From b9dfe0bed999d23ee8838d389637dd8aef83fafa Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Fri, 9 Jan 2015 10:53:21 +0100 Subject: livepatch: handle ancient compilers with more grace We are aborting a build in case when gcc doesn't support fentry on x86_64 (regs->ip modification can't really reliably work with mcount). This however breaks allmodconfig for people with older gccs that don't support -mfentry. Turn the build-time failure into runtime failure, resulting in the whole infrastructure not being initialized if CC_USING_FENTRY is unset. Reported-by: Andrew Morton Signed-off-by: Jiri Kosina Signed-off-by: Andrew Morton Acked-by: Josh Poimboeuf --- arch/x86/include/asm/livepatch.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'arch/x86/include/asm/livepatch.h') diff --git a/arch/x86/include/asm/livepatch.h b/arch/x86/include/asm/livepatch.h index b5608d7757fd..26e58134c8cb 100644 --- a/arch/x86/include/asm/livepatch.h +++ b/arch/x86/include/asm/livepatch.h @@ -25,9 +25,13 @@ #include #ifdef CONFIG_LIVE_PATCHING +static inline int klp_check_compiler_support(void) +{ #ifndef CC_USING_FENTRY -#error Your compiler must support -mfentry for live patching to work + return 1; #endif + return 0; +} extern int klp_write_module_reloc(struct module *mod, unsigned long type, unsigned long loc, unsigned long value); -- cgit v1.2.3