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Commit 287d6070 authored by Philipp Rudo's avatar Philipp Rudo Committed by Martin Schwidefsky
Browse files

s390/purgatory: Remove duplicate variable definitions 



Currently there are some variables in the purgatory (e.g. kernel_entry)
which are defined twice, once in assembler- and once in c-code. The reason
for this is that these variables are set during purgatory load, where
sanity checks on the corresponding Elf_Sym's are made, while they are used
in assembler-code. Thus adding a second definition in c-code is a handy
workaround to guarantee correct Elf_Sym's are created.

When the purgatory is compiled with -fcommon (default for gcc on s390) this
is no problem because both symbols are merged by the linker. However this
is not required by ISO C and when the purgatory is built with -fno-common
the linker fails with errors like

arch/s390/purgatory/purgatory.o:(.bss+0x18): multiple definition of `kernel_entry'
arch/s390/purgatory/head.o:/.../arch/s390/purgatory/head.S:230: first defined here

Thus remove the duplicate definitions and add the required size and type
information to the assembler definition. Also add -fno-common to the
command line options to prevent similar hacks in the future.

Signed-off-by: default avatarPhilipp Rudo <prudo@linux.ibm.com>
Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent c315e693

arch/s390/include/asm/purgatory.h

+0 −6
Original line number Diff line number Diff line
@@ -13,11 +13,5 @@ 


int verify_sha256_digest(void);



extern u64 kernel_entry;

extern u64 kernel_type;



extern u64 crash_start;

extern u64 crash_size;



#endif	/* __ASSEMBLY__ */

#endif /* _S390_PURGATORY_H_ */

arch/s390/purgatory/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ LDFLAGS_purgatory.ro += -z nodefaultlib 
KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes

KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare

KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding

KBUILD_CFLAGS += -c -MD -Os -m64 -msoft-float

KBUILD_CFLAGS += -c -MD -Os -m64 -msoft-float -fno-common

KBUILD_CFLAGS += $(call cc-option,-fno-PIE)

KBUILD_AFLAGS := $(filter-out -DCC_USING_EXPOLINE,$(KBUILD_AFLAGS))

arch/s390/purgatory/head.S

+19 −26
Original line number Diff line number Diff line
@@ -243,33 +243,26 @@ gprregs: 
	.quad	0

	.endr



purgatory_sha256_digest:

	.global purgatory_sha256_digest

	.rept	32	/* SHA256_DIGEST_SIZE */

	.byte	0

	.endr



purgatory_sha_regions:

	.global purgatory_sha_regions

	.rept	16 * __KEXEC_SHA_REGION_SIZE	/* KEXEC_SEGMENTS_MAX */

	.byte	0

	.endr



kernel_entry:

	.global kernel_entry

	.quad	0



kernel_type:

	.global kernel_type

	.quad	0



crash_start:

	.global crash_start

	.quad	0

/* Macro to define a global variable with name and size (in bytes) to be

 * shared with C code.

 *

 * Add the .size and .type attribute to satisfy checks on the Elf_Sym during

 * purgatory load.

 */

.macro GLOBAL_VARIABLE name,size

\name:

	.global \name

	.size	\name,\size

	.type	\name,object

	.skip	\size,0

.endm



crash_size:

	.global crash_size

	.quad	0

GLOBAL_VARIABLE purgatory_sha256_digest,32

GLOBAL_VARIABLE purgatory_sha_regions,16*__KEXEC_SHA_REGION_SIZE

GLOBAL_VARIABLE kernel_entry,8

GLOBAL_VARIABLE kernel_type,8

GLOBAL_VARIABLE crash_start,8

GLOBAL_VARIABLE crash_size,8



	.align	PAGE_SIZE

stack:

arch/s390/purgatory/purgatory.c

+0 −9
Original line number Diff line number Diff line
@@ -12,15 +12,6 @@ 
#include <linux/string.h>

#include <asm/purgatory.h>



struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX];

u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE];



u64 kernel_entry;

u64 kernel_type;



u64 crash_start;

u64 crash_size;



int verify_sha256_digest(void)

{

	struct kexec_sha_region *ptr, *end;