linux-kernel - [PATCH] olpc: fix endian bug in openfirmware workaround

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1222208409.16003.25.camel@brick>
Date:	Tue, 23 Sep 2008 15:20:09 -0700
From:	Harvey Harrison <harvey.harrison@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Ingo Molnar <mingo@...e.hu>, LKML <linux-kernel@...r.kernel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] olpc: fix endian bug in openfirmware workaround

Boardrev is always treated as a u32 everywhere else, no reason to
byteswap the 0xc2 value.  The only use is to print out if it is
a prerelease board, the test being:

(olpc_platform_info.boardrev & 0xf) < 8

Which is currently always true as be32_to_cpu(0xc2) & 0xf = 0
but I doubt that was the intention here.  The consequences of the bug
are pretty minor though (incorrect boardrev displayed in dmesg when
ofw support not configured)

Also annotate the temporary used to read the boardrev in the ofw
case.

The confusion was noticed by sparse:
arch/x86/kernel/olpc.c:206:32: warning: cast to restricted __be32

Signed-off-by: Harvey Harrison <harvey.harrison@...il.com>
---
 arch/x86/kernel/olpc.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/olpc.c b/arch/x86/kernel/olpc.c
index 3e66722..7a13fac 100644
--- a/arch/x86/kernel/olpc.c
+++ b/arch/x86/kernel/olpc.c
@@ -190,12 +190,12 @@ EXPORT_SYMBOL_GPL(olpc_ec_cmd);
 static void __init platform_detect(void)
 {
 	size_t propsize;
-	u32 rev;
+	__be32 rev;
 
 	if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
 			&propsize) || propsize != 4) {
 		printk(KERN_ERR "ofw: getprop call failed!\n");
-		rev = 0;
+		rev = cpu_to_be32(0);
 	}
 	olpc_platform_info.boardrev = be32_to_cpu(rev);
 }
@@ -203,7 +203,7 @@ static void __init platform_detect(void)
 static void __init platform_detect(void)
 {
 	/* stopgap until OFW support is added to the kernel */
-	olpc_platform_info.boardrev = be32_to_cpu(0xc2);
+	olpc_platform_info.boardrev = 0xc2;
 }
 #endif
 
-- 
1.6.0.2.471.g47a76



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/