lguest: update commentry

[linux-2.6-omap-h63xx.git] / include / asm-mips / war.h

diff --git a/include/asm-mips/war.h b/include/asm-mips/war.h
index d2808edfd4e9a516e764dc35517359067211543a..22361d5e3bf00d25ee5a04ff5c6d98b879b6afd0 100644 (file)
--- a/include/asm-mips/war.h
+++ b/include/asm-mips/war.h
@@ -4,12 +4,74 @@
  * for more details.
  *
  * Copyright (C) 2002, 2004, 2007 by Ralf Baechle
+ * Copyright (C) 2007  Maciej W. Rozycki
  */
 #ifndef _ASM_WAR_H
 #define _ASM_WAR_H
 
 #include <war.h>
 
+/*
+ * Work around certain R4000 CPU errata (as implemented by GCC):
+ *
+ * - A double-word or a variable shift may give an incorrect result
+ *   if executed immediately after starting an integer division:
+ *   "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0",
+ *   erratum #28
+ *   "MIPS R4000MC Errata, Processor Revision 2.2 and 3.0", erratum
+ *   #19
+ *
+ * - A double-word or a variable shift may give an incorrect result
+ *   if executed while an integer multiplication is in progress:
+ *   "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0",
+ *   errata #16 & #28
+ *
+ * - An integer division may give an incorrect result if started in
+ *   a delay slot of a taken branch or a jump:
+ *   "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0",
+ *   erratum #52
+ */
+#ifdef CONFIG_CPU_R4000_WORKAROUNDS
+#define R4000_WAR 1
+#else
+#define R4000_WAR 0
+#endif
+
+/*
+ * Work around certain R4400 CPU errata (as implemented by GCC):
+ *
+ * - A double-word or a variable shift may give an incorrect result
+ *   if executed immediately after starting an integer division:
+ *   "MIPS R4400MC Errata, Processor Revision 1.0", erratum #10
+ *   "MIPS R4400MC Errata, Processor Revision 2.0 & 3.0", erratum #4
+ */
+#ifdef CONFIG_CPU_R4400_WORKAROUNDS
+#define R4400_WAR 1
+#else
+#define R4400_WAR 0
+#endif
+
+/*
+ * Work around the "daddi" and "daddiu" CPU errata:
+ *
+ * - The `daddi' instruction fails to trap on overflow.
+ *   "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0",
+ *   erratum #23
+ *
+ * - The `daddiu' instruction can produce an incorrect result.
+ *   "MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0",
+ *   erratum #41
+ *   "MIPS R4000MC Errata, Processor Revision 2.2 and 3.0", erratum
+ *   #15
+ *   "MIPS R4400PC/SC Errata, Processor Revision 1.0", erratum #7
+ *   "MIPS R4400MC Errata, Processor Revision 1.0", erratum #5
+ */
+#ifdef CONFIG_CPU_DADDI_WORKAROUNDS
+#define DADDI_WAR 1
+#else
+#define DADDI_WAR 0
+#endif
+
 /*
  * Another R4600 erratum.  Due to the lack of errata information the exact
  * technical details aren't known.  I've experimentally found that disabling