linux/arch/x86/purgatory/Makefile

purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string.o

targets += $(purgatory-y)
PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))

LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib
targets += purgatory.ro

# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
# in turn leaves some undefined symbols like __fentry__ in purgatory and not
# sure how to relocate those. Like kexec-tools, use custom flags.

KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -MD -Os -mcmodel=large
KBUILD_CFLAGS += -m$(BITS)

$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
		$(call if_changed,ld)

targets += kexec-purgatory.c

quiet_cmd_bin2c = BIN2C   $@
      cmd_bin2c = cat $(obj)/purgatory.ro | $(objtree)/scripts/basic/bin2c kexec_purgatory > $(obj)/kexec-purgatory.c

$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE
	$(call if_changed,bin2c)


obj-$(CONFIG_KEXEC_FILE)	+= kexec-purgatory.o
purgatory: core purgatory functionality Create a stand alone relocatable object purgatory which runs between two kernels. This name, concept and some code has been taken from kexec-tools. Idea is that this code runs after a crash and it runs in minimal environment. So keep it separate from rest of the kernel and in long term we will have to practically do no maintenance of this code. This code also has the logic to do verify sha256 hashes of various segments which have been loaded into memory. So first we verify that the kernel we are jumping to is fine and has not been corrupted and make progress only if checsums are verified. This code also takes care of copying some memory contents to backup region. [sfr@canb.auug.org.au: run host built programs from objtree] Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Greg Kroah-Hartman <greg@kroah.com> Cc: Dave Young <dyoung@redhat.com> Cc: WANG Chao <chaowang@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 2014-08-09 01:26:02 +04:00			`purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string.o`

			`targets += $(purgatory-y)`
			`PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))`

			`LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib`
			`targets += purgatory.ro`

			`# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That`
			`# in turn leaves some undefined symbols like __fentry__ in purgatory and not`
			`# sure how to relocate those. Like kexec-tools, use custom flags.`

			`KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -MD -Os -mcmodel=large`
x86/purgatory: use approprate -m64/-32 build flag for arch/x86/purgatory Thomas reported that build of x86_64 kernel was failing for him. He is using 32bit tool chain. Problem is that while compiling purgatory, I have not specified -m64 flag. And 32bit tool chain must be assuming -m32 by default. Following is error message. (mini) [~/work/linux-2.6] make scripts/kconfig/conf --silentoldconfig Kconfig CHK include/config/kernel.release UPD include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h UPD include/generated/utsrelease.h CC arch/x86/purgatory/purgatory.o arch/x86/purgatory/purgatory.c:1:0: error: code model 'large' not supported in the 32 bit mode Fix it by explicitly passing appropriate -m64/-m32 build flag for purgatory. Reported-by: Thomas Glanzmann <thomas@glanzmann.de> Tested-by: Thomas Glanzmann <thomas@glanzmann.de> Suggested-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 2014-08-30 02:18:55 +04:00			`KBUILD_CFLAGS += -m$(BITS)`
purgatory: core purgatory functionality Create a stand alone relocatable object purgatory which runs between two kernels. This name, concept and some code has been taken from kexec-tools. Idea is that this code runs after a crash and it runs in minimal environment. So keep it separate from rest of the kernel and in long term we will have to practically do no maintenance of this code. This code also has the logic to do verify sha256 hashes of various segments which have been loaded into memory. So first we verify that the kernel we are jumping to is fine and has not been corrupted and make progress only if checsums are verified. This code also takes care of copying some memory contents to backup region. [sfr@canb.auug.org.au: run host built programs from objtree] Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Greg Kroah-Hartman <greg@kroah.com> Cc: Dave Young <dyoung@redhat.com> Cc: WANG Chao <chaowang@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 2014-08-09 01:26:02 +04:00
			`$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE`
			`$(call if_changed,ld)`

			`targets += kexec-purgatory.c`

			`quiet_cmd_bin2c = BIN2C $@`
			`cmd_bin2c = cat $(obj)/purgatory.ro \| $(objtree)/scripts/basic/bin2c kexec_purgatory > $(obj)/kexec-purgatory.c`

			`$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE`
			`$(call if_changed,bin2c)`


kexec: create a new config option CONFIG_KEXEC_FILE for new syscall Currently new system call kexec_file_load() and all the associated code compiles if CONFIG_KEXEC=y. But new syscall also compiles purgatory code which currently uses gcc option -mcmodel=large. This option seems to be available only gcc 4.4 onwards. Hiding new functionality behind a new config option will not break existing users of old gcc. Those who wish to enable new functionality will require new gcc. Having said that, I am trying to figure out how can I move away from using -mcmodel=large but that can take a while. I think there are other advantages of introducing this new config option. As this option will be enabled only on x86_64, other arches don't have to compile generic kexec code which will never be used. This new code selects CRYPTO=y and CRYPTO_SHA256=y. And all other arches had to do this for CONFIG_KEXEC. Now with introduction of new config option, we can remove crypto dependency from other arches. Now CONFIG_KEXEC_FILE is available only on x86_64. So whereever I had CONFIG_X86_64 defined, I got rid of that. For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to "depends on CRYPTO=y". This should be safer as "select" is not recursive. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 2014-08-30 02:18:46 +04:00			`obj-$(CONFIG_KEXEC_FILE) += kexec-purgatory.o`