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authorIlya Leoshkevich <iii@linux.ibm.com>2025-05-19 23:30:04 +0100
committerAlexei Starovoitov <ast@kernel.org>2025-05-22 08:40:56 -0700
commitf7562001c8b854390899b53d06ba4202c89339e6 (patch)
treea285c2a99d579a43899480b32c304a42d28f5563
parent4e2e6841ff761cc15a54e8bebcf35d7325ec78a2 (diff)
s390: always declare expoline thunks
It would be convenient to use the following pattern in the BPF JIT: if (nospec_uses_trampoline()) emit_call(__s390_indirect_jump_r1); Unfortunately with CONFIG_EXPOLINE=n the compiler complains about the missing prototype of __s390_indirect_jump_r1(). One could wrap the whole "if" statement in an #ifdef, but this clutters the code. Instead, declare expoline thunk prototypes even when compiling without expolines. When using the above code structure and compiling without expolines, references to them are optimized away, and there are no linker errors. Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/r/20250519223646.66382-2-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r--arch/s390/include/asm/nospec-branch.h4
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/s390/include/asm/nospec-branch.h b/arch/s390/include/asm/nospec-branch.h
index 192835a3e24d..c7c96282f011 100644
--- a/arch/s390/include/asm/nospec-branch.h
+++ b/arch/s390/include/asm/nospec-branch.h
@@ -26,8 +26,6 @@ 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);
@@ -44,8 +42,6 @@ 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 */