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| author | Jiri Kosina <jkosina@suse.cz> | 2015-01-09 10:53:21 +0100 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2015-01-09 10:55:10 +0100 |
| commit | b9dfe0bed999d23ee8838d389637dd8aef83fafa (patch) | |
| tree | 1e1761aa65759226ca26fe931b1b48de4cf65af9 | |
| parent | 83ac237a950e130c974d0170cce30891dcd8f250 (diff) | |
| download | blackbird-obmc-linux-b9dfe0bed999d23ee8838d389637dd8aef83fafa.tar.gz blackbird-obmc-linux-b9dfe0bed999d23ee8838d389637dd8aef83fafa.zip | |
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 <akpm@linux-foundation.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/livepatch.h | 6 | ||||
| -rw-r--r-- | kernel/livepatch/core.c | 6 |
2 files changed, 11 insertions, 1 deletions
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 <linux/ftrace.h> #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); diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 6f6387912da7..ce42d3b930dc 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -911,6 +911,12 @@ static int klp_init(void) { int ret; + ret = klp_check_compiler_support(); + if (ret) { + pr_info("Your compiler is too old; turning off.\n"); + return -EINVAL; + } + ret = register_module_notifier(&klp_module_nb); if (ret) return ret; |
