linux/arch/loongarch/kernel/vmlinux.lds.S
Xi Ruoyao 11cd8a6483 LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS
If explicit relocation hints are used by the toolchain, -Wa,-mla-*
options will be useless for the C code. So only use them for the
!CONFIG_AS_HAS_EXPLICIT_RELOCS case.

Replace "la" with "la.pcrel" in head.S to keep the semantic consistent
with new and old toolchains for the low level startup code.

For per-CPU variables, the "address" of the symbol is actually an offset
from $r21. The value is near the loading address of main kernel image,
but far from the loading address of modules. So we use model("extreme")
attibute to tell the compiler that a PC-relative addressing with 32-bit
offset is not sufficient for local per-CPU variables.

The behavior with different assemblers and compilers are summarized in
the following table:

AS has            CC has
explicit relocs   explicit relocs * Behavior
==============================================================
No                No                Use la.* macros.
                                    No change from Linux 6.0.
--------------------------------------------------------------
No                Yes               Disable explicit relocs.
                                    No change from Linux 6.0.
--------------------------------------------------------------
Yes               No                Not supported.
--------------------------------------------------------------
Yes               Yes               Enable explicit relocs.
                                    No -Wa,-mla* options used.
==============================================================
*: We assume CC must have model attribute if it has explicit relocs.
   Both features are added in GCC 13 development cycle, so any GCC
   release >= 13 should be OK. Using early GCC 13 development snapshots
   may produce modules with unsupported relocations.

Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f09482a
Link: https://gcc.gnu.org/r13-1834
Link: https://gcc.gnu.org/r13-2199
Tested-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-12 16:36:08 +08:00

130 lines
2.1 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/sizes.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#define PAGE_SIZE _PAGE_SIZE
/*
* Put .bss..swapper_pg_dir as the first thing in .bss. This will
* ensure that it has .bss alignment (64K).
*/
#define BSS_FIRST_SECTIONS *(.bss..swapper_pg_dir)
#include <asm-generic/vmlinux.lds.h>
#include "image-vars.h"
/*
* Max avaliable Page Size is 64K, so we set SectionAlignment
* field of EFI application to 64K.
*/
PECOFF_FILE_ALIGN = 0x200;
PECOFF_SEGMENT_ALIGN = 0x10000;
OUTPUT_ARCH(loongarch)
ENTRY(kernel_entry)
PHDRS {
text PT_LOAD FLAGS(7); /* RWX */
note PT_NOTE FLAGS(4); /* R__ */
}
jiffies = jiffies_64;
SECTIONS
{
. = VMLINUX_LOAD_ADDRESS;
_text = .;
HEAD_TEXT_SECTION
. = ALIGN(PECOFF_SEGMENT_ALIGN);
_stext = .;
.text : {
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
*(.fixup)
*(.gnu.warning)
} :text = 0
. = ALIGN(PECOFF_SEGMENT_ALIGN);
_etext = .;
EXCEPTION_TABLE(16)
.got : ALIGN(16) { *(.got) }
.plt : ALIGN(16) { *(.plt) }
.got.plt : ALIGN(16) { *(.got.plt) }
. = ALIGN(PECOFF_SEGMENT_ALIGN);
__init_begin = .;
__inittext_begin = .;
INIT_TEXT_SECTION(PAGE_SIZE)
.exit.text : {
EXIT_TEXT
}
. = ALIGN(PECOFF_SEGMENT_ALIGN);
__inittext_end = .;
__initdata_begin = .;
INIT_DATA_SECTION(16)
.exit.data : {
EXIT_DATA
}
#ifdef CONFIG_SMP
PERCPU_SECTION(1 << CONFIG_L1_CACHE_SHIFT)
#endif
.rela.dyn : ALIGN(8) { *(.rela.dyn) *(.rela*) }
.init.bss : {
*(.init.bss)
}
. = ALIGN(PECOFF_SEGMENT_ALIGN);
__initdata_end = .;
__init_end = .;
_sdata = .;
RO_DATA(4096)
RW_DATA(1 << CONFIG_L1_CACHE_SHIFT, PAGE_SIZE, THREAD_SIZE)
.sdata : {
*(.sdata)
}
.edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGN); }
_edata = .;
BSS_SECTION(0, SZ_64K, 8)
. = ALIGN(PECOFF_SEGMENT_ALIGN);
_end = .;
STABS_DEBUG
DWARF_DEBUG
ELF_DETAILS
.gptab.sdata : {
*(.gptab.data)
*(.gptab.sdata)
}
.gptab.sbss : {
*(.gptab.bss)
*(.gptab.sbss)
}
DISCARDS
/DISCARD/ : {
*(.gnu.attributes)
*(.options)
*(.eh_frame)
}
}