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/tests/bitops_kunit.c | 205 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 205 insertions(+) create mode 100644 lib/tests/bitops_kunit.c (limited to 'lib/tests/bitops_kunit.c') diff --git a/lib/tests/bitops_kunit.c b/lib/tests/bitops_kunit.c new file mode 100644 index 000000000..7fd9d697f --- /dev/null +++ b/lib/tests/bitops_kunit.c @@ -0,0 +1,205 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 Intel Corporation + * Copyright (C) 2026 Ryota Sakamoto + */ + +#include +#include +#include + +/* use an enum because that's the most common BITMAP usage */ +enum bitops_fun { + BITOPS_4 = 4, + BITOPS_7 = 7, + BITOPS_11 = 11, + BITOPS_31 = 31, + BITOPS_88 = 88, + BITOPS_LENGTH = 256 +}; + +struct bitops_test_case { + const char *str; + const long nr; +}; + +static struct bitops_test_case bitops_cases[] = { + { + .str = "BITOPS_4", + .nr = BITOPS_4, + }, + { + .str = "BITOPS_7", + .nr = BITOPS_7, + }, + { + .str = "BITOPS_11", + .nr = BITOPS_11, + }, + { + .str = "BITOPS_31", + .nr = BITOPS_31, + }, + { + .str = "BITOPS_88", + .nr = BITOPS_88, + }, +}; + +KUNIT_ARRAY_PARAM_DESC(bitops, bitops_cases, str); + +static void test_set_bit_clear_bit(struct kunit *test) +{ + const struct bitops_test_case *params = test->param_value; + DECLARE_BITMAP(bitmap, BITOPS_LENGTH); + int bit_set; + + bitmap_zero(bitmap, BITOPS_LENGTH); + + set_bit(params->nr, bitmap); + KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap)); + + clear_bit(params->nr, bitmap); + KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap)); + + bit_set = find_first_bit(bitmap, BITOPS_LENGTH); + KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH); +} + +static void test_change_bit(struct kunit *test) +{ + const struct bitops_test_case *params = test->param_value; + DECLARE_BITMAP(bitmap, BITOPS_LENGTH); + int bit_set; + + bitmap_zero(bitmap, BITOPS_LENGTH); + + change_bit(params->nr, bitmap); + KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap)); + + change_bit(params->nr, bitmap); + KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap)); + + bit_set = find_first_bit(bitmap, BITOPS_LENGTH); + KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH); +} + +static void test_test_and_set_bit_test_and_clear_bit(struct kunit *test) +{ + const struct bitops_test_case *params = test->param_value; + DECLARE_BITMAP(bitmap, BITOPS_LENGTH); + int bit_set; + + bitmap_zero(bitmap, BITOPS_LENGTH); + + KUNIT_EXPECT_FALSE(test, test_and_set_bit(params->nr, bitmap)); + KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap)); + + KUNIT_EXPECT_TRUE(test, test_and_set_bit(params->nr, bitmap)); + KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap)); + + KUNIT_EXPECT_TRUE(test, test_and_clear_bit(params->nr, bitmap)); + KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap)); + + KUNIT_EXPECT_FALSE(test, test_and_clear_bit(params->nr, bitmap)); + KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap)); + + bit_set = find_first_bit(bitmap, BITOPS_LENGTH); + KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH); +} + +static void test_test_and_change_bit(struct kunit *test) +{ + const struct bitops_test_case *params = test->param_value; + DECLARE_BITMAP(bitmap, BITOPS_LENGTH); + int bit_set; + + bitmap_zero(bitmap, BITOPS_LENGTH); + + KUNIT_EXPECT_FALSE(test, test_and_change_bit(params->nr, bitmap)); + KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap)); + + KUNIT_EXPECT_TRUE(test, test_and_change_bit(params->nr, bitmap)); + KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap)); + + bit_set = find_first_bit(bitmap, BITOPS_LENGTH); + KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH); +} + +struct order_test_case { + const char *str; + const unsigned int count; + const int expected; +}; + +static struct order_test_case order_test_cases[] = { + {"0x00000003", 0x00000003, 2}, + {"0x00000004", 0x00000004, 2}, + {"0x00001fff", 0x00001fff, 13}, + {"0x00002000", 0x00002000, 13}, + {"0x50000000", 0x50000000, 31}, + {"0x80000000", 0x80000000, 31}, + {"0x80003000", 0x80003000, 32}, +}; + +KUNIT_ARRAY_PARAM_DESC(order, order_test_cases, str); + +static void test_get_count_order(struct kunit *test) +{ + const struct order_test_case *params = test->param_value; + + KUNIT_EXPECT_EQ(test, get_count_order(params->count), params->expected); + KUNIT_EXPECT_EQ(test, get_count_order_long(params->count), params->expected); +} + +#ifdef CONFIG_64BIT +struct order_long_test_case { + const char *str; + const unsigned long count; + const int expected; +}; + +static struct order_long_test_case order_long_test_cases[] = { + {"0x0000000300000000", 0x0000000300000000, 34}, + {"0x0000000400000000", 0x0000000400000000, 34}, + {"0x00001fff00000000", 0x00001fff00000000, 45}, + {"0x0000200000000000", 0x0000200000000000, 45}, + {"0x5000000000000000", 0x5000000000000000, 63}, + {"0x8000000000000000", 0x8000000000000000, 63}, + {"0x8000300000000000", 0x8000300000000000, 64}, +}; + +KUNIT_ARRAY_PARAM_DESC(order_long, order_long_test_cases, str); + +static void test_get_count_order_long(struct kunit *test) +{ + const struct order_long_test_case *params = test->param_value; + + KUNIT_EXPECT_EQ(test, get_count_order_long(params->count), params->expected); +} +#endif + +static struct kunit_case bitops_test_cases[] = { + KUNIT_CASE_PARAM(test_set_bit_clear_bit, bitops_gen_params), + KUNIT_CASE_PARAM(test_change_bit, bitops_gen_params), + KUNIT_CASE_PARAM(test_test_and_set_bit_test_and_clear_bit, bitops_gen_params), + KUNIT_CASE_PARAM(test_test_and_change_bit, bitops_gen_params), + KUNIT_CASE_PARAM(test_get_count_order, order_gen_params), +#ifdef CONFIG_64BIT + KUNIT_CASE_PARAM(test_get_count_order_long, order_long_gen_params), +#endif + {}, +}; + +static struct kunit_suite bitops_test_suite = { + .name = "bitops", + .test_cases = bitops_test_cases, +}; + +kunit_test_suite(bitops_test_suite); + +MODULE_AUTHOR("Jesse Brandeburg "); +MODULE_AUTHOR("Wei Yang "); +MODULE_AUTHOR("Ryota Sakamoto "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Bit testing module"); -- cgit v1.3.1