Add the AlphaLinux locore support.

Submitted by:	gallatin

sys/alpha/linux/linux_locore.s

@@ -0,0 +1,50 @@
+/* $FreeBSD$ */
+	
+#include <machine/asm.h>
+#include <alpha/linux/linux_syscall.h>
+
+
+/*
+ * Signal "trampoline" code. Invoked from RTE setup by sendsig().
+ *
+ * On entry, stack & registers look like:
+ *
+ *      a0	signal number
+ *      a1	pointer to siginfo_t
+ *      a2	pointer to signal context frame (scp)
+ *      a3	address of handler
+ *      sp+0	saved hardware state
+ *                      .
+ *                      .
+ *      scp+0	beginning of signal context frame
+ */
+
+/*
+ * System call glue.
+ */
+#define LINUX_SYSCALLNUM(name)                                   \
+        ___CONCAT(LINUX_SYS_,name)
+
+#define LINUX_CALLSYS_NOERROR(name)                              \
+        ldiq    v0, LINUX_SYSCALLNUM(name);                      \
+        call_pal PAL_OSF1_callsys
+
+
+	
+NESTED(linux_sigcode,0,0,ra,0,0)
+	lda	sp, -16(sp)		/* save the sigcontext pointer */
+	stq	a2, 0(sp)
+	jsr	ra, (t12)		/* call the signal handler (t12==pv) */
+	ldq	a0, 0(sp)		/* get the sigcontext pointer */
+	lda	sp, 16(sp)
+					/* and call sigreturn() with it. */
+	LINUX_CALLSYS_NOERROR(osf1_sigreturn)
+	mov	v0, a0			/* if that failed, get error code */
+	LINUX_CALLSYS_NOERROR(exit)	/* and call exit() with it. */
+XNESTED(linux_esigcode,0)
+	END(linux_sigcode)
+
+	.data
+	EXPORT(linux_szsigcode)
+	.quad	linux_esigcode-linux_sigcode
+	.text