On Fri, Nov 15, 2019 at 01:53:57PM +1100, Stephen Rothwell wrote:
> Hi all,
>
> Today's linux-next merge of the ftrace tree got a conflict in:
>
> include/asm-generic/vmlinux.lds.h
>
> between commit:
>
> a1326b17ac03 ("module/ftrace: handle patchable-function-entry")
>
> from the arm64 tree and commit:
>
> b83b43ffc6e4 ("fgraph: Fix function type mismatches of ftrace_graph_return using ftrace_stub")
>
> from the ftrace tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> --
> Cheers,
> Stephen Rothwell
Thanks Stephen!
Steven (Rostedt), what's your preference for handling this?
We can drop revert the arm64 change to vmlinux.lds.h for now (and I can
send it as a subsequent cleanup), or you could merge my
arm64/ftrace-with-regs branch and fix this up in the ftrace tree.
Thanks,
Mark.
>
> diff --cc include/asm-generic/vmlinux.lds.h
> index 63cedc3c0c77,0f358be551cd..000000000000
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@@ -136,19 -110,30 +136,29 @@@
> #endif
>
> #ifdef CONFIG_FTRACE_MCOUNT_RECORD
> -#ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
> +/*
> + * The ftrace call sites are logged to a section whose name depends on the
> + * compiler option used. A given kernel image will only use one, AKA
> + * FTRACE_CALLSITE_SECTION. We capture all of them here to avoid header
> + * dependencies for FTRACE_CALLSITE_SECTION's definition.
> + */
> + /*
> + * Need to also make ftrace_graph_stub point to ftrace_stub
> + * so that the same stub location may have different protocols
> + * and not mess up with C verifiers.
> + */
> -#define MCOUNT_REC() . = ALIGN(8); \
> - __start_mcount_loc = .; \
> - KEEP(*(__patchable_function_entries)) \
> - __stop_mcount_loc = .; \
> - ftrace_graph_stub = ftrace_stub;
> -#else
> #define MCOUNT_REC() . = ALIGN(8); \
> __start_mcount_loc = .; \
> KEEP(*(__mcount_loc)) \
> + KEEP(*(__patchable_function_entries)) \
> - __stop_mcount_loc = .;
> + __stop_mcount_loc = .; \
> + ftrace_graph_stub = ftrace_stub;
> -#endif
> #else
> - #define MCOUNT_REC()
> + # ifdef CONFIG_FUNCTION_TRACER
> + # define MCOUNT_REC() ftrace_graph_stub = ftrace_stub;
> + # else
> + # define MCOUNT_REC()
> + # endif
> #endif
>
> #ifdef CONFIG_TRACE_BRANCH_PROFILING
