From: Daniel Thompson <daniel.thompson@linaro.org>
To: Dave Martin <Dave.Martin@arm.com>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
"Yang Shi" <yang.shi@linaro.org>,
"Zi Shen Lim" <zlim.lnx@gmail.com>,
"Will Deacon" <will.deacon@arm.com>,
"Andrey Ryabinin" <ryabinin.a.a@gmail.com>,
"yalin wang" <yalin.wang2010@gmail.com>,
"Li Bin" <huawei.libin@huawei.com>,
"Jisheng Zhang" <jszhang@marvell.com>,
"John Blackwood" <john.blackwood@ccur.com>,
"Pratyush Anand" <panand@redhat.com>,
"David Long" <dave.long@linaro.org>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Huang Shijie" <shijie.huang@arm.com>,
"Petr Mladek" <pmladek@suse.com>,
"Vladimir Murzin" <Vladimir.Murzin@arm.com>,
"Steve Capper" <steve.capper@linaro.org>,
"Suzuki K Poulose" <suzuki.poulose@arm.com>,
"Marc Zyngier" <marc.zyngier@arm.com>,
"Mark Brown" <broonie@kernel.org>,
"Sandeepa Prabhu" <sandeepa.s.prabhu@gmail.com>,
"William Cohen" <wcohen@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Adam Buchbinder" <adam.buchbinder@gmail.com>,
linux-arm-kernel@lists.infradead.org,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
linux-kernel@vger.kernel.org, "James Morse" <james.morse@arm.com>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Robin Murphy" <robin.murphy@arm.com>,
"Jens Wiklander" <jens.wiklander@linaro.org>,
"Christoffer Dall" <christoffer.dall@linaro.org>
Subject: Re: [PATCH v15 04/10] arm64: Kprobes with single stepping support
Date: Wed, 27 Jul 2016 12:42:53 +0100 [thread overview]
Message-ID: <0bb682ba-aede-97a3-c858-4cd1c28fd68b@linaro.org> (raw)
In-Reply-To: <20160727113759.GB7147@e103592.cambridge.arm.com>
On 27/07/16 12:38, Dave Martin wrote:
> On Wed, Jul 27, 2016 at 12:19:59PM +0100, Daniel Thompson wrote:
>
> [...]
>
>> It is interesting to note that you force large_func() to stack its arguments
>> (by providing 8 dummy int arguments first) then the implicit
>> pass-by-reference behavior is still preserved even for a stacked argument;
>> large_func() ends up as:
>>
>> ~~~
>> large_func:
>> ldr x0, [sp]
>> ldr x0, [x0]
>> ret
>> ~~~
>>
>> Only thing is... I *still* haven't found anything in the AArch64 PCS which
>> describes this behavior.
>>
>> I'm coming to believe that this is a mistake and this information (and the
>> threshold at which implicit pass-by-reference kicks in) should be documented
>> in section 7.
>
> Is that answered by this?
>
> B.3. If the argument type is a Composite Type that is larger than
> 16 bytes, then the argument is copied to memory allocated by the
> caller and the argument is replaced by a pointer to the copy.
>
> Experimenting with gcc's behaviour seems to back this up.
Absolutely answered by that. Thanks (and sorry for the noise)!
Daniel.
next prev parent reply other threads:[~2016-07-27 11:42 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-08 16:35 [PATCH v15 00/10] arm64: Add kernel probes (kprobes) support David Long
2016-07-08 16:35 ` [PATCH v15 01/10] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature David Long
2016-07-15 10:57 ` Catalin Marinas
2016-07-15 14:51 ` David Long
2016-07-15 15:13 ` Catalin Marinas
2016-07-15 17:51 ` David Long
2016-07-19 14:17 ` Catalin Marinas
2016-07-08 16:35 ` [PATCH v15 02/10] arm64: Add more test functions to insn.c David Long
2016-07-08 16:35 ` [PATCH v15 03/10] arm64: add conditional instruction simulation support David Long
2016-07-08 16:35 ` [PATCH v15 04/10] arm64: Kprobes with single stepping support David Long
2016-07-20 9:36 ` Marc Zyngier
2016-07-20 11:16 ` Catalin Marinas
2016-07-20 19:08 ` David Long
2016-07-21 8:44 ` Marc Zyngier
2016-07-20 15:49 ` Catalin Marinas
2016-07-21 14:50 ` David Long
2016-07-20 16:09 ` Marc Zyngier
2016-07-20 16:28 ` Catalin Marinas
2016-07-20 16:31 ` Marc Zyngier
2016-07-20 16:46 ` Marc Zyngier
2016-07-20 17:04 ` Catalin Marinas
2016-07-21 16:33 ` David Long
2016-07-21 17:16 ` Catalin Marinas
2016-07-21 17:23 ` Marc Zyngier
2016-07-21 18:33 ` David Long
2016-07-22 10:16 ` Catalin Marinas
2016-07-22 15:51 ` David Long
2016-07-25 17:13 ` Catalin Marinas
2016-07-25 22:27 ` David Long
2016-07-27 11:50 ` Daniel Thompson
2016-07-27 22:13 ` David Long
2016-07-28 14:40 ` Catalin Marinas
2016-07-29 9:01 ` Daniel Thompson
2016-08-04 4:47 ` David Long
2016-08-08 11:13 ` Daniel Thompson
2016-08-08 14:29 ` David Long
2016-08-08 22:49 ` Masami Hiramatsu
2016-08-09 17:23 ` Catalin Marinas
2016-08-10 20:41 ` David Long
2016-08-08 22:19 ` Masami Hiramatsu
2016-07-26 9:50 ` Daniel Thompson
2016-07-26 16:55 ` Catalin Marinas
2016-07-27 10:01 ` Dave Martin
2016-07-26 17:54 ` Mark Rutland
2016-07-27 11:19 ` Daniel Thompson
2016-07-27 11:38 ` Dave Martin
2016-07-27 11:42 ` Daniel Thompson [this message]
2016-07-27 13:38 ` Mark Rutland
2016-07-08 16:35 ` [PATCH v15 05/10] arm64: Blacklist non-kprobe-able symbol David Long
2016-07-08 16:35 ` [PATCH v15 06/10] arm64: Treat all entry code as non-kprobe-able David Long
2016-07-15 16:47 ` Catalin Marinas
2016-07-19 0:53 ` David Long
2016-07-08 16:35 ` [PATCH v15 07/10] arm64: kprobes instruction simulation support David Long
2016-07-10 22:51 ` Paul Gortmaker
2016-07-08 16:35 ` [PATCH v15 08/10] arm64: Add trampoline code for kretprobes David Long
2016-07-19 13:46 ` Catalin Marinas
2016-07-20 18:28 ` David Long
2016-07-08 16:35 ` [PATCH v15 09/10] arm64: Add kernel return probes support (kretprobes) David Long
2016-07-08 16:35 ` [PATCH v15 10/10] kprobes: Add arm64 case in kprobe example module David Long
2016-07-14 16:22 ` [PATCH v15 00/10] arm64: Add kernel probes (kprobes) support Catalin Marinas
2016-07-14 17:09 ` William Cohen
2016-07-15 7:50 ` Catalin Marinas
2016-07-15 8:01 ` Marc Zyngier
2016-07-15 8:59 ` Alex Bennée
2016-07-15 9:04 ` Marc Zyngier
2016-07-15 9:53 ` Marc Zyngier
2016-07-14 17:56 ` David Long
2016-07-19 13:57 ` Catalin Marinas
2016-07-19 14:01 ` David Long
2016-07-19 18:27 ` Catalin Marinas
2016-07-19 19:38 ` David Long
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