PowerPC optimization of the cond_calls which uses a li instruction, patched with an immediate value 0 or 1 to enable/disable the cond_call. Signed-off-by: Mathieu Desnoyers --- include/asm-powerpc/condcall.h | 68 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 67 insertions(+), 1 deletion(-) Index: linux-2.6-lttng/include/asm-powerpc/condcall.h =================================================================== --- linux-2.6-lttng.orig/include/asm-powerpc/condcall.h 2007-05-29 11:55:58.000000000 -0400 +++ linux-2.6-lttng/include/asm-powerpc/condcall.h 2007-05-29 11:56:43.000000000 -0400 @@ -1 +1,67 @@ -#include +#ifndef _ASM_POWERPC_CONDCALL_H +#define _ASM_POWERPC_CONDCALL_H + +/* + * Conditional function calls. PowerPC architecture optimizations. + * + * (C) Copyright 2006 Mathieu Desnoyers + * + * This file is released under the GPLv2. + * See the file COPYING for more details. + */ + +#include + +#ifdef CONFIG_COND_CALL + +#define CF_DEFAULT (CF_OPTIMIZED | CF_LOCKDEP | CF_PRINTK) + +/* Optimized version of the cond_call */ +#define cond_call_optimized(flags, name, func) \ + ({ \ + static const char __cstrtab_name_##name[] \ + __attribute__((section("__cond_call_strings"))) = #name; \ + char condition; \ + asm ( ".section __cond_call, \"a\", @progbits;\n\t" \ + PPC_LONG "%1, 0f, %2;\n\t" \ + ".previous;\n\t" \ + ".align 4\n\t" \ + "0:\n\t" \ + "li %0,%3;\n\t" \ + : "=r" (condition) \ + : "i" (__cstrtab_name_##name), \ + "i" (flags), \ + "i" ((flags) & CF_STATIC_ENABLE)); \ + (unlikely(condition)) ? \ + (func) : \ + (__typeof__(func))0; \ + }) + +/* cond_call macro selecting the generic or optimized version of cond_call, + * depending on the flags specified. */ +#define _cond_call(flags, name, func) \ +({ \ + ((flags) & CF_OPTIMIZED) ? \ + cond_call_optimized(flags, name, func) : \ + cond_call_generic(flags, name, func); \ +}) + +/* cond_call with default behavior */ +#define cond_call(name, func) _cond_call(CF_DEFAULT, name, func) + +/* Architecture dependant cond_call information, used internally for cond_call + * activation. */ + +/* Offset of the immediate value from the start of the addi instruction (result + * of the li mnemonic), in bytes. */ +#define COND_CALL_OPTIMIZED_ENABLE_IMMEDIATE_OFFSET 2 +#define COND_CALL_OPTIMIZED_ENABLE_TYPE unsigned short +/* Dereference enable as lvalue from a pointer to its instruction */ +#define COND_CALL_OPTIMIZED_ENABLE(a) \ + *(COND_CALL_OPTIMIZED_ENABLE_TYPE*) \ + ((char*)a+COND_CALL_OPTIMIZED_ENABLE_IMMEDIATE_OFFSET) + +extern int cond_call_optimized_set_enable(void *address, char enable); + +#endif +#endif //_ASM_POWERPC_CONDCALL_H -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/