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2020-03-28libbpf: Add function to set link XDP fd while specifying old programToke Høiland-Jørgensen3-1/+42
This adds a new function to set the XDP fd while specifying the FD of the program to replace, using the newly added IFLA_XDP_EXPECTED_FD netlink parameter. The new function uses the opts struct mechanism to be extendable in the future. Signed-off-by: Toke Høiland-Jørgensen <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-28libbpf, xsk: Init all ring members in xsk_umem__create and xsk_socket__createFletcher Dunn1-2/+14
Fix a sharp edge in xsk_umem__create and xsk_socket__create. Almost all of the members of the ring buffer structs are initialized, but the "cached_xxx" variables are not all initialized. The caller is required to zero them. This is needlessly dangerous. The results if you don't do it can be very bad. For example, they can cause xsk_prod_nb_free and xsk_cons_nb_avail to return values greater than the size of the queue. xsk_ring_cons__peek can return an index that does not refer to an item that has been queued. I have confirmed that without this change, my program misbehaves unless I memset the ring buffers to zero before calling the function. Afterwards, my program works without (or with) the memset. Signed-off-by: Fletcher Dunn <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Magnus Karlsson <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-26libbpf: Don't allocate 16M for log buffer by defaultStanislav Fomichev2-13/+29
For each prog/btf load we allocate and free 16 megs of verifier buffer. On production systems it doesn't really make sense because the programs/btf have gone through extensive testing and (mostly) guaranteed to successfully load. Let's assume successful case by default and skip buffer allocation on the first try. If there is an error, start with BPF_LOG_BUF_SIZE and double it on each ENOSPC iteration. v3: * Return -ENOMEM when can't allocate log buffer (Andrii Nakryiko) v2: * Don't allocate the buffer at all on the first try (Andrii Nakryiko) Signed-off-by: Stanislav Fomichev <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-26libbpf: Remove unused parameter `def` to get_map_field_intTobias Klauser1-10/+6
Has been unused since commit ef99b02b23ef ("libbpf: capture value in BTF type info for BTF-defined map defs"). Signed-off-by: Tobias Klauser <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Reviewed-by: Quentin Monnet <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-25.gitignore: add SPDX License IdentifierMasahiro Yamada1-0/+1
Add SPDX License Identifier to all .gitignore files. Signed-off-by: Masahiro Yamada <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-17bpf, libbpf: Fix ___bpf_kretprobe_args1(x) macro definitionWenbo Zhang1-1/+1
Use PT_REGS_RC instead of PT_REGS_RET to get ret correctly. Fixes: df8ff35311c8 ("libbpf: Merge selftests' bpf_trace_helpers.h into libbpf's bpf_tracing.h") Signed-off-by: Wenbo Zhang <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-13libbpf: Provide CO-RE variants of PT_REGS macrosAndrii Nakryiko1-0/+103
Syscall raw tracepoints have struct pt_regs pointer as tracepoint's first argument. After that, reading any of pt_regs fields requires bpf_probe_read(), even for tp_btf programs. Due to that, PT_REGS_PARMx macros are not usable as is. This patch adds CO-RE variants of those macros that use BPF_CORE_READ() to read necessary fields. This provides relocatable architecture-agnostic pt_regs field accesses. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-13libbpf: Ignore incompatible types with matching name during CO-RE relocationAndrii Nakryiko1-0/+4
When finding target type candidates, ignore forward declarations, functions, and other named types of incompatible kind. Not doing this can cause false errors. See [0] for one such case (due to struct pt_regs forward declaration). [0] https://github.com/iovisor/bcc/pull/2806#issuecomment-598543645 Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm") Reported-by: Wenbo Zhang <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-13libbpf: Split BTF presence checks into libbpf- and kernel-specific partsAndrii Nakryiko1-5/+12
Needs for application BTF being present differs between user-space libbpf needs and kernel needs. Currently, BTF is mandatory only in kernel only when BPF application is using STRUCT_OPS. While libbpf itself relies more heavily on presense of BTF: - for BTF-defined maps; - for Kconfig externs; - for STRUCT_OPS as well. Thus, checks for presence and validness of bpf_object's BPF needs to be performed separately, which is patch does. Fixes: 5327644614a1 ("libbpf: Relax check whether BTF is mandatory") Reported-by: Michal Rostecki <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Cc: Quentin Monnet <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-04tools/libbpf: Add support for BPF_MODIFY_RETURNKP Singh1-0/+4
Signed-off-by: KP Singh <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-04libbpf: Assume unsigned values for BTF_KIND_ENUMAndrii Nakryiko1-4/+4
Currently, BTF_KIND_ENUM type doesn't record whether enum values should be interpreted as signed or unsigned. In Linux, most enums are unsigned, though, so interpreting them as unsigned matches real world better. Change btf_dump test case to test maximum 32-bit value, instead of negative value. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-03libbpf: Fix handling of optional field_name in btf_dump__emit_type_declAndrii Nakryiko1-1/+1
Internal functions, used by btf_dump__emit_type_decl(), assume field_name is never going to be NULL. Ensure it's always the case. Fixes: 9f81654eebe8 ("libbpf: Expose BTF-to-C type declaration emitting API") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-02libbpf: Add bpf_link pinning/unpinningAndrii Nakryiko3-27/+114
With bpf_link abstraction supported by kernel explicitly, add pinning/unpinning API for links. Also allow to create (open) bpf_link from BPF FS file. This API allows to have an "ephemeral" FD-based BPF links (like raw tracepoint or fexit/freplace attachments) surviving user process exit, by pinning them in a BPF FS, which is an important use case for long-running BPF programs. As part of this, expose underlying FD for bpf_link. While legacy bpf_link's might not have a FD associated with them (which will be expressed as a bpf_link with fd=-1), kernel's abstraction is based around FD-based usage, so match it closely. This, subsequently, allows to have a generic pinning/unpinning API for generalized bpf_link. For some types of bpf_links kernel might not support pinning, in which case bpf_link__pin() will return error. With FD being part of generic bpf_link, also get rid of bpf_link_fd in favor of using vanialla bpf_link. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-02libbpf: Merge selftests' bpf_trace_helpers.h into libbpf's bpf_tracing.hAndrii Nakryiko1-0/+118
Move BPF_PROG, BPF_KPROBE, and BPF_KRETPROBE macro into libbpf's bpf_tracing.h header to make it available for non-selftests users. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-03-02libbpf: Fix use of PT_REGS_PARM macros with vmlinux.hAndrii Nakryiko1-1/+1
Add detection of vmlinux.h to bpf_tracing.h header for PT_REGS macro. Currently, BPF applications have to define __KERNEL__ symbol to use correct definition of struct pt_regs on x86 arch. This is due to different field names under internal kernel vs UAPI conditions. To make this more transparent for users, detect vmlinux.h by checking __VMLINUX_H__ symbol. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-02-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller3-7/+40
Daniel Borkmann says: ==================== pull-request: bpf-next 2020-02-21 The following pull-request contains BPF updates for your *net-next* tree. We've added 25 non-merge commits during the last 4 day(s) which contain a total of 33 files changed, 2433 insertions(+), 161 deletions(-). The main changes are: 1) Allow for adding TCP listen sockets into sock_map/hash so they can be used with reuseport BPF programs, from Jakub Sitnicki. 2) Add a new bpf_program__set_attach_target() helper for adding libbpf support to specify the tracepoint/function dynamically, from Eelco Chaudron. 3) Add bpf_read_branch_records() BPF helper which helps use cases like profile guided optimizations, from Daniel Xu. 4) Enable bpf_perf_event_read_value() in all tracing programs, from Song Liu. 5) Relax BTF mandatory check if only used for libbpf itself e.g. to process BTF defined maps, from Andrii Nakryiko. 6) Move BPF selftests -mcpu compilation attribute from 'probe' to 'v3' as it has been observed that former fails in envs with low memlock, from Yonghong Song. ==================== Signed-off-by: David S. Miller <[email protected]>
2020-02-20libbpf: Add support for dynamic program attach targetEelco Chaudron3-4/+36
Currently when you want to attach a trace program to a bpf program the section name needs to match the tracepoint/function semantics. However the addition of the bpf_program__set_attach_target() API allows you to specify the tracepoint/function dynamically. The call flow would look something like this: xdp_fd = bpf_prog_get_fd_by_id(id); trace_obj = bpf_object__open_file("func.o", NULL); prog = bpf_object__find_program_by_title(trace_obj, "fentry/myfunc"); bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY); bpf_program__set_attach_target(prog, xdp_fd, "xdpfilt_blk_all"); bpf_object__load(trace_obj) Signed-off-by: Eelco Chaudron <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: Toke Høiland-Jørgensen <[email protected]> Link: https://lore.kernel.org/bpf/158220519486.127661.7964708960649051384.stgit@xdp-tutorial
2020-02-20libbpf: Bump libpf current version to v0.0.8Eelco Chaudron1-0/+3
New development cycles starts, bump to v0.0.8. Signed-off-by: Eelco Chaudron <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Toke Høiland-Jørgensen <[email protected]> Link: https://lore.kernel.org/bpf/158220518424.127661.8278643006567775528.stgit@xdp-tutorial
2020-02-20libbpf: Relax check whether BTF is mandatoryAndrii Nakryiko1-3/+1
If BPF program is using BTF-defined maps, BTF is required only for libbpf itself to process map definitions. If after that BTF fails to be loaded into kernel (e.g., if it doesn't support BTF at all), this shouldn't prevent valid BPF program from loading. Existing retry-without-BTF logic for creating maps will succeed to create such maps without any problems. So, presence of .maps section shouldn't make BTF required for kernel. Update the check accordingly. Validated by ensuring simple BPF program with BTF-defined maps is still loaded on old kernel without BTF support and map is correctly parsed and created. Fixes: abd29c931459 ("libbpf: allow specifying map definitions using BTF") Reported-by: Julia Kartseva <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-02-18libbpf: Sanitise internal map names so they are not rejected by the kernelToke Høiland-Jørgensen1-1/+7
The kernel only accepts map names with alphanumeric characters, underscores and periods in their name. However, the auto-generated internal map names used by libbpf takes their prefix from the user-supplied BPF object name, which has no such restriction. This can lead to "Invalid argument" errors when trying to load a BPF program using global variables. Fix this by sanitising the map names, replacing any non-allowed characters with underscores. Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata sections") Signed-off-by: Toke Høiland-Jørgensen <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-24libbpf: Fix realloc usage in bpf_core_find_candsAndrii Nakryiko1-1/+3
Fix bug requesting invalid size of reallocated array when constructing CO-RE relocation candidate list. This can cause problems if there are many potential candidates and a very fine-grained memory allocator bucket sizes are used. Fixes: ddc7c3042614 ("libbpf: implement BPF CO-RE offset relocation algorithm") Reported-by: William Smith <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-24libbpf: Improve handling of failed CO-RE relocationsAndrii Nakryiko2-40/+61
Previously, if libbpf failed to resolve CO-RE relocation for some instructions, it would either return error immediately, or, if .relaxed_core_relocs option was set, would replace relocatable offset/imm part of an instruction with a bogus value (-1). Neither approach is good, because there are many possible scenarios where relocation is expected to fail (e.g., when some field knowingly can be missing on specific kernel versions). On the other hand, replacing offset with invalid one can hide programmer errors, if this relocation failue wasn't anticipated. This patch deprecates .relaxed_core_relocs option and changes the approach to always replacing instruction, for which relocation failed, with invalid BPF helper call instruction. For cases where this is expected, BPF program should already ensure that that instruction is unreachable, in which case this invalid instruction is going to be silently ignored. But if instruction wasn't guarded, BPF program will be rejected at verification step with verifier log pointing precisely to the place in assembly where the problem is. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-22libbpf: Add support for program extensionsAlexei Starovoitov5-4/+17
Add minimal support for program extensions. bpf_object_open_opts() needs to be called with attach_prog_fd = target_prog_fd and BPF program extension needs to have in .c file section definition like SEC("freplace/func_to_be_replaced"). libbpf will search for "func_to_be_replaced" in the target_prog_fd's BTF and will pass it in attach_btf_id to the kernel. This approach works for tests, but more compex use case may need to request function name (and attach_btf_id that kernel sees) to be more dynamic. Such API will be added in future patches. Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: John Fastabend <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: Toke Høiland-Jørgensen <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-17libbpf: Load btf_vmlinux only once per object.KP Singh1-52/+101
As more programs (TRACING, STRUCT_OPS, and upcoming LSM) use vmlinux BTF information, loading the BTF vmlinux information for every program in an object is sub-optimal. The fix was originally proposed in: https://lore.kernel.org/bpf/CAEf4BzZodr3LKJuM7QwD38BiEH02Cc1UbtnGpVkCJ00Mf+V_Qg@mail.gmail.com/ The btf_vmlinux is populated in the object if any of the programs in the object requires it just before the programs are loaded and freed after the programs finish loading. Reported-by: Andrii Nakryiko <[email protected]> Signed-off-by: KP Singh <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Reviewed-by: Brendan Jackman <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-17libbpf: Fix potential multiplication overflow in mmap() size calculationAndrii Nakryiko1-1/+1
Prevent potential overflow performed in 32-bit integers, before assigning result to size_t. Reported by LGTM static analysis. Fixes: eba9c5f498a1 ("libbpf: Refactor global data map initialization") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-17libbpf: Simplify BTF initialization logicAndrii Nakryiko1-13/+6
Current implementation of bpf_object's BTF initialization is very convoluted and thus prone to errors. It doesn't have to be like that. This patch simplifies it significantly. This code also triggered static analysis issues over logically dead code due to redundant error checks. This simplification should fix that as well. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-17libbpf: Fix error handling bug in btf_dump__newAndrii Nakryiko1-0/+1
Fix missing jump to error handling in btf_dump__new, found by Coverity static code analysis. Fixes: 9f81654eebe8 ("libbpf: Expose BTF-to-C type declaration emitting API") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-16libbpf: Revert bpf_helper_defs.h inclusion regressionAndrii Nakryiko1-1/+1
Revert bpf_helpers.h's change to include auto-generated bpf_helper_defs.h through <> instead of "", which causes it to be searched in include path. This can break existing applications that don't have their include path pointing directly to where libbpf installs its headers. There is ongoing work to make all (not just bpf_helper_defs.h) includes more consistent across libbpf and its consumers, but this unbreaks user code as is right now without any regressions. Selftests still behave sub-optimally (taking bpf_helper_defs.h from libbpf's source directory, if it's present there), which will be fixed in subsequent patches. Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir") Reported-by: Toke Høiland-Jørgensen <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-16libbpf: Fix unneeded extra initialization in bpf_map_batch_commonBrian Vazquez1-1/+1
bpf_attr doesn't required to be declared with '= {}' as memset is used in the code. Fixes: 2ab3d86ea1859 ("libbpf: Add libbpf support to batch ops") Reported-by: Andrii Nakryiko <[email protected]> Signed-off-by: Brian Vazquez <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-15libbpf: Expose bpf_find_kernel_btf as a LIBBPF_APIMartin KaFai Lau4-96/+102
This patch exposes bpf_find_kernel_btf() as a LIBBPF_API. It will be used in 'bpftool map dump' in a following patch to dump a map with btf_vmlinux_value_type_id set. bpf_find_kernel_btf() is renamed to libbpf_find_kernel_btf() and moved to btf.c. As <linux/kernel.h> is included, some of the max/min type casting needs to be fixed. Signed-off-by: Martin KaFai Lau <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-15libbpf: Add libbpf support to batch opsYonghong Song3-0/+84
Added four libbpf API functions to support map batch operations: . int bpf_map_delete_batch( ... ) . int bpf_map_lookup_batch( ... ) . int bpf_map_lookup_and_delete_batch( ... ) . int bpf_map_update_batch( ... ) Signed-off-by: Yonghong Song <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-15libbpf: Support .text sub-calls relocationsAndrii Nakryiko1-7/+22
The LLVM patch https://reviews.llvm.org/D72197 makes LLVM emit function call relocations within the same section. This includes a default .text section, which contains any BPF sub-programs. This wasn't the case before and so libbpf was able to get a way with slightly simpler handling of subprogram call relocations. This patch adds support for .text section relocations. It needs to ensure correct order of relocations, so does two passes: - first, relocate .text instructions, if there are any relocations in it; - then process all the other programs and copy over patched .text instructions for all sub-program calls. v1->v2: - break early once .text program is processed. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Cc: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-13libbpf: Clean up bpf_helper_defs.h generation outputAndrii Nakryiko1-1/+1
bpf_helpers_doc.py script, used to generate bpf_helper_defs.h, unconditionally emits one informational message to stderr. Remove it and preserve stderr to contain only relevant errors. Also make sure script invocations command is muted by default in libbpf's Makefile. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-10libbpf: Poison kernel-only integer typesAndrii Nakryiko12-1/+37
It's been a recurring issue with types like u32 slipping into libbpf source code accidentally. This is not detected during builds inside kernel source tree, but becomes a compilation error in libbpf's Github repo. Libbpf is supposed to use only __{s,u}{8,16,32,64} typedefs, so poison {s,u}{8,16,32,64} explicitly in every .c file. Doing that in a bit more centralized way, e.g., inside libbpf_internal.h breaks selftests, which are both using kernel u32 and libbpf_internal.h. This patch also fixes a new u32 occurence in libbpf.c, added recently. Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-10libbpf: Sanitize global functionsAlexei Starovoitov1-1/+34
In case the kernel doesn't support BTF_FUNC_GLOBAL sanitize BTF produced by the compiler for global functions. Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Song Liu <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-09selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dirAndrii Nakryiko1-1/+1
Reorder includes search path to ensure $(OUTPUT) and $(CURDIR) go before libbpf's directory. Also fix bpf_helpers.h to include bpf_helper_defs.h in such a way as to leverage includes search path. This allows selftests to not use libbpf's local and potentially stale bpf_helper_defs.h. It's important because selftests/bpf's Makefile only re-generates bpf_helper_defs.h in seltests' output directory, not the one in libbpf's directory. Also force regeneration of bpf_helper_defs.h when libbpf.a is updated to reduce staleness. Fixes: fa633a0f8919 ("libbpf: Fix build on read-only filesystems") Reported-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-09libbpf,selftests/bpf: Fix clean targetsAndrii Nakryiko1-4/+5
Libbpf's clean target should clean out generated files in $(OUTPUT) directory and not make assumption that $(OUTPUT) directory is current working directory. Selftest's Makefile should delegate cleaning of libbpf-generated files to libbpf's Makefile. This ensures more robust clean up. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-09libbpf: Make bpf_map order and indices stableAndrii Nakryiko1-14/+0
Currently, libbpf re-sorts bpf_map structs after all the maps are added and initialized, which might change their relative order and invalidate any bpf_map pointer or index taken before that. This is inconvenient and error-prone. For instance, it can cause .kconfig map index to point to a wrong map. Furthermore, libbpf itself doesn't rely on any specific ordering of bpf_maps, so it's just an unnecessary complication right now. This patch drops sorting of maps and makes their relative positions fixed. If efficient index is ever needed, it's better to have a separate array of pointers as a search index, instead of reordering bpf_map struct in-place. This will be less error-prone and will allow multiple independent orderings, if necessary (e.g., either by section index or by name). Fixes: 166750bc1dd2 ("libbpf: Support libbpf-provided extern variables") Reported-by: Martin KaFai Lau <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-09bpf: libbpf: Add STRUCT_OPS supportMartin KaFai Lau6-13/+661
This patch adds BPF STRUCT_OPS support to libbpf. The only sec_name convention is SEC(".struct_ops") to identify the struct_ops implemented in BPF, e.g. To implement a tcp_congestion_ops: SEC(".struct_ops") struct tcp_congestion_ops dctcp = { .init = (void *)dctcp_init, /* <-- a bpf_prog */ /* ... some more func prts ... */ .name = "bpf_dctcp", }; Each struct_ops is defined as a global variable under SEC(".struct_ops") as above. libbpf creates a map for each variable and the variable name is the map's name. Multiple struct_ops is supported under SEC(".struct_ops"). In the bpf_object__open phase, libbpf will look for the SEC(".struct_ops") section and find out what is the btf-type the struct_ops is implementing. Note that the btf-type here is referring to a type in the bpf_prog.o's btf. A "struct bpf_map" is added by bpf_object__add_map() as other maps do. It will then collect (through SHT_REL) where are the bpf progs that the func ptrs are referring to. No btf_vmlinux is needed in the open phase. In the bpf_object__load phase, the map-fields, which depend on the btf_vmlinux, are initialized (in bpf_map__init_kern_struct_ops()). It will also set the prog->type, prog->attach_btf_id, and prog->expected_attach_type. Thus, the prog's properties do not rely on its section name. [ Currently, the bpf_prog's btf-type ==> btf_vmlinux's btf-type matching process is as simple as: member-name match + btf-kind match + size match. If these matching conditions fail, libbpf will reject. The current targeting support is "struct tcp_congestion_ops" which most of its members are function pointers. The member ordering of the bpf_prog's btf-type can be different from the btf_vmlinux's btf-type. ] Then, all obj->maps are created as usual (in bpf_object__create_maps()). Once the maps are created and prog's properties are all set, the libbpf will proceed to load all the progs. bpf_map__attach_struct_ops() is added to register a struct_ops map to a kernel subsystem. Signed-off-by: Martin KaFai Lau <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-01-08libbpf: Add probe for large INSN limitMichal Rostecki3-0/+23
Introduce a new probe which checks whether kernel has large maximum program size which was increased in the following commit: c04c0d2b968a ("bpf: increase complexity limit and maximum program size") Based on the similar check in Cilium[0], authored by Daniel Borkmann. [0] https://github.com/cilium/cilium/commit/657d0f585afd26232cfa5d4e70b6f64d2ea91596 Co-authored-by: Daniel Borkmann <[email protected]> Signed-off-by: Michal Rostecki <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Reviewed-by: Quentin Monnet <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-7/+8
Simple overlapping changes in bpf land wrt. bpf_helper_defs.h handling. Signed-off-by: David S. Miller <[email protected]>
2019-12-26libbpf: Support CO-RE relocations for LDX/ST/STX instructionsAndrii Nakryiko1-3/+28
Clang patch [0] enables emitting relocatable generic ALU/ALU64 instructions (i.e, shifts and arithmetic operations), as well as generic load/store instructions. The former ones are already supported by libbpf as is. This patch adds further support for load/store instructions. Relocatable field offset is encoded in BPF instruction's 16-bit offset section and are adjusted by libbpf based on target kernel BTF. These Clang changes and corresponding libbpf changes allow for more succinct generated BPF code by encoding relocatable field reads as a single ST/LDX/STX instruction. It also enables relocatable access to BPF context. Previously, if context struct (e.g., __sk_buff) was accessed with CO-RE relocations (e.g., due to preserve_access_index attribute), it would be rejected by BPF verifier due to modified context pointer dereference. With Clang patch, such context accesses are both relocatable and have a fixed offset from the point of view of BPF verifier. [0] https://reviews.llvm.org/D71790 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-23libbpf: Fix build on read-only filesystemsNamhyung Kim1-7/+8
I got the following error when I tried to build perf on a read-only filesystem with O=dir option. $ cd /some/where/ro/linux/tools/perf $ make O=$HOME/build/perf ... CC /home/namhyung/build/perf/lib.o /bin/sh: bpf_helper_defs.h: Read-only file system make[3]: *** [Makefile:184: bpf_helper_defs.h] Error 1 make[2]: *** [Makefile.perf:778: /home/namhyung/build/perf/libbpf.a] Error 2 make[2]: *** Waiting for unfinished jobs.... LD /home/namhyung/build/perf/libperf-in.o AR /home/namhyung/build/perf/libperf.a PERF_VERSION = 5.4.0 make[1]: *** [Makefile.perf:225: sub-make] Error 2 make: *** [Makefile:70: all] Error 2 It was becaused bpf_helper_defs.h was generated in current directory. Move it to OUTPUT directory. Signed-off-by: Namhyung Kim <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Tested-by: Andrii Nakryiko <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-19libbpf: Introduce bpf_prog_attach_xattrAndrey Ignatov3-1/+28
Introduce a new bpf_prog_attach_xattr function that, in addition to program fd, target fd and attach type, accepts an extendable struct bpf_prog_attach_opts. bpf_prog_attach_opts relies on DECLARE_LIBBPF_OPTS macro to maintain backward and forward compatibility and has the following "optional" attach attributes: * existing attach_flags, since it's not required when attaching in NONE mode. Even though it's quite often used in MULTI and OVERRIDE mode it seems to be a good idea to reduce number of arguments to bpf_prog_attach_xattr; * newly introduced attribute of BPF_PROG_ATTACH command: replace_prog_fd that is fd of previously attached cgroup-bpf program to replace if BPF_F_REPLACE flag is used. The new function is named to be consistent with other xattr-functions (bpf_prog_test_run_xattr, bpf_create_map_xattr, bpf_load_program_xattr). The struct bpf_prog_attach_opts is supposed to be used with DECLARE_LIBBPF_OPTS macro. Signed-off-by: Andrey Ignatov <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/bd6e0732303eb14e4b79cb128268d9e9ad6db208.1576741281.git.rdna@fb.com
2019-12-19libbpf: Fix another __u64 printf warningAndrii Nakryiko1-2/+2
Fix yet another printf warning for %llu specifier on ppc64le. This time size_t casting won't work, so cast to verbose `unsigned long long`. Fixes: 166750bc1dd2 ("libbpf: Support libbpf-provided extern variables") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-19libbpf: Fix printing of ulimit valueToke Høiland-Jørgensen1-1/+1
Naresh pointed out that libbpf builds fail on 32-bit architectures because rlimit.rlim_cur is defined as 'unsigned long long' on those architectures. Fix this by using %zu in printf and casting to size_t. Fixes: dc3a2d254782 ("libbpf: Print hint about ulimit when getting permission denied error") Reported-by: Naresh Kamboju <[email protected]> Signed-off-by: Toke Høiland-Jørgensen <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-19libbpf: Add missing newline in opts validation macroToke Høiland-Jørgensen1-1/+1
The error log output in the opts validation macro was missing a newline. Fixes: 2ce8450ef5a3 ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts") Signed-off-by: Toke Høiland-Jørgensen <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-18libbpf: BTF is required when externs are presentAndrii Nakryiko1-1/+2
BTF is required to get type information about extern variables. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-18libbpf: Allow to augment system Kconfig through extra optional configAndrii Nakryiko2-84/+128
Instead of all or nothing approach of overriding Kconfig file location, allow to extend it with extra values and override chosen subset of values though optional user-provided extra config, passed as a string through open options' .kconfig option. If same config key is present in both user-supplied config and Kconfig, user-supplied one wins. This allows applications to more easily test various conditions despite host kernel's real configuration. If all of BPF object's __kconfig externs are satisfied from user-supplied config, system Kconfig won't be read at all. Simplify selftests by not needing to create temporary Kconfig files. Suggested-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2019-12-18libbpf: Put Kconfig externs into .kconfig sectionAndrii Nakryiko2-23/+37
Move Kconfig-provided externs into custom .kconfig section. Add __kconfig into bpf_helpers.h for user convenience. Update selftests accordingly. Suggested-by: Daniel Borkmann <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
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