From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Date: Fri, 23 Jan 2009 23:49:41 +0000 (-0800)
Subject: x86: uaccess: introduce try and catch framework
X-Git-Tag: v2.6.30-rc1~2^2~50^2~39^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe40c0af3cff3ea461cf25bddb979abc7279d4df;p=pandora-kernel.git

x86: uaccess: introduce try and catch framework

Impact: introduce new uaccess exception handling framework

Introduce {get|put}_user_try and {get|put}_user_catch as new uaccess exception
handling framework.
{get|put}_user_try begins exception block and {get|put}_user_catch(err) ends
the block and gets err if an exception occured in {get|put}_user_ex() in the
block. The exception is stored thread_info->uaccess_err.

The example usage of this framework is below;
int func()
{
	int err = 0;

	get_user_try {
		get_user_ex(...);
		get_user_ex(...);
		:
	} get_user_catch(err);

	return err;
}

Note: get_user_ex() is not clear the value when an exception occurs, it's
different from the behavior of __get_user(), but I think it doesn't matter.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---

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