Existing BPF_CORE_READ() macro generates slightly suboptimal code. If
there are intermediate pointers to be read, initial source pointer is
going to be assigned into a temporary variable and then temporary
variable is going to be uniformly used as a "source" pointer for all
intermediate pointer reads. Schematically (ignoring all the type casts),
BPF_CORE_READ(s, a, b, c) is expanded into:
({
const void *__t = src;
bpf_probe_read(&__t, sizeof(*__t), &__t->a);
bpf_probe_read(&__t, sizeof(*__t), &__t->b);
typeof(s->a->b->c) __r;
bpf_probe_read(&__r, sizeof(*__r), &__t->c);
})
This initial `__t = src` makes calls more uniform, but causes slightly
less optimal register usage sometimes when compiled with Clang. This can
cascase into, e.g., more register spills.
This patch fixes this issue by generating more optimal sequence:
({
const void *__t;
bpf_probe_read(&__t, sizeof(*__t), &src->a); /* <-- src here */
bpf_probe_read(&__t, sizeof(*__t), &__t->b);
typeof(s->a->b->c) __r;
bpf_probe_read(&__r, sizeof(*__r), &__t->c);
})
Fixes: 7db3822ab991 ("libbpf: Add BPF_CORE_READ/BPF_CORE_READ_INTO helpers")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191011023847.275936-1-andriin@fb.com
'struct xdp_umem_reg' has 4 bytes of padding at the end that makes
valgrind complain about passing uninitialized stack memory to the
syscall:
Syscall param socketcall.setsockopt() points to uninitialised byte(s)
at 0x4E7AB7E: setsockopt (in /usr/lib64/libc-2.29.so)
by 0x4BDE035: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:172)
Uninitialised value was created by a stack allocation
at 0x4BDDEBA: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:140)
Padding bytes appeared after introducing of a new 'flags' field.
memset() is required to clear them.
Fixes: 10d30e301732 ("libbpf: add flags to umem config")
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191009164929.17242-1-i.maximets@ovn.org
Linux repo doesn't commit bpf_helper_defs.h, as it's re-generated on
build every time. For Github projection, though, it's much nicer to have
this header be pre-generated during sync and commited. This makes
integration story easier for all the users that use libbpf as
a submodule.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Various small fixes to BPF helper documentation comments, enabling
automatic header generation with a list of BPF helpers.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add new set of bpf_object__open APIs using new approach to optional
parameters extensibility allowing simpler ABI compatibility approach.
This patch demonstrates an approach to implementing libbpf APIs that
makes it easy to extend existing APIs with extra optional parameters in
such a way, that ABI compatibility is preserved without having to do
symbol versioning and generating lots of boilerplate code to handle it.
To facilitate succinct code for working with options, add OPTS_VALID,
OPTS_HAS, and OPTS_GET macros that hide all the NULL, size, and zero
checks.
Additionally, newly added libbpf APIs are encouraged to follow similar
pattern of having all mandatory parameters as formal function parameters
and always have optional (NULL-able) xxx_opts struct, which should
always have real struct size as a first field and the rest would be
optional parameters added over time, which tune the behavior of existing
API, if specified by user.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Kernel version enforcement for kprobes/kretprobes was removed from
5.0 kernel in 6c4fc209fcf9 ("bpf: remove useless version check for prog load").
Since then, BPF programs were specifying SEC("version") just to please
libbpf. We should stop enforcing this in libbpf, if even kernel doesn't
care. Furthermore, libbpf now will pre-populate current kernel version
of the host system, in case we are still running on old kernel.
This patch also removes __bpf_object__open_xattr from libbpf.h, as
nothing in libbpf is relying on having it in that header. That function
was never exported as LIBBPF_API and even name suggests its internal
version. So this should be safe to remove, as it doesn't break ABI.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Meson.build was added to facilitate systemd integration, but systemd
integration went different direction and we don't need meson.build
anymore. So remove it and not maintain it anymore.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
After latest shared vs static libraries fixes, `make install` target
broke as it relied on now removed $(LIBS) variable. This patch fixes
issue by listing $(SHARED_LIBS) and $(STATIC_LIBS) explicitly.
Tested with and without BUILD_STATIC_ONLY.
Fixes: 8b2782a1f2 ("makefile: support libbpf symbol versioning in shared library mode")
Reported-by: Michal Rostecki <mrostecki@opensuse.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Similarly to Linux's 1bd63524593b ("libbpf: handle symbol versioning properly
for libbpf.a"), add necessary changes to build static and shared object
files separately with extra shared library flags. This allows to
properly handle symbol versioning in shared library mode, while still
having statically linkable library.
Cc: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
bcc uses libbpf repo as a submodule. It brings in libbpf source
code and builds everything together to produce shared libraries.
With latest libbpf, I got the following errors:
/bin/ld: libbcc_bpf.so.0.10.0: version node not found for symbol xsk_umem__create@LIBBPF_0.0.2
/bin/ld: failed to set dynamic section sizes: Bad value
collect2: error: ld returned 1 exit status
make[2]: *** [src/cc/libbcc_bpf.so.0.10.0] Error 1
In xsk.c, we have
asm(".symver xsk_umem__create_v0_0_2, xsk_umem__create@LIBBPF_0.0.2");
asm(".symver xsk_umem__create_v0_0_4, xsk_umem__create@@LIBBPF_0.0.4");
The linker thinks the built is for LIBBPF but cannot find proper version
LIBBPF_0.0.2/4, so emit errors.
I also confirmed that using libbpf.a to produce a shared library also
has issues:
-bash-4.4$ cat t.c
extern void *xsk_umem__create;
void * test() { return xsk_umem__create; }
-bash-4.4$ gcc -c -fPIC t.c
-bash-4.4$ gcc -shared t.o libbpf.a -o t.so
/bin/ld: t.so: version node not found for symbol xsk_umem__create@LIBBPF_0.0.2
/bin/ld: failed to set dynamic section sizes: Bad value
collect2: error: ld returned 1 exit status
-bash-4.4$
Symbol versioning does happens in commonly used libraries, e.g., elfutils
and glibc. For static libraries, for a versioned symbol, the old definitions
will be ignored, and the symbol will be an alias to the latest definition.
For example, glibc sched_setaffinity is versioned.
-bash-4.4$ readelf -s /usr/lib64/libc.so.6 | grep sched_setaffinity
756: 000000000013d3d0 13 FUNC GLOBAL DEFAULT 13 sched_setaffinity@GLIBC_2.3.3
757: 00000000000e2e70 455 FUNC GLOBAL DEFAULT 13 sched_setaffinity@@GLIBC_2.3.4
1800: 0000000000000000 0 FILE LOCAL DEFAULT ABS sched_setaffinity.c
4228: 00000000000e2e70 455 FUNC LOCAL DEFAULT 13 __sched_setaffinity_new
4648: 000000000013d3d0 13 FUNC LOCAL DEFAULT 13 __sched_setaffinity_old
7338: 000000000013d3d0 13 FUNC GLOBAL DEFAULT 13 sched_setaffinity@GLIBC_2
7380: 00000000000e2e70 455 FUNC GLOBAL DEFAULT 13 sched_setaffinity@@GLIBC_
-bash-4.4$
For static library, the definition of sched_setaffinity aliases to the new definition.
-bash-4.4$ readelf -s /usr/lib64/libc.a | grep sched_setaffinity
File: /usr/lib64/libc.a(sched_setaffinity.o)
8: 0000000000000000 455 FUNC GLOBAL DEFAULT 1 __sched_setaffinity_new
12: 0000000000000000 455 FUNC WEAK DEFAULT 1 sched_setaffinity
For both elfutils and glibc, additional macros are used to control different handling
of symbol versioning w.r.t static and shared libraries.
For elfutils, the macro is SYMBOL_VERSIONING
(https://sourceware.org/git/?p=elfutils.git;a=blob;f=lib/eu-config.h).
For glibc, the macro is SHARED
(https://sourceware.org/git/?p=glibc.git;a=blob;f=include/shlib-compat.h;hb=refs/heads/master)
This patch used SHARED as the macro name. After this patch, the libbpf.a has
-bash-4.4$ readelf -s libbpf.a | grep xsk_umem__create
372: 0000000000017145 1190 FUNC GLOBAL DEFAULT 1 xsk_umem__create_v0_0_4
405: 0000000000017145 1190 FUNC GLOBAL DEFAULT 1 xsk_umem__create
499: 00000000000175eb 103 FUNC GLOBAL DEFAULT 1 xsk_umem__create_v0_0_2
-bash-4.4$
No versioned symbols for xsk_umem__create.
The libbpf.a can be used to build a shared library succesfully.
-bash-4.4$ cat t.c
extern void *xsk_umem__create;
void * test() { return xsk_umem__create; }
-bash-4.4$ gcc -c -fPIC t.c
-bash-4.4$ gcc -shared t.o libbpf.a -o t.so
-bash-4.4$
Fixes: 10d30e301732 ("libbpf: add flags to umem config")
Cc: Kevin Laatz <kevin.laatz@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When appying urgent fix to Github mirror, before it was pushed to linux
repo, there were some indentation issues, which eventually got fixed
upstream, but are still in Github mirror. Fix it to prevent future merge
conflicts.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
BTF-to-C converter previously skipped anonymous enums in an assumption
that those are embedded in struct's field definitions. This is not
always the case and a lot of kernel constants are defined as part of
anonymous enums. This change fixes the logic by eagerly marking all
types as either referenced by any other type or not. This is enough to
distinguish two classes of anonymous enums and emit previously omitted
enum definitions.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20190925203745.3173184-1-andriin@fb.com
Some compilers emit warning for potential uninitialized next_id usage.
The code is correct, but control flow is too complicated for some
compilers to figure this out. Re-initialize next_id to satisfy
compiler.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The xsk_socket__create() function fails and returns an error if it cannot
get the XDP_OPTIONS through getsockopt(). However, support for XDP_OPTIONS
was not added until kernel 5.3, so this means that creating XSK sockets
always fails on older kernels.
Since the option is just used to set the zero-copy flag in the xsk struct,
and that flag is not really used for anything yet, just remove the
getsockopt() call until a proper use for it is introduced.
Suggested-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This patch adds a 'flags' field to the umem_config and umem_reg structs.
This will allow for more options to be added for configuring umems.
The first use for the flags field is to add a flag for unaligned chunks
mode. These flags can either be user-provided or filled with a default.
Since we change the size of the xsk_umem_config struct, we need to version
the ABI. This patch includes the ABI versioning for xsk_umem__create. The
Makefile was also updated to handle multiple function versions in
check-abi.
Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
The -lelf flag needs to be specified *after* the object files, otherwise
the output library produced by some compilers doesn't contain a link to
libelf.so:
(Example from Debian testing run on Travis.)
$ ldd libelf.so
linux-vdso.so.1 (0x00007ffcbfda9000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f75f8d24000)
/lib64/ld-linux-x86-64.so.2 (0x00007f75f8f0f000)
Linking against such library then produces 'undefined reference to ...'
errors unless the target links against libelf as well. After this commit
the built library references the libelf library correctly:
$ ldd libbpf.so
linux-vdso.so.1 (0x00007ffc821f1000)
libelf.so.1 => /usr/lib/x86_64-linux-gnu/libelf.so.1 (0x00007f70ea3ec000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f70ea22c000)
libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f70ea20f000)
/lib64/ld-linux-x86-64.so.2 (0x00007f70ea433000)
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Drop __NR_mmap2 fork in flavor of LFS, that is _FILE_OFFSET_BITS=64
(glibc & bionic) / LARGEFILE64_SOURCE (for musl) decision. It allows
mmap() to use 64bit offset that is passed to mmap2 syscall. As result
pgoff is not truncated and no need to use direct access to mmap2 for
32 bits systems.
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Add an API function taking a BTF object id and providing the id of the
next BTF object in the kernel. This can be used to list all BTF objects
loaded on the system.
v2:
- Rebase on top of Andrii's changes regarding libbpf versioning.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation for the introduction of a similar function for retrieving
the id of the next BTF object, consolidate the code from
bpf_prog_get_next_id() and bpf_map_get_next_id() in libbpf.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Synchronise the bpf.h header under tools, to report the addition of the
new BPF_BTF_GET_NEXT_ID syscall command for bpf().
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit adds support for the new need_wakeup flag in AF_XDP. The
xsk_socket__create function is updated to handle this and a new
function is introduced called xsk_ring_prod__needs_wakeup(). This
function can be used by the application to check if Rx and/or Tx
processing needs to be explicitly woken up.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Currently libbpf version is specified in 2 places: libbpf.map and
Makefile. They easily get out of sync and it's very easy to update one,
but forget to update another one. In addition, Github projection of
libbpf has to maintain its own version which has to be remembered to be
kept in sync manually, which is very error-prone approach.
This patch makes libbpf.map a source of truth for libbpf version and
uses shell invocation to parse out correct full and major libbpf version
to use during build. Now we need to make sure that once new release
cycle starts, we need to add (initially) empty section to libbpf.map
with correct latest version.
This also will make it possible to keep Github projection consistent
with kernel sources version of libbpf by adopting similar parsing of
version from libbpf.map.
v2->v3:
- grep -o + sort -rV (Andrey);
v1->v2:
- eager version vars evaluation (Jakub);
- simplified version regex (Andrey);
Cc: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The current definition calls BPF_LD_IMM64_RAW_FULL with
BPF_PSEUDO_MAP_FD but the original patch[0] invokes it with
BPF_PSEUDO_MAP_VALUE.
[0] https://patchwork.ozlabs.org/patch/1082785/
Fix how non-empty merge detection is done. Allow to proceed despite
non-empty merges (they will typically will cause conflicts during
applying patches, but if conflicts were handled already, it should be ok
to ignore this problem).
Also ensure that diff's output is in unified diff format.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Pull in updates in BPF helper function description.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for loading kernel BTF from sysfs (/sys/kernel/btf/vmlinux)
as a target BTF. Also extend the list of on disk search paths for
vmlinux ELF image with entries that perf is searching for.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
hashmap.h depends on __WORDSIZE being defined. It is defined by
glibc/musl in different headers. It's an explicit goal for musl to be
"non-detectable" at compilation time, so instead include glibc header if
glibc is explicitly detected and fall back to musl header otherwise.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Fixes: e3b924224028 ("libbpf: add resizable non-thread safe internal hashmap")
Link: https://lkml.kernel.org/r/20190718173021.2418606-1-andriin@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add patches sync from both bpf and bpf-next trees at the same time.
Baseline checkpoint commits are tracked independently for both.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Give more control over patching process to allow manual intervention and
fix up, after which process will continue. Also allow an option to
ignore consistency check results (when having both bpf and bpf-next
changes).
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
If cherry-picked commit contains non-libbpf files, chances are high that
this will result in conflict, because we are generally skipping commits
that didn't touch libbpf files, which means that our working copy will
not be up-to-date for non-libbpf files. This change checks if conflicts
are only in non-libbpf files and marks them as resolved. This will work
fine as long as we don't cherry-pick some more non-libbpf changes to
same set of files that happen to conflict with not-so-resolved version
of non-libbpf files. But anyways, this should help in a lot of cases.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
