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linux/arch/xtensa/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

318 lines
7.6 KiB
ArmAsm

/*
* arch/xtensa/kernel/vmlinux.lds.S
*
* Xtensa linker script
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2005 Tensilica Inc.
*
* Chris Zankel <chris@zankel.net>
* Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca>
* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
*/
#include <asm-generic/vmlinux.lds.h>
#include <asm/variant/core.h>
OUTPUT_ARCH(xtensa)
ENTRY(_start)
#ifdef __XTENSA_EB__
jiffies = jiffies_64 + 4;
#else
jiffies = jiffies_64;
#endif
#define KERNELOFFSET 0xd0001000
/* Note: In the following macros, it would be nice to specify only the
vector name and section kind and construct "sym" and "section" using
CPP concatenation, but that does not work reliably. Concatenating a
string with "." produces an invalid token. CPP will not print a
warning because it thinks this is an assembly file, but it leaves
them as multiple tokens and there may or may not be whitespace
between them. */
/* Macro for a relocation entry */
#define RELOCATE_ENTRY(sym, section) \
LONG(sym ## _start); \
LONG(sym ## _end); \
LONG(LOADADDR(section))
/* Macro to define a section for a vector.
*
* Use of the MIN function catches the types of errors illustrated in
* the following example:
*
* Assume the section .DoubleExceptionVector.literal is completely
* full. Then a programmer adds code to .DoubleExceptionVector.text
* that produces another literal. The final literal position will
* overlay onto the first word of the adjacent code section
* .DoubleExceptionVector.text. (In practice, the literals will
* overwrite the code, and the first few instructions will be
* garbage.)
*/
#define SECTION_VECTOR(sym, section, addr, max_prevsec_size, prevsec) \
section addr : AT((MIN(LOADADDR(prevsec) + max_prevsec_size, \
LOADADDR(prevsec) + SIZEOF(prevsec)) + 3) & ~ 3) \
{ \
. = ALIGN(4); \
sym ## _start = ABSOLUTE(.); \
*(section) \
sym ## _end = ABSOLUTE(.); \
}
/*
* Mapping of input sections to output sections when linking.
*/
SECTIONS
{
. = KERNELOFFSET;
/* .text section */
_text = .;
_stext = .;
_ftext = .;
.text :
{
/* The .head.text section must be the first section! */
*(.head.text)
*(.literal .text)
VMLINUX_SYMBOL(__sched_text_start) = .;
*(.sched.literal .sched.text)
VMLINUX_SYMBOL(__sched_text_end) = .;
VMLINUX_SYMBOL(__lock_text_start) = .;
*(.spinlock.literal .spinlock.text)
VMLINUX_SYMBOL(__lock_text_end) = .;
}
_etext = .;
PROVIDE (etext = .);
. = ALIGN(16);
RODATA
/* Relocation table */
.fixup : { *(.fixup) }
. = ALIGN(16);
__ex_table : {
__start___ex_table = .;
*(__ex_table)
__stop___ex_table = .;
}
/* Data section */
. = ALIGN(XCHAL_ICACHE_LINESIZE);
_fdata = .;
.data :
{
*(.data) CONSTRUCTORS
. = ALIGN(XCHAL_ICACHE_LINESIZE);
*(.data.cacheline_aligned)
}
_edata = .;
/* The initial task */
. = ALIGN(8192);
.data.init_task : { *(.data.init_task) }
/* Initialization code and data: */
. = ALIGN(1 << 12);
__init_begin = .;
.init.text : {
_sinittext = .;
*(.init.literal) *(.init.text)
_einittext = .;
}
.init.data :
{
*(.init.data)
. = ALIGN(0x4);
__tagtable_begin = .;
*(.taglist)
__tagtable_end = .;
. = ALIGN(16);
__boot_reloc_table_start = ABSOLUTE(.);
RELOCATE_ENTRY(_WindowVectors_text,
.WindowVectors.text);
RELOCATE_ENTRY(_KernelExceptionVector_text,
.KernelExceptionVector.text);
RELOCATE_ENTRY(_UserExceptionVector_text,
.UserExceptionVector.text);
RELOCATE_ENTRY(_DoubleExceptionVector_literal,
.DoubleExceptionVector.literal);
RELOCATE_ENTRY(_DoubleExceptionVector_text,
.DoubleExceptionVector.text);
__boot_reloc_table_end = ABSOLUTE(.) ;
}
. = ALIGN(XCHAL_ICACHE_LINESIZE);
__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
#ifdef CONFIG_BLK_DEV_INITRD
. = ALIGN(4096);
__initramfs_start =.;
.init.ramfs : { *(.init.ramfs) }
__initramfs_end = .;
#endif
PERCPU(4096)
/* We need this dummy segment here */
. = ALIGN(4);
.dummy : { LONG(0) }
/* The vectors are relocated to the real position at startup time */
SECTION_VECTOR (_WindowVectors_text,
.WindowVectors.text,
XCHAL_WINDOW_VECTORS_VADDR, 4,
.dummy)
SECTION_VECTOR (_DebugInterruptVector_literal,
.DebugInterruptVector.literal,
XCHAL_DEBUG_VECTOR_VADDR - 4,
SIZEOF(.WindowVectors.text),
.WindowVectors.text)
SECTION_VECTOR (_DebugInterruptVector_text,
.DebugInterruptVector.text,
XCHAL_DEBUG_VECTOR_VADDR,
4,
.DebugInterruptVector.literal)
SECTION_VECTOR (_KernelExceptionVector_literal,
.KernelExceptionVector.literal,
XCHAL_KERNEL_VECTOR_VADDR - 4,
SIZEOF(.DebugInterruptVector.text),
.DebugInterruptVector.text)
SECTION_VECTOR (_KernelExceptionVector_text,
.KernelExceptionVector.text,
XCHAL_KERNEL_VECTOR_VADDR,
4,
.KernelExceptionVector.literal)
SECTION_VECTOR (_UserExceptionVector_literal,
.UserExceptionVector.literal,
XCHAL_USER_VECTOR_VADDR - 4,
SIZEOF(.KernelExceptionVector.text),
.KernelExceptionVector.text)
SECTION_VECTOR (_UserExceptionVector_text,
.UserExceptionVector.text,
XCHAL_USER_VECTOR_VADDR,
4,
.UserExceptionVector.literal)
SECTION_VECTOR (_DoubleExceptionVector_literal,
.DoubleExceptionVector.literal,
XCHAL_DOUBLEEXC_VECTOR_VADDR - 16,
SIZEOF(.UserExceptionVector.text),
.UserExceptionVector.text)
SECTION_VECTOR (_DoubleExceptionVector_text,
.DoubleExceptionVector.text,
XCHAL_DOUBLEEXC_VECTOR_VADDR,
32,
.DoubleExceptionVector.literal)
. = (LOADADDR( .DoubleExceptionVector.text ) + SIZEOF( .DoubleExceptionVector.text ) + 3) & ~ 3;
. = ALIGN(1 << 12);
__init_end = .;
. = ALIGN(8192);
/* BSS section */
_bss_start = .;
.bss : { *(.bss.page_aligned) *(.bss) }
_bss_end = .;
_end = .;
/* only used by the boot loader */
. = ALIGN(0x10);
.bootstrap : { *(.bootstrap.literal .bootstrap.text .bootstrap.data) }
. = ALIGN(0x1000);
__initrd_start = .;
.initrd : { *(.initrd) }
__initrd_end = .;
.ResetVector.text XCHAL_RESET_VECTOR_VADDR :
{
*(.ResetVector.text)
}
/* Sections to be discarded */
/DISCARD/ :
{
*(.exit.literal .exit.text)
*(.exit.data)
*(.exitcall.exit)
}
.xt.lit : { *(.xt.lit) }
.xt.prop : { *(.xt.prop) }
.debug 0 : { *(.debug) }
.line 0 : { *(.line) }
.debug_srcinfo 0 : { *(.debug_srcinfo) }
.debug_sfnames 0 : { *(.debug_sfnames) }
.debug_aranges 0 : { *(.debug_aranges) }
.debug_pubnames 0 : { *(.debug_pubnames) }
.debug_info 0 : { *(.debug_info) }
.debug_abbrev 0 : { *(.debug_abbrev) }
.debug_line 0 : { *(.debug_line) }
.debug_frame 0 : { *(.debug_frame) }
.debug_str 0 : { *(.debug_str) }
.debug_loc 0 : { *(.debug_loc) }
.debug_macinfo 0 : { *(.debug_macinfo) }
.debug_weaknames 0 : { *(.debug_weaknames) }
.debug_funcnames 0 : { *(.debug_funcnames) }
.debug_typenames 0 : { *(.debug_typenames) }
.debug_varnames 0 : { *(.debug_varnames) }
.xt.insn 0 :
{
*(.xt.insn)
*(.gnu.linkonce.x*)
}
.xt.lit 0 :
{
*(.xt.lit)
*(.gnu.linkonce.p*)
}
}