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* [PATCH v2 bpf-next 00/25] libbpf: extend [ku]probe and syscall argument tracing support
@ 2023-01-20 20:08 Andrii Nakryiko
  2023-01-20 20:08 ` [PATCH v2 bpf-next 01/25] libbpf: add support for fetching up to 8 arguments in kprobes Andrii Nakryiko
                   ` (25 more replies)
  0 siblings, 26 replies; 27+ messages in thread
From: Andrii Nakryiko @ 2023-01-20 20:08 UTC (permalink / raw)
  To: bpf, ast, daniel; +Cc: andrii, kernel-team

This patch set fixes and extends libbpf's bpf_tracing.h support for tracing
arguments of kprobes/uprobes, and syscall as a special case.

Depending on the architecture, anywhere between 3 and 8 arguments can be
passed to a function in registers (so relevant to kprobes and uprobes), but
before this patch set libbpf's macros in bpf_tracing.h only supported up to
5 arguments, which is limiting in practice. This patch set extends
bpf_tracing.h to support up to 8 arguments, if architecture allows. This
includes explicit PT_REGS_PARMx() macro family, as well as BPF_KPROBE() macro.

Now, with tracing syscall arguments situation is sometimes quite different.
For a lot of architectures syscall argument passing through registers differs
from function call sequence at least a little. For i386 it differs *a lot*.
This patch set addresses this issue across all currently supported
architectures and hopefully fixes existing issues. syscall(2) manpage defines
that either 6 or 7 arguments can be supported, depending on architecture, so
libbpf defines 6 or 7 registers per architecture to be used to fetch syscall
arguments.

Also, BPF_UPROBE and BPF_URETPROBE are introduced as part of this patch set.
They are aliases for BPF_KPROBE and BPF_KRETPROBE (as mechanics of argument
fetching of kernel functions and user-space functions are identical), but it
allows BPF users to have less confusing BPF-side code when working with
uprobes.

For both sets of changes selftests are extended to test these new register
definitions to architecture-defined limits. Unfortunately I don't have ability
to test it on all architectures, and BPF CI only tests 3 architecture (x86-64,
arm64, and s390x), so it would be greatly appreciated if people with access to
architectures other than above 3 helped review and test changes.

v1->v2:
  - switched from mmap() to splice() syscall (Ilya);
  - updated ABI spec link for s390x (Ilya);
  - added a bunch of Tested-by and acks tags, thank you;
  - dropped direct CCs because vger/patchworks blocked v1 patches, probably
    due to too long CC list.


Andrii Nakryiko (25):
  libbpf: add support for fetching up to 8 arguments in kprobes
  libbpf: add 6th argument support for x86-64 in bpf_tracing.h
  libbpf: fix arm and arm64 specs in bpf_tracing.h
  libbpf: complete mips spec in bpf_tracing.h
  libbpf: complete powerpc spec in bpf_tracing.h
  libbpf: complete sparc spec in bpf_tracing.h
  libbpf: complete riscv arch spec in bpf_tracing.h
  libbpf: fix and complete ARC spec in bpf_tracing.h
  libbpf: complete LoongArch (loongarch) spec in bpf_tracing.h
  libbpf: add BPF_UPROBE and BPF_URETPROBE macro aliases
  selftests/bpf: validate arch-specific argument registers limits
  libbpf: improve syscall tracing support in bpf_tracing.h
  libbpf: define x86-64 syscall regs spec in bpf_tracing.h
  libbpf: define i386 syscall regs spec in bpf_tracing.h
  libbpf: define s390x syscall regs spec in bpf_tracing.h
  libbpf: define arm syscall regs spec in bpf_tracing.h
  libbpf: define arm64 syscall regs spec in bpf_tracing.h
  libbpf: define mips syscall regs spec in bpf_tracing.h
  libbpf: define powerpc syscall regs spec in bpf_tracing.h
  libbpf: define sparc syscall regs spec in bpf_tracing.h
  libbpf: define riscv syscall regs spec in bpf_tracing.h
  libbpf: define arc syscall regs spec in bpf_tracing.h
  libbpf: define loongarch syscall regs spec in bpf_tracing.h
  selftests/bpf: add 6-argument syscall tracing test
  libbpf: clean up now not needed __PT_PARM{1-6}_SYSCALL_REG defaults

 tools/lib/bpf/bpf_tracing.h                   | 303 +++++++++++++++---
 .../bpf/prog_tests/test_bpf_syscall_macro.c   |  17 +
 .../bpf/prog_tests/uprobe_autoattach.c        |  33 +-
 tools/testing/selftests/bpf/progs/bpf_misc.h  |  25 ++
 .../selftests/bpf/progs/bpf_syscall_macro.c   |  26 ++
 .../bpf/progs/test_uprobe_autoattach.c        |  48 ++-
 6 files changed, 407 insertions(+), 45 deletions(-)

-- 
2.30.2


^ permalink raw reply	[flat|nested] 27+ messages in thread
end of thread, other threads:[~2023-01-23 20:10 UTC | newest]

Thread overview: 27+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-01-20 20:08 [PATCH v2 bpf-next 00/25] libbpf: extend [ku]probe and syscall argument tracing support Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 01/25] libbpf: add support for fetching up to 8 arguments in kprobes Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 02/25] libbpf: add 6th argument support for x86-64 in bpf_tracing.h Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 03/25] libbpf: fix arm and arm64 specs " Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 04/25] libbpf: complete mips spec " Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 05/25] libbpf: complete powerpc " Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 06/25] libbpf: complete sparc " Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 07/25] libbpf: complete riscv arch " Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 08/25] libbpf: fix and complete ARC " Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 09/25] libbpf: complete LoongArch (loongarch) " Andrii Nakryiko
2023-01-20 20:08 ` [PATCH v2 bpf-next 10/25] libbpf: add BPF_UPROBE and BPF_URETPROBE macro aliases Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 11/25] selftests/bpf: validate arch-specific argument registers limits Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 12/25] libbpf: improve syscall tracing support in bpf_tracing.h Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 13/25] libbpf: define x86-64 syscall regs spec " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 14/25] libbpf: define i386 " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 15/25] libbpf: define s390x " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 16/25] libbpf: define arm " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 17/25] libbpf: define arm64 " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 18/25] libbpf: define mips " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 19/25] libbpf: define powerpc " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 20/25] libbpf: define sparc " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 21/25] libbpf: define riscv " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 22/25] libbpf: define arc " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 23/25] libbpf: define loongarch " Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 24/25] selftests/bpf: add 6-argument syscall tracing test Andrii Nakryiko
2023-01-20 20:09 ` [PATCH v2 bpf-next 25/25] libbpf: clean up now not needed __PT_PARM{1-6}_SYSCALL_REG defaults Andrii Nakryiko
2023-01-23 20:10 ` [PATCH v2 bpf-next 00/25] libbpf: extend [ku]probe and syscall argument tracing support patchwork-bot+netdevbpf

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