[PATCH v3 0/8] perf: Support multiple system call tables in the build
Ian Rogers
irogers at google.com
Mon Feb 24 20:22:50 PST 2025
On Mon, Feb 24, 2025 at 7:20 PM Namhyung Kim <namhyung at kernel.org> wrote:
>
> On Wed, Feb 19, 2025 at 10:56:49AM -0800, Ian Rogers wrote:
> > This work builds on the clean up of system call tables and removal of
> > libaudit by Charlie Jenkins <charlie at rivosinc.com>.
> >
> > The system call table in perf trace is used to map system call numbers
> > to names and vice versa. Prior to these changes, a single table
> > matching the perf binary's build was present. The table would be
> > incorrect if tracing say a 32-bit binary from a 64-bit version of
> > perf, the names and numbers wouldn't match.
> >
> > Change the build so that a single system call file is built and the
> > potentially multiple tables are identifiable from the ELF machine type
> > of the process being examined. To determine the ELF machine type, the
> > executable's header is read from /proc/pid/exe with fallbacks to using
> > the perf's binary type when unknown.
>
> Hmm.. then this is limited to live mode and potentially detect wrong
> machine type if it reads an old data, right?
>
> Also IIUC fallback to the perf binary means it cannot use cross-machine
> table. For example, it cannot process data from ARM64 on x86, no? It
> seems it should use perf_env.arch.
The perf env arch is kind of horrid. On x86 it has the value x86 and
then there is an extra 64bit flag, who knows how x32 should be encoded
- but we barely support x32 as-is. I'd rather we added a new feature
for the e_machine/e_flags of the executable and worked with those, but
it is kind of weird with doing system wide mode. I didn't want to drag
that into this patch series anyway as there is already enough here.
> One more concern is BPF. The BPF should know about the ABI of the
> current process so that it can augment the syscall arguments correctly.
> Currently it only checks the syscall number but it can be different on
> 32-bit and 64-bit.
That's right. This change is trying to clean up
tools/perf/util/syscalltbl.c and the perf trace usage. I didn't go as
far as making BPF programs pair system call number with e_machine and
e_flags, there is enough here and the behavior after these patches
matches the behavior before - that is to assume the system call ABI
matches that of the perf binary.
Thanks,
Ian
> Thanks,
> Namhyung
>
>
> >
> > Remove some runtime types used by the system call tables and make
> > equivalents generated at build time.
> >
> > v3: Add Charlie's reviewed-by tags. Incorporate feedback from Arnd
> > Bergmann <arnd at arndb.de> on additional optional column and MIPS
> > system call numbering. Rebase past Namhyung's global system call
> > statistics and add comments that they don't yet support an
> > e_machine other than EM_HOST.
> >
> > v2: Change the 1 element cache for the last table as suggested by
> > Howard Chu, add Howard's reviewed-by tags.
> > Add a comment and apology to Charlie for not doing better in
> > guiding:
> > https://lore.kernel.org/all/20250114-perf_syscall_arch_runtime-v1-1-5b304e408e11@rivosinc.com/
> > After discussion on v1 and he agreed this patch series would be
> > the better direction.
> >
> > Ian Rogers (8):
> > perf syscalltble: Remove syscall_table.h
> > perf trace: Reorganize syscalls
> > perf syscalltbl: Remove struct syscalltbl
> > perf thread: Add support for reading the e_machine type for a thread
> > perf trace beauty: Add syscalltbl.sh generating all system call tables
> > perf syscalltbl: Use lookup table containing multiple architectures
> > perf build: Remove Makefile.syscalls
> > perf syscalltbl: Mask off ABI type for MIPS system calls
> >
> > tools/perf/Makefile.perf | 10 +-
> > tools/perf/arch/alpha/entry/syscalls/Kbuild | 2 -
> > .../alpha/entry/syscalls/Makefile.syscalls | 5 -
> > tools/perf/arch/alpha/include/syscall_table.h | 2 -
> > tools/perf/arch/arc/entry/syscalls/Kbuild | 2 -
> > .../arch/arc/entry/syscalls/Makefile.syscalls | 3 -
> > tools/perf/arch/arc/include/syscall_table.h | 2 -
> > tools/perf/arch/arm/entry/syscalls/Kbuild | 4 -
> > .../arch/arm/entry/syscalls/Makefile.syscalls | 2 -
> > tools/perf/arch/arm/include/syscall_table.h | 2 -
> > tools/perf/arch/arm64/entry/syscalls/Kbuild | 3 -
> > .../arm64/entry/syscalls/Makefile.syscalls | 6 -
> > tools/perf/arch/arm64/include/syscall_table.h | 8 -
> > tools/perf/arch/csky/entry/syscalls/Kbuild | 2 -
> > .../csky/entry/syscalls/Makefile.syscalls | 3 -
> > tools/perf/arch/csky/include/syscall_table.h | 2 -
> > .../perf/arch/loongarch/entry/syscalls/Kbuild | 2 -
> > .../entry/syscalls/Makefile.syscalls | 3 -
> > .../arch/loongarch/include/syscall_table.h | 2 -
> > tools/perf/arch/mips/entry/syscalls/Kbuild | 2 -
> > .../mips/entry/syscalls/Makefile.syscalls | 5 -
> > tools/perf/arch/mips/include/syscall_table.h | 2 -
> > tools/perf/arch/parisc/entry/syscalls/Kbuild | 3 -
> > .../parisc/entry/syscalls/Makefile.syscalls | 6 -
> > .../perf/arch/parisc/include/syscall_table.h | 8 -
> > tools/perf/arch/powerpc/entry/syscalls/Kbuild | 3 -
> > .../powerpc/entry/syscalls/Makefile.syscalls | 6 -
> > .../perf/arch/powerpc/include/syscall_table.h | 8 -
> > tools/perf/arch/riscv/entry/syscalls/Kbuild | 2 -
> > .../riscv/entry/syscalls/Makefile.syscalls | 4 -
> > tools/perf/arch/riscv/include/syscall_table.h | 8 -
> > tools/perf/arch/s390/entry/syscalls/Kbuild | 2 -
> > .../s390/entry/syscalls/Makefile.syscalls | 5 -
> > tools/perf/arch/s390/include/syscall_table.h | 2 -
> > tools/perf/arch/sh/entry/syscalls/Kbuild | 2 -
> > .../arch/sh/entry/syscalls/Makefile.syscalls | 4 -
> > tools/perf/arch/sh/include/syscall_table.h | 2 -
> > tools/perf/arch/sparc/entry/syscalls/Kbuild | 3 -
> > .../sparc/entry/syscalls/Makefile.syscalls | 5 -
> > tools/perf/arch/sparc/include/syscall_table.h | 8 -
> > tools/perf/arch/x86/entry/syscalls/Kbuild | 3 -
> > .../arch/x86/entry/syscalls/Makefile.syscalls | 6 -
> > tools/perf/arch/x86/include/syscall_table.h | 8 -
> > tools/perf/arch/xtensa/entry/syscalls/Kbuild | 2 -
> > .../xtensa/entry/syscalls/Makefile.syscalls | 4 -
> > .../perf/arch/xtensa/include/syscall_table.h | 2 -
> > tools/perf/builtin-trace.c | 290 +++++++++++-------
> > tools/perf/scripts/Makefile.syscalls | 61 ----
> > tools/perf/scripts/syscalltbl.sh | 86 ------
> > tools/perf/trace/beauty/syscalltbl.sh | 274 +++++++++++++++++
> > tools/perf/util/syscalltbl.c | 148 ++++-----
> > tools/perf/util/syscalltbl.h | 22 +-
> > tools/perf/util/thread.c | 50 +++
> > tools/perf/util/thread.h | 14 +-
> > 54 files changed, 616 insertions(+), 509 deletions(-)
> > delete mode 100644 tools/perf/arch/alpha/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/alpha/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/alpha/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/arc/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/arc/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/arc/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/arm/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/arm/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/arm/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/arm64/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/arm64/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/arm64/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/csky/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/csky/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/csky/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/loongarch/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/loongarch/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/loongarch/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/mips/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/mips/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/mips/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/parisc/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/parisc/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/parisc/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/powerpc/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/powerpc/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/powerpc/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/riscv/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/riscv/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/riscv/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/s390/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/s390/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/s390/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/sh/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/sh/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/sh/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/sparc/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/sparc/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/sparc/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/x86/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/x86/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/x86/include/syscall_table.h
> > delete mode 100644 tools/perf/arch/xtensa/entry/syscalls/Kbuild
> > delete mode 100644 tools/perf/arch/xtensa/entry/syscalls/Makefile.syscalls
> > delete mode 100644 tools/perf/arch/xtensa/include/syscall_table.h
> > delete mode 100644 tools/perf/scripts/Makefile.syscalls
> > delete mode 100755 tools/perf/scripts/syscalltbl.sh
> > create mode 100755 tools/perf/trace/beauty/syscalltbl.sh
> >
> > --
> > 2.48.1.601.g30ceb7b040-goog
> >
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