Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 805bc0bc authored by Gerald Schaefer's avatar Gerald Schaefer Committed by Martin Schwidefsky
Browse files

s390/kernel: build a relocatable kernel 



This patch adds support for building a relocatable kernel with -fPIE.
The kernel will be relocated to 0 early in the boot process.

Signed-off-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: default avatarPhilipp Rudo <prudo@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 833b441e

arch/s390/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -624,6 +624,19 @@ config EXPOLINE_FULL 


endchoice



config RELOCATABLE

	bool "Build a relocatable kernel"

	select MODULE_REL_CRCS if MODVERSIONS

	default y

	help

	  This builds a kernel image that retains relocation information

	  so it can be loaded at an arbitrary address.

	  The kernel is linked as a position-independent executable (PIE)

	  and contains dynamic relocations which are processed early in the

	  bootup process.

	  The relocations make the kernel image about 15% larger (compressed

	  10%), but are discarded at runtime.



endmenu



menu "Memory setup"

arch/s390/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -16,6 +16,10 @@ KBUILD_AFLAGS_MODULE += -fPIC 
KBUILD_CFLAGS_MODULE += -fPIC

KBUILD_AFLAGS	+= -m64

KBUILD_CFLAGS	+= -m64

ifeq ($(CONFIG_RELOCATABLE),y)

KBUILD_CFLAGS	+= -fPIE

LDFLAGS_vmlinux	:= -pie

endif

aflags_dwarf	:= -Wa,-gdwarf-2

KBUILD_AFLAGS_DECOMPRESSOR := -m64 -D__ASSEMBLY__

KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf))

arch/s390/boot/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ obj-y := head.o als.o startup.o mem_detect.o ipl_parm.o ipl_report.o 
obj-y	+= string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o

obj-y	+= ctype.o

obj-$(CONFIG_PROTECTED_VIRTUALIZATION_GUEST)	+= uv.o

obj-$(CONFIG_RELOCATABLE)	+= machine_kexec_reloc.o

targets	:= bzImage startup.a section_cmp.boot.data section_cmp.boot.preserved.data $(obj-y)

subdir-	:= compressed

arch/s390/boot/compressed/decompressor.h

+3 −0
Original line number Diff line number Diff line
@@ -19,6 +19,9 @@ struct vmlinux_info { 
	unsigned long bootdata_size;

	unsigned long bootdata_preserved_off;

	unsigned long bootdata_preserved_size;

	unsigned long dynsym_start;

	unsigned long rela_dyn_start;

	unsigned long rela_dyn_end;

};



extern char _vmlinux_info[];

arch/s390/boot/machine_kexec_reloc.c

0 → 100644
+2 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include "../kernel/machine_kexec_reloc.c"