On Thu, Jun 25, 2020 at 10:02:35PM +0200, Peter Zijlstra wrote: > On Thu, Jun 25, 2020 at 09:15:03AM -0700, Sami Tolvanen wrote: > > On Thu, Jun 25, 2020 at 09:45:30AM +0200, Peter Zijlstra wrote: > > > > At least for x86_64 I can do a really quick take for a recordmcount pass > > > in objtool, but I suppose you also need this for ARM64 ? > > > > Sure, sounds good. arm64 uses -fpatchable-function-entry with clang, so we > > don't need recordmcount there. > > This is on top of my local pile: > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git master > > which notably includes the static_call series. > > Not boot tested, but it generates the required sections and they look > more or less as expected, ymmv. > > --- > arch/x86/Kconfig | 1 - > scripts/Makefile.build | 3 ++ > scripts/link-vmlinux.sh | 2 +- > tools/objtool/builtin-check.c | 9 ++--- > tools/objtool/builtin.h | 2 +- > tools/objtool/check.c | 81 +++++++++++++++++++++++++++++++++++++++++++ > tools/objtool/check.h | 1 + > tools/objtool/objtool.h | 1 + > 8 files changed, 91 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index a291823f3f26..189575c12434 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -174,7 +174,6 @@ config X86 > select HAVE_EXIT_THREAD > select HAVE_FAST_GUP > select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE > - select HAVE_FTRACE_MCOUNT_RECORD > select HAVE_FUNCTION_GRAPH_TRACER > select HAVE_FUNCTION_TRACER > select HAVE_GCC_PLUGINS This breaks DYNAMIC_FTRACE according to kernel/trace/ftrace.c: #ifndef CONFIG_FTRACE_MCOUNT_RECORD # error Dynamic ftrace depends on MCOUNT_RECORD #endif And the build errors after that seem to confirm this. It looks like we might need another flag to skip recordmcount. Anyway, since objtool is run before recordmcount, I just left this unchanged for testing and ignored the recordmcount warnings about __mcount_loc already existing. Something is a bit off still though, I see this at boot: ------------[ ftrace bug ]------------ ftrace failed to modify [<ffffffff81000660>] __tracepoint_iter_initcall_level+0x0/0x40 actual: 0f:1f:44:00:00 Initializing ftrace call sites ftrace record flags: 0 (0) expected tramp: ffffffff81056500 ------------[ cut here ]------------ Otherwise, this looks pretty good. Sami
