_MEMTAG_MTE;
phdr.p_offset = offset;
phdr.p_vaddr = vma->vm_start;
phdr.p_paddr = 0;
phdr.p_filesz = mte_vma_tag_dump_size(vma);
phdr.p_memsz = vma->vm_end - vma->vm_start;
offset += phdr.p_filesz;
phdr.p_flags = 0;
phdr.p_align = 0;
if (!dump_emit(cprm, &phdr, sizeof(phdr)))
return 0;
}
return 1;
}
size_t elf_core_extra_data_size(void)
{
struct vm_area_struct *vma;
size_t data_size = 0;
for_each_mte_vma(current, vma)
data_size += mte_vma_tag_dump_size(vma);
return data_size;
}
int elf_core_write_extra_data(struct coredump_params *cprm)
{
struct vm_area_struct *vma;
for_each_mte_vma(current, vma) {
if (vma->vm_flags & VM_DONTDUMP)
continue;
if (!mte_dump_tag_range(cprm, vma->vm_start, vma->vm_end))
return 0;
}
return 1;
}