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From: Leo Yan <leo.yan@arm.com>
To: Justinien Bouron <jbouron@amazon.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	David Hildenbrand <david@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Ryan Roberts <ryan.roberts@arm.com>,
	Ada Couprie Diaz <ada.coupriediaz@arm.com>,
	Kevin Brodsky <kevin.brodsky@arm.com>,
	Lorenzo Stoakes <ljs@kernel.org>,
	Quentin Perret <qperret@google.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Gunnar Kudrjavets <gunnarku@amazon.com>
Subject: Re: [PATCH] arm64: Add user and kernel page-fault tracepoints
Date: Wed, 20 May 2026 08:36:06 +0100	[thread overview]
Message-ID: <20260520073606.GA101133@e132581.arm.com> (raw)
In-Reply-To: <20260520045524.75670-1-jbouron@amazon.com>

On Tue, May 19, 2026 at 09:55:24PM -0700, Justinien Bouron wrote:

[...]

> @@ -606,6 +609,11 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
>  	int si_code;
>  	int pkey = -1;
>  
> +	if (user_mode(regs))
> +		trace_page_fault_user(addr, regs, esr);
> +	else
> +		trace_page_fault_kernel(addr, regs, esr);

Based on the discussion [1], Arm64 has already supported perf sw event
for page-faults:

  perf record -e page-faults ...

Seems there have a plan to consolidate perf event and tracepoints but I
have no idea how it is going. I would leave this to maintainers.

> +
>  	if (kprobe_page_fault(regs, esr))
>  		return 0;

tracepoints should be after kprobe_page_fault(), as explained [2] by Mark.

Thanks,
Leo

[1] https://lore.kernel.org/all/20250520140453.GA18711@willie-the-truck/
[2] https://lore.kernel.org/all/aCtZfiU8bgkSAgLh@J2N7QTR9R3/

WARNING: multiple messages have this Message-ID (diff)
From: Leo Yan <leo.yan@arm.com>
To: Justinien Bouron <jbouron@amazon.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Gunnar Kudrjavets <gunnarku@amazon.com>,
	Ryan Roberts <ryan.roberts@arm.com>,
	Quentin Perret <qperret@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Kevin Brodsky <kevin.brodsky@arm.com>,
	linux-kernel@vger.kernel.org,
	David Hildenbrand <david@kernel.org>,
	Lorenzo Stoakes <ljs@kernel.org>, Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: Add user and kernel page-fault tracepoints
Date: Wed, 20 May 2026 08:36:06 +0100	[thread overview]
Message-ID: <20260520073606.GA101133@e132581.arm.com> (raw)
In-Reply-To: <20260520045524.75670-1-jbouron@amazon.com>

On Tue, May 19, 2026 at 09:55:24PM -0700, Justinien Bouron wrote:

[...]

> @@ -606,6 +609,11 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
>  	int si_code;
>  	int pkey = -1;
>  
> +	if (user_mode(regs))
> +		trace_page_fault_user(addr, regs, esr);
> +	else
> +		trace_page_fault_kernel(addr, regs, esr);

Based on the discussion [1], Arm64 has already supported perf sw event
for page-faults:

  perf record -e page-faults ...

Seems there have a plan to consolidate perf event and tracepoints but I
have no idea how it is going. I would leave this to maintainers.

> +
>  	if (kprobe_page_fault(regs, esr))
>  		return 0;

tracepoints should be after kprobe_page_fault(), as explained [2] by Mark.

Thanks,
Leo

[1] https://lore.kernel.org/all/20250520140453.GA18711@willie-the-truck/
[2] https://lore.kernel.org/all/aCtZfiU8bgkSAgLh@J2N7QTR9R3/


  reply	other threads:[~2026-05-20  7:36 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-20  4:55 [PATCH] arm64: Add user and kernel page-fault tracepoints Justinien Bouron
2026-05-20  7:36 ` Leo Yan [this message]
2026-05-20  7:36   ` Leo Yan
2026-05-20 16:45   ` Justinien Bouron
2026-05-20 16:45     ` Justinien Bouron
2026-09-09 13:13   ` Bouron, Justinien
2026-09-09 17:50     ` Leo Yan
2026-09-23 14:40       ` Catalin Marinas

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