linux/arch/parisc/kernel/vmlinux.lds.S
Helge Deller 161bd3bf60 parisc: fix kernel memory layout in vmlinux.ld.S
When building a 64bit kernel sometimes functions in the .init section were not
able to reach the standard kernel function. Main reason for this problem is,
that the linkage tables (.plt, .opd, .dlt) tend to become pretty huge and thus
the distance gets too big for short calls.

One option to avoid this is to use the -mlong-calls compiler option, but this
increases the binary size and introduces a performance penalty.

Instead, with this patch we just lay out the binary differently.  Init code is
stored first, followed by text, R/O and finally R/W data. This means, that init
and text code is now much closer to each other, which is sufficient to reach
each other by short calls.

Signed-off-by: Helge Deller <deller@gmx.de>
2013-11-30 22:09:21 +01:00

161 lines
3.1 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) 2006-2013 Helge Deller <deller@gmx.de>
*/
/*
* Put page table entries (swapper_pg_dir) as the first thing in .bss. This
* will ensure that it has .bss alignment (PAGE_SIZE).
*/
#define BSS_FIRST_SECTIONS *(.data..vm0.pmd) \
*(.data..vm0.pgd) \
*(.data..vm0.pte)
#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>
#include <asm/thread_info.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(parisc_kernel_start)
#ifndef CONFIG_64BIT
jiffies = jiffies_64 + 4;
#else
jiffies = jiffies_64;
#endif
SECTIONS
{
. = KERNEL_BINARY_TEXT_START;
__init_begin = .;
HEAD_TEXT_SECTION
INIT_TEXT_SECTION(8)
. = ALIGN(PAGE_SIZE);
INIT_DATA_SECTION(PAGE_SIZE)
/* we have to discard exit text and such at runtime, not link time */
.exit.text :
{
EXIT_TEXT
}
.exit.data :
{
EXIT_DATA
}
PERCPU_SECTION(8)
. = ALIGN(PAGE_SIZE);
__init_end = .;
/* freed after init ends here */
_text = .; /* Text and read-only data */
_stext = .;
.text ALIGN(PAGE_SIZE) : {
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
*(.text.do_softirq)
*(.text.sys_exit)
*(.text.do_sigaltstack)
*(.text.do_fork)
*(.text.*)
*(.fixup)
*(.lock.text) /* out-of-line lock text */
*(.gnu.warning)
}
. = ALIGN(PAGE_SIZE);
_etext = .;
/* End of text section */
/* Start of data section */
_sdata = .;
RO_DATA_SECTION(8)
#ifdef CONFIG_64BIT
. = ALIGN(16);
/* Linkage tables */
.opd : {
*(.opd)
} PROVIDE (__gp = .);
.plt : {
*(.plt)
}
.dlt : {
*(.dlt)
}
#endif
/* unwind info */
.PARISC.unwind : {
__start___unwind = .;
*(.PARISC.unwind)
__stop___unwind = .;
}
/* writeable */
/* Make sure this is page aligned so
* that we can properly leave these
* as writable
*/
. = ALIGN(PAGE_SIZE);
data_start = .;
EXCEPTION_TABLE(8)
NOTES
/* Data */
RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, PAGE_SIZE)
/* PA-RISC locks requires 16-byte alignment */
. = ALIGN(16);
.data..lock_aligned : {
*(.data..lock_aligned)
}
/* End of data section */
_edata = .;
/* BSS */
BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 8)
_end = . ;
STABS_DEBUG
.note 0 : { *(.note) }
/* Sections to be discarded */
DISCARDS
/DISCARD/ : {
#ifdef CONFIG_64BIT
/* temporary hack until binutils is fixed to not emit these
* for static binaries
*/
*(.interp)
*(.dynsym)
*(.dynstr)
*(.dynamic)
*(.hash)
*(.gnu.hash)
#endif
}
}