linux/arch/s390/kernel/vmlinux.lds.S
Heiko Carstens 702644249d s390/fpu: get rid of test_fp_ctl()
It is quite subtle to use test_fp_ctl() correctly. Therefore remove it -
instead copy whatever new floating point control (fpc) register values are
supposed to be used into its save area.

Test the validity of the new value when loading it. If the new value is
invalid, load the fpc register with zero.

This seems to be a the best way to approach this problem. Even though this
changes behavior:

- sigreturn with an invalid fpc value on the stack will succeed, and
  continue with zero value, instead of returning with SIGSEGV

- ptraced processes will also use a zero value instead of letting the
  request fail with -EINVAL

However all of this seems to acceptable. After all testing of the value was
only implemented to avoid that user space can crash the kernel. It is not
there to test values for validity; and the assumption is that there is no
existing user space which is doing this.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-12-11 14:33:06 +01:00

245 lines
5.2 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
{
. = 0x100000;
.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)
. = 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)
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)
}
. = 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)
. = ALIGN(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 */
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
/* Sections to be discarded */
DISCARDS
/DISCARD/ : {
*(.eh_frame)
*(.interp)
}
}