From: Sami Tolvanen <samitolvanen@google.com>
To: "Miguel Ojeda" <ojeda@kernel.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <benno.lossin@proton.me>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>
Cc: Sami Tolvanen <samitolvanen@google.com>,
	rust-for-linux@vger.kernel.org,  linux-kernel@vger.kernel.org
Subject: [PATCH] rust: kbuild: Don't export __pfx symbols
Date: Tue, 18 Mar 2025 23:18:16 +0000	[thread overview]
Message-ID: <20250318231815.917621-2-samitolvanen@google.com> (raw)

With CONFIG_PREFIX_SYMBOLS, objtool adds __pfx prefix symbols
to claim the compiler emitted call padding bytes. When
CONFIG_X86_KERNEL_IBT is not selected, the symbols are added to
individual object files and for Rust objects, they end up being
exported, resulting in warnings with CONFIG_GENDWARFKSYMS as the
symbols have no debugging information:

warning: gendwarfksyms: symbol_print_versions: no information for symbol __pfx_rust_helper_put_task_struct
warning: gendwarfksyms: symbol_print_versions: no information for symbol __pfx_rust_helper_task_euid
warning: gendwarfksyms: symbol_print_versions: no information for symbol __pfx_rust_helper_readq_relaxed
...

Filter out the __pfx prefix from exported symbols similarly to
the existing __cfi and __odr_asan prefixes.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 rust/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/Makefile b/rust/Makefile
index ea3849eb78f6..eb18b59d4f39 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -332,7 +332,7 @@ $(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/ && $$3!~/__odr_asan/ { printf $(2),$$3 }'
+rust_exports = $(NM) -p --defined-only $(1) | awk '$$2~/(T|R|D|B)/ && $$3!~/__(pfx|cfi|odr_asan)/ { printf $(2),$$3 }'
 
 quiet_cmd_exports = EXPORTS $@
       cmd_exports = \
-- 
2.49.0.rc1.451.g8f38331e32-goog

next             reply	other threads:[~2025-03-18 23:18 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-18 23:18 Sami Tolvanen [this message]
2025-03-19 12:06 ` [PATCH] rust: kbuild: Don't export __pfx symbols Alice Ryhl
2025-04-08 19:50 ` Miguel Ojeda

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