[PATCH v3 0/2] scs: switch to vmapped shadow stacks

[Sami Tolvanen]

As discussed a few months ago [1][2], virtually mapped shadow call stacks
are better for safety and robustness. This series dusts off the VMAP
option from the original SCS patch series and switches the kernel to use
virtually mapped shadow stacks unconditionally when SCS is enabled.

 [1] https://lore.kernel.org/lkml/20200515172355.GD23334@willie-the-truck/
 [2] https://lore.kernel.org/lkml/20200427220942.GB80713@google.com/

Changes in v3:
- Split the actual allocation to __scs_alloc().
- Moved SDEI SCS initialization to init_sdei_scs().

Changes in v2:
- Added SCS_ORDER and used it to define SCS_SIZE, switched vmalloc() to
  use SCS_SIZE and removed the alignment.
- Moved the kasan_unpoison_vmalloc() to scs_alloc() when using a cached
  shadow stack instead of calling it in scs_free().
- Added a comment to scs_free().
- Moved arm64 IRQ and SDEI shadow stack initialization to irq/sdei.c,
  and removed the now unneeded scs.c.

Sami Tolvanen (2):
  scs: switch to vmapped shadow stacks
  arm64: scs: use vmapped IRQ and SDEI shadow stacks

 arch/arm64/kernel/Makefile |  1 -
 arch/arm64/kernel/entry.S  |  6 ++--
 arch/arm64/kernel/irq.c    | 19 ++++++++++
 arch/arm64/kernel/scs.c    | 16 ---------
 arch/arm64/kernel/sdei.c   | 70 +++++++++++++++++++++++++++++++++++++
 include/linux/scs.h        | 16 ++++-----
 kernel/scs.c               | 71 ++++++++++++++++++++++++++++++++------
 7 files changed, 158 insertions(+), 41 deletions(-)
 delete mode 100644 arch/arm64/kernel/scs.c


base-commit: b65054597872ce3aefbc6a666385eabdf9e288da
-- 
2.29.2.454.gaff20da3a2-goog