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] v4: - Separate many args test logic from tracing_struct. (Daniel) v3: https://lore.kernel.org/all/20240403072818.1462811-1-pulehui@xxxxxxxxxxxxxxx/ - 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@xxxxxxxxxxxxxxx/ - 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@xxxxxxxxxxxxxxx/ 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 | 46 ++++++++- .../selftests/bpf/progs/tracing_struct.c | 54 ----------- .../bpf/progs/tracing_struct_many_args.c | 97 +++++++++++++++++++ 6 files changed, 206 insertions(+), 77 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/tracing_struct_many_args.c -- 2.34.1
