From 90a866ed34d844a97559e0178b75d0ef2d8fbfe5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= Date: Tue, 25 Oct 2022 09:20:55 +0000 Subject: [PATCH] bpfloader - remove dead code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As with Android U we know the kernel is at least 4.14 Test: TreeHugger Signed-off-by: Maciej Żenczykowski Change-Id: I789d5e8c9b0fe9e2200f716034d1ec1151f258dc --- libbpf_android/Loader.cpp | 23 ++--------------------- 1 file changed, 2 insertions(+), 21 deletions(-) diff --git a/libbpf_android/Loader.cpp b/libbpf_android/Loader.cpp index 4c0f5c7..bc7ea76 100644 --- a/libbpf_android/Loader.cpp +++ b/libbpf_android/Loader.cpp @@ -30,9 +30,9 @@ #include #include -// This is BpfLoader v0.28 +// This is BpfLoader v0.29 #define BPFLOADER_VERSION_MAJOR 0u -#define BPFLOADER_VERSION_MINOR 28u +#define BPFLOADER_VERSION_MINOR 29u #define BPFLOADER_VERSION ((BPFLOADER_VERSION_MAJOR << 16) | BPFLOADER_VERSION_MINOR) #include "bpf/BpfUtils.h" @@ -648,15 +648,6 @@ static std::optional getMapBtfInfo(const char* elfPath, static bool mapMatchesExpectations(const unique_fd& fd, const string& mapName, const struct bpf_map_def& mapDef, const enum bpf_map_type type) { - // bpfGetFd... family of functions require at minimum a 4.14 kernel, - // so on 4.9 kernels just pretend the map matches our expectations. - // This isn't really a problem as we only really support 4.14+ anyway... - // Additionally we'll get almost equivalent test coverage on newer devices/kernels. - // This is because the primary failure mode we're trying to detect here - // is either a source code misconfiguration (which is likely kernel independent) - // or a newly introduced kernel feature/bug (which is unlikely to get backported to 4.9). - if (!isAtLeastKernelVersion(4, 14, 0)) return true; - // Assuming fd is a valid Bpf Map file descriptor then // all the following should always succeed on a 4.14+ kernel. // If they somehow do fail, they'll return -1 (and set errno), @@ -777,16 +768,6 @@ static int createMaps(const char* elfPath, ifstream& elfFile, vector& } enum bpf_map_type type = md[i].type; - if (type == BPF_MAP_TYPE_DEVMAP && !isAtLeastKernelVersion(4, 14, 0)) { - // On Linux Kernels older than 4.14 this map type doesn't exist, but it can kind - // of be approximated: ARRAY has the same userspace api, though it is not usable - // by the same ebpf programs. However, that's okay because the bpf_redirect_map() - // helper doesn't exist on 4.9 anyway (so the bpf program would fail to load, - // and thus needs to be tagged as 4.14+ either way), so there's nothing useful you - // could do with a DEVMAP anyway (that isn't already provided by an ARRAY)... - // Hence using an ARRAY instead of a DEVMAP simply makes life easier for userspace. - type = BPF_MAP_TYPE_ARRAY; - } if (type == BPF_MAP_TYPE_DEVMAP_HASH && !isAtLeastKernelVersion(5, 4, 0)) { // On Linux Kernels older than 5.4 this map type doesn't exist, but it can kind // of be approximated: HASH has the same userspace visible api.