Re: [PATCH bpf-next v6 0/3] Add 12-argument support for RV64 bpf trampoline

Jiri Olsa
2024-07-02T13:57:55Z

On Tue, Jul 02, 2024 at 12:19:41PM +0000, Pu Lehui wrote:
> This patch adds 12 function arguments support for riscv64 bpf
> trampoline. The current bpf trampoline supports <= sizeof(u64) bytes
> scalar arguments [0] and <= 16 bytes struct arguments [1]. Therefore, we
> focus on the situation where scalars are at most XLEN bits and
> aggregates whose total size does not exceed 2×XLEN bits in the riscv
> calling convention [2].
>
> Link: https://elixir.bootlin.com/linux/v6.8/source/kernel/bpf/btf.c#L6184 [0]
> Link: https://elixir.bootlin.com/linux/v6.8/source/kernel/bpf/btf.c#L6769 [1]
> Link: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/releases/download/draft-20230929-e5c800e661a53efe3c2678d71a306323b60eb13b/riscv-abi.pdf [2]
>
> v6:
> - Remove unnecessary skel detach ops as it will be covered by skel destroy ops.

selftests bits lgtm

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

>
> v5: https://lore.kernel.org/all/20240702013730.1082285-1-pulehui@huaweicloud.com/
> - Remove unnecessary copyright.
>
> v4: https://lore.kernel.org/all/20240622022129.3844473-1-pulehui@huaweicloud.com/
> - Separate many args test logic from tracing_struct. (Daniel)
>
> v3: https://lore.kernel.org/all/20240403072818.1462811-1-pulehui@huaweicloud.com/
> - Variable and macro name alignment:
> nr_reg_args: number of args in reg
> nr_stack_args: number of args on stack
> RV_MAX_REG_ARGS: macro for riscv max args in reg
>
> v2: https://lore.kernel.org/all/20240403041710.1416369-1-pulehui@huaweicloud.com/
> - Add tracing_struct to DENYLIST.aarch64 while aarch64 does not yet support
> bpf trampoline with more than 8 args.
> - Change the macro RV_MAX_ARG_REGS to RV_MAX_ARGS_REG to synchronize with
> the variable definition below.
> - Add some comments for stk_arg_off and magic number of skip slots for loading
> args on stack.
>
> v1: https://lore.kernel.org/all/20240331092405.822571-1-pulehui@huaweicloud.com/
>
> Pu Lehui (3):
> riscv, bpf: Add 12-argument support for RV64 bpf trampoline
> selftests/bpf: Factor out many args tests from tracing_struct
> selftests/bpf: Add testcase where 7th argment is struct
>
> arch/riscv/net/bpf_jit_comp64.c | 66 +++++++++----
> tools/testing/selftests/bpf/DENYLIST.aarch64 | 1 +
> .../selftests/bpf/bpf_testmod/bpf_testmod.c | 19 ++++
> .../selftests/bpf/prog_tests/tracing_struct.c | 44 ++++++++-
> .../selftests/bpf/progs/tracing_struct.c | 54 -----------
> .../bpf/progs/tracing_struct_many_args.c | 95 +++++++++++++++++++
> 6 files changed, 202 insertions(+), 77 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/progs/tracing_struct_many_args.c
>
> --
> 2.34.1
>