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2022-07-26libbpf: Extend BPF_KSYSCALL documentationIlya Leoshkevich1-4/+11
Explicitly list known quirks. Mention that socket-related syscalls can be invoked via socketcall(). Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20220726134008.256968-2-iii@linux.ibm.com
2022-07-19libbpf: improve BPF_KPROBE_SYSCALL macro and rename it to BPF_KSYSCALLAndrii Nakryiko1-13/+38
Improve BPF_KPROBE_SYSCALL (and rename it to shorter BPF_KSYSCALL to match libbpf's SEC("ksyscall") section name, added in next patch) to use __kconfig variable to determine how to properly fetch syscall arguments. Instead of relying on hard-coded knowledge of whether kernel's architecture uses syscall wrapper or not (which only reflects the latest kernel versions, but is not necessarily true for older kernels and won't necessarily hold for later kernel versions on some particular host architecture), determine this at runtime by attempting to create perf_event (with fallback to kprobe event creation through tracefs on legacy kernels, just like kprobe attachment code is doing) for kernel function that would correspond to bpf() syscall on a system that has CONFIG_ARCH_HAS_SYSCALL_WRAPPER set (e.g., for x86-64 it would try '__x64_sys_bpf'). If host kernel uses syscall wrapper, syscall kernel function's first argument is a pointer to struct pt_regs that then contains syscall arguments. In such case we need to use bpf_probe_read_kernel() to fetch actual arguments (which we do through BPF_CORE_READ() macro) from inner pt_regs. But if the kernel doesn't use syscall wrapper approach, input arguments can be read from struct pt_regs directly with no probe reading. All this feature detection is done without requiring /proc/config.gz existence and parsing, and BPF-side helper code uses newly added LINUX_HAS_SYSCALL_WRAPPER virtual __kconfig extern to keep in sync with user-side feature detection of libbpf. BPF_KSYSCALL() macro can be used both with SEC("kprobe") programs that define syscall function explicitly (e.g., SEC("kprobe/__x64_sys_bpf")) and SEC("ksyscall") program added in the next patch (which are the same kprobe program with added benefit of libbpf determining correct kernel function name automatically). Kretprobe and kretsyscall (added in next patch) programs don't need BPF_KSYSCALL as they don't provide access to input arguments. Normal BPF_KRETPROBE is completely sufficient and is recommended. Tested-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220714070755.3235561-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-07libbpf, riscv: Use a0 for RC registerYixun Lan1-1/+1
According to the RISC-V calling convention register usage here [0], a0 is used as return value register, so rename it to make it consistent with the spec. [0] section 18.2, table 18.2 https://riscv.org/wp-content/uploads/2015/01/riscv-calling.pdf Fixes: 589fed479ba1 ("riscv, libbpf: Add RISC-V (RV64) support to bpf_tracing.h") Signed-off-by: Yixun Lan <dlan@gentoo.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn@kernel.org> Acked-by: Amjad OULED-AMEUR <ouledameur.amjad@gmail.com> Link: https://lore.kernel.org/bpf/20220706140204.47926-1-dlan@gentoo.org
2022-04-10libbpf: Add ARC support to bpf_tracing.hVladimir Isaev1-0/+23
Add PT_REGS macros suitable for ARCompact and ARCv2. Signed-off-by: Vladimir Isaev <isaev@synopsys.com> Signed-off-by: Sergey Matyukevich <geomatsi@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20220408224442.599566-1-geomatsi@gmail.com
2022-02-08libbpf: Add BPF_KPROBE_SYSCALL macroHengqi Chen1-0/+35
Add syscall-specific variant of BPF_KPROBE named BPF_KPROBE_SYSCALL ([0]). The new macro hides the underlying way of getting syscall input arguments. With the new macro, the following code: SEC("kprobe/__x64_sys_close") int BPF_KPROBE(do_sys_close, struct pt_regs *regs) { int fd; fd = PT_REGS_PARM1_CORE(regs); /* do something with fd */ } can be written as: SEC("kprobe/__x64_sys_close") int BPF_KPROBE_SYSCALL(do_sys_close, int fd) { /* do something with fd */ } [0] Closes: https://github.com/libbpf/libbpf/issues/425 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220207143134.2977852-2-hengqi.chen@gmail.com
2022-02-08libbpf: Fix accessing the first syscall argument on s390Ilya Leoshkevich1-0/+6
On s390, the first syscall argument should be accessed via orig_gpr2 (see arch/s390/include/asm/syscall.h). Currently gpr[2] is used instead, leading to bpf_syscall_macro test failure. orig_gpr2 cannot be added to user_pt_regs, since its layout is a part of the ABI. Therefore provide access to it only through PT_REGS_PARM1_CORE_SYSCALL() by using a struct pt_regs flavor. Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-11-iii@linux.ibm.com
2022-02-08libbpf: Fix accessing the first syscall argument on arm64Ilya Leoshkevich1-0/+6
On arm64, the first syscall argument should be accessed via orig_x0 (see arch/arm64/include/asm/syscall.h). Currently regs[0] is used instead, leading to bpf_syscall_macro test failure. orig_x0 cannot be added to struct user_pt_regs, since its layout is a part of the ABI. Therefore provide access to it only through PT_REGS_PARM1_CORE_SYSCALL() by using a struct pt_regs flavor. Reported-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-10-iii@linux.ibm.com
2022-02-08libbpf: Allow overriding PT_REGS_PARM1{_CORE}_SYSCALLIlya Leoshkevich1-8/+12
arm64 and s390 need a special way to access the first syscall argument. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-9-iii@linux.ibm.com
2022-02-08libbpf: Fix accessing syscall arguments on riscvIlya Leoshkevich1-0/+2
riscv does not select ARCH_HAS_SYSCALL_WRAPPER, so its syscall handlers take "unpacked" syscall arguments. Indicate this to libbpf using PT_REGS_SYSCALL_REGS macro. Reported-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-7-iii@linux.ibm.com
2022-02-08libbpf: Fix riscv register namesIlya Leoshkevich1-2/+2
riscv registers are accessed via struct user_regs_struct, not struct pt_regs. The program counter member in this struct is called pc, not epc. The frame pointer is called s0, not fp. Fixes: 3cc31d794097 ("libbpf: Normalize PT_REGS_xxx() macro definitions") Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-6-iii@linux.ibm.com
2022-02-08libbpf: Fix accessing syscall arguments on powerpcIlya Leoshkevich1-0/+2
powerpc does not select ARCH_HAS_SYSCALL_WRAPPER, so its syscall handlers take "unpacked" syscall arguments. Indicate this to libbpf using PT_REGS_SYSCALL_REGS macro. Reported-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Link: https://lore.kernel.org/bpf/20220209021745.2215452-5-iii@linux.ibm.com
2022-02-08libbpf: Add PT_REGS_SYSCALL_REGS macroIlya Leoshkevich1-0/+10
Architectures that select ARCH_HAS_SYSCALL_WRAPPER pass a pointer to struct pt_regs to syscall handlers, others unpack it into individual function parameters. Introduce a macro to describe what a particular arch does. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-3-iii@linux.ibm.com
2022-01-24libbpf: Fix the incorrect register read for syscalls on x86_64Kenta Tada1-0/+34
Currently, rcx is read as the fourth parameter of syscall on x86_64. But x86_64 Linux System Call convention uses r10 actually. This commit adds the wrapper for users who want to access to syscall params to analyze the user space. Signed-off-by: Kenta Tada <Kenta.Tada@sony.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220124141622.4378-3-Kenta.Tada@sony.com
2021-12-28libbpf: Use 100-character limit to make bpf_tracing.h easier to readAndrii Nakryiko1-32/+22
Improve bpf_tracing.h's macro definition readability by keeping them single-line and better aligned. This makes it easier to follow all those variadic patterns. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20211222213924.1869758-2-andrii@kernel.org
2021-12-28libbpf: Normalize PT_REGS_xxx() macro definitionsAndrii Nakryiko1-225/+152
Refactor PT_REGS macros definitions in bpf_tracing.h to avoid excessive duplication. We currently have classic PT_REGS_xxx() and CO-RE-enabled PT_REGS_xxx_CORE(). We are about to add also _SYSCALL variants, which would require excessive copying of all the per-architecture definitions. Instead, separate architecture-specific field/register names from the final macro that utilize them. That way for upcoming _SYSCALL variants we'll be able to just define x86_64 exception and otherwise have one common set of _SYSCALL macro definitions common for all architectures. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Ilya Leoshkevich <iii@linux.ibm.com> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/bpf/20211222213924.1869758-1-andrii@kernel.org
2021-11-01riscv, libbpf: Add RISC-V (RV64) support to bpf_tracing.hBjörn Töpel1-0/+32
Add macros for 64-bit RISC-V PT_REGS to bpf_tracing.h. Signed-off-by: Björn Töpel <bjorn@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211028161057.520552-4-bjorn@kernel.org
2021-06-16libbpf: Fail compilation if target arch is missingLorenz Bauer1-4/+42
bpf2go is the Go equivalent of libbpf skeleton. The convention is that the compiled BPF is checked into the repository to facilitate distributing BPF as part of Go packages. To make this portable, bpf2go by default generates both bpfel and bpfeb variants of the C. Using bpf_tracing.h is inherently non-portable since the fields of struct pt_regs differ between platforms, so CO-RE can't help us here. The only way of working around this is to compile for each target platform independently. bpf2go can't do this by default since there are too many platforms. Define the various PT_... macros when no target can be determined and turn them into compilation failures. This works because bpf2go always compiles for bpf targets, so the compiler fallback doesn't kick in. Conditionally define __BPF_MISSING_TARGET so that we can inject a more appropriate error message at build time. The user can then choose which platform to target explicitly. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210616083635.11434-1-lmb@cloudflare.com
2021-05-26libbpf: Move BPF_SEQ_PRINTF and BPF_SNPRINTF to bpf_helpers.hFlorent Revest1-54/+8
These macros are convenient wrappers around the bpf_seq_printf and bpf_snprintf helpers. They are currently provided by bpf_tracing.h which targets low level tracing primitives. bpf_helpers.h is a better fit. The __bpf_narg and __bpf_apply are needed in both files and provided twice. __bpf_empty isn't used anywhere and is removed from bpf_tracing.h Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Florent Revest <revest@chromium.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210526164643.2881368-1-revest@chromium.org
2021-04-19libbpf: Introduce a BPF_SNPRINTF helper macroFlorent Revest1-0/+18
Similarly to BPF_SEQ_PRINTF, this macro turns variadic arguments into an array of u64, making it more natural to call the bpf_snprintf helper. Signed-off-by: Florent Revest <revest@chromium.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210419155243.1632274-6-revest@chromium.org
2021-04-19libbpf: Initialize the bpf_seq_printf parameters array field by fieldFlorent Revest1-11/+29
When initializing the __param array with a one liner, if all args are const, the initial array value will be placed in the rodata section but because libbpf does not support relocation in the rodata section, any pointer in this array will stay NULL. Fixes: c09add2fbc5a ("tools/libbpf: Add bpf_iter support") Signed-off-by: Florent Revest <revest@chromium.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210419155243.1632274-5-revest@chromium.org
2020-08-18libbpf: Switch tracing and CO-RE helper macros to bpf_probe_read_kernel()Andrii Nakryiko1-2/+2
Now that libbpf can automatically fallback to bpf_probe_read() on old kernels not yet supporting bpf_probe_read_kernel(), switch libbpf BPF-side helper macros to use appropriate BPF helper for reading kernel data. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/bpf/20200818213356.2629020-7-andriin@fb.com
2020-07-31libbpf: Fix register in PT_REGS MIPS macrosJerry Crunchtime1-2/+2
The o32, n32 and n64 calling conventions require the return value to be stored in $v0 which maps to $2 register, i.e., the register 2. Fixes: c1932cd ("bpf: Add MIPS support to samples/bpf.") Signed-off-by: Jerry Crunchtime <jerry.c.t@web.de> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/43707d31-0210-e8f0-9226-1af140907641@web.de
2020-05-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-2/+2
Move the bpf verifier trace check into the new switch statement in HEAD. Resolve the overlapping changes in hinic, where bug fixes overlap the addition of VF support. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-14libbpf: Fix register naming in PT_REGS s390 macrosSumanth Korikkar1-2/+2
Fix register naming in PT_REGS s390 macros Fixes: b8ebce86ffe6 ("libbpf: Provide CO-RE variants of PT_REGS macros") Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200513154414.29972-1-sumanthk@linux.ibm.com
2020-05-09tools/libbpf: Add bpf_iter supportYonghong Song1-0/+16
Two new libbpf APIs are added to support bpf_iter: - bpf_program__attach_iter Given a bpf program and additional parameters, which is none now, returns a bpf_link. - bpf_iter_create syscall level API to create a bpf iterator. The macro BPF_SEQ_PRINTF are also introduced. The format looks like: BPF_SEQ_PRINTF(seq, "task id %d\n", pid); This macro can help bpf program writers with nicer bpf_seq_printf syntax similar to the kernel one. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200509175917.2476936-1-yhs@fb.com
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 <ethercflow@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200315083252.22274-1-ethercflow@gmail.com
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 <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200313172336.1879637-4-andriin@fb.com
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 <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200229231112.1240137-5-andriin@fb.com
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 <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200229231112.1240137-3-andriin@fb.com
2019-10-08libbpf: Move bpf_{helpers, helper_defs, endian, tracing}.h into libbpfAndrii Nakryiko1-0/+195
Move bpf_helpers.h, bpf_tracing.h, and bpf_endian.h into libbpf. Move bpf_helper_defs.h generation into libbpf's Makefile. Ensure all those headers are installed along the other libbpf headers. Also, adjust selftests and samples include path to include libbpf now. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-6-andriin@fb.com
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