2014-01-06 18:52:26

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH v7 6/7] arm64, jump label: optimize jump label implementation

On Sun, Dec 22, 2013 at 03:25:42PM +0000, Jiang Liu wrote:
> Optimize jump label implementation for ARM64 by dynamically patching
> kernel text.

Almost!

> diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h
> new file mode 100644
> index 0000000..47cd130
> --- /dev/null
> +++ b/arch/arm64/include/asm/jump_label.h
> @@ -0,0 +1,51 @@
> +/*
> + * Copyright (C) 2013 Huawei Ltd.
> + * Author: Jiang Liu <[email protected]>
> + *
> + * Based on arch/arm/include/asm/jump_label.h
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +#ifndef _ASM_JUMP_LABEL_H
> +#define _ASM_JUMP_LABEL_H

It's actually prefixed with double-underscore in our other headers.

> +#include <linux/types.h>
> +
> +#ifdef __KERNEL__
> +
> +#define JUMP_LABEL_NOP_SIZE 4

I know you didn't like including asm/insn.h, but I don't see why that's such
a problem. Does it cause a circular dependency or something?

Will


2014-01-07 13:43:46

by Jiang Liu

[permalink] [raw]
Subject: Re: [PATCH v7 6/7] arm64, jump label: optimize jump label implementation

On 01/07/2014 02:51 AM, Will Deacon wrote:
> On Sun, Dec 22, 2013 at 03:25:42PM +0000, Jiang Liu wrote:
>> Optimize jump label implementation for ARM64 by dynamically patching
>> kernel text.
>
> Almost!
>
>> diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h
>> new file mode 100644
>> index 0000000..47cd130
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/jump_label.h
>> @@ -0,0 +1,51 @@
>> +/*
>> + * Copyright (C) 2013 Huawei Ltd.
>> + * Author: Jiang Liu <[email protected]>
>> + *
>> + * Based on arch/arm/include/asm/jump_label.h
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +#ifndef _ASM_JUMP_LABEL_H
>> +#define _ASM_JUMP_LABEL_H
>
> It's actually prefixed with double-underscore in our other headers.
OK, will fix.

>
>> +#include <linux/types.h>
>> +
>> +#ifdef __KERNEL__
>> +
>> +#define JUMP_LABEL_NOP_SIZE 4
>
> I know you didn't like including asm/insn.h, but I don't see why that's such
> a problem. Does it cause a circular dependency or something?
Not a big deal, just saving some compilation times. Will change to
include asm/insn.h.

>
> Will
>