5ac47f7a6e
The ppc64 kernel can get loaded at any address which means our very early init code in prom_init.c must be relocatable. We do this with a pretty nasty RELOC() macro that we wrap accesses of variables with. It is very fragile and sometimes we forget to add a RELOC() to an uncommon path or sometimes a compiler change breaks it. 32bit has a much more elegant solution where we build prom_init.c with -mrelocatable and then process the relocations manually. Unfortunately we can't do the equivalent on 64bit and we would have to build the entire kernel relocatable (-pie), resulting in a large increase in kernel footprint (megabytes of relocation data). The relocation data will be marked __initdata but it still creates more pressure on our already tight memory layout at boot. Alan Modra pointed out that the 64bit ABI is relocatable even if we don't build with -pie, we just need to relocate the TOC. This patch implements that idea and relocates the TOC entries of prom_init.c. An added bonus is there are very few relocations to process which helps keep boot times on simulators down. gcc does not put 64bit integer constants into the TOC but to be safe we may want a build time script which passes through the prom_init.c TOC entries to make sure everything looks reasonable. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
268 lines
5.4 KiB
ArmAsm
268 lines
5.4 KiB
ArmAsm
#ifdef CONFIG_PPC64
|
|
#define PROVIDE32(x) PROVIDE(__unused__##x)
|
|
#else
|
|
#define PROVIDE32(x) PROVIDE(x)
|
|
#endif
|
|
#include <asm/page.h>
|
|
#include <asm-generic/vmlinux.lds.h>
|
|
#include <asm/cache.h>
|
|
#include <asm/thread_info.h>
|
|
|
|
ENTRY(_stext)
|
|
|
|
PHDRS {
|
|
kernel PT_LOAD FLAGS(7); /* RWX */
|
|
notes PT_NOTE FLAGS(0);
|
|
dummy PT_NOTE FLAGS(0);
|
|
|
|
/* binutils < 2.18 has a bug that makes it misbehave when taking an
|
|
ELF file with all segments at load address 0 as input. This
|
|
happens when running "strip" on vmlinux, because of the AT() magic
|
|
in this linker script. People using GCC >= 4.2 won't run into
|
|
this problem, because the "build-id" support will put some data
|
|
into the "notes" segment (at a non-zero load address).
|
|
|
|
To work around this, we force some data into both the "dummy"
|
|
segment and the kernel segment, so the dummy segment will get a
|
|
non-zero load address. It's not enough to always create the
|
|
"notes" segment, since if nothing gets assigned to it, its load
|
|
address will be zero. */
|
|
}
|
|
|
|
#ifdef CONFIG_PPC64
|
|
OUTPUT_ARCH(powerpc:common64)
|
|
jiffies = jiffies_64;
|
|
#else
|
|
OUTPUT_ARCH(powerpc:common)
|
|
jiffies = jiffies_64 + 4;
|
|
#endif
|
|
SECTIONS
|
|
{
|
|
. = 0;
|
|
reloc_start = .;
|
|
|
|
. = KERNELBASE;
|
|
|
|
/*
|
|
* Text, read only data and other permanent read-only sections
|
|
*/
|
|
|
|
/* Text and gots */
|
|
.text : AT(ADDR(.text) - LOAD_OFFSET) {
|
|
ALIGN_FUNCTION();
|
|
HEAD_TEXT
|
|
_text = .;
|
|
/* careful! __ftr_alt_* sections need to be close to .text */
|
|
*(.text .fixup __ftr_alt_* .ref.text)
|
|
SCHED_TEXT
|
|
LOCK_TEXT
|
|
KPROBES_TEXT
|
|
IRQENTRY_TEXT
|
|
|
|
#ifdef CONFIG_PPC32
|
|
*(.got1)
|
|
__got2_start = .;
|
|
*(.got2)
|
|
__got2_end = .;
|
|
#endif /* CONFIG_PPC32 */
|
|
|
|
} :kernel
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_etext = .;
|
|
PROVIDE32 (etext = .);
|
|
|
|
/* Read-only data */
|
|
RODATA
|
|
|
|
EXCEPTION_TABLE(0)
|
|
|
|
NOTES :kernel :notes
|
|
|
|
/* The dummy segment contents for the bug workaround mentioned above
|
|
near PHDRS. */
|
|
.dummy : AT(ADDR(.dummy) - LOAD_OFFSET) {
|
|
LONG(0)
|
|
LONG(0)
|
|
LONG(0)
|
|
} :kernel :dummy
|
|
|
|
/*
|
|
* Init sections discarded at runtime
|
|
*/
|
|
. = ALIGN(PAGE_SIZE);
|
|
__init_begin = .;
|
|
INIT_TEXT_SECTION(PAGE_SIZE) :kernel
|
|
|
|
/* .exit.text is discarded at runtime, not link time,
|
|
* to deal with references from __bug_table
|
|
*/
|
|
.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
|
|
EXIT_TEXT
|
|
}
|
|
|
|
.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
|
|
INIT_DATA
|
|
__vtop_table_begin = .;
|
|
*(.vtop_fixup);
|
|
__vtop_table_end = .;
|
|
__ptov_table_begin = .;
|
|
*(.ptov_fixup);
|
|
__ptov_table_end = .;
|
|
}
|
|
|
|
.init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
|
|
INIT_SETUP(16)
|
|
}
|
|
|
|
.initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
|
|
INIT_CALLS
|
|
}
|
|
|
|
.con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
|
|
CON_INITCALL
|
|
}
|
|
|
|
SECURITY_INIT
|
|
|
|
. = ALIGN(8);
|
|
__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
|
|
__start___ftr_fixup = .;
|
|
*(__ftr_fixup)
|
|
__stop___ftr_fixup = .;
|
|
}
|
|
. = ALIGN(8);
|
|
__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
|
|
__start___mmu_ftr_fixup = .;
|
|
*(__mmu_ftr_fixup)
|
|
__stop___mmu_ftr_fixup = .;
|
|
}
|
|
. = ALIGN(8);
|
|
__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
|
|
__start___lwsync_fixup = .;
|
|
*(__lwsync_fixup)
|
|
__stop___lwsync_fixup = .;
|
|
}
|
|
#ifdef CONFIG_PPC64
|
|
. = ALIGN(8);
|
|
__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
|
|
__start___fw_ftr_fixup = .;
|
|
*(__fw_ftr_fixup)
|
|
__stop___fw_ftr_fixup = .;
|
|
}
|
|
#endif
|
|
.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
|
|
INIT_RAM_FS
|
|
}
|
|
|
|
PERCPU_SECTION(L1_CACHE_BYTES)
|
|
|
|
. = ALIGN(8);
|
|
.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
|
|
__machine_desc_start = . ;
|
|
*(.machine.desc)
|
|
__machine_desc_end = . ;
|
|
}
|
|
#ifdef CONFIG_RELOCATABLE
|
|
. = ALIGN(8);
|
|
.dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET)
|
|
{
|
|
#ifdef CONFIG_RELOCATABLE_PPC32
|
|
__dynamic_symtab = .;
|
|
#endif
|
|
*(.dynsym)
|
|
}
|
|
.dynstr : AT(ADDR(.dynstr) - LOAD_OFFSET) { *(.dynstr) }
|
|
.dynamic : AT(ADDR(.dynamic) - LOAD_OFFSET)
|
|
{
|
|
__dynamic_start = .;
|
|
*(.dynamic)
|
|
}
|
|
.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
|
|
.interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
|
|
.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
|
|
{
|
|
__rela_dyn_start = .;
|
|
*(.rela*)
|
|
}
|
|
#endif
|
|
|
|
/* freed after init ends here */
|
|
. = ALIGN(PAGE_SIZE);
|
|
__init_end = .;
|
|
|
|
/*
|
|
* And now the various read/write data
|
|
*/
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_sdata = .;
|
|
|
|
#ifdef CONFIG_PPC32
|
|
.data : AT(ADDR(.data) - LOAD_OFFSET) {
|
|
DATA_DATA
|
|
*(.sdata)
|
|
*(.got.plt) *(.got)
|
|
}
|
|
#else
|
|
.data : AT(ADDR(.data) - LOAD_OFFSET) {
|
|
DATA_DATA
|
|
*(.data.rel*)
|
|
*(.toc1)
|
|
*(.branch_lt)
|
|
}
|
|
|
|
.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
|
|
*(.opd)
|
|
}
|
|
|
|
.got : AT(ADDR(.got) - LOAD_OFFSET) {
|
|
__toc_start = .;
|
|
#ifndef CONFIG_RELOCATABLE
|
|
__prom_init_toc_start = .;
|
|
arch/powerpc/kernel/prom_init.o*(.toc .got)
|
|
__prom_init_toc_end = .;
|
|
#endif
|
|
*(.got)
|
|
*(.toc)
|
|
}
|
|
#endif
|
|
|
|
/* The initial task and kernel stack */
|
|
INIT_TASK_DATA_SECTION(THREAD_SIZE)
|
|
|
|
.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
|
|
PAGE_ALIGNED_DATA(PAGE_SIZE)
|
|
}
|
|
|
|
.data..cacheline_aligned : AT(ADDR(.data..cacheline_aligned) - LOAD_OFFSET) {
|
|
CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
|
|
}
|
|
|
|
.data..read_mostly : AT(ADDR(.data..read_mostly) - LOAD_OFFSET) {
|
|
READ_MOSTLY_DATA(L1_CACHE_BYTES)
|
|
}
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
|
|
NOSAVE_DATA
|
|
}
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_edata = .;
|
|
PROVIDE32 (edata = .);
|
|
|
|
/*
|
|
* And finally the bss
|
|
*/
|
|
|
|
BSS_SECTION(0, 0, 0)
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_end = . ;
|
|
PROVIDE32 (end = .);
|
|
|
|
/* Sections to be discarded. */
|
|
DISCARDS
|
|
}
|