[all-commits] [llvm/llvm-project] b19105: [compiler-rt][hwasan] Support for new Intel LAM API

[Alexander Potapenko via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b191056f44701a91c7cd7282e3ba82512d56391a
      https://github.com/llvm/llvm-project/commit/b191056f44701a91c7cd7282e3ba82512d56391a
  Author: Alexander Potapenko <glider at google.com>
  Date:   2022-07-13 (Wed, 13 Jul 2022)

  Changed paths:
    M compiler-rt/lib/hwasan/hwasan_linux.cpp
    M compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
    M compiler-rt/lib/sanitizer_common/sanitizer_linux.h

  Log Message:
  -----------
  [compiler-rt][hwasan] Support for new Intel LAM API

New version of Intel LAM patches
(https://lore.kernel.org/linux-mm/20220712231328.5294-1-kirill.shutemov@linux.intel.com/)
uses a different interface based on arch_prctl():
 - arch_prctl(ARCH_GET_UNTAG_MASK, &mask) returns the current mask for
   untagging the pointers. We use it to detect kernel LAM support.
 - arch_prctl(ARCH_ENABLE_TAGGED_ADDR, nr_bits) enables pointer tagging
   for the current process.

Because __NR_arch_prctl is defined in different headers, and no other
platforms need it at the moment, we only declare internal_arch_prctl()
on x86_64.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D129645