From: Sergey Ryazanov <ryazanov.s.a@gmail.com>
To: Jeff Johnson <quic_jjohnson@quicinc.com>,
Ziyang Huang <hzyitc@outlook.com>,
kvalo@kernel.org
Cc: jjohnson@kernel.org, linux-wireless@vger.kernel.org,
ath11k@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] wifi: ath11k: fix remapped ce accessing issue on 64bit OS
Date: Thu, 2 May 2024 22:27:31 +0300 [thread overview]
Message-ID: <b3999eec-e370-4c85-80b9-759f25ed98bf@gmail.com> (raw)
In-Reply-To: <6336ffc7-d8ae-4cfd-8b66-d6d91cb0d15e@quicinc.com>
Hi Jeff,
On 01.05.2024 19:56, Jeff Johnson wrote:
> On 5/1/2024 9:14 AM, Ziyang Huang wrote:
>> On 64bit OS, when ab->mem_ce is lower than or 4G far away from ab->mem,
>> u32 is not enough to store the offsets, which makes ath11k_ahb_read32()
>> and ath11k_ahb_write32() access incorrect address and causes Data Abort
>> Exception.
>
> Are you actually observing this issue?
> Or is this a hypothetical situation?
Yep. This is the real issue. I faced it on IPQ5018 with 64bits kernel.
>> Let's use the high bits of offsets to decide where to access, which is
>> similar as ath11k_pci_get_window_start() done. In the future, we can merge
>> these functions for unified regs accessing.
>
> Performing unnecessary tests and masking for every ioread/write operation will
> potentially impact performance.
>
> What other fixes were considered (i.e. did you consider making all the
> register addresses u64?)
Probably, making argument u64 could also be too much. I/O address space
of this chip fits 4GB so u32 should be enough. I have a bit different
fix for this bug. It introduces an indirect call for the CE registers
access and a dedicated set of accessing functions for chips that has the
CE region outside the main I/O area. I am going to publish it in a
couple of weeks, when I will come from a trip. The patch still needs
some polishing.
--
Sergey
prev parent reply other threads:[~2024-05-02 19:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-01 16:14 [PATCH] wifi: ath11k: fix remapped ce accessing issue on 64bit OS Ziyang Huang
2024-05-01 16:55 ` Larry Finger
2024-05-02 7:03 ` Kalle Valo
2024-05-01 16:56 ` Jeff Johnson
2024-05-02 7:05 ` Kalle Valo
2024-05-02 16:24 ` Ziyang Huang
2024-05-02 19:27 ` Sergey Ryazanov [this message]
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