From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- lib/kunit/resource.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 178 insertions(+) create mode 100644 lib/kunit/resource.c (limited to 'lib/kunit/resource.c') diff --git a/lib/kunit/resource.c b/lib/kunit/resource.c new file mode 100644 index 000000000..45e55238c --- /dev/null +++ b/lib/kunit/resource.c @@ -0,0 +1,178 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit resource API for test managed resources (allocations, etc.). + * + * Copyright (C) 2022, Google LLC. + * Author: Daniel Latypov + */ + +#include +#include +#include + +/* + * Used for static resources and when a kunit_resource * has been created by + * kunit_alloc_resource(). When an init function is supplied, @data is passed + * into the init function; otherwise, we simply set the resource data field to + * the data value passed in. Doesn't initialize res->should_kfree. + */ +int __kunit_add_resource(struct kunit *test, + kunit_resource_init_t init, + kunit_resource_free_t free, + struct kunit_resource *res, + void *data) +{ + int ret = 0; + unsigned long flags; + + res->free = free; + kref_init(&res->refcount); + + if (init) { + ret = init(res, data); + if (ret) + return ret; + } else { + res->data = data; + } + + spin_lock_irqsave(&test->lock, flags); + list_add_tail(&res->node, &test->resources); + /* refcount for list is established by kref_init() */ + spin_unlock_irqrestore(&test->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(__kunit_add_resource); + +void kunit_remove_resource(struct kunit *test, struct kunit_resource *res) +{ + unsigned long flags; + bool was_linked; + + spin_lock_irqsave(&test->lock, flags); + was_linked = !list_empty(&res->node); + list_del_init(&res->node); + spin_unlock_irqrestore(&test->lock, flags); + + if (was_linked) + kunit_put_resource(res); +} +EXPORT_SYMBOL_GPL(kunit_remove_resource); + +int kunit_destroy_resource(struct kunit *test, kunit_resource_match_t match, + void *match_data) +{ + struct kunit_resource *res = kunit_find_resource(test, match, + match_data); + + if (!res) + return -ENOENT; + + kunit_remove_resource(test, res); + + /* We have a reference also via _find(); drop it. */ + kunit_put_resource(res); + + return 0; +} +EXPORT_SYMBOL_GPL(kunit_destroy_resource); + +struct kunit_action_ctx { + struct kunit_resource res; + kunit_action_t *func; + void *ctx; +}; + +static void __kunit_action_free(struct kunit_resource *res) +{ + struct kunit_action_ctx *action_ctx = container_of(res, struct kunit_action_ctx, res); + + action_ctx->func(action_ctx->ctx); +} + + +int kunit_add_action(struct kunit *test, void (*action)(void *), void *ctx) +{ + struct kunit_action_ctx *action_ctx; + + KUNIT_ASSERT_NOT_NULL_MSG(test, action, "Tried to action a NULL function!"); + + action_ctx = kzalloc_obj(*action_ctx); + if (!action_ctx) + return -ENOMEM; + + action_ctx->func = action; + action_ctx->ctx = ctx; + + action_ctx->res.should_kfree = true; + /* As init is NULL, this cannot fail. */ + __kunit_add_resource(test, NULL, __kunit_action_free, &action_ctx->res, action_ctx); + + return 0; +} +EXPORT_SYMBOL_GPL(kunit_add_action); + +int kunit_add_action_or_reset(struct kunit *test, void (*action)(void *), + void *ctx) +{ + int res = kunit_add_action(test, action, ctx); + + if (res) + action(ctx); + return res; +} +EXPORT_SYMBOL_GPL(kunit_add_action_or_reset); + +static bool __kunit_action_match(struct kunit *test, + struct kunit_resource *res, void *match_data) +{ + struct kunit_action_ctx *match_ctx = (struct kunit_action_ctx *)match_data; + struct kunit_action_ctx *res_ctx = container_of(res, struct kunit_action_ctx, res); + + /* Make sure this is a free function. */ + if (res->free != __kunit_action_free) + return false; + + /* Both the function and context data should match. */ + return (match_ctx->func == res_ctx->func) && (match_ctx->ctx == res_ctx->ctx); +} + +void kunit_remove_action(struct kunit *test, + kunit_action_t *action, + void *ctx) +{ + struct kunit_action_ctx match_ctx; + struct kunit_resource *res; + + match_ctx.func = action; + match_ctx.ctx = ctx; + + res = kunit_find_resource(test, __kunit_action_match, &match_ctx); + if (res) { + /* Remove the free function so we don't run the action. */ + res->free = NULL; + kunit_remove_resource(test, res); + kunit_put_resource(res); + } +} +EXPORT_SYMBOL_GPL(kunit_remove_action); + +void kunit_release_action(struct kunit *test, + kunit_action_t *action, + void *ctx) +{ + struct kunit_action_ctx match_ctx; + struct kunit_resource *res; + + match_ctx.func = action; + match_ctx.ctx = ctx; + + res = kunit_find_resource(test, __kunit_action_match, &match_ctx); + if (res) { + kunit_remove_resource(test, res); + /* We have to put() this here, else free won't be called. */ + kunit_put_resource(res); + } +} +EXPORT_SYMBOL_GPL(kunit_release_action); -- cgit v1.3.1