[PATCH] kexec/powerpc fix optimization for size (gcc -Os) build

Tue Oct 19 01:11:56 EDT 2010

On Thu, 2010-09-30 at 19:52 +0400, Maxim Uvarov wrote:
> crt.S patch had fixes for gcc -Os (optimaze for size), same as
>     kernel has. Without this fixes powerpc gcc 4.4 generates forever
>     loop functions for kexec.
> 
>     This happends because crtsavres code was spit up to individual files
>     (http://gcc.gnu.org/ml/gcc-patches/2008-03/msg01294.html) and
>     kexec purgatory code has following options:
>     --no-undefined -nostartfiles -nostdlib -nodefaultlibs
>     So in that case crtasaveregs function are not defined and final object
>     file has been linked without them.  This does not happen with applications
>     built without -nostdlib, because gcc will add it's standard functions.
> Signed-off-by: Maxim Uvarov <muvarov at gmail.com>

Acked-by: Matthew McClintock <msm at freescale.com> 

In lieu of
http://lists.infradead.org/pipermail/kexec/2010-October/004600.html

-M

> ---
> 
>  purgatory/arch/ppc/misc.S |  229 +++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 229 insertions(+), 0 deletions(-)
> 
> diff --git a/purgatory/arch/ppc/misc.S b/purgatory/arch/ppc/misc.S
> index b0a5486..bc6a18d 100644
> --- a/purgatory/arch/ppc/misc.S
> +++ b/purgatory/arch/ppc/misc.S
> @@ -16,6 +16,235 @@
>  
>  #include "ppc_asm.h"	
>  
> +/* This is from linux-2.6/arch/powerpc/lib/crtsavres.S:
> + *
> + * Special support for eabi and SVR4
> + *
> + *   Copyright (C) 1995, 1996, 1998, 2000, 2001 Free Software Foundation, Inc.
> + *   Copyright 2008 Freescale Semiconductor, Inc.
> + *   Written By Michael Meissner
> + *
> + * Based on gcc/config/rs6000/crtsavres.asm from gcc
> + *
> + * This file is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2, or (at your option) any
> + * later version.
> + *
> + * In addition to the permissions in the GNU General Public License, the
> + * Free Software Foundation gives you unlimited permission to link the
> + * compiled version of this file with other programs, and to distribute
> + * those programs without any restriction coming from the use of this
> + * file.  (The General Public License restrictions do apply in other
> + * respects; for example, they cover modification of the file, and
> + * distribution when not linked into another program.)
> + *
> + * This file is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; see the file COPYING.  If not, write to
> + * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
> + * Boston, MA 02110-1301, USA.
> + *
> + *    As a special exception, if you link this library with files
> + *    compiled with GCC to produce an executable, this does not cause
> + *    the resulting executable to be covered by the GNU General Public License.
> + *    This exception does not however invalidate any other reasons why
> + *    the executable file might be covered by the GNU General Public License.
> + */
> +#include "config.h"
> +
> +#define _GLOBAL(name) \
> +	.type name, at function; \
> +	.globl name; \
> +name:
> +
> +/* Routines for saving integer registers, called by the compiler.  */
> +/* Called with r11 pointing to the stack header word of the caller of the */
> +/* function, just beyond the end of the integer save area.  */
> +
> +_GLOBAL(_savegpr_14)
> +_GLOBAL(_save32gpr_14)
> +	stw	14,-72(11)	/* save gp registers */
> +_GLOBAL(_savegpr_15)
> +_GLOBAL(_save32gpr_15)
> +	stw	15,-68(11)
> +_GLOBAL(_savegpr_16)
> +_GLOBAL(_save32gpr_16)
> +	stw	16,-64(11)
> +_GLOBAL(_savegpr_17)
> +_GLOBAL(_save32gpr_17)
> +	stw	17,-60(11)
> +_GLOBAL(_savegpr_18)
> +_GLOBAL(_save32gpr_18)
> +	stw	18,-56(11)
> +_GLOBAL(_savegpr_19)
> +_GLOBAL(_save32gpr_19)
> +	stw	19,-52(11)
> +_GLOBAL(_savegpr_20)
> +_GLOBAL(_save32gpr_20)
> +	stw	20,-48(11)
> +_GLOBAL(_savegpr_21)
> +_GLOBAL(_save32gpr_21)
> +	stw	21,-44(11)
> +_GLOBAL(_savegpr_22)
> +_GLOBAL(_save32gpr_22)
> +	stw	22,-40(11)
> +_GLOBAL(_savegpr_23)
> +_GLOBAL(_save32gpr_23)
> +	stw	23,-36(11)
> +_GLOBAL(_savegpr_24)
> +_GLOBAL(_save32gpr_24)
> +	stw	24,-32(11)
> +_GLOBAL(_savegpr_25)
> +_GLOBAL(_save32gpr_25)
> +	stw	25,-28(11)
> +_GLOBAL(_savegpr_26)
> +_GLOBAL(_save32gpr_26)
> +	stw	26,-24(11)
> +_GLOBAL(_savegpr_27)
> +_GLOBAL(_save32gpr_27)
> +	stw	27,-20(11)
> +_GLOBAL(_savegpr_28)
> +_GLOBAL(_save32gpr_28)
> +	stw	28,-16(11)
> +_GLOBAL(_savegpr_29)
> +_GLOBAL(_save32gpr_29)
> +	stw	29,-12(11)
> +_GLOBAL(_savegpr_30)
> +_GLOBAL(_save32gpr_30)
> +	stw	30,-8(11)
> +_GLOBAL(_savegpr_31)
> +_GLOBAL(_save32gpr_31)
> +	stw	31,-4(11)
> +	blr
> +
> +/* Routines for restoring integer registers, called by the compiler.  */
> +/* Called with r11 pointing to the stack header word of the caller of the */
> +/* function, just beyond the end of the integer restore area.  */
> +
> +_GLOBAL(_restgpr_14)
> +_GLOBAL(_rest32gpr_14)
> +	lwz	14,-72(11)	/* restore gp registers */
> +_GLOBAL(_restgpr_15)
> +_GLOBAL(_rest32gpr_15)
> +	lwz	15,-68(11)
> +_GLOBAL(_restgpr_16)
> +_GLOBAL(_rest32gpr_16)
> +	lwz	16,-64(11)
> +_GLOBAL(_restgpr_17)
> +_GLOBAL(_rest32gpr_17)
> +	lwz	17,-60(11)
> +_GLOBAL(_restgpr_18)
> +_GLOBAL(_rest32gpr_18)
> +	lwz	18,-56(11)
> +_GLOBAL(_restgpr_19)
> +_GLOBAL(_rest32gpr_19)
> +	lwz	19,-52(11)
> +_GLOBAL(_restgpr_20)
> +_GLOBAL(_rest32gpr_20)
> +	lwz	20,-48(11)
> +_GLOBAL(_restgpr_21)
> +_GLOBAL(_rest32gpr_21)
> +	lwz	21,-44(11)
> +_GLOBAL(_restgpr_22)
> +_GLOBAL(_rest32gpr_22)
> +	lwz	22,-40(11)
> +_GLOBAL(_restgpr_23)
> +_GLOBAL(_rest32gpr_23)
> +	lwz	23,-36(11)
> +_GLOBAL(_restgpr_24)
> +_GLOBAL(_rest32gpr_24)
> +	lwz	24,-32(11)
> +_GLOBAL(_restgpr_25)
> +_GLOBAL(_rest32gpr_25)
> +	lwz	25,-28(11)
> +_GLOBAL(_restgpr_26)
> +_GLOBAL(_rest32gpr_26)
> +	lwz	26,-24(11)
> +_GLOBAL(_restgpr_27)
> +_GLOBAL(_rest32gpr_27)
> +	lwz	27,-20(11)
> +_GLOBAL(_restgpr_28)
> +_GLOBAL(_rest32gpr_28)
> +	lwz	28,-16(11)
> +_GLOBAL(_restgpr_29)
> +_GLOBAL(_rest32gpr_29)
> +	lwz	29,-12(11)
> +_GLOBAL(_restgpr_30)
> +_GLOBAL(_rest32gpr_30)
> +	lwz	30,-8(11)
> +_GLOBAL(_restgpr_31)
> +_GLOBAL(_rest32gpr_31)
> +	lwz	31,-4(11)
> +	blr
> +
> +/* Routines for restoring integer registers, called by the compiler.  */
> +/* Called with r11 pointing to the stack header word of the caller of the */
> +/* function, just beyond the end of the integer restore area.  */
> +
> +_GLOBAL(_restgpr_14_x)
> +_GLOBAL(_rest32gpr_14_x)
> +	lwz	14,-72(11)	/* restore gp registers */
> +_GLOBAL(_restgpr_15_x)
> +_GLOBAL(_rest32gpr_15_x)
> +	lwz	15,-68(11)
> +_GLOBAL(_restgpr_16_x)
> +_GLOBAL(_rest32gpr_16_x)
> +	lwz	16,-64(11)
> +_GLOBAL(_restgpr_17_x)
> +_GLOBAL(_rest32gpr_17_x)
> +	lwz	17,-60(11)
> +_GLOBAL(_restgpr_18_x)
> +_GLOBAL(_rest32gpr_18_x)
> +	lwz	18,-56(11)
> +_GLOBAL(_restgpr_19_x)
> +_GLOBAL(_rest32gpr_19_x)
> +	lwz	19,-52(11)
> +_GLOBAL(_restgpr_20_x)
> +_GLOBAL(_rest32gpr_20_x)
> +	lwz	20,-48(11)
> +_GLOBAL(_restgpr_21_x)
> +_GLOBAL(_rest32gpr_21_x)
> +	lwz	21,-44(11)
> +_GLOBAL(_restgpr_22_x)
> +_GLOBAL(_rest32gpr_22_x)
> +	lwz	22,-40(11)
> +_GLOBAL(_restgpr_23_x)
> +_GLOBAL(_rest32gpr_23_x)
> +	lwz	23,-36(11)
> +_GLOBAL(_restgpr_24_x)
> +_GLOBAL(_rest32gpr_24_x)
> +	lwz	24,-32(11)
> +_GLOBAL(_restgpr_25_x)
> +_GLOBAL(_rest32gpr_25_x)
> +	lwz	25,-28(11)
> +_GLOBAL(_restgpr_26_x)
> +_GLOBAL(_rest32gpr_26_x)
> +	lwz	26,-24(11)
> +_GLOBAL(_restgpr_27_x)
> +_GLOBAL(_rest32gpr_27_x)
> +	lwz	27,-20(11)
> +_GLOBAL(_restgpr_28_x)
> +_GLOBAL(_rest32gpr_28_x)
> +	lwz	28,-16(11)
> +_GLOBAL(_restgpr_29_x)
> +_GLOBAL(_rest32gpr_29_x)
> +	lwz	29,-12(11)
> +_GLOBAL(_restgpr_30_x)
> +_GLOBAL(_rest32gpr_30_x)
> +	lwz	30,-8(11)
> +_GLOBAL(_restgpr_31_x)
> +_GLOBAL(_rest32gpr_31_x)
> +	lwz	0,4(11)
> +	lwz	31,-4(11)
> +	mtlr	0
> +	mr	1,11
> +	blr
> +
>  	.text
>  
>  /*
> 
> 
> Best regards,
> Maxim Uvarov.
> 
> 
>