forked from Minki/linux
d924cc3fed
For CONFIG_STRICT_KERNEL_RWX align __init_begin to 16M. We use 16M since its the larger of 2M on radix and 16M on hash for our linear mapping. The plan is to have .text, .rodata and everything upto __init_begin marked as RX. Note we still have executable read only data. We could further align rodata to another 16M boundary. I've used keeping text plus rodata as read-only-executable as a trade-off to doing read-only-executable for text and read-only for rodata. We don't use multi PT_LOAD in PHDRS because we are not sure if all bootloaders support them. This patch keeps PHDRS in vmlinux.lds.S as the same they are with just one PT_LOAD for all of the kernel marked as RWX (7). mpe: What this means is the added alignment bloats the resulting binary on disk, a powernv kernel goes from 17M to 22M. Signed-off-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
345 lines
7.3 KiB
ArmAsm
345 lines
7.3 KiB
ArmAsm
#ifdef CONFIG_PPC64
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#define PROVIDE32(x) PROVIDE(__unused__##x)
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#else
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#define PROVIDE32(x) PROVIDE(x)
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#endif
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#include <asm/page.h>
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#include <asm-generic/vmlinux.lds.h>
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#include <asm/cache.h>
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#include <asm/thread_info.h>
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#ifdef CONFIG_STRICT_KERNEL_RWX
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#define STRICT_ALIGN_SIZE (1 << 24)
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#else
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#define STRICT_ALIGN_SIZE PAGE_SIZE
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#endif
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ENTRY(_stext)
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PHDRS {
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kernel PT_LOAD FLAGS(7); /* RWX */
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notes PT_NOTE FLAGS(0);
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dummy PT_NOTE FLAGS(0);
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/* binutils < 2.18 has a bug that makes it misbehave when taking an
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ELF file with all segments at load address 0 as input. This
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happens when running "strip" on vmlinux, because of the AT() magic
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in this linker script. People using GCC >= 4.2 won't run into
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this problem, because the "build-id" support will put some data
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into the "notes" segment (at a non-zero load address).
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To work around this, we force some data into both the "dummy"
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segment and the kernel segment, so the dummy segment will get a
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non-zero load address. It's not enough to always create the
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"notes" segment, since if nothing gets assigned to it, its load
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address will be zero. */
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}
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#ifdef CONFIG_PPC64
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OUTPUT_ARCH(powerpc:common64)
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jiffies = jiffies_64;
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#else
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OUTPUT_ARCH(powerpc:common)
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jiffies = jiffies_64 + 4;
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#endif
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SECTIONS
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{
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. = KERNELBASE;
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/*
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* Text, read only data and other permanent read-only sections
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*/
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_text = .;
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_stext = .;
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/*
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* Head text.
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* This needs to be in its own output section to avoid ld placing
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* branch trampoline stubs randomly throughout the fixed sections,
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* which it will do (even if the branch comes from another section)
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* in order to optimize stub generation.
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*/
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.head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
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#ifdef CONFIG_PPC64
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KEEP(*(.head.text.first_256B));
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#ifdef CONFIG_PPC_BOOK3E
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#else
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KEEP(*(.head.text.real_vectors));
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*(.head.text.real_trampolines);
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KEEP(*(.head.text.virt_vectors));
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*(.head.text.virt_trampolines);
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# if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
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KEEP(*(.head.data.fwnmi_page));
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# endif
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#endif
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#else /* !CONFIG_PPC64 */
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HEAD_TEXT
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#endif
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} :kernel
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__head_end = .;
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#ifdef CONFIG_PPC64
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/*
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* BLOCK(0) overrides the default output section alignment because
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* this needs to start right after .head.text in order for fixed
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* section placement to work.
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*/
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.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
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#ifdef CONFIG_LD_HEAD_STUB_CATCH
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*(.linker_stub_catch);
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. = . ;
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#endif
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#else
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.text : AT(ADDR(.text) - LOAD_OFFSET) {
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ALIGN_FUNCTION();
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#endif
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/* careful! __ftr_alt_* sections need to be close to .text */
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*(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* .ref.text);
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SCHED_TEXT
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CPUIDLE_TEXT
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LOCK_TEXT
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KPROBES_TEXT
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IRQENTRY_TEXT
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SOFTIRQENTRY_TEXT
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/*
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* -Os builds call FP save/restore functions. The powerpc64
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* linker generates those on demand in the .sfpr section.
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* .sfpr gets placed at the beginning of a group of input
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* sections, which can break start-of-text offset if it is
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* included with the main text sections, so put it by itself.
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*/
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*(.sfpr);
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MEM_KEEP(init.text)
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MEM_KEEP(exit.text)
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#ifdef CONFIG_PPC32
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*(.got1)
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__got2_start = .;
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*(.got2)
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__got2_end = .;
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#endif /* CONFIG_PPC32 */
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} :kernel
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. = ALIGN(PAGE_SIZE);
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_etext = .;
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PROVIDE32 (etext = .);
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/* Read-only data */
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RO_DATA(PAGE_SIZE)
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EXCEPTION_TABLE(0)
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NOTES :kernel :notes
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/* The dummy segment contents for the bug workaround mentioned above
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near PHDRS. */
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.dummy : AT(ADDR(.dummy) - LOAD_OFFSET) {
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LONG(0)
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LONG(0)
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LONG(0)
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} :kernel :dummy
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/*
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* Init sections discarded at runtime
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*/
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. = ALIGN(STRICT_ALIGN_SIZE);
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__init_begin = .;
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INIT_TEXT_SECTION(PAGE_SIZE) :kernel
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/* .exit.text is discarded at runtime, not link time,
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* to deal with references from __bug_table
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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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.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
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INIT_DATA
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__vtop_table_begin = .;
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*(.vtop_fixup);
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__vtop_table_end = .;
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__ptov_table_begin = .;
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*(.ptov_fixup);
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__ptov_table_end = .;
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}
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.init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
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INIT_SETUP(16)
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}
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.initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
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INIT_CALLS
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}
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.con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
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CON_INITCALL
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}
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SECURITY_INIT
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. = ALIGN(8);
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__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
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__start___ftr_fixup = .;
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*(__ftr_fixup)
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__stop___ftr_fixup = .;
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}
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. = ALIGN(8);
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__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
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__start___mmu_ftr_fixup = .;
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*(__mmu_ftr_fixup)
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__stop___mmu_ftr_fixup = .;
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}
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. = ALIGN(8);
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__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
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__start___lwsync_fixup = .;
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*(__lwsync_fixup)
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__stop___lwsync_fixup = .;
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}
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#ifdef CONFIG_PPC64
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. = ALIGN(8);
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__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
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__start___fw_ftr_fixup = .;
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*(__fw_ftr_fixup)
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__stop___fw_ftr_fixup = .;
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}
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#endif
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.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
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INIT_RAM_FS
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}
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PERCPU_SECTION(L1_CACHE_BYTES)
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. = ALIGN(8);
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.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
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__machine_desc_start = . ;
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*(.machine.desc)
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__machine_desc_end = . ;
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}
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#ifdef CONFIG_RELOCATABLE
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. = ALIGN(8);
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.dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET)
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{
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#ifdef CONFIG_PPC32
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__dynamic_symtab = .;
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#endif
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*(.dynsym)
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}
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.dynstr : AT(ADDR(.dynstr) - LOAD_OFFSET) { *(.dynstr) }
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.dynamic : AT(ADDR(.dynamic) - LOAD_OFFSET)
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{
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__dynamic_start = .;
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*(.dynamic)
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}
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.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
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.interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
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.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
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{
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__rela_dyn_start = .;
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*(.rela*)
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}
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#endif
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/* .exit.data is discarded at runtime, not link time,
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* to deal with references from .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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/* freed after init ends here */
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. = ALIGN(PAGE_SIZE);
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__init_end = .;
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/*
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* And now the various read/write data
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*/
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. = ALIGN(PAGE_SIZE);
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_sdata = .;
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#ifdef CONFIG_PPC32
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.data : AT(ADDR(.data) - LOAD_OFFSET) {
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DATA_DATA
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*(.sdata)
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*(.sdata2)
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*(.got.plt) *(.got)
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*(.plt)
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}
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#else
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.data : AT(ADDR(.data) - LOAD_OFFSET) {
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DATA_DATA
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*(.data.rel*)
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*(.toc1)
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*(.branch_lt)
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}
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.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
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*(.opd)
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}
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. = ALIGN(256);
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.got : AT(ADDR(.got) - LOAD_OFFSET) {
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__toc_start = .;
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#ifndef CONFIG_RELOCATABLE
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__prom_init_toc_start = .;
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arch/powerpc/kernel/prom_init.o*(.toc .got)
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__prom_init_toc_end = .;
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#endif
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*(.got)
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*(.toc)
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}
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#endif
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/* The initial task and kernel stack */
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INIT_TASK_DATA_SECTION(THREAD_SIZE)
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.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
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PAGE_ALIGNED_DATA(PAGE_SIZE)
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}
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.data..cacheline_aligned : AT(ADDR(.data..cacheline_aligned) - LOAD_OFFSET) {
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CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
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}
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.data..read_mostly : AT(ADDR(.data..read_mostly) - LOAD_OFFSET) {
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READ_MOSTLY_DATA(L1_CACHE_BYTES)
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}
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. = ALIGN(PAGE_SIZE);
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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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BUG_TABLE
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. = ALIGN(PAGE_SIZE);
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_edata = .;
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PROVIDE32 (edata = .);
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/*
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* And finally the bss
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*/
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BSS_SECTION(0, 0, 0)
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. = ALIGN(PAGE_SIZE);
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_end = . ;
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PROVIDE32 (end = .);
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STABS_DEBUG
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DWARF_DEBUG
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DISCARDS
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/DISCARD/ : {
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*(*.EMB.apuinfo)
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*(.glink .iplt .plt .rela* .comment)
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*(.gnu.version*)
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*(.gnu.attributes)
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*(.eh_frame)
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}
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}
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