linux-kernel - [PATCH] scripts: Fix size mismatch of kexec_purgatory

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Date:	Mon, 4 Jul 2016 13:55:04 +0000
From:	"Tautschnig, Michael" <tautschn@...zon.co.uk>
To:	"linux-kbuild@...r.kernel.org" <linux-kbuild@...r.kernel.org>,
	"kexec@...ts.infradead.org" <kexec@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	Michal Marek <mmarek@...e.com>, Vivek Goyal <vgoyal@...hat.com>
Subject: [PATCH] scripts: Fix size mismatch of kexec_purgatory_size

bin2c is used to create a valid C file out of a binary file where two
symbols will be globally defined: <name> and <name>_size. <name> is
passed as the first parameter of the host binary.

Building using goto-cc reported that the purgatory binary code (the only
current user of this utility) declares kexec_purgatory_size as 'size_t'
where bin2c generate <name>_size to be 'int' so in a 64-bit host where
sizeof(size_t) > sizeof(int) this type mismatch will always yield the
wrong value for big-endian architectures while for little-endian it will
be wrong if the object laid in memory directly after
kexec_purgatory_size contains non-zero value at the time of reading.

This commit changes <name>_size to be size_t instead.

Note:

Another way to fix the problem is to change the type of
kexec_purgatory_size to be 'int' as there's this check in code:
(kexec_purgatory_size <= 0)

Signed-off-by: Michael Tautschnig <tautschn@...zon.com>
Cc: Michal Marek <mmarek@...e.com>
Cc: Vivek Goyal <vgoyal@...hat.com>
---
 scripts/basic/bin2c.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/basic/bin2c.c b/scripts/basic/bin2c.c
index af187e6..c3d7eef 100644
--- a/scripts/basic/bin2c.c
+++ b/scripts/basic/bin2c.c
@@ -29,7 +29,8 @@ int main(int argc, char *argv[])
 	} while (ch != EOF);

 	if (argc > 1)
-		printf("\t;\n\nconst int %s_size = %d;\n", argv[1], total);
+		printf("\t;\n\n#include <linux/types.h>\n\nconst size_t %s_size = %d;\n",
+		       argv[1], total);

 	return 0;
 }
--
2.7.3.AMZN