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authorHugh Dickins <hughd@google.com>2018-02-13 16:45:20 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-16 20:09:40 +0100
commit4f3e6ab44b928ef70b77aa374886cb59fd9e4171 (patch)
treefe1ac513aff0abe35f2c7f584d7f689c6090bd85 /arch/x86/include
parent9b6cab80102ff73bf099c623c778af48a3684d2e (diff)
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 <tjakobi@math.uni-bielefeld.de> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/vsyscall.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/vsyscall.h b/arch/x86/include/asm/vsyscall.h
index 9ee85066f407..62210da19a92 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 */