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Date: Fri, 18 Feb 2005 11:12:45 -0800
From: "Randy.Dunlap" <rddunlap@osdl.org>
Organization: OSDL
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To: joern@wohnheim.fh-wedel.de, lkml <linux-kernel@vger.kernel.org>
Subject: checkstack.pl <large_number>
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Hi,

In checkstack.pl, do you recall the reason for this code snippet:

		if ($size > 0x80000000) {
			$size = - $size;
			$size += 0x80000000;
			$size += 0x80000000;
		}

There is one (unusual:) case where it fails.  Is it needed?

For arch/i386/kernel/efi_stub.S, checkstack reports:

0xc0116f5d efi_call_phys:				1073741824
which is 0x4000_0000 (_ added for readability only), however the
actual change in %esp there is __PAGE_OFFSET (0xc000_0000 on ia32),

so if I alter the "if" test above to check for > 0xf000_0000,
checkstack reports the correct value:
0xc0116f5d efi_call_phys:				3221225472
which is 0xc000_0000.


from objdump of efi_stub.o:
    5:	81 ea 00 00 00 c0    	sub    $0xc0000000,%edx

or I can just ignore it, like I've been doing for awhile...

-- 
~Randy