- Define a new md function 'casuptr'. This atomically compares and sets

   a pointer that is in user space.  It will be used as the basic primitive
   for a kernel supported user space lock implementation.
 - Implement this function in x86's support.s
 - Provide stubs that return -1 in all other architectures.  Implementations
   will follow along shortly.

Reviewed by:	jake

1 files changed, 6 insertions, 0 deletions

diff --git a/sys/alpha/alpha/machdep.c b/sys/alpha/alpha/machdep.c
index 055d3f8..50627d9 100644
--- a/sys/alpha/alpha/machdep.c
+++ b/sys/alpha/alpha/machdep.c
@@ -2324,3 +2324,9 @@ cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t sz)
 	pcpu->pc_idlepcb.apcb_ptbr = thread0.td_pcb->pcb_hw.apcb_ptbr;
 	pcpu->pc_current_asngen = 1;
 }
+
+intptr_t
+casuptr(intptr_t *p, intptr_t old, intptr_t new)
+{
+	return (-1);
+}