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From: Dave Martin <Dave.Martin@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arch@vger.kernel.org, Will Deacon <will.deacon@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH v2 4/6] arm64: signal: Allocate extra sigcontext space as needed
Date: Tue, 6 Jun 2017 14:58:18 +0100	[thread overview]
Message-ID: <20170606135815.GG30160@e103592.cambridge.arm.com> (raw)
In-Reply-To: <20170606113739.GF30160@e103592.cambridge.arm.com>

On Tue, Jun 06, 2017 at 12:37:53PM +0100, Dave Martin wrote:
> On Mon, Jun 05, 2017 at 03:17:44PM +0100, Catalin Marinas wrote:

[...]

[extra_context.size]

> > I'd rather have the time size_t or __u64 to avoid implicit padding.
> 
> Sure, it can be a u64.  I wanted to avoid the suggestion that the frame
> should be that large, but 32 bits already allows it to be crazy large
> anyway, so I don't think making it 32-bit helps.

Actually, there is still implicit padding even with u64, since the total
size is 16 bytes + sizeof(extra_context.size).

Since u64 is much bigger then we'd ever want, and to avoid introducing
new bugs, do you object to keeping size as u32 and adding explicit
padding instead?

Cheers
---Dave

WARNING: multiple messages have this Message-ID (diff)
From: Dave.Martin@arm.com (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v2 4/6] arm64: signal: Allocate extra sigcontext space as needed
Date: Tue, 6 Jun 2017 14:58:18 +0100	[thread overview]
Message-ID: <20170606135815.GG30160@e103592.cambridge.arm.com> (raw)
In-Reply-To: <20170606113739.GF30160@e103592.cambridge.arm.com>

On Tue, Jun 06, 2017 at 12:37:53PM +0100, Dave Martin wrote:
> On Mon, Jun 05, 2017 at 03:17:44PM +0100, Catalin Marinas wrote:

[...]

[extra_context.size]

> > I'd rather have the time size_t or __u64 to avoid implicit padding.
> 
> Sure, it can be a u64.  I wanted to avoid the suggestion that the frame
> should be that large, but 32 bits already allows it to be crazy large
> anyway, so I don't think making it 32-bit helps.

Actually, there is still implicit padding even with u64, since the total
size is 16 bytes + sizeof(extra_context.size).

Since u64 is much bigger then we'd ever want, and to avoid introducing
new bugs, do you object to keeping size as u32 and adding explicit
padding instead?

Cheers
---Dave

  reply	other threads:[~2017-06-06 13:58 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-12 16:56 [RFC PATCH v2 0/6] Signal frame expansion support Dave Martin
2017-04-12 16:56 ` Dave Martin
2017-04-12 17:01 ` [RFC PATCH v2 1/6] arm64: signal: Refactor sigcontext parsing in rt_sigreturn Dave Martin
2017-04-12 17:01   ` Dave Martin
2017-04-12 17:01   ` [RFC PATCH v2 2/6] arm64: signal: factor frame layout and population into separate passes Dave Martin
2017-04-12 17:01     ` Dave Martin
2017-04-12 17:01   ` [RFC PATCH v2 3/6] arm64: signal: factor out signal frame record allocation Dave Martin
2017-04-12 17:01     ` Dave Martin
2017-04-12 17:01   ` [RFC PATCH v2 4/6] arm64: signal: Allocate extra sigcontext space as needed Dave Martin
2017-04-12 17:01     ` Dave Martin
2017-05-12 16:57     ` Catalin Marinas
2017-05-12 16:57       ` Catalin Marinas
2017-05-15 13:24       ` Dave Martin
2017-05-15 13:24         ` Dave Martin
2017-05-23 11:30         ` Catalin Marinas
2017-05-23 11:30           ` Catalin Marinas
2017-05-26 11:37           ` Dave Martin
2017-05-26 11:37             ` Dave Martin
2017-06-05 14:17             ` Catalin Marinas
2017-06-05 14:17               ` Catalin Marinas
2017-06-06 11:37               ` Dave Martin
2017-06-06 11:37                 ` Dave Martin
2017-06-06 13:58                 ` Dave Martin [this message]
2017-06-06 13:58                   ` Dave Martin
2017-06-06 16:15                   ` Catalin Marinas
2017-06-06 16:15                     ` Catalin Marinas
2017-06-06 16:15                 ` Catalin Marinas
2017-06-06 16:15                   ` Catalin Marinas
2017-06-08  8:46           ` Dave Martin
2017-06-08  8:46             ` Dave Martin
2017-04-12 17:01   ` [RFC PATCH v2 5/6] arm64: signal: Parse extra_context during sigreturn Dave Martin
2017-04-12 17:01     ` Dave Martin
2017-04-12 17:01   ` [RFC PATCH v2 6/6] arm64: signal: Report signal frame size to userspace via auxv Dave Martin
2017-04-12 17:01     ` Dave Martin
2017-04-20 11:49 ` [RFC PATCH v2 0/6] Signal frame expansion support Michael Ellerman
2017-04-20 11:49   ` Michael Ellerman
2017-04-20 12:45   ` Dave Martin
2017-04-20 12:45     ` Dave Martin

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