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From: Julien Grall <julien.grall@arm.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: andre.przywara@arm.com, sstabellini@kernel.org,
	steve.capper@arm.com, wei.chen@arm.com, xen-devel@lists.xen.org
Subject: Re: [PATCH v3 09/16] xen/arm: Introduce alternative runtime patching
Date: Wed, 8 Jun 2016 19:22:45 +0100	[thread overview]
Message-ID: <57586275.4040305@arm.com> (raw)
In-Reply-To: <20160608181718.GA28071@char.us.oracle.com>

Hi Konrad,

On 08/06/16 19:17, Konrad Rzeszutek Wilk wrote:
>>>> diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
>>>> index 1f010bd..495f9d8 100644
>>>> --- a/xen/arch/arm/xen.lds.S
>>>> +++ b/xen/arch/arm/xen.lds.S
>>>> @@ -129,6 +129,9 @@ SECTIONS
>>>>         _sinittext = .;
>>>>         *(.init.text)
>>>>         _einittext = .;
>>>> +#ifdef CONFIG_ALTERNATIVE
>>>> +       *(.altinstr_replacement)
>>>> +#endif
>>>
>>> This is outside the _einittext? x86 looks to have .altinstr_replacement
>>> inside the _einittext.
>>
>> Yes, I looked at the x86 code when I did the implement and I did not find
>> any good reason to keep .altinstr_replace inside the inittext.
>>
>> altinstr_replacement contains replacement instructions. Anything inside the
>> inittext region will be mark executable, which is not what we want here.
>
> Right, but we don't this code after the bootup (as in we patch the
> .text and we can eject the .altinstr_replacement).

I don't see any problem, .altinstr_replacement is within __init_begin 
and __init_end. So it will be free when free_init_memory will be called.

_sinittex and _einittext are used to know which page will be executable.

Regards,

-- 
Julien Grall

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  reply	other threads:[~2016-06-08 18:22 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-07 16:06 [PATCH v3 00/16] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
2016-06-07 16:06 ` [PATCH v3 01/16] xen/arm: Makefile: Sort the entries alphabetically Julien Grall
2016-06-07 16:06 ` [PATCH v3 02/16] xen/arm: Include the header asm-arm/system.h in asm-arm/page.h Julien Grall
2016-06-07 16:06 ` [PATCH v3 03/16] xen/arm: Add macros to handle the MIDR Julien Grall
2016-06-07 16:06 ` [PATCH v3 04/16] xen/arm: Add cpu_hwcap bitmap Julien Grall
2016-06-07 16:06 ` [PATCH v3 05/16] xen/arm64: Add an helper to invalidate all instruction caches Julien Grall
2016-06-07 16:06 ` [PATCH v3 06/16] xen/arm: arm64: Move the define BRK_BUG_FRAME into a separate header Julien Grall
2016-06-07 16:06 ` [PATCH v3 07/16] xen/arm: arm64: Reserve a brk immediate to fault on purpose Julien Grall
2016-06-07 16:06 ` [PATCH v3 08/16] xen/arm: arm64: Add helpers to decode and encode branch instructions Julien Grall
2016-06-07 16:06 ` [PATCH v3 09/16] xen/arm: Introduce alternative runtime patching Julien Grall
2016-06-07 17:24   ` Konrad Rzeszutek Wilk
2016-06-08  9:39     ` Julien Grall
2016-06-08 18:17       ` Konrad Rzeszutek Wilk
2016-06-08 18:22         ` Julien Grall [this message]
2016-06-08 18:35           ` Konrad Rzeszutek Wilk
2016-06-09 13:33   ` Julien Grall
2016-06-07 16:06 ` [PATCH v3 10/16] xen/arm: cpufeature: Provide an helper to check if a capability is supported Julien Grall
2016-06-22  9:59   ` Stefano Stabellini
2016-06-22 10:09     ` Julien Grall
2016-06-22 10:14       ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 11/16] xen/arm: Detect silicon revision and set cap bits accordingly Julien Grall
2016-06-22 10:00   ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 12/16] xen/arm: Document the errata implemented in Xen Julien Grall
2016-06-22 10:03   ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 13/16] xen/arm: arm64: Add Cortex-A53 cache errata workaround Julien Grall
2016-06-22 10:04   ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 14/16] xen/arm: arm64: Add cortex-A57 erratum 832075 workaround Julien Grall
2016-06-22 10:10   ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 15/16] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails Julien Grall
2016-06-07 16:06 ` [PATCH v3 16/16] xen/arm: arm64: Document Cortex-A57 erratum 834220 Julien Grall
2016-06-14 12:15   ` Julien Grall
2016-06-22 10:08   ` Stefano Stabellini
2016-06-22 10:18     ` Julien Grall
2016-06-22 10:37       ` Stefano Stabellini

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