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549e8152de
This implements CONFIG_RELOCATABLE for 64-bit by making the kernel as a position-independent executable (PIE) when it is set. This involves processing the dynamic relocations in the image in the early stages of booting, even if the kernel is being run at the address it is linked at, since the linker does not necessarily fill in words in the image for which there are dynamic relocations. (In fact the linker does fill in such words for 64-bit executables, though not for 32-bit executables, so in principle we could avoid calling relocate() entirely when we're running a 64-bit kernel at the linked address.) The dynamic relocations are processed by a new function relocate(addr), where the addr parameter is the virtual address where the image will be run. In fact we call it twice; once before calling prom_init, and again when starting the main kernel. This means that reloc_offset() returns 0 in prom_init (since it has been relocated to the address it is running at), which necessitated a few adjustments. This also changes __va and __pa to use an equivalent definition that is simpler. With the relocatable kernel, PAGE_OFFSET and MEMORY_START are constants (for 64-bit) whereas PHYSICAL_START is a variable (and KERNELBASE ideally should be too, but isn't yet). With this, relocatable kernels still copy themselves down to physical address 0 and run there. Signed-off-by: Paul Mackerras <paulus@samba.org>
295 lines
6.0 KiB
ArmAsm
295 lines
6.0 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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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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/* Sections to be discarded. */
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/DISCARD/ : {
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*(.exitcall.exit)
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EXIT_DATA
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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 and gots */
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.text : AT(ADDR(.text) - LOAD_OFFSET) {
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ALIGN_FUNCTION();
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*(.text.head)
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_text = .;
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*(.text .fixup .text.init.refok .exit.text.refok __ftr_alt_*)
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SCHED_TEXT
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LOCK_TEXT
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KPROBES_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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RODATA
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/* Exception & bug tables */
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__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
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__start___ex_table = .;
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*(__ex_table)
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__stop___ex_table = .;
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}
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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(0xf177)
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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(PAGE_SIZE);
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__init_begin = .;
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.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
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_sinittext = .;
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INIT_TEXT
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_einittext = .;
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} :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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#ifdef CONFIG_PPC_ISERIES
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__dt_strings_start = .;
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*(.dt_strings);
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__dt_strings_end = .;
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#endif
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}
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. = ALIGN(16);
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.init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
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__setup_start = .;
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*(.init.setup)
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__setup_end = .;
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}
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.initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
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__initcall_start = .;
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INITCALLS
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__initcall_end = .;
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}
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.con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
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__con_initcall_start = .;
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*(.con_initcall.init)
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__con_initcall_end = .;
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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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__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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#ifdef CONFIG_BLK_DEV_INITRD
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. = ALIGN(PAGE_SIZE);
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.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
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__initramfs_start = .;
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*(.init.ramfs)
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__initramfs_end = .;
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}
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#endif
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. = ALIGN(PAGE_SIZE);
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.data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) {
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__per_cpu_start = .;
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*(.data.percpu)
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*(.data.percpu.shared_aligned)
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__per_cpu_end = .;
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}
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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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. = ALIGN(8);
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.dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET) { *(.dynsym) }
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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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/* 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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*(.got.plt) *(.got)
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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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.got : AT(ADDR(.got) - LOAD_OFFSET) {
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__toc_start = .;
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*(.got)
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*(.toc)
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}
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#endif
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. = ALIGN(PAGE_SIZE);
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_edata = .;
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PROVIDE32 (edata = .);
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/* The initial task and kernel stack */
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#ifdef CONFIG_PPC32
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. = ALIGN(8192);
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#else
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. = ALIGN(16384);
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#endif
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.data.init_task : AT(ADDR(.data.init_task) - LOAD_OFFSET) {
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*(.data.init_task)
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}
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. = ALIGN(PAGE_SIZE);
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.data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) {
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*(.data.page_aligned)
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}
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.data.cacheline_aligned : AT(ADDR(.data.cacheline_aligned) - LOAD_OFFSET) {
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*(.data.cacheline_aligned)
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}
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. = ALIGN(L1_CACHE_BYTES);
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.data.read_mostly : AT(ADDR(.data.read_mostly) - LOAD_OFFSET) {
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*(.data.read_mostly)
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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_begin = .;
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*(.data.nosave)
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. = ALIGN(PAGE_SIZE);
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__nosave_end = .;
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}
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/*
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* And finally the bss
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*/
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.bss : AT(ADDR(.bss) - LOAD_OFFSET) {
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__bss_start = .;
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*(.sbss) *(.scommon)
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*(.dynbss)
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*(.bss)
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*(COMMON)
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__bss_stop = .;
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}
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. = ALIGN(PAGE_SIZE);
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_end = . ;
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PROVIDE32 (end = .);
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}
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