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From: "Arnd Bergmann" <arnd@arndb.de>
To: "Qingfang Deng" <qingfang.deng@linux.dev>
Cc: Linux-Arch <linux-arch@vger.kernel.org>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Will Deacon" <will@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Anshuman Khandual" <anshuman.khandual@arm.com>,
	"Vikram Sethi" <vsethi@nvidia.com>,
	"Mike Rapoport" <rppt@kernel.org>,
	"Shanker Donthineni" <sdonthineni@nvidia.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/3] arm64: use generic MMIO accessors
Date: Sun, 20 Sep 2026 11:30:34 +0200	[thread overview]
Message-ID: <3250a625-7900-40a9-8f3c-612d333122dc@app.fastmail.com> (raw)
In-Reply-To: <9895e60c-6a3c-40c8-b188-51891ee6b216@linux.dev>

On Sun, Sep 20, 2026, at 11:24, Qingfang Deng wrote:
>
> Regarding unaligned accesses, the splitting can only happen when the 
> address is known to be unaligned at compile-time. Do these accessors 
> need to support unaligned MMIO? If so, I could add 
> OPTIMIZER_HIDE_VAR(addr) to the generic accessors.

I think all architectures that have had this problem just started
using the inline asm variant, and I'd probably try to encourage
that more.

What might be helpful here would be to split out the __raw_* helpers
into a separate header that is explicitly included on architectures
without their own definitions, and an updated comment that explains
that architectures are encouraged to implement these as inline asm
instead of using the volatile load/store.

     Arnd


  reply	other threads:[~2026-09-20  9:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20260920014357.7069-1-qingfang.deng@linux.dev>
2026-09-20  1:43 ` [PATCH v2 3/3] arm64: use generic MMIO accessors Qingfang Deng
2026-09-20  8:08   ` Arnd Bergmann
2026-09-20  9:24     ` Qingfang Deng
2026-09-20  9:30       ` Arnd Bergmann [this message]
2026-09-20  9:35         ` Arnd Bergmann

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