netdev - [PATCH 11/24] make atomic_read() behave consistently on m68knommu

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20070809135623.GA16554@shell.boston.redhat.com>
Date:	Thu, 9 Aug 2007 09:56:23 -0400
From:	Chris Snook <csnook@...hat.com>
To:	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	torvalds@...ux-foundation.org
Cc:	netdev@...r.kernel.org, akpm@...ux-foundation.org, ak@...e.de,
	heiko.carstens@...ibm.com, davem@...emloft.net,
	schwidefsky@...ibm.com, wensong@...ux-vs.org, horms@...ge.net.au,
	wjiang@...ilience.com, cfriesen@...tel.com, zlynx@....org,
	rpjday@...dspring.com, jesper.juhl@...il.com
Subject: [PATCH 11/24] make atomic_read() behave consistently on m68knommu

From: Chris Snook <csnook@...hat.com>

Make atomic_read() volatile on m68knommu.  This ensures that busy-waiting
for an interrupt handler to change an atomic_t won't get compiled to an
infinite loop, consistent with SMP architectures.

Signed-off-by: Chris Snook <csnook@...hat.com>

--- linux-2.6.23-rc2-orig/include/asm-m68knommu/atomic.h	2007-07-08 19:32:17.000000000 -0400
+++ linux-2.6.23-rc2/include/asm-m68knommu/atomic.h	2007-08-09 07:00:24.000000000 -0400
@@ -15,7 +15,11 @@
 typedef struct { int counter; } atomic_t;
 #define ATOMIC_INIT(i)	{ (i) }
 
-#define atomic_read(v)		((v)->counter)
+/*
+ * Casting to volatile here minimizes the need for barriers,
+ * without having to declare the type itself as volatile.
+ */
+#define atomic_read(v)		(*(volatile int *)&(v)->counter)
 #define atomic_set(v, i)	(((v)->counter) = i)
 
 static __inline__ void atomic_add(int i, atomic_t *v)
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html