Gerald Schaefer a80313ff91 s390/kernel: introduce .dma sections
With a relocatable kernel that could reside at any place in memory, code
and data that has to stay below 2 GB needs special handling.

This patch introduces .dma sections for such text, data and ex_table.
The sections will be part of the decompressor kernel, so they will not
be relocated and stay below 2 GB. Their location is passed over to the
decompressed / relocated kernel via the .boot.preserved.data section.

The duald and aste for control register setup also need to stay below
2 GB, so move the setup code from arch/s390/kernel/head64.S to
arch/s390/boot/head.S. The duct and linkage_stack could reside above
2 GB, but their content has to be preserved for the decompresed kernel,
so they are also moved into the .dma section.

The start and end address of the .dma sections is added to vmcoreinfo,
for crash support, to help debugging in case the kernel crashed there.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-29 10:47:10 +02:00

100 lines
1.7 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
#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)
SECTIONS
{
. = 0;
.head.text : {
_head = . ;
HEAD_TEXT
_ehead = . ;
}
.text : {
_text = .; /* Text */
*(.text)
*(.text.*)
_etext = . ;
}
.rodata : {
_rodata = . ;
*(.rodata) /* read-only data */
*(.rodata.*)
_erodata = . ;
}
.data : {
_data = . ;
*(.data)
*(.data.*)
_edata = . ;
}
/*
* .dma section for code, data, ex_table that need to stay below 2 GB,
* even when the kernel is relocate: above 2 GB.
*/
_sdma = .;
.dma.text : {
. = ALIGN(PAGE_SIZE);
_stext_dma = .;
*(.dma.text)
. = ALIGN(PAGE_SIZE);
_etext_dma = .;
}
. = ALIGN(16);
.dma.ex_table : {
_start_dma_ex_table = .;
KEEP(*(.dma.ex_table))
_stop_dma_ex_table = .;
}
.dma.data : { *(.dma.data) }
_edma = .;
BOOT_DATA
BOOT_DATA_PRESERVED
/*
* uncompressed image info used by the decompressor it should match
* struct vmlinux_info. It comes from .vmlinux.info section of
* uncompressed vmlinux in a form of info.o
*/
. = ALIGN(8);
.vmlinux.info : {
_vmlinux_info = .;
*(.vmlinux.info)
}
#ifdef CONFIG_KERNEL_UNCOMPRESSED
. = 0x100000;
#else
. = ALIGN(8);
#endif
.rodata.compressed : {
_compressed_start = .;
*(.vmlinux.bin.compressed)
_compressed_end = .;
}
. = ALIGN(256);
.bss : {
_bss = . ;
*(.bss)
*(.bss.*)
*(COMMON)
. = ALIGN(8); /* For convenience during zeroing */
_ebss = .;
}
_end = .;
/* Sections to be discarded */
/DISCARD/ : {
*(.eh_frame)
*(__ex_table)
*(*__ksymtab*)
*(___kcrctab*)
}
}