From: Catalin Marinas <catalin.marinas@arm.com>
To: "Liao, Chang" <liaochang1@huawei.com>
Cc: mhiramat@kernel.org, oleg@redhat.com, peterz@infradead.org,
will@kernel.org, mark.rutland@arm.com,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: uprobes: Optimize cache flushes for xol slot
Date: Thu, 7 Nov 2024 18:35:57 +0000 [thread overview]
Message-ID: <Zy0IjTkqlCZ9DRWN@arm.com> (raw)
In-Reply-To: <3d166642-4062-42ed-9e24-1771cd819110@huawei.com>
On Wed, Nov 06, 2024 at 05:55:16PM +0800, Liao, Chang wrote:
> 在 2024/9/19 20:17, Liao Chang 写道:
> > On 09/23, Will Deacon wrote:
> >> However, we should use __GFP_ZERO anyway
> >> because I don't think it's a good idea to map an uninitialised page into
> >> userspace.
> > Agreed, and imo this even needs a separate "fix info leak" patch.
> >
> > Oleg.
>
> Given that Oleg's fix info leak patch has been merged [1], the risk of leakage
> is gone. So I am looking forward to your options about this patch. As many
> functions start with same instructions like 'stp fp, lr, [sp, #imm]' or
> 'paciasp'. So I think this patch could avoid unnecessary D/I cache synchronization.
>
> [1] https://lore.kernel.org/all/20240929162047.GA12611@redhat.com/
The patch is fine with the fix in __create_xol_area(). But please add a
comment on why it is safe to skip the cache maintenance, something like
"the initial cache maintenance was done via set_pte_at()" (well, I can
do this when applying).
--
Catalin
next prev parent reply other threads:[~2024-11-07 18:36 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-19 12:17 [PATCH] arm64: uprobes: Optimize cache flushes for xol slot Liao Chang
2024-09-19 14:18 ` Oleg Nesterov
2024-09-20 8:58 ` Liao, Chang
2024-09-20 11:03 ` Oleg Nesterov
2024-09-20 15:32 ` Catalin Marinas
2024-09-20 17:32 ` Oleg Nesterov
2024-09-22 14:09 ` Will Deacon
2024-09-22 14:39 ` Oleg Nesterov
2024-09-23 11:16 ` Liao, Chang
2024-09-23 1:57 ` Liao, Chang
2024-09-23 7:18 ` Will Deacon
2024-09-23 10:52 ` Oleg Nesterov
2024-09-26 12:06 ` Liao, Chang
2024-09-26 16:08 ` Oleg Nesterov
2024-09-23 11:16 ` Liao, Chang
2024-09-23 16:03 ` Catalin Marinas
2024-11-06 9:55 ` Liao, Chang
2024-11-07 18:35 ` Catalin Marinas [this message]
2024-11-08 16:49 ` Catalin Marinas
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