From e4e835c87bb5ef7e7923e72da57c923bfcade418 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Mauricio=20V=C3=A1squez?= Date: Mon, 7 Feb 2022 09:50:50 -0500 Subject: [PATCH 1/3] libbpf: Remove mode check in libbpf_set_strict_mode() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit libbpf_set_strict_mode() checks that the passed mode doesn't contain extra bits for LIBBPF_STRICT_* flags that don't exist yet. It makes it difficult for applications to disable some strict flags as something like "LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS" is rejected by this check and they have to use a rather complicated formula to calculate it.[0] One possibility is to change LIBBPF_STRICT_ALL to only contain the bits of all existing LIBBPF_STRICT_* flags instead of 0xffffffff. However it's not possible because the idea is that applications compiled against older libbpf_legacy.h would still be opting into latest LIBBPF_STRICT_ALL features.[1] The other possibility is to remove that check so something like "LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS" is allowed. It's what this commit does. [0]: https://lore.kernel.org/bpf/20220204220435.301896-1-mauricio@kinvolk.io/ [1]: https://lore.kernel.org/bpf/CAEf4BzaTWa9fELJLh+bxnOb0P1EMQmaRbJVG0L+nXZdy0b8G3Q@mail.gmail.com/ Fixes: 93b8952d223a ("libbpf: deprecate legacy BPF map definitions") Signed-off-by: Mauricio Vásquez Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220207145052.124421-2-mauricio@kinvolk.io --- tools/lib/bpf/libbpf.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 904cdf83002b..2262bcdfee92 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -156,14 +156,6 @@ enum libbpf_strict_mode libbpf_mode = LIBBPF_STRICT_NONE; int libbpf_set_strict_mode(enum libbpf_strict_mode mode) { - /* __LIBBPF_STRICT_LAST is the last power-of-2 value used + 1, so to - * get all possible values we compensate last +1, and then (2*x - 1) - * to get the bit mask - */ - if (mode != LIBBPF_STRICT_ALL - && (mode & ~((__LIBBPF_STRICT_LAST - 1) * 2 - 1))) - return errno = EINVAL, -EINVAL; - libbpf_mode = mode; return 0; } From da7af0aa20f8ad89f09d50d262e44cd5eafab816 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Mauricio=20V=C3=A1squez?= Date: Mon, 7 Feb 2022 09:50:51 -0500 Subject: [PATCH 2/3] bpftool: Fix strict mode calculation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit "(__LIBBPF_STRICT_LAST - 1) & ~LIBBPF_STRICT_MAP_DEFINITIONS" is wrong as it is equal to 0 (LIBBPF_STRICT_NONE). Let's use "LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS" now that the previous commit makes it possible in libbpf. Fixes: 93b8952d223a ("libbpf: deprecate legacy BPF map definitions") Signed-off-by: Mauricio Vásquez Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220207145052.124421-3-mauricio@kinvolk.io --- tools/bpf/bpftool/main.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c index 9d01fa9de033..490f7bd54e4c 100644 --- a/tools/bpf/bpftool/main.c +++ b/tools/bpf/bpftool/main.c @@ -478,14 +478,11 @@ int main(int argc, char **argv) } if (!legacy_libbpf) { - enum libbpf_strict_mode mode; - /* Allow legacy map definitions for skeleton generation. * It will still be rejected if users use LIBBPF_STRICT_ALL * mode for loading generated skeleton. */ - mode = (__LIBBPF_STRICT_LAST - 1) & ~LIBBPF_STRICT_MAP_DEFINITIONS; - ret = libbpf_set_strict_mode(mode); + ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS); if (ret) p_err("failed to enable libbpf strict mode: %d", ret); } From 2b9e2eadc9c899af3b508503677afecc85e44766 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Mauricio=20V=C3=A1squez?= Date: Mon, 7 Feb 2022 09:50:52 -0500 Subject: [PATCH 3/3] selftests/bpf: Fix strict mode calculation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit "(__LIBBPF_STRICT_LAST - 1) & ~LIBBPF_STRICT_MAP_DEFINITIONS" is wrong as it is equal to 0 (LIBBPF_STRICT_NONE). Let's use "LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS" now that the previous commit makes it possible in libbpf. Fixes: 93b8952d223a ("libbpf: deprecate legacy BPF map definitions") Signed-off-by: Mauricio Vásquez Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220207145052.124421-4-mauricio@kinvolk.io --- tools/testing/selftests/bpf/prog_tests/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index 4038108aa499..8b652f5ce423 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -4580,7 +4580,7 @@ static void do_test_file(unsigned int test_num) btf_ext__free(btf_ext); /* temporary disable LIBBPF_STRICT_MAP_DEFINITIONS to test legacy maps */ - libbpf_set_strict_mode((__LIBBPF_STRICT_LAST - 1) & ~LIBBPF_STRICT_MAP_DEFINITIONS); + libbpf_set_strict_mode(LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS); obj = bpf_object__open(test->file); err = libbpf_get_error(obj); if (CHECK(err, "obj: %d", err))