powerpc/kcsan: Add KCSAN Support

Enable HAVE_ARCH_KCSAN for 64-bit Book3S, permitting use of the kernel
concurrency sanitiser through the CONFIG_KCSAN_* kconfig options. KCSAN
requires compiler builtins __atomic_* 64-bit values, and so only report
support on 64-bit.

See documentation in Documentation/dev-tools/kcsan.rst for more
information.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
[mpe: Limit to Book3S to avoid build failure on Book3E]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230206021801.105268-6-rmclure@linux.ibm.com

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 24e023da4d2eca5e2f3db60004ce47dc4d4b6c78..1f3306e9d622ebdbe947af2d1c2d3e3bae651ad9 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -198,6 +198,7 @@ config PPC
        select HAVE_ARCH_KASAN                  if PPC_RADIX_MMU
        select HAVE_ARCH_KASAN                  if PPC_BOOK3E_64
        select HAVE_ARCH_KASAN_VMALLOC          if HAVE_ARCH_KASAN
+       select HAVE_ARCH_KCSAN                  if PPC_BOOK3S_64
        select HAVE_ARCH_KFENCE                 if ARCH_SUPPORTS_DEBUG_PAGEALLOC
        select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
        select HAVE_ARCH_KGDB