PowerPC optimization of the immediate values which uses a li instruction,
patched with an immediate value.

Changelog:
- Put imv_set and _imv_set in the architecture independent header.
- Pack the __imv section. Use smallest types required for size (char).
- Remove architecture specific update code : now handled by architecture
  agnostic code.
- Use imv_* instead of immediate_*.

Signed-off-by: Mathieu Desnoyers <[EMAIL PROTECTED]>
CC: Rusty Russell <[EMAIL PROTECTED]>
CC: Christoph Hellwig <[EMAIL PROTECTED]>
CC: Paul Mackerras <[EMAIL PROTECTED]>
---
 arch/powerpc/Kconfig            |    1 
 include/asm-powerpc/immediate.h |   55 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

Index: linux-2.6-lttng/include/asm-powerpc/immediate.h
===================================================================
--- /dev/null   1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng/include/asm-powerpc/immediate.h     2007-11-19 
12:26:16.000000000 -0500
@@ -0,0 +1,55 @@
+#ifndef _ASM_POWERPC_IMMEDIATE_H
+#define _ASM_POWERPC_IMMEDIATE_H
+
+/*
+ * Immediate values. PowerPC architecture optimizations.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <[EMAIL PROTECTED]>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm/asm-compat.h>
+
+/**
+ * imv_read - read immediate variable
+ * @name: immediate value name
+ *
+ * Reads the value of @name.
+ * Optimized version of the immediate.
+ * Do not use in __init and __exit functions. Use _imv_read() instead.
+ */
+#define imv_read(name)                                                 \
+       ({                                                              \
+               __typeof__(name##__imv) value;                          \
+               BUILD_BUG_ON(sizeof(value) > 8);                        \
+               switch (sizeof(value)) {                                \
+               case 1:                                                 \
+                       asm(".section __imv,\"a\",@progbits\n\t"        \
+                                       PPC_LONG "%c1, ((1f)-1)\n\t"    \
+                                       ".byte 1\n\t"                   \
+                                       ".previous\n\t"                 \
+                                       "li %0,0\n\t"                   \
+                                       "1:\n\t"                        \
+                               : "=r" (value)                          \
+                               : "i" (&name##__imv));                  \
+                       break;                                          \
+               case 2:                                                 \
+                       asm(".section __imv,\"a\",@progbits\n\t"        \
+                                       PPC_LONG "%c1, ((1f)-2)\n\t"    \
+                                       ".byte 2\n\t"                   \
+                                       ".previous\n\t"                 \
+                                       "li %0,0\n\t"                   \
+                                       "1:\n\t"                        \
+                               : "=r" (value)                          \
+                               : "i" (&name##__imv));                  \
+                       break;                                          \
+               case 4:                                                 \
+               case 8: value = name##__imv;                            \
+                       break;                                          \
+               };                                                      \
+               value;                                                  \
+       })
+
+#endif /* _ASM_POWERPC_IMMEDIATE_H */
Index: linux-2.6-lttng/arch/powerpc/Kconfig
===================================================================
--- linux-2.6-lttng.orig/arch/powerpc/Kconfig   2007-11-19 12:25:21.000000000 
-0500
+++ linux-2.6-lttng/arch/powerpc/Kconfig        2007-11-19 12:26:01.000000000 
-0500
@@ -81,6 +81,7 @@ config PPC
        default y
        select HAVE_OPROFILE
        select HAVE_KPROBES
+       select HAVE_IMMEDIATE
 
 config EARLY_PRINTK
        bool

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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