On Tue, Jan 14, 2025 at 5:04 AM Sami Tolvanen <samitolvanen@xxxxxxxxxx> wrote:
>
> Hi Masahiro,
>
> On Fri, Jan 10, 2025 at 6:26 PM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> >
> > On Sat, Jan 4, 2025 at 2:37 AM Matthew Maurer <mmaurer@xxxxxxxxxx> wrote:
> > >
> > > From: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> > >
> > > Previously, two things stopped Rust from using MODVERSIONS:
> > > 1. Rust symbols are occasionally too long to be represented in the
> > > original versions table
> > > 2. Rust types cannot be properly hashed by the existing genksyms
> > > approach because:
> > > * Looking up type definitions in Rust is more complex than C
> > > * Type layout is potentially dependent on the compiler in Rust,
> > > not just the source type declaration.
> > >
> > > CONFIG_EXTENDED_MODVERSIONS addresses the first point, and
> > > CONFIG_GENDWARFKSYMS the second. If Rust wants to use MODVERSIONS, allow
> > > it to do so by selecting both features.
> > >
> > > Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> > > Co-developed-by: Matthew Maurer <mmaurer@xxxxxxxxxx>
> > > Signed-off-by: Matthew Maurer <mmaurer@xxxxxxxxxx>
> > > ---
> > > init/Kconfig | 3 ++-
> > > rust/Makefile | 34 ++++++++++++++++++++++++++++++++--
> > > 2 files changed, 34 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/init/Kconfig b/init/Kconfig
> > > index c1f9eb3d5f2e892e977ba1425599502dc830f552..b60acfd9431e0ac2bf401ecb6523b5104ad31150 100644
> > > --- a/init/Kconfig
> > > +++ b/init/Kconfig
> > > @@ -1959,7 +1959,8 @@ config RUST
> > > bool "Rust support"
> > > depends on HAVE_RUST
> > > depends on RUST_IS_AVAILABLE
> > > - depends on !MODVERSIONS
> > > + select EXTENDED_MODVERSIONS if MODVERSIONS
> > > + depends on !MODVERSIONS || GENDWARFKSYMS
> > > depends on !GCC_PLUGIN_RANDSTRUCT
> > > depends on !RANDSTRUCT
> > > depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
> > > diff --git a/rust/Makefile b/rust/Makefile
> > > index a40a3936126d603836e0ec9b42a1285916b60e45..80f970ad81f7989afe5ff2b5f633f50feb7f6006 100644
> > > --- a/rust/Makefile
> > > +++ b/rust/Makefile
> > > @@ -329,10 +329,11 @@ $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ;
> > > $(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers/helpers.c FORCE
> > > $(call if_changed_dep,bindgen)
> > >
> > > +rust_exports = $(NM) -p --defined-only $(1) | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ { printf $(2),$(3) }'
> > > +
> > > quiet_cmd_exports = EXPORTS $@
> > > cmd_exports = \
> > > - $(NM) -p --defined-only $< \
> > > - | awk '$$2~/(T|R|D|B)/ && $$3!~/__cfi/ {printf "EXPORT_SYMBOL_RUST_GPL(%s);\n",$$3}' > $@
> > > + $(call rust_exports,$<,"EXPORT_SYMBOL_RUST_GPL(%s);\n",$$3) > $@
> >
> > I noticed a nit:
> >
> > Both of the two callsites of rust_exports pass
> > '$$3' to the last parameter instead of hardcoding it.
> >
> > Is it a flexibility for future extensions?
> >
> > I cannot think of any other use except for printing
> > the third column, i.e. symbol name.
>
> Good catch, the last parameter isn't necessary anymore. It was used in
> early versions of the series to also pass symbol addresses to
> gendwarfksyms, but that's not needed since we read the symbol table
> directly now.
If you submit a diff, I will squash it to 5/5.
(You do not need to input commit description body)
--
Best Regards
Masahiro Yamada
