scripts: Fix size mismatch of kexec_purgatory_size

Tautschnig, Michael · Michal Marek · commit 21532b9e5bd5 · 2016-07-22T14:05:40.000+02:00
bin2c is used to create a valid C file out of a binary file where two
symbols will be globally defined: &lt;name&gt; and &lt;name&gt;_size. &lt;name&gt; 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 &lt;name&gt;_size to be 'int' so in a 64-bit host where
sizeof(size_t) &gt; 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 &lt;name&gt;_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 &lt;= 0)

Signed-off-by: Michael Tautschnig &lt;tautschn@amazon.com&gt;
Cc: Vivek Goyal &lt;vgoyal@redhat.com&gt;
Acked-by: Dave Young &lt;dyoung@redhat.com&gt;
Signed-off-by: Michal Marek &lt;mmarek@suse.com&gt;
diff --git 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;
 }

Original file line number	Diff line number	Diff line change
`@@ -29,7 +29,8 @@ int main(int argc, char *argv[])`
`29`	`29`	`} while (ch != EOF);`
`30`	`30`
`31`	`31`	`if (argc > 1)`
`32`		`- printf("\t;\n\nconst int %s_size = %d;\n", argv[1], total);`
	`32`	`+ printf("\t;\n\n#include <linux/types.h>\n\nconst size_t %s_size = %d;\n",`
	`33`	`+ argv[1], total);`
`33`	`34`
`34`	`35`	`return 0;`
`35`	`36`	`}`