linux-stable/arch/s390/kernel/vmlinux.lds.S
Josh Poimboeuf c9305b6c1f s390: fix nospec table alignments
Add proper alignment for .nospec_call_table and .nospec_return_table in
vmlinux.

[hca@linux.ibm.com]: The problem with the missing alignment of the nospec
tables exist since a long time, however only since commit e6ed91fd07
("s390/alternatives: remove padding generation code") and with
CONFIG_RELOCATABLE=n the kernel may also crash at boot time.

The above named commit reduced the size of struct alt_instr by one byte,
so its new size is 11 bytes. Therefore depending on the number of cpu
alternatives the size of the __alt_instructions array maybe odd, which
again also causes that the addresses of the nospec tables will be odd.

If the address of __nospec_call_start is odd and the kernel is compiled
With CONFIG_RELOCATABLE=n the compiler may generate code that loads the
address of __nospec_call_start with a 'larl' instruction.

This will generate incorrect code since the 'larl' instruction only works
with even addresses. In result the members of the nospec tables will be
accessed with an off-by-one offset, which subsequently may lead to
addressing exceptions within __nospec_revert().

Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/8719bf1ce4a72ebdeb575200290094e9ce047bcc.1661557333.git.jpoimboe@kernel.org
Cc: <stable@vger.kernel.org> # 4.16
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-08-30 21:57:07 +02:00

228 lines
4.9 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)
/* Handle ro_after_init data on our own. */
#define RO_AFTER_INIT_DATA
#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
{
. = 0x100000;
.text : {
_stext = .; /* Start of text section */
_text = .; /* Text and read-only data */
HEAD_TEXT
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
FTRACE_HOTPATCH_TRAMPOLINES_TEXT
*(.text.*_indirect_*)
*(.gnu.warning)
. = ALIGN(PAGE_SIZE);
_etext = .; /* End of text section */
} :text = 0x0700
RO_DATA(PAGE_SIZE)
. = 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
EXCEPTION_TABLE(16)
. = ALIGN(PAGE_SIZE);
__end_ro_after_init = .;
RW_DATA(0x100, PAGE_SIZE, THREAD_SIZE)
BOOT_DATA_PRESERVED
. = ALIGN(8);
.amode31.refs : {
_start_amode31_refs = .;
*(.amode31.refs)
_end_amode31_refs = .;
}
_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)
}
. = ALIGN(PAGE_SIZE);
_eamode31 = .;
/* early.c uses stsi, which requires page aligned data. */
. = ALIGN(PAGE_SIZE);
INIT_DATA_SECTION(0x100)
PERCPU_SECTION(0x100)
.dynsym ALIGN(8) : {
__dynsym_start = .;
*(.dynsym)
__dynsym_end = .;
}
.rela.dyn ALIGN(8) : {
__rela_dyn_start = .;
*(.rela*)
__rela_dyn_end = .;
}
. = ALIGN(PAGE_SIZE);
__init_end = .; /* freed after init ends here */
BSS_SECTION(PAGE_SIZE, 4 * PAGE_SIZE, PAGE_SIZE)
_end = . ;
/*
* uncompressed image info used by the decompressor
* it should match struct vmlinux_info
*/
.vmlinux.info 0 (INFO) : {
QUAD(_stext) /* default_lma */
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(__dynsym_start) /* dynsym_start */
QUAD(__rela_dyn_start) /* rela_dyn_start */
QUAD(__rela_dyn_end) /* rela_dyn_end */
QUAD(_eamode31 - _samode31) /* amode31_size */
} :NONE
/* Debugging sections. */
STABS_DEBUG
DWARF_DEBUG
ELF_DETAILS
/* Sections to be discarded */
DISCARDS
/DISCARD/ : {
*(.eh_frame)
}
}