lkml.org 
[lkml]   [2007]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    Subject[patch 6/9] Conditional Calls - PowerPC Optimization
    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 <mathieu.desnoyers@polymtl.ca>
    ---
    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 <asm-generic/condcall.h>
    +#ifndef _ASM_POWERPC_CONDCALL_H
    +#define _ASM_POWERPC_CONDCALL_H
    +
    +/*
    + * Conditional function calls. PowerPC architecture optimizations.
    + *
    + * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
    + *
    + * This file is released under the GPLv2.
    + * See the file COPYING for more details.
    + */
    +
    +#include <asm/asm-compat.h>
    +
    +#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/

    \
     
     \ /
      Last update: 2007-05-29 20:41    [W:0.023 / U:89.776 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site