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From: Andi Kleen <andi@firstfloor.org>
To: Namhyung Kim <namhyung@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: remove __phys_reloc_hide
Date: Mon, 09 Aug 2010 08:22:34 +0200	[thread overview]
Message-ID: <87k4o08fv9.fsf@basil.nowhere.org> (raw)
In-Reply-To: <1281303490-390-1-git-send-email-namhyung@gmail.com> (Namhyung Kim's message of "Mon, 9 Aug 2010 06:38:10 +0900")

Namhyung Kim <namhyung@gmail.com> writes:

> remove unnecessary use of RELOC_HIDE(). It only does simple addition of ptr
> and offset, and in this case, offset 0, does nothing. It does NOT do anything
> with linker relocation things. I could find no reason to use it.

It's for the benefit of the compiler, we've had miscompilations
due to undefined overflow for addresses in the past. The optimizer
assumes this won't happen.

Given the x86-64 version normally doesn't overflow, but it's
still safer to have it.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

  reply	other threads:[~2010-08-09  6:22 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-08 21:38 [PATCH] x86: remove __phys_reloc_hide Namhyung Kim
2010-08-09  6:22 ` Andi Kleen [this message]
2010-08-09  6:40   ` Namhyung Kim
2010-08-09  6:44     ` Andi Kleen
2010-08-09  7:04       ` Namhyung Kim
2010-08-09  7:22         ` Andi Kleen
2010-08-09  7:47           ` Namhyung Kim
2010-08-09 18:56           ` H. Peter Anvin
2010-08-10  7:05             ` Ingo Molnar
2010-08-10 10:46               ` Namhyung Kim
2010-08-11  5:44                 ` Namhyung Kim
2010-08-11 19:09                   ` H. Peter Anvin
2010-08-11  6:37               ` [PATCH] x86: add a comment to __pa_symbol Namhyung Kim
2010-08-11  7:44                 ` [tip:x86/urgent] x86: Document __phys_reloc_hide() usage in __pa_symbol() tip-bot for Namhyung Kim
2018-06-19 23:00   ` [PATCH] x86: remove __phys_reloc_hide Thomas Gleixner
2010-08-09  8:07 ` Ingo Molnar
2010-08-09 18:56   ` H. Peter Anvin

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