On Thu, Aug 18, 2022 at 02:00:21PM -0700, Alexei Starovoitov wrote: > On Thu, Aug 18, 2022 at 1:50 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > > > > On Thu, 18 Aug 2022 22:27:07 +0200 > > Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > > > > ok, so the problem with __attribute__((patchable_function_entry(5))) is that > > > it puts function address into __patchable_function_entries section, which is > > > one of ftrace locations source: > > > > > > #define MCOUNT_REC() . = ALIGN(8); \ > > > __start_mcount_loc = .; \ > > > KEEP(*(__mcount_loc)) \ > > > KEEP(*(__patchable_function_entries)) \ > > > __stop_mcount_loc = .; \ > > > ... > > > > > > > > > it looks like __patchable_function_entries is used for other than x86 archs, > > > so we perhaps we could have x86 specific MCOUNT_REC macro just with > > > __mcount_loc section? > > > > So something like this: > > > > #ifdef CONFIG_X86 > > # define NON_MCOUNT_PATCHABLE KEEP(*(__patchable_function_entries)) > > # define MCOUNT_PATCHABLE > > #else > > # define NON_MCOUNT_PATCHABLE > > # define MCOUNT_PATCHABLE KEEP(*(__patchable_function_entries)) > > #endif > > > > #define MCOUNT_REC() . = ALIGN(8); \ > > __start_mcount_loc = .; \ > > KEEP(*(__mcount_loc)) \ > > MCOUNT_PATCHABLE \ > > __stop_mcount_loc = .; \ > > NON_MCOUNT_PATCHABLE \ > > ... > > > > ?? > > That's what more or less Peter's patch is doing: > Here it is again for reference: > https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?id=8d075bdf11193f1d276bf19fa56b4b8dfe24df9e ah nice, and discards the __patchable_function_entries section, great jirka
