linux/arch/s390/kernel/vmlinux.lds.S
Sumanth Korikkar 00cda11d3b s390: Compile kernel with -fPIC and link with -no-pie
When the kernel is built with CONFIG_PIE_BUILD option enabled it
uses dynamic symbols, for which the linker does not allow more
than 64K number of entries. This can break features like kpatch.

Hence, whenever possible the kernel is built with CONFIG_PIE_BUILD
option disabled. For that support of unaligned symbols generated by
linker scripts in the compiler is necessary.

However, older compilers might lack such support. In that case the
build process resorts to CONFIG_PIE_BUILD option-enabled build.

Compile object files with -fPIC option and then link the kernel
binary with -no-pie linker option.

As result, the dynamic symbols are not generated and not only kpatch
feature succeeds, but also the whole CONFIG_PIE_BUILD option-enabled
code could be dropped.

[ agordeev: Reworded the commit message ]

Suggested-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-04-29 17:33:30 +02:00

265 lines
5.8 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
/* ld script to make s390 Linux kernel
* Written by Martin Schwidefsky (schwidefsky@de.ibm.com)
*/
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/ftrace.lds.h>
/*
* Put .bss..swapper_pg_dir as the first thing in .bss. This will
* make sure it has 16k alignment.
*/
#define BSS_FIRST_SECTIONS *(.bss..swapper_pg_dir) \
*(.bss..invalid_pg_dir)
#define RO_EXCEPTION_TABLE_ALIGN 16
/* Handle ro_after_init data on our own. */
#define RO_AFTER_INIT_DATA
#define RUNTIME_DISCARD_EXIT
#define EMITS_PT_NOTE
#include <asm-generic/vmlinux.lds.h>
#include <asm/vmlinux.lds.h>
OUTPUT_FORMAT("elf64-s390", "elf64-s390", "elf64-s390")
OUTPUT_ARCH(s390:64-bit)
ENTRY(startup_continue)
jiffies = jiffies_64;
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
data PT_LOAD FLAGS(7); /* RWE */
note PT_NOTE FLAGS(0); /* ___ */
}
SECTIONS
{
. = __START_KERNEL;
.text : {
_stext = .; /* Start of text section */
_text = .; /* Text and read-only data */
HEAD_TEXT
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
FTRACE_HOTPATCH_TRAMPOLINES_TEXT
*(.text.*_indirect_*)
*(.fixup)
*(.gnu.warning)
. = ALIGN(PAGE_SIZE);
_etext = .; /* End of text section */
} :text = 0x0700
RO_DATA(PAGE_SIZE)
.data.rel.ro : {
*(.data.rel.ro .data.rel.ro.*)
}
.got : {
__got_start = .;
*(.got)
__got_end = .;
}
. = ALIGN(PAGE_SIZE);
_sdata = .; /* Start of data section */
. = ALIGN(PAGE_SIZE);
__start_ro_after_init = .;
.data..ro_after_init : {
*(.data..ro_after_init)
JUMP_TABLE_DATA
} :data
. = ALIGN(PAGE_SIZE);
__end_ro_after_init = .;
RW_DATA(0x100, PAGE_SIZE, THREAD_SIZE)
.data.rel : {
*(.data.rel*)
}
BOOT_DATA_PRESERVED
. = ALIGN(8);
.amode31.refs : {
_start_amode31_refs = .;
*(.amode31.refs)
_end_amode31_refs = .;
}
. = ALIGN(PAGE_SIZE);
_edata = .; /* End of data section */
/* will be freed after init */
. = ALIGN(PAGE_SIZE); /* Init code and data */
__init_begin = .;
. = ALIGN(PAGE_SIZE);
.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
_sinittext = .;
INIT_TEXT
. = ALIGN(PAGE_SIZE);
_einittext = .;
}
/*
* .exit.text is discarded at runtime, not link time,
* to deal with references from __bug_table
*/
.exit.text : {
EXIT_TEXT
}
.exit.data : {
EXIT_DATA
}
/*
* struct alt_inst entries. From the header (alternative.h):
* "Alternative instructions for different CPU types or capabilities"
* Think locking instructions on spinlocks.
* Note, that it is a part of __init region.
*/
. = ALIGN(8);
.altinstructions : {
__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.
* Note, that it is a part of __init region.
*/
.altinstr_replacement : {
*(.altinstr_replacement)
}
/*
* Table with the patch locations to undo expolines
*/
. = ALIGN(4);
.nospec_call_table : {
__nospec_call_start = . ;
*(.s390_indirect*)
__nospec_call_end = . ;
}
.nospec_return_table : {
__nospec_return_start = . ;
*(.s390_return*)
__nospec_return_end = . ;
}
BOOT_DATA
/*
* .amode31 section for code, data, ex_table that need to stay
* below 2 GB, even when the kernel is relocated above 2 GB.
*/
. = ALIGN(PAGE_SIZE);
_samode31 = .;
.amode31.text : {
_stext_amode31 = .;
*(.amode31.text)
*(.amode31.text.*_indirect_*)
. = ALIGN(PAGE_SIZE);
_etext_amode31 = .;
}
. = ALIGN(16);
.amode31.ex_table : {
_start_amode31_ex_table = .;
KEEP(*(.amode31.ex_table))
_stop_amode31_ex_table = .;
}
. = ALIGN(PAGE_SIZE);
.amode31.data : {
*(.amode31.data)
}
. = _samode31 + AMODE31_SIZE;
_eamode31 = .;
/* early.c uses stsi, which requires page aligned data. */
. = ALIGN(PAGE_SIZE);
INIT_DATA_SECTION(0x100)
PERCPU_SECTION(0x100)
. = ALIGN(PAGE_SIZE);
__init_end = .; /* freed after init ends here */
BSS_SECTION(PAGE_SIZE, 4 * PAGE_SIZE, PAGE_SIZE)
. = ALIGN(PAGE_SIZE);
_end = . ;
/*
* uncompressed image info used by the decompressor
* it should match struct vmlinux_info
*/
.vmlinux.info 0 (INFO) : {
QUAD(startup_continue) /* entry */
QUAD(__bss_start - _stext) /* image_size */
QUAD(__bss_stop - __bss_start) /* bss_size */
QUAD(__boot_data_start) /* bootdata_off */
QUAD(__boot_data_end - __boot_data_start) /* bootdata_size */
QUAD(__boot_data_preserved_start) /* bootdata_preserved_off */
QUAD(__boot_data_preserved_end -
__boot_data_preserved_start) /* bootdata_preserved_size */
QUAD(__got_start) /* got_start */
QUAD(__got_end) /* got_end */
QUAD(_eamode31 - _samode31) /* amode31_size */
QUAD(init_mm)
QUAD(swapper_pg_dir)
QUAD(invalid_pg_dir)
#ifdef CONFIG_KASAN
QUAD(kasan_early_shadow_page)
QUAD(kasan_early_shadow_pte)
QUAD(kasan_early_shadow_pmd)
QUAD(kasan_early_shadow_pud)
QUAD(kasan_early_shadow_p4d)
#endif
} :NONE
/* Debugging sections. */
STABS_DEBUG
DWARF_DEBUG
ELF_DETAILS
/*
* Make sure that the .got.plt is either completely empty or it
* contains only the three reserved double words.
*/
.got.plt : {
*(.got.plt)
}
ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0x18, "Unexpected GOT/PLT entries detected!")
/*
* Sections that should stay zero sized, which is safer to
* explicitly check instead of blindly discarding.
*/
.plt : {
*(.plt) *(.plt.*) *(.iplt) *(.igot .igot.plt)
}
ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")
.rela.dyn : {
*(.rela.*) *(.rela_*)
}
ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!")
/* Sections to be discarded */
DISCARDS
/DISCARD/ : {
*(.eh_frame)
*(.interp)
}
}