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/packing_test.c | 474 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 474 insertions(+) create mode 100644 lib/packing_test.c (limited to 'lib/packing_test.c') diff --git a/lib/packing_test.c b/lib/packing_test.c new file mode 100644 index 000000000..ce3b83d33 --- /dev/null +++ b/lib/packing_test.c @@ -0,0 +1,474 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024, Vladimir Oltean + * Copyright (c) 2024, Intel Corporation. + */ +#include +#include + +struct packing_test_case { + const char *desc; + const u8 *pbuf; + size_t pbuf_size; + u64 uval; + size_t start_bit; + size_t end_bit; + u8 quirks; +}; + +#define NO_QUIRKS 0 + +/** + * PBUF - Initialize .pbuf and .pbuf_size + * @array: elements of constant physical buffer + * + * Initializes the .pbuf and .pbuf_size fields of a struct packing_test_case + * with a constant array of the specified elements. + */ +#define PBUF(array...) \ + .pbuf = (const u8[]){ array }, \ + .pbuf_size = sizeof((const u8 []){ array }) + +static const struct packing_test_case cases[] = { + /* These tests pack and unpack a magic 64-bit value + * (0xcafedeadbeefcafe) at a fixed logical offset (32) within an + * otherwise zero array of 128 bits (16 bytes). They test all possible + * bit layouts of the 128 bit buffer. + */ + { + .desc = "no quirks, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xca, 0xfe, 0xde, 0xad, + 0xbe, 0xef, 0xca, 0xfe, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = NO_QUIRKS, + }, + { + .desc = "lsw32 first, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xbe, 0xef, 0xca, 0xfe, + 0xca, 0xfe, 0xde, 0xad, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LSW32_IS_FIRST, + }, + { + .desc = "little endian words, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xad, 0xde, 0xfe, 0xca, + 0xfe, 0xca, 0xef, 0xbe, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "lsw32 first + little endian words, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe, + 0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "msb right, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x53, 0x7f, 0x7b, 0xb5, + 0x7d, 0xf7, 0x53, 0x7f, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_MSB_ON_THE_RIGHT, + }, + { + .desc = "msb right + lsw32 first, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x7d, 0xf7, 0x53, 0x7f, + 0x53, 0x7f, 0x7b, 0xb5, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST, + }, + { + .desc = "msb right + little endian words, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xb5, 0x7b, 0x7f, 0x53, + 0x7f, 0x53, 0xf7, 0x7d, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "msb right + lsw32 first + little endian words, 16 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x7f, 0x53, 0xf7, 0x7d, + 0xb5, 0x7b, 0x7f, 0x53, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + /* These tests pack and unpack a magic 64-bit value + * (0xcafedeadbeefcafe) at a fixed logical offset (32) within an + * otherwise zero array of varying size from 18 bytes to 24 bytes. + */ + { + .desc = "no quirks, 18 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xca, 0xfe, + 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe, 0x00, 0x00, + 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = NO_QUIRKS, + }, + { + .desc = "no quirks, 19 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xca, + 0xfe, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe, 0x00, + 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = NO_QUIRKS, + }, + { + .desc = "no quirks, 20 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0xca, 0xfe, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe, + 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = NO_QUIRKS, + }, + { + .desc = "no quirks, 22 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0xca, 0xfe, 0xde, 0xad, 0xbe, 0xef, + 0xca, 0xfe, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = NO_QUIRKS, + }, + { + .desc = "no quirks, 24 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0xca, 0xfe, 0xde, 0xad, + 0xbe, 0xef, 0xca, 0xfe, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = NO_QUIRKS, + }, + { + .desc = "lsw32 first + little endian words, 18 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe, + 0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "lsw32 first + little endian words, 19 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe, + 0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "lsw32 first + little endian words, 20 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe, + 0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "lsw32 first + little endian words, 22 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe, + 0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "lsw32 first + little endian words, 24 bytes", + PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe, + 0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00), + .uval = 0xcafedeadbeefcafe, + .start_bit = 95, + .end_bit = 32, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + /* These tests pack and unpack a magic 64-bit value + * (0x1122334455667788) at an odd starting bit (43) within an + * otherwise zero array of 128 bits (16 bytes). They test all possible + * bit layouts of the 128 bit buffer. + */ + { + .desc = "no quirks, 16 bytes, non-aligned", + PBUF(0x00, 0x00, 0x00, 0x89, 0x11, 0x9a, 0x22, 0xab, + 0x33, 0xbc, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = NO_QUIRKS, + }, + { + .desc = "lsw32 first, 16 bytes, non-aligned", + PBUF(0x00, 0x00, 0x00, 0x00, 0x33, 0xbc, 0x40, 0x00, + 0x11, 0x9a, 0x22, 0xab, 0x00, 0x00, 0x00, 0x89), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_LSW32_IS_FIRST, + }, + { + .desc = "little endian words, 16 bytes, non-aligned", + PBUF(0x89, 0x00, 0x00, 0x00, 0xab, 0x22, 0x9a, 0x11, + 0x00, 0x40, 0xbc, 0x33, 0x00, 0x00, 0x00, 0x00), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "lsw32 first + little endian words, 16 bytes, non-aligned", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0xbc, 0x33, + 0xab, 0x22, 0x9a, 0x11, 0x89, 0x00, 0x00, 0x00), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "msb right, 16 bytes, non-aligned", + PBUF(0x00, 0x00, 0x00, 0x91, 0x88, 0x59, 0x44, 0xd5, + 0xcc, 0x3d, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT, + }, + { + .desc = "msb right + lsw32 first, 16 bytes, non-aligned", + PBUF(0x00, 0x00, 0x00, 0x00, 0xcc, 0x3d, 0x02, 0x00, + 0x88, 0x59, 0x44, 0xd5, 0x00, 0x00, 0x00, 0x91), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST, + }, + { + .desc = "msb right + little endian words, 16 bytes, non-aligned", + PBUF(0x91, 0x00, 0x00, 0x00, 0xd5, 0x44, 0x59, 0x88, + 0x00, 0x02, 0x3d, 0xcc, 0x00, 0x00, 0x00, 0x00), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "msb right + lsw32 first + little endian words, 16 bytes, non-aligned", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x3d, 0xcc, + 0xd5, 0x44, 0x59, 0x88, 0x91, 0x00, 0x00, 0x00), + .uval = 0x1122334455667788, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + /* These tests pack and unpack a u64 with all bits set + * (0xffffffffffffffff) at an odd starting bit (43) within an + * otherwise zero array of 128 bits (16 bytes). They test all possible + * bit layouts of the 128 bit buffer. + */ + { + .desc = "no quirks, 16 bytes, non-aligned, 0xff", + PBUF(0x00, 0x00, 0x07, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xf8, 0x00, 0x00, 0x00, 0x00, 0x00), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = NO_QUIRKS, + }, + { + .desc = "lsw32 first, 16 bytes, non-aligned, 0xff", + PBUF(0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xf8, 0x00, + 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x07, 0xff), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_LSW32_IS_FIRST, + }, + { + .desc = "little endian words, 16 bytes, non-aligned, 0xff", + PBUF(0xff, 0x07, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, + 0x00, 0xf8, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "lsw32 first + little endian words, 16 bytes, non-aligned, 0xff", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0xf8, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0x07, 0x00, 0x00), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "msb right, 16 bytes, non-aligned, 0xff", + PBUF(0x00, 0x00, 0xe0, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0x1f, 0x00, 0x00, 0x00, 0x00, 0x00), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT, + }, + { + .desc = "msb right + lsw32 first, 16 bytes, non-aligned, 0xff", + PBUF(0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x1f, 0x00, + 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0xe0, 0xff), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST, + }, + { + .desc = "msb right + little endian words, 16 bytes, non-aligned, 0xff", + PBUF(0xff, 0xe0, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, + 0x00, 0x1f, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LITTLE_ENDIAN, + }, + { + .desc = "msb right + lsw32 first + little endian words, 16 bytes, non-aligned, 0xff", + PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x00), + .uval = 0xffffffffffffffff, + .start_bit = 106, + .end_bit = 43, + .quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN, + }, +}; + +KUNIT_ARRAY_PARAM_DESC(packing, cases, desc); + +static void packing_test_pack(struct kunit *test) +{ + const struct packing_test_case *params = test->param_value; + u8 *pbuf; + int err; + + pbuf = kunit_kzalloc(test, params->pbuf_size, GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, pbuf); + + err = pack(pbuf, params->uval, params->start_bit, params->end_bit, + params->pbuf_size, params->quirks); + + KUNIT_EXPECT_EQ_MSG(test, err, 0, "pack() returned %pe\n", ERR_PTR(err)); + KUNIT_EXPECT_MEMEQ(test, pbuf, params->pbuf, params->pbuf_size); +} + +static void packing_test_unpack(struct kunit *test) +{ + const struct packing_test_case *params = test->param_value; + u64 uval; + int err; + + err = unpack(params->pbuf, &uval, params->start_bit, params->end_bit, + params->pbuf_size, params->quirks); + KUNIT_EXPECT_EQ_MSG(test, err, 0, "unpack() returned %pe\n", ERR_PTR(err)); + KUNIT_EXPECT_EQ(test, uval, params->uval); +} + +#define PACKED_BUF_SIZE 8 + +typedef struct __packed { u8 buf[PACKED_BUF_SIZE]; } packed_buf_t; + +struct test_data { + u32 field3; + u16 field2; + u16 field4; + u16 field6; + u8 field1; + u8 field5; +}; + +static const struct packed_field_u8 test_fields[] = { + PACKED_FIELD(63, 61, struct test_data, field1), + PACKED_FIELD(60, 52, struct test_data, field2), + PACKED_FIELD(51, 28, struct test_data, field3), + PACKED_FIELD(27, 14, struct test_data, field4), + PACKED_FIELD(13, 9, struct test_data, field5), + PACKED_FIELD(8, 0, struct test_data, field6), +}; + +static void packing_test_pack_fields(struct kunit *test) +{ + const struct test_data data = { + .field1 = 0x2, + .field2 = 0x100, + .field3 = 0xF00050, + .field4 = 0x7D3, + .field5 = 0x9, + .field6 = 0x10B, + }; + packed_buf_t expect = { + .buf = { 0x50, 0x0F, 0x00, 0x05, 0x01, 0xF4, 0xD3, 0x0B }, + }; + packed_buf_t buf = {}; + + pack_fields(&buf, sizeof(buf), &data, test_fields, 0); + + KUNIT_EXPECT_MEMEQ(test, &expect, &buf, sizeof(buf)); +} + +static void packing_test_unpack_fields(struct kunit *test) +{ + const packed_buf_t buf = { + .buf = { 0x17, 0x28, 0x10, 0x19, 0x3D, 0xA9, 0x07, 0x9C }, + }; + struct test_data data = {}; + + unpack_fields(&buf, sizeof(buf), &data, test_fields, 0); + + KUNIT_EXPECT_EQ(test, 0, data.field1); + KUNIT_EXPECT_EQ(test, 0x172, data.field2); + KUNIT_EXPECT_EQ(test, 0x810193, data.field3); + KUNIT_EXPECT_EQ(test, 0x36A4, data.field4); + KUNIT_EXPECT_EQ(test, 0x3, data.field5); + KUNIT_EXPECT_EQ(test, 0x19C, data.field6); +} + +static struct kunit_case packing_test_cases[] = { + KUNIT_CASE_PARAM(packing_test_pack, packing_gen_params), + KUNIT_CASE_PARAM(packing_test_unpack, packing_gen_params), + KUNIT_CASE(packing_test_pack_fields), + KUNIT_CASE(packing_test_unpack_fields), + {}, +}; + +static struct kunit_suite packing_test_suite = { + .name = "packing", + .test_cases = packing_test_cases, +}; + +kunit_test_suite(packing_test_suite); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("KUnit tests for packing library"); -- cgit v1.3.1