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From: Qais Yousef <qais.yousef@arm.com>
To: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	Russell King <linux@armlinux.org.uk>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Florian Fainelli <f.fainelli@gmail.com>
Subject: Re: [PATCH v7 2/2] ARM: ftrace: Add MODULE_PLTS support
Date: Wed, 24 Mar 2021 16:46:47 +0000	[thread overview]
Message-ID: <20210324164647.ebqvb7ll3l2fbswr@e107158-lin> (raw)
In-Reply-To: <169a0b1e-beee-bae6-8625-9b9ceb8bb0ea@nokia.com>

On 03/24/21 17:33, Alexander Sverdlin wrote:
> Hello Qais,
> 
> On 24/03/2021 16:57, Qais Yousef wrote:
> >>> FWIW my main concern is about duplicating the range check in
> >>> ftrace_call_replace() and using magic values that already exist in
> >>> __arm_gen_branch_{arm, thumb2}() and better remain encapsulated there.
> >> could you please check the negative limits? I have an opinion, my limits are
> >> correct. I could add extra parameter to arm_gen_branch_link(), but for this
> >> I first need to fix its negative limits, which, I believe, well... Approximate :)
> > Can you elaborate please?
> > 
> > If you look at Arm ARM [1] the ranges are defined in page 347
> > 
> > 	Encoding T1 Even numbers in the range –16777216 to 16777214.
> > 	Encoding T2 Multiples of 4 in the range –16777216 to 16777212.
> > 	Encoding A1 Multiples of 4 in the range –33554432 to 33554428.
> > 	Encoding A2 Even numbers in the range –33554432 to 33554430.
> > 
> > which matches what's in the code (T1 for thumb2 and A1 for arm).
> > 
> > Why do you think it's wrong?
> 
> thanks for checking this! I'll re-send v8 with your proposal.

If you felt some details need tweaking I don't mind, my proposal was an attempt
to help rather than impose.

Thanks!

--
Qais Yousef

WARNING: multiple messages have this Message-ID (diff)
From: Qais Yousef <qais.yousef@arm.com>
To: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	Russell King <linux@armlinux.org.uk>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Florian Fainelli <f.fainelli@gmail.com>
Subject: Re: [PATCH v7 2/2] ARM: ftrace: Add MODULE_PLTS support
Date: Wed, 24 Mar 2021 16:46:47 +0000	[thread overview]
Message-ID: <20210324164647.ebqvb7ll3l2fbswr@e107158-lin> (raw)
In-Reply-To: <169a0b1e-beee-bae6-8625-9b9ceb8bb0ea@nokia.com>

On 03/24/21 17:33, Alexander Sverdlin wrote:
> Hello Qais,
> 
> On 24/03/2021 16:57, Qais Yousef wrote:
> >>> FWIW my main concern is about duplicating the range check in
> >>> ftrace_call_replace() and using magic values that already exist in
> >>> __arm_gen_branch_{arm, thumb2}() and better remain encapsulated there.
> >> could you please check the negative limits? I have an opinion, my limits are
> >> correct. I could add extra parameter to arm_gen_branch_link(), but for this
> >> I first need to fix its negative limits, which, I believe, well... Approximate :)
> > Can you elaborate please?
> > 
> > If you look at Arm ARM [1] the ranges are defined in page 347
> > 
> > 	Encoding T1 Even numbers in the range –16777216 to 16777214.
> > 	Encoding T2 Multiples of 4 in the range –16777216 to 16777212.
> > 	Encoding A1 Multiples of 4 in the range –33554432 to 33554428.
> > 	Encoding A2 Even numbers in the range –33554432 to 33554430.
> > 
> > which matches what's in the code (T1 for thumb2 and A1 for arm).
> > 
> > Why do you think it's wrong?
> 
> thanks for checking this! I'll re-send v8 with your proposal.

If you felt some details need tweaking I don't mind, my proposal was an attempt
to help rather than impose.

Thanks!

--
Qais Yousef

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-03-24 16:47 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-27 11:09 [PATCH v7 0/2] ARM: Implement MODULE_PLT support in FTRACE Alexander A Sverdlin
2021-01-27 11:09 ` Alexander A Sverdlin
2021-01-27 11:09 ` [PATCH v7 1/2] ARM: PLT: Move struct plt_entries definition to header Alexander A Sverdlin
2021-01-27 11:09   ` Alexander A Sverdlin
2021-01-27 20:25   ` Florian Fainelli
2021-01-27 20:25     ` Florian Fainelli
2021-01-27 11:09 ` [PATCH v7 2/2] ARM: ftrace: Add MODULE_PLTS support Alexander A Sverdlin
2021-01-27 11:09   ` Alexander A Sverdlin
2021-01-27 19:36   ` Florian Fainelli
2021-01-27 19:36     ` Florian Fainelli
2021-03-07 17:26   ` Qais Yousef
2021-03-07 17:26     ` Qais Yousef
2021-03-08  7:58     ` Alexander Sverdlin
2021-03-08  7:58       ` Alexander Sverdlin
2021-03-09 17:42       ` Qais Yousef
2021-03-09 17:42         ` Qais Yousef
2021-03-10  7:23         ` Alexander Sverdlin
2021-03-10  7:23           ` Alexander Sverdlin
2021-03-10 16:14           ` Florian Fainelli
2021-03-10 16:14             ` Florian Fainelli
2021-03-10 17:17             ` Alexander Sverdlin
2021-03-10 17:17               ` Alexander Sverdlin
2021-03-12 17:24               ` Qais Yousef
2021-03-12 17:24                 ` Qais Yousef
2021-03-12 18:35                 ` Florian Fainelli
2021-03-12 18:35                   ` Florian Fainelli
2021-03-14 22:02                   ` Qais Yousef
2021-03-14 22:02                     ` Qais Yousef
2021-03-21 19:06                     ` Qais Yousef
2021-03-21 19:06                       ` Qais Yousef
2021-03-22 15:01                       ` Steven Rostedt
2021-03-22 15:01                         ` Steven Rostedt
2021-03-22 16:32                         ` Qais Yousef
2021-03-22 16:32                           ` Qais Yousef
2021-03-22 17:02                           ` Alexander Sverdlin
2021-03-22 17:02                             ` Alexander Sverdlin
2021-03-23 22:22                             ` Qais Yousef
2021-03-23 22:22                               ` Qais Yousef
2021-03-24  3:37                               ` Florian Fainelli
2021-03-24  3:37                                 ` Florian Fainelli
2021-03-24 16:10                                 ` Qais Yousef
2021-03-24 16:10                                   ` Qais Yousef
2021-03-24  9:04                               ` Alexander Sverdlin
2021-03-24  9:04                                 ` Alexander Sverdlin
2021-03-24 15:57                                 ` Qais Yousef
2021-03-24 15:57                                   ` Qais Yousef
2021-03-24 16:33                                   ` Alexander Sverdlin
2021-03-24 16:33                                     ` Alexander Sverdlin
2021-03-24 16:46                                     ` Qais Yousef [this message]
2021-03-24 16:46                                       ` Qais Yousef
2021-03-15  9:19                   ` Alexander Sverdlin
2021-03-15  9:19                     ` Alexander Sverdlin
2021-02-03 18:23 ` [PATCH v7 0/2] ARM: Implement MODULE_PLT support in FTRACE Florian Fainelli
2021-02-03 18:23   ` Florian Fainelli
2021-02-15 18:31   ` Ard Biesheuvel
2021-02-15 18:31     ` Ard Biesheuvel
2021-03-02  8:29     ` Linus Walleij
2021-03-02  8:29       ` Linus Walleij
2021-03-02 10:00       ` Alexander Sverdlin
2021-03-02 10:00         ` Alexander Sverdlin

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