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([140.174.215.88]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e8976ec158sm73622826d6.119.2025.03.04.18.10.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 18:10:54 -0800 (PST) From: Emil Tsalapatis To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, yonghong.song@linux.dev, tj@kernel.org, memxor@gmail.com, houtao@huaweicloud.com, Emil Tsalapatis Subject: [PATCH v2 1/2] bpf: add kfunc for populating cpumask bits Date: Tue, 4 Mar 2025 21:10:19 -0500 Message-ID: <20250305021020.1004858-2-emil@etsalapatis.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250305021020.1004858-1-emil@etsalapatis.com> References: <20250305021020.1004858-1-emil@etsalapatis.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Signed-off-by: Emil Tsalapatis (Meta) --- kernel/bpf/cpumask.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c index cfa1c18e3a48..e4e4109b72ad 100644 --- a/kernel/bpf/cpumask.c +++ b/kernel/bpf/cpumask.c @@ -420,6 +420,32 @@ __bpf_kfunc u32 bpf_cpumask_weight(const struct cpumask *cpumask) return cpumask_weight(cpumask); } +/** + * bpf_cpumask_fill() - Populate the CPU mask from the contents of + * a BPF memory region. + * + * @cpumask: The cpumask being populated. + * @src: The BPF memory holding the bit pattern. + * @src__sz: Length of the BPF memory region in bytes. + * + */ +__bpf_kfunc int bpf_cpumask_fill(struct cpumask *cpumask, void *src, size_t src__sz) +{ + unsigned long source = (unsigned long)src; + + /* The memory region must be large enough to populate the entire CPU mask. */ + if (src__sz < bitmap_size(nr_cpu_ids)) + return -EACCES; + + /* The input region must be aligned to the nearest long. */ + if (!IS_ALIGNED(source, sizeof(long))) + return -EINVAL; + + bitmap_copy(cpumask_bits(cpumask), src, nr_cpu_ids); + + return 0; +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(cpumask_kfunc_btf_ids) @@ -448,6 +474,7 @@ BTF_ID_FLAGS(func, bpf_cpumask_copy, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_any_distribute, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_any_and_distribute, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_weight, KF_RCU) +BTF_ID_FLAGS(func, bpf_cpumask_fill, KF_RCU) BTF_KFUNCS_END(cpumask_kfunc_btf_ids) static const struct btf_kfunc_id_set cpumask_kfunc_set = { From patchwork Wed Mar 5 02:10:20 2025 Content-Type: text/plain; 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([140.174.215.88]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e8976ec158sm73622826d6.119.2025.03.04.18.10.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 18:10:56 -0800 (PST) From: Emil Tsalapatis To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, yonghong.song@linux.dev, tj@kernel.org, memxor@gmail.com, houtao@huaweicloud.com, Emil Tsalapatis Subject: [PATCH v2 2/2] selftests: bpf: add bpf_cpumask_fill selftests Date: Tue, 4 Mar 2025 21:10:20 -0500 Message-ID: <20250305021020.1004858-3-emil@etsalapatis.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250305021020.1004858-1-emil@etsalapatis.com> References: <20250305021020.1004858-1-emil@etsalapatis.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Signed-off-by: Emil Tsalapatis (Meta) --- .../selftests/bpf/prog_tests/cpumask.c | 3 + .../selftests/bpf/progs/cpumask_failure.c | 38 ++++++ .../selftests/bpf/progs/cpumask_success.c | 109 ++++++++++++++++++ 3 files changed, 150 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cpumask.c b/tools/testing/selftests/bpf/prog_tests/cpumask.c index e58a04654238..6185b63b931b 100644 --- a/tools/testing/selftests/bpf/prog_tests/cpumask.c +++ b/tools/testing/selftests/bpf/prog_tests/cpumask.c @@ -25,6 +25,9 @@ static const char * const cpumask_success_testcases[] = { "test_global_mask_nested_deep_rcu", "test_global_mask_nested_deep_array_rcu", "test_cpumask_weight", + "test_fill_reject_unaligned", + "test_fill_reject_small_mask", + "test_fill", }; static void verify_success(const char *prog_name) diff --git a/tools/testing/selftests/bpf/progs/cpumask_failure.c b/tools/testing/selftests/bpf/progs/cpumask_failure.c index b40b52548ffb..acecded8b155 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_failure.c +++ b/tools/testing/selftests/bpf/progs/cpumask_failure.c @@ -222,3 +222,41 @@ int BPF_PROG(test_invalid_nested_array, struct task_struct *task, u64 clone_flag return 0; } + +SEC("tp_btf/task_newtask") +__failure __msg("type=scalar expected=fp") +int BPF_PROG(test_fill_invalid_destination, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *invalid = (struct bpf_cpumask *)0x123456; + u64 bits; + int ret; + + ret = bpf_cpumask_fill((struct cpumask *)invalid, &bits, sizeof(bits)); + if (!ret) + err = 2; + + return 0; +} + +SEC("tp_btf/task_newtask") +__failure __msg("leads to invalid memory access") +int BPF_PROG(test_fill_invalid_source, struct task_struct *task, u64 clone_flags) +{ + void *garbage = (void *)0x123456; + struct bpf_cpumask *local; + int ret; + + local = create_cpumask(); + if (!local) { + err = 1; + return 0; + } + + ret = bpf_cpumask_fill((struct cpumask *)local, garbage, 8); + if (!ret) + err = 2; + + bpf_cpumask_release(local); + + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/cpumask_success.c b/tools/testing/selftests/bpf/progs/cpumask_success.c index 80ee469b0b60..8f782e929af1 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_success.c +++ b/tools/testing/selftests/bpf/progs/cpumask_success.c @@ -757,6 +757,7 @@ int BPF_PROG(test_refcount_null_tracking, struct task_struct *task, u64 clone_fl mask1 = bpf_cpumask_create(); mask2 = bpf_cpumask_create(); + if (!mask1 || !mask2) goto free_masks_return; @@ -770,3 +771,111 @@ int BPF_PROG(test_refcount_null_tracking, struct task_struct *task, u64 clone_fl bpf_cpumask_release(mask2); return 0; } + +SEC("tp_btf/task_newtask") +__success +int BPF_PROG(test_fill_reject_small_mask, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *local; + u8 toofewbits; + int ret; + + local = create_cpumask(); + if (!local) + return 0; + + /* The kfunc should prevent this operation */ + ret = bpf_cpumask_fill((struct cpumask *)local, &toofewbits, sizeof(toofewbits)); + if (ret != -EACCES) + err = 2; + + bpf_cpumask_release(local); + + return 0; +} + +/* Mask is guaranteed to be large enough for bpf_cpumask_t. */ +#define CPUMASK_TEST_MASKLEN (sizeof(cpumask_t)) + +/* Add an extra word for the test_fill_reject_unaligned test. */ +u64 bits[CPUMASK_TEST_MASKLEN / 8 + 1]; + +SEC("tp_btf/task_newtask") +__success +int BPF_PROG(test_fill_reject_unaligned, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *mask; + char *src; + int ret; + + mask = bpf_cpumask_create(); + if (!mask) { + err = 1; + return 0; + } + + /* Misalign the source array by a byte. */ + src = &((char *)bits)[1]; + + ret = bpf_cpumask_fill((struct cpumask *)mask, src, CPUMASK_TEST_MASKLEN); + if (ret != -EINVAL) + err = 2; + + bpf_cpumask_release(mask); + + return 0; +} + + +SEC("tp_btf/task_newtask") +__success +int BPF_PROG(test_fill, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *mask; + bool bit; + int ret; + int i; + + /* Set only odd bits. */ + __builtin_memset(bits, 0xaa, CPUMASK_TEST_MASKLEN); + + mask = bpf_cpumask_create(); + if (!mask) { + err = 1; + return 0; + } + + /* Pass the entire bits array, the kfunc will only copy the valid bits. */ + ret = bpf_cpumask_fill((struct cpumask *)mask, bits, CPUMASK_TEST_MASKLEN); + if (ret) { + err = 2; + goto out; + } + + /* + * Test is there to appease the verifier. We cannot directly + * access NR_CPUS, the upper bound for nr_cpus, so we infer + * it from the size of cpumask_t. + */ + if (nr_cpus < 0 || nr_cpus >= CPUMASK_TEST_MASKLEN * 8) { + err = 3; + goto out; + } + + bpf_for(i, 0, nr_cpus) { + /* Odd-numbered bits should be set, even ones unset. */ + bit = bpf_cpumask_test_cpu(i, (const struct cpumask *)mask); + if (bit == (i % 2 != 0)) + continue; + + err = 4; + break; + } + +out: + bpf_cpumask_release(mask); + + return 0; +} + +#undef CPUMASK_TEST_MASKLEN