From: Ralf Baechle <ralf@linux-mips.org>
To: "Steven J. Hill" <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Subject: Re: [PATCH 04/11] MIPS: Removal of execute bit in page tables for HEAP/BSS.
Date: Thu, 13 Nov 2014 12:36:58 +0100 [thread overview]
Message-ID: <20141113113658.GD13753@linux-mips.org> (raw)
In-Reply-To: <1415858743-24492-5-git-send-email-Steven.Hill@imgtec.com>
On Thu, Nov 13, 2014 at 12:05:36AM -0600, Steven J. Hill wrote:
> From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
>
> Patch removes eXecute bit in the page tables for HEAP/BSS. It
> boosts performance because page marked X is flushed each time
> after COW/swap from cache even for cache coherent systems in
> Harvard architectures (!cpu_has_ic_fills_f_dc). This patch also
> sets eXecute Inhibit (XI) protection of HEAP/BSS on CPUs which
> support it, like proAptiv cores.
While I generally like the idea to limited execute permission to just
what really needs it all approaches to do so have ran into compatibility
issue. This patch only modifies the brk space which is a bit of a
special case for which I don't know the impact on existing software.
Ralf
next prev parent reply other threads:[~2014-11-13 11:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-13 6:05 [PATCH 00/11] Add support for eXtended Physical Addressing Steven J. Hill
2014-11-13 6:05 ` [PATCH 01/11] MIPS: HIGHMEM fixes for cache aliasing and non-DMA I/O Steven J. Hill
2014-11-13 6:05 ` [PATCH 02/11] MIPS: Revert fixrange_init() limiting to the FIXMAP region Steven J. Hill
2014-11-13 11:13 ` Ralf Baechle
2014-11-13 6:05 ` [PATCH 03/11] MIPS: Rearrange PTE bits into fixed positions for MIPS R2 Steven J. Hill
2014-11-13 6:05 ` [PATCH 04/11] MIPS: Removal of execute bit in page tables for HEAP/BSS Steven J. Hill
2014-11-13 11:36 ` Ralf Baechle [this message]
2014-11-13 6:05 ` [PATCH 05/11] MIPS: mm: c-r4k: Ensure CCA is set to non-coherent on UP kernels Steven J. Hill
2014-11-13 10:31 ` Ralf Baechle
2014-11-13 6:05 ` [PATCH 06/11] MIPS: Add CP0 macros for extended EntryLo registers Steven J. Hill
2014-11-13 12:25 ` Sergei Shtylyov
2014-11-13 6:05 ` [PATCH 07/11] MIPS: Fix address type used for early memory detection Steven J. Hill
2014-11-13 6:05 ` [PATCH 08/11] MIPS: Cosmetic cleanups of page table headers Steven J. Hill
2014-11-13 6:05 ` [PATCH 09/11] MIPS: Add MFHC0 and MTHC0 instructions to uasm Steven J. Hill
2014-11-13 6:05 ` [PATCH 10/11] MIPS: Add support for XPA Steven J. Hill
2014-11-13 6:05 ` [PATCH 11/11] MIPS: XPA: Add new configuration file Steven J. Hill
2014-11-13 6:21 ` [PATCH 00/11] Add support for eXtended Physical Addressing Ralf Baechle
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