Re: [PATCH v7 3/3] rust: Use gendwarfksyms + extended modversions for CONFIG_MODVERSIONS
From: Sami Tolvanen <samitolvanen@google.com>
Date: 2024-10-24 23:06:27
Also in:
linux-kbuild, linux-modules, lkml, rust-for-linux
On Wed, Oct 23, 2024 at 02:31:30AM +0000, Matthew Maurer wrote:
quoted hunk ↗ jump to hunk
From: Sami Tolvanen <samitolvanen@google.com> 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@google.com> Co-developed-by: Matthew Maurer <redacted> Signed-off-by: Matthew Maurer <redacted> --- init/Kconfig | 3 ++- rust/Makefile | 32 ++++++++++++++++++++++++++++++-- 2 files changed, 32 insertions(+), 3 deletions(-)diff --git a/init/Kconfig b/init/Kconfig index 530a382ee0feb391b4717abdba3672e584a462d0..f5cce579f29b2ed89e97f8075a3bf70e32e71ad0 100644 --- a/init/Kconfig +++ b/init/Kconfig@@ -1942,7 +1942,8 @@ config RUST bool "Rust support" depends on HAVE_RUST depends on RUST_IS_AVAILABLE - depends on !MODVERSIONS + select EXTENDED_MODVERSIONS if MODVERSIONS + depends on (GENDWARFKSYMS || !MODVERSIONS)
Nit: `depends on !MODVERSIONS || GENDWARFKSYMS` would match the convention used below.
+cmd_gendwarfksyms = $(if $(skip_gendwarfksyms),, \ + $(call rust_exports,$@,"%s\n",$$3) | \ + scripts/gendwarfksyms/gendwarfksyms \ + $(if $(KBUILD_SYMTYPES), --symtypes $(@:.o=.symtypes),) \ + $@ >> $(dot-target).cmd)
Note that Petr suggested adding a KBUILD_ flag for passing the --stable parameter to gendwarfksyms, which I think would be useful, so once I send out v5 of that series, we'll have to update this to also use the parameter when processing Rust objects: https://lore.kernel.org/linux-modules/8017c328-f039-46c3-b472-f203cd6e2cfe@suse.com/ (local) Sami