/*
* ld script for the x86 kernel
*
* Historic 32-bit version written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
*
* Modernisation, unification and other changes and fixes:
* Copyright (C) 2007-2009 Sam Ravnborg <sam@ravnborg.org>
*
*
* Don't define absolute symbols until and unless you know that symbol
* value is should remain constant even if kernel image is relocated
* at run time. Absolute symbols are not relocated. If symbol value should
* change if kernel is relocated, make the symbol section relative and
* put it inside the section definition.
*/
#ifdef CONFIG_X86_32
#define LOAD_OFFSET __PAGE_OFFSET
#else
#define LOAD_OFFSET __START_KERNEL_map
#endif
#include <asm-generic/vmlinux.lds.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page_types.h>
#include <asm/cache.h>
#include <asm/boot.h>
#undef i386 /* in case the preprocessor is a 32bit one */
OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT)
#ifdef CONFIG_X86_32
OUTPUT_ARCH(i386)
ENTRY(phys_startup_32)
jiffies = jiffies_64;
#else
OUTPUT_ARCH(i386:x86-64)
ENTRY(phys_startup_64)
jiffies_64 = jiffies;
#endif
#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
/*
* On 64-bit, align RODATA to 2MB so that even with CONFIG_DEBUG_RODATA
* we retain large page mappings for boundaries spanning kernel text, rodata
* and data sections.
*
* However, kernel identity mappings will have different RWX permissions
* to the pages mapping to text and to the pages padding (which are freed) the
* text section. Hence kernel identity mappings will be broken to smaller
* pages. For 64-bit, kernel text and kernel identity mappings are different,
* so we can enable protection checks that come with CONFIG_DEBUG_RODATA,
* as well as retain 2MB large page mappings for kernel text.
*/
#define X64_ALIGN_DEBUG_RODATA_BEGIN . = ALIGN(HPAGE_SIZE);
#define X64_ALIGN_DEBUG_RODATA_END \
. = ALIGN(HPAGE_SIZE); \
__end_rodata_hpage_align = .;
#else
#define X64_ALIGN_DEBUG_RODATA_BEGIN
#define X64_ALIGN_DEBUG_RODATA_END
#endif
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
data PT_LOAD FLAGS(6); /* RW_ */
#ifdef CONFIG_X86_64
user PT_LOAD FLAGS(5); /* R_E */
#ifdef CONFIG_SMP
percpu PT_LOAD FLAGS(6); /* RW_ */
#endif
init PT_LOAD FLAGS(7); /* RWE */
#endif
note PT_NOTE FLAGS(0); /* ___ */
}
SECTIONS
{
#ifdef CONFIG_X86_32
. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
phys_startup_32 = startup_32 - LOAD_OFFSET;
#else
. = __START_KERNEL;
phys_startup_64 = startup_64 - LOAD_OFFSET;
#endif
/* Text and read-only data */
.text : AT(ADDR(.text) - LOAD_OFFSET) {
_text = .;
/* bootstrapping code */
HEAD_TEXT
#ifdef CONFIG_X86_32
. = ALIGN(PAGE_SIZE);
*(.text..page_aligned)
#endif
. = ALIGN(8);
_stext = .;
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
ENTRY_TEXT
IRQENTRY_TEXT
*(.fixup)
*(.gnu.warning)
/* End of text section */
_etext = .;
} :text = 0x9090
NOTES :text :note
EXCEPTION_TABLE(16) :text = 0x9090
#if defined(CONFIG_DEBUG_RODATA)
/* .text should occupy whole number of pages */
. = ALIGN(PAGE_SIZE);
#endif
X64_ALIGN_DEBUG_RODATA_BEGIN
RO_DATA(PAGE_SIZE)
X64_ALIGN_DEBUG_RODATA_END
/* Data */
.data : AT(ADDR(.data) - LOAD_OFFSET) {
/* Start of data section */
_sdata = .;
/* init_task */
INIT_TASK_DATA(THREAD_SIZE)
#ifdef CONFIG_X86_32
/* 32 bit has nosave before _edata */
NOSAVE_DATA
#endif
PAGE_ALIGNED_DATA(PAGE_SIZE)
CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
DATA_DATA
CONSTRUCTORS
/* rarely changed data like cpu maps */
READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
/* End of data section */
_edata = .;
} :data
#ifdef CONFIG_X86_64
#define VSYSCALL_ADDR (-10*1024*1024)
#define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET)
#define VLOAD(x) (ADDR(x) - VLOAD_OFFSET)
#define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0)
#define VVIRT(x) (ADDR(x) - VVIRT_OFFSET)
#define EMIT_VVAR(x, offset) .vsyscall_var_ ## x \
ADDR(.vsyscall_0) + offset \
: AT(VLOAD(.vsyscall_var_ ## x)) { \
*(.vsyscall_var_ ## x) \
} \
x = VVIRT(.vsyscall_var_ ## x);
. = ALIGN(4096);
__vsyscall_0 = .;
. = VSYSCALL_ADDR;
.vsyscall_0 : AT(VLOAD(.vsyscall_0)) {
*(.vsyscall_0)
} :user
. = ALIGN(L1_CACHE_BYTES);
.vsyscall_fn : AT(VLOAD(.vsyscall_fn)) {
*(.vsyscall_fn)
}
.vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) {
*(.vsyscall_1)
}
.vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) {
*(.vsyscall_2)
}
.vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) {
*(.vsyscall_3)
}
#define __VVAR_KERNEL_LDS
#include <asm/vvar.h>
#undef __VVAR_KERNEL_LDS
. = __vsyscall_0 + PAGE_SIZE;
#undef VSYSCALL_ADDR
#undef VLOAD_OFFSET
#undef VLOAD
#undef VVIRT_OFFSET
#undef VVIRT
#undef EMIT_VVAR
#endif /* CONFIG_X86_64 */
/* Init code and data - will be freed after init */
. = ALIGN(PAGE_SIZE);
.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
__init_begin = .; /* paired with __init_end */
}
#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
/*
* percpu offsets are zero-based on SMP. PERCPU_VADDR() changes the
* output PHDR, so the next output section - .init.text - should
* start another segment - init.
*/
PERCPU_VADDR(INTERNODE_CACHE_BYTES, 0, :percpu)
#endif
INIT_TEXT_SECTION(PAGE_SIZE)
#ifdef CONFIG_X86_64
:init
#endif
INIT_DATA_SECTION(16)
/*
* Code and data for a variety of lowlevel trampolines, to be
* copied into base memory (< 1 MiB) during initialization.
* Since it is copied early, the main copy can be discarded
* afterwards.
*/
.x86_trampoline : AT(ADDR(.x86_trampoline) - LOAD_OFFSET) {
x86_trampoline_start = .;
*(.x86_trampoline)
x86_trampoline_end = .;
}
.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
__x86_cpu_dev_start = .;
*(.x86_cpu_dev.init)
__x86_cpu_dev_end = .;
}
/*
* start address and size of operations which during runtime
* can be patched with virtualization friendly instructions or
* baremetal native ones. Think page table operations.
* Details in paravirt_types.h
*/
. = ALIGN(8);
.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
__parainstructions = .;
*(.parainstructions)
__parainstructions_end = .;
}
/*
* struct alt_inst entries. From the header (alternative.h):
* "Alternative instructions for different CPU types or capabilities"
* Think locking instructions on spinlocks.
*/
. = ALIGN(8);
.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
__alt_instructions = .;
*(.altinstructions)
__alt_instructions_end = .;
}
/*
* And here are the replacement instructions. The linker sticks
* them as binary blobs. The .altinstructions has enough data to
* get the address and the length of them to patch the kernel safely.
*/
.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
*(.altinstr_replacement)
}
/*
* struct iommu_table_entry entries are injected in this section.
* It is an array of IOMMUs which during run time gets sorted depending
* on its dependency order. After rootfs_initcall is complete
* this section can be safely removed.
*/
.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
__iommu_table = .;
*(.iommu_table)
__iommu_table_end = .;
}
. = ALIGN(8);
.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
__apicdrivers = .;
*(.apicdrivers);
__apicdrivers_end = .;
}
. = ALIGN(8);
/*
* .exit.text is discard at runtime, not link time, to deal with
* references from .altinstructions and .eh_frame
*/
.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
EXIT_TEXT
}
.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
EXIT_DATA
}
#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
PERCPU_SECTION(INTERNODE_CACHE_BYTES)
#endif
. = ALIGN(PAGE_SIZE);
/* freed after init ends here */
.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
__init_end = .;
}
/*
* smp_locks might be freed after init
* start/end must be page aligned
*/
. = ALIGN(PAGE_SIZE);
.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
__smp_locks = .;
*(.smp_locks)
. = ALIGN(PAGE_SIZE);
__smp_locks_end = .;
}
#ifdef CONFIG_X86_64
.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
NOSAVE_DATA
}
#endif
/* BSS */
. = ALIGN(PAGE_SIZE);
.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
__bss_start = .;
*(.bss..page_aligned)
*(.bss)
. = ALIGN(PAGE_SIZE);
__bss_stop = .;
}
. = ALIGN(PAGE_SIZE);
.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
__brk_base = .;
. += 64 * 1024; /* 64k alignment slop space */
*(.brk_reservation) /* areas brk users have reserved */
__brk_limit = .;
}
_end = .;
STABS_DEBUG
DWARF_DEBUG
/* Sections to be discarded */
DISCARDS
/DISCARD/ : { *(.eh_frame) }
}
#ifdef CONFIG_X86_32
/*
* The ASSERT() sink to . is intentional, for binutils 2.14 compatibility:
*/
. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
"kernel image bigger than KERNEL_IMAGE_SIZE");
#else
/*
* Per-cpu symbols which need to be offset from __per_cpu_load
* for the boot processor.
*/
#define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load
INIT_PER_CPU(gdt_page);
INIT_PER_CPU(irq_stack_union);
/*
* Build-time check on the image size:
*/
. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
"kernel image bigger than KERNEL_IMAGE_SIZE");
#ifdef CONFIG_SMP
. = ASSERT((irq_stack_union == 0),
"irq_stack_union is not at start of per-cpu area");
#endif
#endif /* CONFIG_X86_32 */
#ifdef CONFIG_KEXEC
#include <asm/kexec.h>
. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
"kexec control code size is too big");
#endif
