74e081797b
CONFIG_DEBUG_RODATA chops the large pages spanning boundaries of kernel text/rodata/data to small 4KB pages as they are mapped with different attributes (text as RO, RODATA as RO and NX etc). On x86_64, preserve the large page mappings for kernel text/rodata/data boundaries when CONFIG_DEBUG_RODATA is enabled. This is done by allowing the RODATA section to be hugepage aligned and having same RWX attributes for the 2MB page boundaries Extra Memory pages padding the sections will be freed during the end of the boot and the kernel identity mappings will have different RWX permissions compared to the kernel text mappings. Kernel identity mappings to these physical pages will be mapped with smaller pages but large page mappings are still retained for kernel text,rodata,data mappings. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <20091014220254.190119924@sbs-t61.sc.intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
356 lines
7.6 KiB
ArmAsm
356 lines
7.6 KiB
ArmAsm
/*
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* ld script for the x86 kernel
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*
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* Historic 32-bit version written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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*
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* Modernisation, unification and other changes and fixes:
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* Copyright (C) 2007-2009 Sam Ravnborg <sam@ravnborg.org>
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*
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*
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* Don't define absolute symbols until and unless you know that symbol
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* value is should remain constant even if kernel image is relocated
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* at run time. Absolute symbols are not relocated. If symbol value should
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* change if kernel is relocated, make the symbol section relative and
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* put it inside the section definition.
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*/
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#ifdef CONFIG_X86_32
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#define LOAD_OFFSET __PAGE_OFFSET
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#else
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#define LOAD_OFFSET __START_KERNEL_map
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#endif
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#include <asm-generic/vmlinux.lds.h>
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#include <asm/asm-offsets.h>
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#include <asm/thread_info.h>
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#include <asm/page_types.h>
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#include <asm/cache.h>
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#include <asm/boot.h>
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#undef i386 /* in case the preprocessor is a 32bit one */
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OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT)
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#ifdef CONFIG_X86_32
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OUTPUT_ARCH(i386)
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ENTRY(phys_startup_32)
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jiffies = jiffies_64;
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#else
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OUTPUT_ARCH(i386:x86-64)
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ENTRY(phys_startup_64)
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jiffies_64 = jiffies;
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#endif
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#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
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#define X64_ALIGN_DEBUG_RODATA_BEGIN . = ALIGN(HPAGE_SIZE);
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#define X64_ALIGN_DEBUG_RODATA_END \
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. = ALIGN(HPAGE_SIZE); \
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__end_rodata_hpage_align = .;
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#else
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#define X64_ALIGN_DEBUG_RODATA_BEGIN
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#define X64_ALIGN_DEBUG_RODATA_END
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#endif
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PHDRS {
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text PT_LOAD FLAGS(5); /* R_E */
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data PT_LOAD FLAGS(7); /* RWE */
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#ifdef CONFIG_X86_64
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user PT_LOAD FLAGS(5); /* R_E */
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#ifdef CONFIG_SMP
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percpu PT_LOAD FLAGS(6); /* RW_ */
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#endif
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init PT_LOAD FLAGS(7); /* RWE */
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#endif
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note PT_NOTE FLAGS(0); /* ___ */
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}
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SECTIONS
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{
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#ifdef CONFIG_X86_32
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. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
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phys_startup_32 = startup_32 - LOAD_OFFSET;
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#else
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. = __START_KERNEL;
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phys_startup_64 = startup_64 - LOAD_OFFSET;
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#endif
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/* Text and read-only data */
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.text : AT(ADDR(.text) - LOAD_OFFSET) {
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_text = .;
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/* bootstrapping code */
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HEAD_TEXT
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#ifdef CONFIG_X86_32
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. = ALIGN(PAGE_SIZE);
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*(.text.page_aligned)
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#endif
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. = ALIGN(8);
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_stext = .;
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TEXT_TEXT
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SCHED_TEXT
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LOCK_TEXT
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KPROBES_TEXT
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IRQENTRY_TEXT
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*(.fixup)
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*(.gnu.warning)
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/* End of text section */
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_etext = .;
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} :text = 0x9090
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NOTES :text :note
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EXCEPTION_TABLE(16) :text = 0x9090
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X64_ALIGN_DEBUG_RODATA_BEGIN
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RO_DATA(PAGE_SIZE)
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X64_ALIGN_DEBUG_RODATA_END
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/* Data */
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.data : AT(ADDR(.data) - LOAD_OFFSET) {
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/* Start of data section */
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_sdata = .;
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/* init_task */
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INIT_TASK_DATA(THREAD_SIZE)
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#ifdef CONFIG_X86_32
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/* 32 bit has nosave before _edata */
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NOSAVE_DATA
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#endif
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PAGE_ALIGNED_DATA(PAGE_SIZE)
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CACHELINE_ALIGNED_DATA(CONFIG_X86_L1_CACHE_BYTES)
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DATA_DATA
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CONSTRUCTORS
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/* rarely changed data like cpu maps */
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READ_MOSTLY_DATA(CONFIG_X86_INTERNODE_CACHE_BYTES)
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/* End of data section */
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_edata = .;
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} :data
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#ifdef CONFIG_X86_64
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#define VSYSCALL_ADDR (-10*1024*1024)
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#define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET)
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#define VLOAD(x) (ADDR(x) - VLOAD_OFFSET)
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#define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0)
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#define VVIRT(x) (ADDR(x) - VVIRT_OFFSET)
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. = ALIGN(4096);
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__vsyscall_0 = .;
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. = VSYSCALL_ADDR;
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.vsyscall_0 : AT(VLOAD(.vsyscall_0)) {
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*(.vsyscall_0)
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} :user
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. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
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.vsyscall_fn : AT(VLOAD(.vsyscall_fn)) {
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*(.vsyscall_fn)
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}
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. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
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.vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data)) {
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*(.vsyscall_gtod_data)
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}
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vsyscall_gtod_data = VVIRT(.vsyscall_gtod_data);
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.vsyscall_clock : AT(VLOAD(.vsyscall_clock)) {
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*(.vsyscall_clock)
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}
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vsyscall_clock = VVIRT(.vsyscall_clock);
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.vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) {
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*(.vsyscall_1)
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}
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.vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) {
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*(.vsyscall_2)
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}
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.vgetcpu_mode : AT(VLOAD(.vgetcpu_mode)) {
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*(.vgetcpu_mode)
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}
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vgetcpu_mode = VVIRT(.vgetcpu_mode);
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. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
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.jiffies : AT(VLOAD(.jiffies)) {
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*(.jiffies)
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}
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jiffies = VVIRT(.jiffies);
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.vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) {
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*(.vsyscall_3)
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}
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. = __vsyscall_0 + PAGE_SIZE;
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#undef VSYSCALL_ADDR
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#undef VLOAD_OFFSET
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#undef VLOAD
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#undef VVIRT_OFFSET
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#undef VVIRT
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#endif /* CONFIG_X86_64 */
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/* Init code and data - will be freed after init */
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. = ALIGN(PAGE_SIZE);
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.init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) {
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__init_begin = .; /* paired with __init_end */
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}
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#if defined(CONFIG_X86_64) && defined(CONFIG_SMP)
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/*
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* percpu offsets are zero-based on SMP. PERCPU_VADDR() changes the
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* output PHDR, so the next output section - .init.text - should
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* start another segment - init.
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*/
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PERCPU_VADDR(0, :percpu)
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#endif
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INIT_TEXT_SECTION(PAGE_SIZE)
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#ifdef CONFIG_X86_64
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:init
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#endif
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INIT_DATA_SECTION(16)
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.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
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__x86_cpu_dev_start = .;
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*(.x86_cpu_dev.init)
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__x86_cpu_dev_end = .;
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}
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. = ALIGN(8);
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.parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
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__parainstructions = .;
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*(.parainstructions)
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__parainstructions_end = .;
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}
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. = ALIGN(8);
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.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
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__alt_instructions = .;
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*(.altinstructions)
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__alt_instructions_end = .;
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}
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.altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
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*(.altinstr_replacement)
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}
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/*
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* .exit.text is discard at runtime, not link time, to deal with
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* references from .altinstructions and .eh_frame
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*/
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.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
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EXIT_TEXT
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}
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.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
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EXIT_DATA
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}
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#if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
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PERCPU(PAGE_SIZE)
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#endif
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. = ALIGN(PAGE_SIZE);
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/* freed after init ends here */
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.init.end : AT(ADDR(.init.end) - LOAD_OFFSET) {
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__init_end = .;
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}
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/*
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* smp_locks might be freed after init
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* start/end must be page aligned
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*/
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. = ALIGN(PAGE_SIZE);
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.smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
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__smp_locks = .;
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*(.smp_locks)
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__smp_locks_end = .;
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. = ALIGN(PAGE_SIZE);
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}
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#ifdef CONFIG_X86_64
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.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
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NOSAVE_DATA
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}
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#endif
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/* BSS */
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. = ALIGN(PAGE_SIZE);
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.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
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__bss_start = .;
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*(.bss.page_aligned)
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*(.bss)
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. = ALIGN(4);
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__bss_stop = .;
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}
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. = ALIGN(PAGE_SIZE);
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.brk : AT(ADDR(.brk) - LOAD_OFFSET) {
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__brk_base = .;
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. += 64 * 1024; /* 64k alignment slop space */
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*(.brk_reservation) /* areas brk users have reserved */
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__brk_limit = .;
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}
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.end : AT(ADDR(.end) - LOAD_OFFSET) {
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_end = .;
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}
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STABS_DEBUG
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DWARF_DEBUG
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/* Sections to be discarded */
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DISCARDS
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/DISCARD/ : { *(.eh_frame) }
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}
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#ifdef CONFIG_X86_32
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. = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE),
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"kernel image bigger than KERNEL_IMAGE_SIZE");
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#else
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/*
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* Per-cpu symbols which need to be offset from __per_cpu_load
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* for the boot processor.
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*/
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#define INIT_PER_CPU(x) init_per_cpu__##x = per_cpu__##x + __per_cpu_load
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INIT_PER_CPU(gdt_page);
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INIT_PER_CPU(irq_stack_union);
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/*
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* Build-time check on the image size:
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*/
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. = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
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"kernel image bigger than KERNEL_IMAGE_SIZE");
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#ifdef CONFIG_SMP
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. = ASSERT((per_cpu__irq_stack_union == 0),
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"irq_stack_union is not at start of per-cpu area");
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#endif
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#endif /* CONFIG_X86_32 */
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#ifdef CONFIG_KEXEC
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#include <asm/kexec.h>
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. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
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"kexec control code size is too big");
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#endif
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