kernel-ark/arch/xtensa/kernel/vmlinux.lds.S
Chris Zankel 78f3cdfa2a xtensa: Fix linker script to include .literal sections
Fix resembles implementation from Marc Gauthier and Piet Denaly:

In the Xtensa architecture, assembly generates literals which must always
precede the code (the L32R instruction that loads them only uses negative
PC-relative offsets).  For any *.text section, literals are placed in a
corresponding *.literal section.  The linker script (vmlinux.lds) must
place these in the correct order.  It must also combine them, when the
*.text section can be larger than L32R's 256 kB range.

For example, this doesn't work:  *(.literal) *(.text) because L32R
instructions at the end of .text can't reach the literals.

The linker can solve this if they are combined in parentheses, like this:
       *(.literal .text)
because it is now allowed mix literals in .text to bring them in range.

None of this is done by standard vmlinux.lds.h macros such as TEXT_TEXT
and INIT_TEXT.  To avoid replicating the logic of that header file, we
instead post-process the generated linker script to convert *(xxx.text)
to *(xxx.literal xxx.text) for the following text sections:
       .text .ref.text .*init.text .*exit.text .text.*
using a sed script.  To do this we must override the default rule for
vmlinux.lds (see scripts/Makefile.build and the top-level Makefile)
to insert this extra step.

Signed-off-by: Marc Gauthier <marc@tensilica.com>
Signed-off-by: Pete Delaney <piet@tensilica.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
2009-05-11 23:40:33 -07:00

325 lines
7.7 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 <variant/core.h>
#include <platform/hardware.h>
OUTPUT_ARCH(xtensa)
ENTRY(_start)
#ifdef __XTENSA_EB__
jiffies = jiffies_64 + 4;
#else
jiffies = jiffies_64;
#endif
#ifndef KERNELOFFSET
#define KERNELOFFSET 0xd0001000
#endif
/* 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
TEXT_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_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_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);
RELOCATE_ENTRY(_DebugInterruptVector_text,
.DebugInterruptVector.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*)
}
}