Commit ba05b39d authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Alexander Gordeev
Browse files

s390/expoline: Make modules use kernel expolines 



Currently, kernel modules contain their own set of expoline thunks. In
the case of EXPOLINE_EXTERN, this involves postlinking of precompiled
expoline.o. expoline.o is also necessary for out-of-source tree module
builds.

Now that the kernel modules area is less than 4 GB away from
kernel expoline thunks, make modules use kernel expolines. Also make
EXPOLINE_EXTERN the default if the compiler supports it. This simplifies
build and aligns with the approach adopted by other architectures.

Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent ea84f14d

arch/s390/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -555,7 +555,7 @@ config EXPOLINE 
	  If unsure, say N.



config EXPOLINE_EXTERN

	def_bool n

	def_bool y if EXPOLINE

	depends on EXPOLINE

	depends on CC_IS_GCC && GCC_VERSION >= 110200

	depends on $(success,$(srctree)/arch/s390/tools/gcc-thunk-extern.sh $(CC))

arch/s390/Makefile

+0 −6
Original line number Diff line number Diff line
@@ -88,7 +88,6 @@ endif 


ifdef CONFIG_EXPOLINE

  ifdef CONFIG_EXPOLINE_EXTERN

    KBUILD_LDFLAGS_MODULE += arch/s390/lib/expoline/expoline.o

    CC_FLAGS_EXPOLINE := -mindirect-branch=thunk-extern

    CC_FLAGS_EXPOLINE += -mfunction-return=thunk-extern

  else
@@ -167,11 +166,6 @@ vdso_prepare: prepare0 
vdso-install-y			+= arch/s390/kernel/vdso64/vdso64.so.dbg

vdso-install-$(CONFIG_COMPAT)	+= arch/s390/kernel/vdso32/vdso32.so.dbg



ifdef CONFIG_EXPOLINE_EXTERN

modules_prepare: expoline_prepare

expoline_prepare: scripts

	$(Q)$(MAKE) $(build)=arch/s390/lib/expoline arch/s390/lib/expoline/expoline.o

endif

endif



# Don't use tabs in echo arguments

arch/s390/include/asm/asm-prototypes.h

+1 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <linux/kvm_host.h>

#include <linux/ftrace.h>

#include <asm/fpu.h>

#include <asm/nospec-branch.h>

#include <asm-generic/asm-prototypes.h>



__int128_t __ashlti3(__int128_t a, int b);

arch/s390/include/asm/nospec-branch.h

+20 −0
Original line number Diff line number Diff line
@@ -17,6 +17,26 @@ static inline bool nospec_uses_trampoline(void) 
	return __is_defined(CC_USING_EXPOLINE) && !nospec_disable;

}



#ifdef CONFIG_EXPOLINE_EXTERN



void __s390_indirect_jump_r1(void);

void __s390_indirect_jump_r2(void);

void __s390_indirect_jump_r3(void);

void __s390_indirect_jump_r4(void);

void __s390_indirect_jump_r5(void);

void __s390_indirect_jump_r6(void);

void __s390_indirect_jump_r7(void);

void __s390_indirect_jump_r8(void);

void __s390_indirect_jump_r9(void);

void __s390_indirect_jump_r10(void);

void __s390_indirect_jump_r11(void);

void __s390_indirect_jump_r12(void);

void __s390_indirect_jump_r13(void);

void __s390_indirect_jump_r14(void);

void __s390_indirect_jump_r15(void);



#endif



#endif /* __ASSEMBLY__ */



#endif /* _ASM_S390_EXPOLINE_H */

arch/s390/include/asm/nospec-insn.h

+7 −6
Original line number Diff line number Diff line
@@ -16,24 +16,25 @@ 
 */

	.macro __THUNK_PROLOG_NAME name

#ifdef CONFIG_EXPOLINE_EXTERN

	.pushsection .text,"ax",@progbits

	__ALIGN

	SYM_CODE_START(\name)

#else

	.pushsection .text.\name,"axG",@progbits,\name,comdat

#endif

	.globl \name

	.hidden \name

	.type \name,@function

\name:

	CFI_STARTPROC

#endif

	.endm



	.macro __THUNK_EPILOG_NAME name

	CFI_ENDPROC

#ifdef CONFIG_EXPOLINE_EXTERN

	.size \name, .-\name

#endif

	SYM_CODE_END(\name)

	EXPORT_SYMBOL(\name)

#else

	CFI_ENDPROC

	.popsection

#endif

	.endm



	.macro __THUNK_PROLOG_BR r1