svn commit: r254391 - projects/atomic64/sys/i386/i386

[Jung-uk Kim]

Author: jkim
Date: Fri Aug 16 00:00:36 2013
New Revision: 254391
URL: http://svnweb.freebsd.org/changeset/base/254391

Log:
  MFC:	r254384
  
  Simplify check for CMPXCHG8B instruction.  Note CMPXCHG8B instruction is
  always available for Rise mP6 processors although it is not set by CPUID.

Modified:
  projects/atomic64/sys/i386/i386/initcpu.c
  projects/atomic64/sys/i386/i386/machdep.c

Modified: projects/atomic64/sys/i386/i386/initcpu.c
==============================================================================
--- projects/atomic64/sys/i386/i386/initcpu.c	Thu Aug 15 23:58:16 2013	(r254390)
+++ projects/atomic64/sys/i386/i386/initcpu.c	Fri Aug 16 00:00:36 2013	(r254391)
@@ -424,6 +424,19 @@ init_6x86(void)
 
 #ifdef I586_CPU
 /*
+ * Rise mP6
+ */
+static void
+init_rise(void)
+{
+
+	/*
+	 * The CMPXCHG8B instruction is always available but hidden.
+	 */
+	cpu_feature |= CPUID_CX8;
+}
+
+/*
  * IDT WinChip C6/2/2A/2B/3
  *
  * http://www.centtech.com/winchip_bios_writers_guide_v4_0.pdf
@@ -690,6 +703,9 @@ initializecpu(void)
 		case CPU_VENDOR_TRANSMETA:
 			init_transmeta();
 			break;
+		case CPU_VENDOR_RISE:
+			init_rise();
+			break;
 		}
 		break;
 #endif

Modified: projects/atomic64/sys/i386/i386/machdep.c
==============================================================================
--- projects/atomic64/sys/i386/i386/machdep.c	Thu Aug 15 23:58:16 2013	(r254390)
+++ projects/atomic64/sys/i386/i386/machdep.c	Fri Aug 16 00:00:36 2013	(r254391)
@@ -1554,8 +1554,7 @@ static void
 cpu_probe_cmpxchg8b(void)
 {
 
-	if ((cpu_feature & CPUID_CX8) != 0 ||
-	    cpu_vendor_id == CPU_VENDOR_RISE)
+	if ((cpu_feature & CPUID_CX8) != 0)
 		cpu_ident_cmxchg8b = 1;
 }