From: Hugh Dickins Date: Tue, 13 Feb 2018 15:45:20 +0000 (+0100) Subject: kaiser: fix compile error without vsyscall X-Git-Tag: v4.9.82~82 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=83946c33b9b99b5bc6157cfbf3970265f006c2bf;p=thirdparty%2Fkernel%2Fstable.git kaiser: fix compile error without vsyscall Tobias noticed a compile error on 4.4.115, and it's the same on 4.9.80: arch/x86/mm/kaiser.c: In function ‘kaiser_init’: arch/x86/mm/kaiser.c:348:8: error: ‘vsyscall_pgprot’ undeclared (first use in this function) It seems like his combination of kernel options doesn't work for KAISER. X86_VSYSCALL_EMULATION is not set on his system, while LEGACY_VSYSCALL is set to NONE (LEGACY_VSYSCALL_NONE=y). He managed to get things compiling again, by moving the 'extern unsigned long vsyscall_pgprot' outside of the preprocessor statement. This works because the optimizer removes that code (vsyscall_enabled() is always false) - and that's how it was done in some older backports. Reported-by: Tobias Jakobi Signed-off-by: Hugh Dickins Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/include/asm/vsyscall.h b/arch/x86/include/asm/vsyscall.h index 9ee85066f4072..62210da19a929 100644 --- a/arch/x86/include/asm/vsyscall.h +++ b/arch/x86/include/asm/vsyscall.h @@ -13,7 +13,6 @@ extern void map_vsyscall(void); */ extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address); extern bool vsyscall_enabled(void); -extern unsigned long vsyscall_pgprot; #else static inline void map_vsyscall(void) {} static inline bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) @@ -22,5 +21,6 @@ static inline bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) } static inline bool vsyscall_enabled(void) { return false; } #endif +extern unsigned long vsyscall_pgprot; #endif /* _ASM_X86_VSYSCALL_H */