Re: [RFC PATCH v3 1/1] arch: arm64: Implement unaligned atomic emulation

From: Will Deacon

Date: Wed Sep 30 2026 - 03:49:09 EST


On Tue, Sep 29, 2026 at 11:01:38PM -0300, André Almeida wrote:
> Implement support for emulating unaligned atomic operations on arm64.
> User applications that wish to enable support for this should use the
> pctrl() flag `PR_ARM64_UNALIGN_ATOMIC_EMULATE`.
>
> Signed-off-by: André Almeida <andrealmeid@xxxxxxxxxx>
> ---
> arch/arm64/Kconfig | 6 +
> arch/arm64/include/asm/exception.h | 1 +
> arch/arm64/include/asm/processor.h | 5 +
> arch/arm64/include/asm/rwonce.h | 14 +-
> arch/arm64/include/asm/thread_info.h | 1 +
> arch/arm64/kernel/Makefile | 3 +-
> arch/arm64/kernel/process.c | 15 +
> arch/arm64/kernel/unaligned_atomic.c | 521 +++++++++++++++++++++++++++
> arch/arm64/mm/fault.c | 10 +
> include/uapi/linux/prctl.h | 5 +
> kernel/sys.c | 7 +-
> 11 files changed, 579 insertions(+), 9 deletions(-)
> create mode 100644 arch/arm64/kernel/unaligned_atomic.c

No.

I already explained to you why this doesn't work:

https://lore.kernel.org/r/aV1YnOetDHhKe4hz@willie-the-truck

Will