[PATCH mm v3 00/38] kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS

[andrey.konovalov at linux.dev]

From: Andrey Konovalov <andreyknvl at google.com>

Hi,

This patchset adds vmalloc tagging support for SW_TAGS and HW_TAGS
KASAN modes.

The tree with patches is available here:

https://github.com/xairy/linux/tree/up-kasan-vmalloc-tags-v3-akpm

About half of patches are cleanups I went for along the way. None of
them seem to be important enough to go through stable, so I decided
not to split them out into separate patches/series.

The patchset is partially based on an early version of the HW_TAGS
patchset by Vincenzo that had vmalloc support. Thus, I added a
Co-developed-by tag into a few patches.

SW_TAGS vmalloc tagging support is straightforward. It reuses all of
the generic KASAN machinery, but uses shadow memory to store tags
instead of magic values. Naturally, vmalloc tagging requires adding
a few kasan_reset_tag() annotations to the vmalloc code.

HW_TAGS vmalloc tagging support stands out. HW_TAGS KASAN is based on
Arm MTE, which can only assigns tags to physical memory. As a result,
HW_TAGS KASAN only tags vmalloc() allocations, which are backed by
page_alloc memory. It ignores vmap() and others.

Changes in v2->v3:
- Rebase onto mm.
- New patch: "kasan, arm64: reset pointer tags of vmapped stacks".
- New patch: "kasan, vmalloc: don't tag executable vmalloc allocations".
- New patch: "kasan, arm64: don't tag executable vmalloc allocations".
- Allowing enabling KASAN_VMALLOC with SW/HW_TAGS is moved to
  "kasan: allow enabling KASAN_VMALLOC and SW/HW_TAGS", as this can only
  be done once executable allocations are no longer tagged.
- Minor fixes, see patches for lists of changes.

Changes in v1->v2:
- Move memory init for vmalloc() into vmalloc code for HW_TAGS KASAN.
- Minor fixes and code reshuffling, see patches for lists of changes.

Thanks!

Andrey Konovalov (38):
  kasan, page_alloc: deduplicate should_skip_kasan_poison
  kasan, page_alloc: move tag_clear_highpage out of
    kernel_init_free_pages
  kasan, page_alloc: merge kasan_free_pages into free_pages_prepare
  kasan, page_alloc: simplify kasan_poison_pages call site
  kasan, page_alloc: init memory of skipped pages on free
  kasan: drop skip_kasan_poison variable in free_pages_prepare
  mm: clarify __GFP_ZEROTAGS comment
  kasan: only apply __GFP_ZEROTAGS when memory is zeroed
  kasan, page_alloc: refactor init checks in post_alloc_hook
  kasan, page_alloc: merge kasan_alloc_pages into post_alloc_hook
  kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook
  kasan, page_alloc: move SetPageSkipKASanPoison in post_alloc_hook
  kasan, page_alloc: move kernel_init_free_pages in post_alloc_hook
  kasan, page_alloc: simplify kasan_unpoison_pages call site
  kasan: clean up metadata byte definitions
  kasan: define KASAN_VMALLOC_INVALID for SW_TAGS
  kasan, x86, arm64, s390: rename functions for modules shadow
  kasan, vmalloc: drop outdated VM_KASAN comment
  kasan: reorder vmalloc hooks
  kasan: add wrappers for vmalloc hooks
  kasan, vmalloc: reset tags in vmalloc functions
  kasan, fork: reset pointer tags of vmapped stacks
  kasan, arm64: reset pointer tags of vmapped stacks
  kasan, vmalloc: add vmalloc tagging for SW_TAGS
  kasan, vmalloc, arm64: mark vmalloc mappings as pgprot_tagged
  kasan, vmalloc: don't unpoison VM_ALLOC pages before mapping
  kasan, page_alloc: allow skipping unpoisoning for HW_TAGS
  kasan, page_alloc: allow skipping memory init for HW_TAGS
  kasan, vmalloc: add vmalloc tagging for HW_TAGS
  kasan, vmalloc: don't tag executable vmalloc allocations
  kasan, arm64: don't tag executable vmalloc allocations
  kasan: mark kasan_arg_stacktrace as __initdata
  kasan: simplify kasan_init_hw_tags
  kasan: add kasan.vmalloc command line flag
  kasan: allow enabling KASAN_VMALLOC and SW/HW_TAGS
  arm64: select KASAN_VMALLOC for SW/HW_TAGS modes
  kasan: documentation updates
  kasan: improve vmalloc tests

 Documentation/dev-tools/kasan.rst   |  17 ++-
 arch/arm64/Kconfig                  |   2 +-
 arch/arm64/include/asm/vmalloc.h    |  10 ++
 arch/arm64/include/asm/vmap_stack.h |   5 +-
 arch/arm64/kernel/module.c          |   5 +-
 arch/arm64/net/bpf_jit_comp.c       |   3 +-
 arch/s390/kernel/module.c           |   2 +-
 arch/x86/kernel/module.c            |   2 +-
 include/linux/gfp.h                 |  28 +++--
 include/linux/kasan.h               |  97 +++++++++------
 include/linux/vmalloc.h             |  18 ++-
 kernel/fork.c                       |   1 +
 kernel/scs.c                        |   4 +-
 lib/Kconfig.kasan                   |  20 +--
 lib/test_kasan.c                    | 181 +++++++++++++++++++++++++++-
 mm/kasan/common.c                   |   4 +-
 mm/kasan/hw_tags.c                  | 166 ++++++++++++++++++++-----
 mm/kasan/kasan.h                    |  16 ++-
 mm/kasan/shadow.c                   |  63 ++++++----
 mm/page_alloc.c                     | 150 +++++++++++++++--------
 mm/vmalloc.c                        |  78 ++++++++++--
 21 files changed, 668 insertions(+), 204 deletions(-)

-- 
2.25.1