From 0f1e01960c3e082feac098be5b754ad3e06c820a Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 13 Feb 2018 16:45:20 +0100 Subject: [PATCH 01/12] kaiser: fix compile error without vsyscall MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- arch/x86/include/asm/vsyscall.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/vsyscall.h b/arch/x86/include/asm/vsyscall.h index 9ee8506..62210da 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 */ -- 2.7.4