CCing BPF kernel community who is defining the ISA and various runtime stuff. Also two inline comments below about the assembler > On 20 May 2019, at 17:45, Jose E. Marchesi <jose.marchesi oracle ! com> wrote: > > Hi people! > > This patch series introduces support for eBPF, which is a virtual > machine that resides in the Linux kernel. Initially intended for > user-level packet capture and filtering, eBPF is nowadays generalized > to serve as a general-purpose infrastructure also for non-networking > purposes. > > The first patch is preparatory, and adds support to config.guess to > recognize bpf-*-* triplets. This will be submitted as a patch to the > `config' project as soon as this series gets upstreamed. > > The second and third patches add support for an ELF64 based eBPF > target to BFD, in both little-endian and big-endian vectors. > > The fourth patch adds a CGEN cpu description for eBPF, plus support > code. This description covers the full eBPF ISA. Due to the 64-bit > instruction fields used in some instructions, we needed to fix a > bug/limitation in CGEN impacting 32-bit hosts. The fix is in a patch > submitted to CGEN last week, that is still waiting for review: > http://www.sourceware.org/ml/cgen/2019-q2/msg00008.html None of the > existing CGEN ports in binutils are impacted by that patch: the code > generated for these remains exactly the same. > > The fifth patch adds opcodes and disassembler support for eBPF, based > on the CGEN description. > > The sixth patch adds a GAS port, including a testsuite and manual > updates. By default the assembler generates objects using the same > endianness than the host. This can be overrided by the usual -EB and > -EB command-line options. > > Support for linking eBPF ELF files with ld/bfd is provided in the > seventh patch. A couple of simple tests are included. > > The eighth patch adds support for eBPF to readelf, and makes a little > adjustment in the `nm' testsuite to not fail in bpf-*-* targets. > > Finally, the last patch adds myself as the maintainer of the BPF > target. We are committing to maintain this port. > > Future work on the binutils port: > * Support for semantic actions in bpf.cpu, and support code for a > simulator in sim/. > * Support for ld.gold. > > Next stop is GCC. An eBPF backend is on the works. We plan to > upstream it before September. > > Regressions tested in all targets. > Regressions tested with --enable-targets=all > Tested in 64-bit x86_64 host. > Tested in 32-bit x86 host. > > Oh, a little note regarding interoperability: > > There is a clang/llvm based toolchain for eBPF. However, at this > moment compiled eBPF doesn't have established conventions. The > details on what is expected to be in an ELF file containing eBPF is > determined, in practice, by what the llvm BPF backend supports and > what the sample bpf_load.c in the Linux kernel source tree expects > [1]. > > Despite using a different syntax for the assembler (the llvm assembler > uses a C-ish expression-based syntax while the GNU assembler opts for > a more classic assembly-language syntax) this implementation tries to > provide inter-operability with clang/llvm generated objects. I also noticed your implementation doesn’t seem to use the same sub-register syntax as what LLVM assembler is doing. x register for 64-bit, and w register for 32-bit sub-register. So: add r0, r1, r2 means BPF_ALU64 | BPF_ADD | BFF_X add w0, w1, w1 means BPF_ALU | BPF_ADD | BPF_X ASAICT, different register prefix for different register width is also adopted by quite a few other GNU assembler targets like AArch64, X86_64. > > In particular, the numbers of the relocations used for instruction > fields are the same. These are R_BPF_INSN_64 and R_BPF_INSN_DISP32. > The later is resolved at load-time by bpf_load.c. I think you missed the latest JMP32 instructions. https://github.com/torvalds/linux/blob/master/Documentation/networking/filter.txt#L870 > > [1] We expect/hope that the addition of eBPF support to the GNU > toolchain will help to mature the domain of compiled eBPF. We > will certainly be working with the kernel people to that effect. > > Salud! > > Jose E. Marchesi (9): > config: recognize eBPF triplets > include: add elf/bpf.h > bfd: add support for eBPF > cpu: add eBPF cpu description > opcodes: add support for eBPF > gas: add support for eBPF > ld: add support for eBPF > binutils: add support for eBPF > binutils: add myself as the maintainer for BPF > > ChangeLog | 4 + > bfd/ChangeLog | 20 + > bfd/Makefile.am | 4 + > bfd/Makefile.in | 7 + > bfd/archures.c | 4 + > bfd/bfd-in2.h | 9 + > bfd/config.bfd | 6 + > bfd/configure | 30 +- > bfd/configure.ac | 2 + > bfd/cpu-bpf.c | 41 + > bfd/elf64-bpf.c | 463 +++++++++ > bfd/libbfd.h | 5 + > bfd/reloc.c | 13 + > bfd/targets.c | 7 + > binutils/ChangeLog | 13 + > binutils/MAINTAINERS | 1 + > binutils/readelf.c | 8 + > binutils/testsuite/binutils-all/nm.exp | 3 +- > config.sub | 4 +- > cpu/ChangeLog | 5 + > cpu/bpf.cpu | 647 +++++++++++++ > cpu/bpf.opc | 191 ++++ > gas/ChangeLog | 45 + > gas/Makefile.am | 2 + > gas/Makefile.in | 6 + > gas/config/tc-bpf.c | 357 +++++++ > gas/config/tc-bpf.h | 51 + > gas/configure | 38 +- > gas/configure.ac | 6 + > gas/configure.tgt | 1 + > gas/doc/Makefile.am | 1 + > gas/doc/Makefile.in | 6 +- > gas/doc/all.texi | 1 + > gas/doc/as.texi | 34 + > gas/doc/c-bpf.texi | 364 +++++++ > gas/testsuite/gas/all/gas.exp | 3 + > gas/testsuite/gas/all/org-1.l | 2 +- > gas/testsuite/gas/all/org-1.s | 2 + > gas/testsuite/gas/bpf/alu-be.d | 59 ++ > gas/testsuite/gas/bpf/alu.d | 58 ++ > gas/testsuite/gas/bpf/alu.s | 51 + > gas/testsuite/gas/bpf/alu32-be.d | 65 ++ > gas/testsuite/gas/bpf/alu32.d | 64 ++ > gas/testsuite/gas/bpf/alu32.s | 57 ++ > gas/testsuite/gas/bpf/atomic-be.d | 12 + > gas/testsuite/gas/bpf/atomic.d | 11 + > gas/testsuite/gas/bpf/atomic.s | 5 + > gas/testsuite/gas/bpf/bpf.exp | 38 + > gas/testsuite/gas/bpf/call-be.d | 19 + > gas/testsuite/gas/bpf/call.d | 18 + > gas/testsuite/gas/bpf/call.s | 11 + > gas/testsuite/gas/bpf/exit-be.d | 11 + > gas/testsuite/gas/bpf/exit.d | 10 + > gas/testsuite/gas/bpf/exit.s | 2 + > gas/testsuite/gas/bpf/jump-be.d | 32 + > gas/testsuite/gas/bpf/jump.d | 31 + > gas/testsuite/gas/bpf/jump.s | 25 + > gas/testsuite/gas/bpf/lddw-be.d | 18 + > gas/testsuite/gas/bpf/lddw.d | 17 + > gas/testsuite/gas/bpf/lddw.s | 6 + > gas/testsuite/gas/bpf/mem-be.d | 30 + > gas/testsuite/gas/bpf/mem.d | 29 + > gas/testsuite/gas/bpf/mem.s | 24 + > include/ChangeLog | 4 + > include/elf/bpf.h | 45 + > ld/ChangeLog | 15 + > ld/Makefile.am | 2 + > ld/Makefile.in | 4 + > ld/configure | 28 +- > ld/configure.tgt | 1 + > ld/emulparams/elf64bpf.sh | 10 + > ld/testsuite/ld-bpf/bar.s | 5 + > ld/testsuite/ld-bpf/baz.s | 5 + > ld/testsuite/ld-bpf/bpf.exp | 29 + > ld/testsuite/ld-bpf/call-1.d | 23 + > ld/testsuite/ld-bpf/foo.s | 5 + > ld/testsuite/ld-bpf/jump-1.d | 23 + > ld/testsuite/lib/ld-lib.exp | 1 + > opcodes/ChangeLog | 24 + > opcodes/Makefile.am | 17 + > opcodes/Makefile.in | 23 + > opcodes/bpf-asm.c | 590 ++++++++++++ > opcodes/bpf-desc.c | 1638 ++++++++++++++++++++++++++++++++ > opcodes/bpf-desc.h | 266 ++++++ > opcodes/bpf-dis.c | 624 ++++++++++++ > opcodes/bpf-ibld.c | 956 +++++++++++++++++++ > opcodes/bpf-opc.c | 1495 +++++++++++++++++++++++++++++ > opcodes/bpf-opc.h | 151 +++ > opcodes/configure | 19 +- > opcodes/configure.ac | 1 + > opcodes/disassemble.c | 35 + > opcodes/disassemble.h | 1 + > 92 files changed, 9116 insertions(+), 33 deletions(-) > create mode 100644 bfd/cpu-bpf.c > create mode 100644 bfd/elf64-bpf.c > create mode 100644 cpu/bpf.cpu > create mode 100644 cpu/bpf.opc > create mode 100644 gas/config/tc-bpf.c > create mode 100644 gas/config/tc-bpf.h > create mode 100644 gas/doc/c-bpf.texi > create mode 100644 gas/testsuite/gas/bpf/alu-be.d > create mode 100644 gas/testsuite/gas/bpf/alu.d > create mode 100644 gas/testsuite/gas/bpf/alu.s > create mode 100644 gas/testsuite/gas/bpf/alu32-be.d > create mode 100644 gas/testsuite/gas/bpf/alu32.d > create mode 100644 gas/testsuite/gas/bpf/alu32.s > create mode 100644 gas/testsuite/gas/bpf/atomic-be.d > create mode 100644 gas/testsuite/gas/bpf/atomic.d > create mode 100644 gas/testsuite/gas/bpf/atomic.s > create mode 100644 gas/testsuite/gas/bpf/bpf.exp > create mode 100644 gas/testsuite/gas/bpf/call-be.d > create mode 100644 gas/testsuite/gas/bpf/call.d > create mode 100644 gas/testsuite/gas/bpf/call.s > create mode 100644 gas/testsuite/gas/bpf/exit-be.d > create mode 100644 gas/testsuite/gas/bpf/exit.d > create mode 100644 gas/testsuite/gas/bpf/exit.s > create mode 100644 gas/testsuite/gas/bpf/jump-be.d > create mode 100644 gas/testsuite/gas/bpf/jump.d > create mode 100644 gas/testsuite/gas/bpf/jump.s > create mode 100644 gas/testsuite/gas/bpf/lddw-be.d > create mode 100644 gas/testsuite/gas/bpf/lddw.d > create mode 100644 gas/testsuite/gas/bpf/lddw.s > create mode 100644 gas/testsuite/gas/bpf/mem-be.d > create mode 100644 gas/testsuite/gas/bpf/mem.d > create mode 100644 gas/testsuite/gas/bpf/mem.s > create mode 100644 include/elf/bpf.h > create mode 100644 ld/emulparams/elf64bpf.sh > create mode 100644 ld/testsuite/ld-bpf/bar.s > create mode 100644 ld/testsuite/ld-bpf/baz.s > create mode 100644 ld/testsuite/ld-bpf/bpf.exp > create mode 100644 ld/testsuite/ld-bpf/call-1.d > create mode 100644 ld/testsuite/ld-bpf/foo.s > create mode 100644 ld/testsuite/ld-bpf/jump-1.d > create mode 100644 opcodes/bpf-asm.c > create mode 100644 opcodes/bpf-desc.c > create mode 100644 opcodes/bpf-desc.h > create mode 100644 opcodes/bpf-dis.c > create mode 100644 opcodes/bpf-ibld.c > create mode 100644 opcodes/bpf-opc.c > create mode 100644 opcodes/bpf-opc.h > > -- > 2.11.0
