I wonder if clang folks have seen this and perhaps have a comment as to why the volatile gets ingored... Added. On Wed, Dec 22, 2021 at 09:10:30AM -0000, tip-bot2 for Josh Poimboeuf wrote: > The following commit has been merged into the objtool/urgent branch of tip: > > Commit-ID: dcce50e6cc4d86a63dc0a9a6ee7d4f948ccd53a1 > Gitweb: https://git.kernel.org/tip/dcce50e6cc4d86a63dc0a9a6ee7d4f948ccd53a1 > Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > AuthorDate: Mon, 08 Nov 2021 14:35:59 -08:00 > Committer: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > CommitterDate: Tue, 21 Dec 2021 15:09:46 -08:00 > > compiler.h: Fix annotation macro misplacement with Clang > > When building with Clang and CONFIG_TRACE_BRANCH_PROFILING, there are a > lot of unreachable warnings, like: > > arch/x86/kernel/traps.o: warning: objtool: handle_xfd_event()+0x134: unreachable instruction > > Without an input to the inline asm, 'volatile' is ignored for some > reason and Clang feels free to move the reachable() annotation away from > its intended location. > > Fix that by re-adding the counter value to the inputs. > > Fixes: f1069a8756b9 ("compiler.h: Avoid using inline asm operand modifiers") > Fixes: c199f64ff93c ("instrumentation.h: Avoid using inline asm operand modifiers") > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > Link: https://lore.kernel.org/r/0417e96909b97a406323409210de7bf13df0b170.1636410380.git.jpoimboe@xxxxxxxxxx > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: x86@xxxxxxxxxx > Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> > Cc: Miroslav Benes <mbenes@xxxxxxx> > --- > include/linux/compiler.h | 4 ++-- > include/linux/instrumentation.h | 4 ++-- > 2 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index 3d5af56..429dceb 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -121,7 +121,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, > asm volatile(__stringify_label(c) ":\n\t" \ > ".pushsection .discard.reachable\n\t" \ > ".long " __stringify_label(c) "b - .\n\t" \ > - ".popsection\n\t"); \ > + ".popsection\n\t" : : "i" (c)); \ > }) > #define annotate_reachable() __annotate_reachable(__COUNTER__) > > @@ -129,7 +129,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, > asm volatile(__stringify_label(c) ":\n\t" \ > ".pushsection .discard.unreachable\n\t" \ > ".long " __stringify_label(c) "b - .\n\t" \ > - ".popsection\n\t"); \ > + ".popsection\n\t" : : "i" (c)); \ > }) > #define annotate_unreachable() __annotate_unreachable(__COUNTER__) > > diff --git a/include/linux/instrumentation.h b/include/linux/instrumentation.h > index fa2cd8c..24359b4 100644 > --- a/include/linux/instrumentation.h > +++ b/include/linux/instrumentation.h > @@ -11,7 +11,7 @@ > asm volatile(__stringify(c) ": nop\n\t" \ > ".pushsection .discard.instr_begin\n\t" \ > ".long " __stringify(c) "b - .\n\t" \ > - ".popsection\n\t"); \ > + ".popsection\n\t" : : "i" (c)); \ > }) > #define instrumentation_begin() __instrumentation_begin(__COUNTER__) > > @@ -50,7 +50,7 @@ > asm volatile(__stringify(c) ": nop\n\t" \ > ".pushsection .discard.instr_end\n\t" \ > ".long " __stringify(c) "b - .\n\t" \ > - ".popsection\n\t"); \ > + ".popsection\n\t" : : "i" (c)); \ > }) > #define instrumentation_end() __instrumentation_end(__COUNTER__) > #else -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
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