[PATCH V6 0/3] eBPF support

Jose E. Marchesi
2020-08-03T14:02:48Z

[The GDB part has already been approved (both code and docs) subject
to the amendments done in this version. The sim part still needs
approval.

Changes from V5:
- Rebased to today's master.
- Use BPF_BP_KIND_BRKPT instead of a hardcoded value, and do not
base its value in the size of the breakpoint instruction.
- Add an entry for the bpf target in gdb/MAINTAINERS. Make sure
that gdb_mbuild.sh still works fine.
- Trailing blanks removed. (There are some pending "empty line added
at EOF" but they are all in generated files, such as aclocal.m4)]

Hi good peoples!

This patch series adds support for the eBPF virtual architecture to
GDB [1].

The first patch contains the basic bits to GDB in order to support the
bpf-unknown-none target. Breakpointing and instruction
single-stepping works, but the debugging support in eBPF is still very
minimal. This is mainly due to the many limitations imposed by the
architecture (disjoint stack, maximum stack size, etc). We are
working to overcome these limitations, by introducing a variant called
xbpf, already supported in GCC with the -mxbpf option, whose purpose
is to ease debugging and to be used in other contexts different than
the Linux kernel, less restrictive.

The second patch adds a basic CGEN-based instruction simulator for
eBPF. It can run many eBPF programs and works well with GDB. A
testsuite covering the supported instructions is also included. We
will be expanding it in order to emulate the several kernel contexts
in which eBPF programs can run, so eBPF developers can use GDB to
debug their programs without having to load them in a running kernel.
Currently the only kernel helper implemented in the simulator is
printk, which is used by the tests.

We of course commit to maintain and evolve this stuff :)

[1] Support for eBPF has been already added to both binutils and GCC.

Jose E. Marchesi (3):
gdb: support for eBPF
sim: eBPF simulator
sim: generated files for the eBPF simulator

gdb/ChangeLog | 13 +
gdb/MAINTAINERS | 3 +
gdb/Makefile.in | 2 +
gdb/bpf-tdep.c | 387 +
gdb/configure.tgt | 6 +
gdb/doc/ChangeLog | 6 +
gdb/doc/gdb.texinfo | 21 +
sim/ChangeLog | 42 +
sim/MAINTAINERS | 1 +
sim/bpf/Makefile.in | 203 +
sim/bpf/aclocal.m4 | 119 +
sim/bpf/arch.c | 35 +
sim/bpf/arch.h | 50 +
sim/bpf/bpf-helpers.c | 175 +
sim/bpf/bpf-helpers.def | 194 +
sim/bpf/bpf-helpers.h | 31 +
sim/bpf/bpf-sim.h | 31 +
sim/bpf/bpf.c | 327 +
sim/bpf/config.in | 248 +
sim/bpf/configure | 15942 ++++++++++++++++++++++++++
sim/bpf/configure.ac | 13 +
sim/bpf/cpu.c | 69 +
sim/bpf/cpu.h | 81 +
sim/bpf/cpuall.h | 65 +
sim/bpf/decode-be.c | 1129 ++
sim/bpf/decode-be.h | 94 +
sim/bpf/decode-le.c | 1129 ++
sim/bpf/decode-le.h | 94 +
sim/bpf/decode.h | 37 +
sim/bpf/defs-be.h | 383 +
sim/bpf/defs-le.h | 383 +
sim/bpf/eng.h | 23 +
sim/bpf/mloop.in | 165 +
sim/bpf/sem-be.c | 3207 ++++++
sim/bpf/sem-le.c | 3207 ++++++
sim/bpf/sim-if.c | 214 +
sim/bpf/sim-main.h | 51 +
sim/bpf/traps.c | 33 +
sim/configure | 8 +
sim/configure.tgt | 3 +
sim/testsuite/ChangeLog | 17 +
sim/testsuite/configure | 3 +
sim/testsuite/sim/bpf/allinsn.exp | 26 +
sim/testsuite/sim/bpf/alu.s | 109 +
sim/testsuite/sim/bpf/alu32.s | 99 +
sim/testsuite/sim/bpf/endbe.s | 46 +
sim/testsuite/sim/bpf/endle.s | 43 +
sim/testsuite/sim/bpf/jmp.s | 120 +
sim/testsuite/sim/bpf/jmp32.s | 120 +
sim/testsuite/sim/bpf/ldabs.s | 87 +
sim/testsuite/sim/bpf/mem.s | 56 +
sim/testsuite/sim/bpf/mov.s | 54 +
sim/testsuite/sim/bpf/testutils.inc | 38 +
sim/testsuite/sim/bpf/xadd.s | 44 +
54 files changed, 29086 insertions(+)
create mode 100644 gdb/bpf-tdep.c
create mode 100644 sim/bpf/Makefile.in
create mode 100644 sim/bpf/aclocal.m4
create mode 100644 sim/bpf/arch.c
create mode 100644 sim/bpf/arch.h
create mode 100644 sim/bpf/bpf-helpers.c
create mode 100644 sim/bpf/bpf-helpers.def
create mode 100644 sim/bpf/bpf-helpers.h
create mode 100644 sim/bpf/bpf-sim.h
create mode 100644 sim/bpf/bpf.c
create mode 100644 sim/bpf/config.in
create mode 100755 sim/bpf/configure
create mode 100644 sim/bpf/configure.ac
create mode 100644 sim/bpf/cpu.c
create mode 100644 sim/bpf/cpu.h
create mode 100644 sim/bpf/cpuall.h
create mode 100644 sim/bpf/decode-be.c
create mode 100644 sim/bpf/decode-be.h
create mode 100644 sim/bpf/decode-le.c
create mode 100644 sim/bpf/decode-le.h
create mode 100644 sim/bpf/decode.h
create mode 100644 sim/bpf/defs-be.h
create mode 100644 sim/bpf/defs-le.h
create mode 100644 sim/bpf/eng.h
create mode 100644 sim/bpf/mloop.in
create mode 100644 sim/bpf/sem-be.c
create mode 100644 sim/bpf/sem-le.c
create mode 100644 sim/bpf/sim-if.c
create mode 100644 sim/bpf/sim-main.h
create mode 100644 sim/bpf/traps.c
create mode 100644 sim/testsuite/sim/bpf/allinsn.exp
create mode 100644 sim/testsuite/sim/bpf/alu.s
create mode 100644 sim/testsuite/sim/bpf/alu32.s
create mode 100644 sim/testsuite/sim/bpf/endbe.s
create mode 100644 sim/testsuite/sim/bpf/endle.s
create mode 100644 sim/testsuite/sim/bpf/jmp.s
create mode 100644 sim/testsuite/sim/bpf/jmp32.s
create mode 100644 sim/testsuite/sim/bpf/ldabs.s
create mode 100644 sim/testsuite/sim/bpf/mem.s
create mode 100644 sim/testsuite/sim/bpf/mov.s
create mode 100644 sim/testsuite/sim/bpf/testutils.inc
create mode 100644 sim/testsuite/sim/bpf/xadd.s

--
2.25.0.2.g232378479e