linux-kernel - Re: [PATCH] x86: use bitmap library functions

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Date:	Thu, 17 Feb 2011 14:00:01 +0900
From:	Akinobu Mita <akinobu.mita@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Subject: Re: [PATCH] x86: use bitmap library functions

2011/2/17 Ingo Molnar <mingo@...e.hu>:
>
> * Akinobu Mita <akinobu.mita@...il.com> wrote:
>
>> Use bitmap_set()/bitmap_clear() to fill/zero a region of a bitmap
>> instead of doing set_bit()/clear_bit() each bit.
>>
>> Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
>> Cc: Thomas Gleixner <tglx@...utronix.de>
>> Cc: Ingo Molnar <mingo@...hat.com>
>> Cc: "H. Peter Anvin" <hpa@...or.com>
>> Cc: x86@...nel.org
>> ---
>>  arch/x86/kernel/ioport.c |   20 +++++---------------
>>  1 files changed, 5 insertions(+), 15 deletions(-)
>
> Before we can merge this it would be nice to tested this using sys_ioperm(), to make
> sure port IO still gets denied/allowed as expected. You can check /proc/ioperm to
> see which ports are (probably) safe to read: 0x80/0xed is usually safe to
> read/write.

I have tested with this program and there is no difference in behavior
with this patch.

#include <sys/io.h>
#include <stdio.h>
#include <err.h>

int main(void)
{
	unsigned long from = 0xed;
	unsigned long num = 1;
	int ret;
	int i;

	ret = ioperm(from, num, 1);
	if (ret)
		err(1, "ioperm");

	for (i = 0; i < num; i++)
		ret = inb(from + i);

	printf("OK\n");

	ret = ioperm(from, num, 0);
	if (ret)
		err(1, "ioperm");

	printf("will receive a segmentation fault\n");

	ret = inb(from);
	errx(1, "Oops");
}
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