Like i wrote earlier, i don't think it's supported, because of
-march=armv6 and gcc version 4.2.1 20070719, unless i have missed
something.
On 08/01/13 02:28, Richard Allen wrote:
Could we just use GCC intrinsics in C?
On Jul 31, 2013 9:08 AM, "Artturi Alm" <artturi....@gmail.com> wrote:
On 07/31/13 16:37, Artturi Alm wrote:
On 07/31/13 08:57, Richard Allen wrote:
Hi,
I just wanted to let you know that _atomic_lock(), from _atomic_lock.c,
as used by librthread should probably have a barrier instruction added
to prevent the processor from reordering loads/stores around the
atomic_lock.
For more information about barriers on ARM, see:
http://infocenter.arm.com/**help/index.jsp?topic=/com.arm.**
doc.dui0489c/CIHGHHIE.html<http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0489c/CIHGHHIE.html>
For some examples, see sections 7.2.1 and 7.2.2
http://infocenter.arm.com/**help/topic/com.arm.doc.**
genc007826/Barrier_Litmus_**Tests_and_Cookbook_A08.pdf<http://infocenter.arm.com/help/topic/com.arm.doc.genc007826/Barrier_Litmus_Tests_and_Cookbook_A08.pdf>
-Richard
Hi,
I'm not sure what the diff against _atomic_lock.c would look like,
since i'm guessing it might not be supported, and i don't like
inline asm so i'll leave it to someone else, however, diff for
using it in cpufunc_asm_armv7.S would be something like below
Wow, that was unclear. what i meant with 'it' was of course the dmb
instruction, and fwiw freebsd uses it exclusively in atomic.h inlines.
-Artturi
Index: cpufunc_asm_armv7.S
==============================**==============================**=======
RCS file: /cvs/src/sys/arch/arm/arm/**cpufunc_asm_armv7.S,v
retrieving revision 1.6
diff -u -p -r1.6 cpufunc_asm_armv7.S
--- cpufunc_asm_armv7.S 30 Mar 2013 01:30:30 -0000 1.6
+++ cpufunc_asm_armv7.S 31 Jul 2013 13:26:18 -0000
@@ -19,6 +19,7 @@
#include <machine/asm.h>
#define DSB .long 0xf57ff040
+#define DMB .long 0xf57ff050
#define ISB .long 0xf57ff060
#define WFI .long 0xe320f003
