Re: [PATCH v2 3/3] arm64: use generic MMIO accessors
From: Arnd Bergmann
Date: Sun Sep 20 2026 - 04:08:54 EST
On Sun, Sep 20, 2026, at 03:43, Qingfang Deng wrote:
> Use the generic raw write accessors in place of the inline assembly
> stores. Include asm-generic/mmio.h after the arm64 ordering hooks so
> these accessors are also available to the write-combining helpers
> before asm-generic/io.h is included.
>
> Retain the raw read overrides when either the Cortex-A57 erratum 832075
> or NVIDIA Olympus erratum 1027 workaround is configured. This preserves
> the alternative-patched load-acquire instructions and pre-load barriers.
> Use generic raw reads when neither workaround is enabled.
>
> Assisted-by: Codex:gpt-6-astra
> Signed-off-by: Qingfang Deng <qingfang.deng@xxxxxxxxx>
Sorry, this is no good, we need the compiler to issue the exact
instructions from the inline asm here, both in order to guarantee
these can be virtualized, and to prevent it from splitting up
larger register accesses into byte load/store on unaligned pointers.
Arnd