On Tue, Oct 29, 2019 at 04:58:26PM +0000, Mark Rutland wrote:
> When using patchable-function-entry, the compiler will record the
> callsites into a section named "__patchable_function_entries" rather
> than "__mcount_loc". Let's abstract this difference behind a new
> FTRACE_CALLSITE_SECTION, so that architectures don't have to handle this
> explicitly (e.g. with custom module linker scripts).
>
> As parisc currently handles this explicitly, it is fixed up accordingly,
> with its custom linker script removed. Since FTRACE_CALLSITE_SECTION is
> only defined when DYNAMIC_FTRACE is selected, the parisc module loading
> code is updated to only use the definition in that case. When
> DYNAMIC_FTRACE is not selected, modules shouldn't have this section, so
> this removes some redundant work in that case.
>
> I built parisc generic-{32,64}bit_defconfig with DYNAMIC_FTRACE enabled,
> and verified that the section made it into the .ko files for modules.
This is because of remaining #ifdeffery in include/asm-generic/vmlinux.lds.h:
#ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
#define MCOUNT_REC() . = ALIGN(8); \
__start_mcount_loc = .; \
KEEP(*(__patchable_function_entries)) \
__stop_mcount_loc = .;
#else
#define MCOUNT_REC() . = ALIGN(8); \
__start_mcount_loc = .; \
KEEP(*(__mcount_loc)) \
__stop_mcount_loc = .;
#endif
Maybe you want to tackle that as well? I suggest to have at least one
FTRACE_CALLSITE_SECTION definition without double quotes. Alternatively, my
earlier solution just kept both sections, in case either one or both are
present.
KEEP(*(__patchable_function_entries)) \
KEEP(*(__mcount_loc)) \
Torsten
