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.gb80...@google.com/ 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 | 71 +++++++++++++++++++++++++++++++------- include/linux/scs.h | 16 ++++----- kernel/scs.c | 66 +++++++++++++++++++++++++++++------ 7 files changed, 142 insertions(+), 53 deletions(-) delete mode 100644 arch/arm64/kernel/scs.c base-commit: d5beb3140f91b1c8a3d41b14d729aefa4dcc58bc -- 2.29.2.454.gaff20da3a2-goog
