kernel-ark/arch/parisc/kernel/vmlinux.lds.S
Fenghua Yu 5fb7dc37dc define new percpu interface for shared data
per cpu data section contains two types of data.  One set which is
exclusively accessed by the local cpu and the other set which is per cpu,
but also shared by remote cpus.  In the current kernel, these two sets are
not clearely separated out.  This can potentially cause the same data
cacheline shared between the two sets of data, which will result in
unnecessary bouncing of the cacheline between cpus.

One way to fix the problem is to cacheline align the remotely accessed per
cpu data, both at the beginning and at the end.  Because of the padding at
both ends, this will likely cause some memory wastage and also the
interface to achieve this is not clean.

This patch:

Moves the remotely accessed per cpu data (which is currently marked
as ____cacheline_aligned_in_smp) into a different section, where all the data
elements are cacheline aligned. And as such, this differentiates the local
only data and remotely accessed data cleanly.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:44 -07:00

212 lines
5.5 KiB
ArmAsm

/* Kernel link layout for various "sections"
*
* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
* Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
* Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
* Copyright (C) 2003 James Bottomley <jejb with parisc-linux.org>
* Copyright (C) 2006 Helge Deller <deller@gmx.de>
*
*
* This program 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 of the License, or
* (at your option) any later version.
*
* This program 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; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <asm-generic/vmlinux.lds.h>
/* needed for the processor specific cache alignment size */
#include <asm/cache.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
/* ld script to make hppa Linux kernel */
#ifndef CONFIG_64BIT
OUTPUT_FORMAT("elf32-hppa-linux")
OUTPUT_ARCH(hppa)
#else
OUTPUT_FORMAT("elf64-hppa-linux")
OUTPUT_ARCH(hppa:hppa2.0w)
#endif
ENTRY(_stext)
#ifndef CONFIG_64BIT
jiffies = jiffies_64 + 4;
#else
jiffies = jiffies_64;
#endif
SECTIONS
{
. = KERNEL_BINARY_TEXT_START;
_text = .; /* Text and read-only data */
.text ALIGN(16) : {
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
*(.text.do_softirq)
*(.text.sys_exit)
*(.text.do_sigaltstack)
*(.text.do_fork)
*(.text.*)
*(.fixup)
*(.lock.text) /* out-of-line lock text */
*(.gnu.warning)
} = 0
_etext = .; /* End of text section */
RODATA
BUG_TABLE
/* writeable */
. = ALIGN(ASM_PAGE_SIZE); /* Make sure this is page aligned so
that we can properly leave these
as writable */
data_start = .;
. = ALIGN(16); /* Exception table */
__start___ex_table = .;
__ex_table : { *(__ex_table) }
__stop___ex_table = .;
__start___unwind = .; /* unwind info */
.PARISC.unwind : { *(.PARISC.unwind) }
__stop___unwind = .;
/* rarely changed data like cpu maps */
. = ALIGN(16);
.data.read_mostly : { *(.data.read_mostly) }
. = ALIGN(L1_CACHE_BYTES);
.data : { /* Data */
DATA_DATA
CONSTRUCTORS
}
. = ALIGN(L1_CACHE_BYTES);
.data.cacheline_aligned : { *(.data.cacheline_aligned) }
/* PA-RISC locks requires 16-byte alignment */
. = ALIGN(16);
.data.lock_aligned : { *(.data.lock_aligned) }
. = ALIGN(ASM_PAGE_SIZE);
/* nosave data is really only used for software suspend...it's here
* just in case we ever implement it */
__nosave_begin = .;
.data_nosave : { *(.data.nosave) }
. = ALIGN(ASM_PAGE_SIZE);
__nosave_end = .;
_edata = .; /* End of data section */
__bss_start = .; /* BSS */
/* page table entries need to be PAGE_SIZE aligned */
. = ALIGN(ASM_PAGE_SIZE);
.data.vmpages : {
*(.data.vm0.pmd)
*(.data.vm0.pgd)
*(.data.vm0.pte)
}
.bss : { *(.bss) *(COMMON) }
__bss_stop = .;
/* assembler code expects init_task to be 16k aligned */
. = ALIGN(16384); /* init_task */
.data.init_task : { *(.data.init_task) }
/* The interrupt stack is currently partially coded, but not yet
* implemented */
. = ALIGN(16384);
init_istack : { *(init_istack) }
#ifdef CONFIG_64BIT
. = ALIGN(16); /* Linkage tables */
.opd : { *(.opd) } PROVIDE (__gp = .);
.plt : { *(.plt) }
.dlt : { *(.dlt) }
#endif
/* reserve space for interrupt stack by aligning __init* to 16k */
. = ALIGN(16384);
__init_begin = .;
.init.text : {
_sinittext = .;
*(.init.text)
_einittext = .;
}
.init.data : { *(.init.data) }
. = ALIGN(16);
__setup_start = .;
.init.setup : { *(.init.setup) }
__setup_end = .;
__initcall_start = .;
.initcall.init : {
INITCALLS
}
__initcall_end = .;
__con_initcall_start = .;
.con_initcall.init : { *(.con_initcall.init) }
__con_initcall_end = .;
SECURITY_INIT
/* alternate instruction replacement. This is a mechanism x86 uses
* to detect the CPU type and replace generic instruction sequences
* with CPU specific ones. We don't currently do this in PA, but
* it seems like a good idea... */
. = ALIGN(4);
__alt_instructions = .;
.altinstructions : { *(.altinstructions) }
__alt_instructions_end = .;
.altinstr_replacement : { *(.altinstr_replacement) }
/* .exit.text is discard at runtime, not link time, to deal with references
from .altinstructions and .eh_frame */
.exit.text : { *(.exit.text) }
.exit.data : { *(.exit.data) }
#ifdef CONFIG_BLK_DEV_INITRD
. = ALIGN(ASM_PAGE_SIZE);
__initramfs_start = .;
.init.ramfs : { *(.init.ramfs) }
__initramfs_end = .;
#endif
PERCPU(ASM_PAGE_SIZE)
. = ALIGN(ASM_PAGE_SIZE);
__init_end = .;
/* freed after init ends here */
_end = . ;
/* Sections to be discarded */
/DISCARD/ : {
*(.exitcall.exit)
#ifdef CONFIG_64BIT
/* temporary hack until binutils is fixed to not emit these
for static binaries */
*(.interp)
*(.dynsym)
*(.dynstr)
*(.dynamic)
*(.hash)
*(.gnu.hash)
#endif
}
STABS_DEBUG
.note 0 : { *(.note) }
}