On 08/27/2010 02:39 PM, Glauber Costa wrote:
On Fri, Aug 27, 2010 at 01:49:20PM +0800, Jason Wang wrote:
+u64 atomic64_cmpxchg(atomic64_t *v, u64 old, u64 new)
+{
+ u64 ret;
+ u64 _old = old;
+ u64 _new = new;
+
+ asm volatile("lock cmpxchgq %1,%2"
+ : "=a" (ret)
+ : "r" (_new),
+ "m" (*(volatile long *)&v->counter), "0"(_old)
+ : "memory"
+ );
+ return ret;
+}
+
This is wrong.
See
http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commitdiff;h=113fc5a6e8c2288619ff7e8187a6f556b7e0d372
you need to explicitly mark you are changing the memory, here.
Btw, this is mostly header copying, and can miss bug fixes like the one above.
Isn't there
a way to just specify in the test they are needed, and then grab them from
linux automatically?
That may pull in dependencies. I'd prefer using builtins like
__sync_val_compare_and_swap() (but many atomics are not available). Is
there some library we can use for this?
--
error compiling committee.c: too many arguments to function
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