Hi all, These patches were previously posted as part of a larger series enabling architectures to override __READ_ONCE():
v3: https://lore.kernel.org/lkml/[email protected]/ With the bulk of that merged, the four patches here override READ_ONCE() so that it gains RCpc acquire semantics on arm64 when LTO is enabled. We can revisit this as and when the compiler provides a means for us to reason about the result of dependency-breaking optimisations. In the meantime, this unblocks LTO for arm64, which I would really like to see merged so that we can focus on enabling CFI. I plan to queue these on their own branch in the arm64 tree for 5.11 at -rc3. Cheers, Will Cc: Kees Cook <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Sami Tolvanen <[email protected]> Cc: Masahiro Yamada <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected] --->8 Will Deacon (4): arm64: alternatives: Split up alternative.h arm64: cpufeatures: Add capability for LDAPR instruction arm64: alternatives: Remove READ_ONCE() usage during patch operation arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y arch/arm64/Kconfig | 3 + arch/arm64/include/asm/alternative-macros.h | 276 ++++++++++++++++++++ arch/arm64/include/asm/alternative.h | 267 +------------------ arch/arm64/include/asm/cpucaps.h | 3 +- arch/arm64/include/asm/insn.h | 3 +- arch/arm64/include/asm/rwonce.h | 63 +++++ arch/arm64/kernel/alternative.c | 7 +- arch/arm64/kernel/cpufeature.c | 10 + arch/arm64/kernel/vdso/Makefile | 2 +- arch/arm64/kernel/vdso32/Makefile | 2 +- arch/arm64/kernel/vmlinux.lds.S | 2 +- 11 files changed, 364 insertions(+), 274 deletions(-) create mode 100644 arch/arm64/include/asm/alternative-macros.h create mode 100644 arch/arm64/include/asm/rwonce.h -- 2.29.1.341.ge80a0c044ae-goog
