BPF trampoline is the critical infrastructure of the bpf subsystem, acting as a mediator between kernel functions and BPF programs. Numerous important features, such as using ebpf program for zero overhead kernel introspection, rely on this key component. We can't wait to support bpf trampoline on RV64. Since RV64 does not support ftrace direct call yet, the current RV64 bpf trampoline is only used in bpf context. As most of riscv cpu support unaligned memory accesses, we temporarily use patch [1] to facilitate testing. The test results are as follow, and test_verifier with no new failure ceses. - fexit_bpf2bpf:OK - dummy_st_ops:OK - xdp_bpf2bpf:OK [1] https://lore.kernel.org/linux-riscv/20210916130855.4054926-2-chenhuang5@xxxxxxxxxx/ v1: - Remove the logic of bpf_arch_text_poke supported for kernel functions. (Kuohai and Björn) - Extend patch_text for multiple instructions. (Björn) - Fix OOB issue when image too big. (Björn) RFC: https://lore.kernel.org/bpf/20230103090756.1993820-1-pulehui@xxxxxxxxxxxxxxx/ Pu Lehui (4): riscv: Extend patch_text for multiple instructions riscv, bpf: Factor out emit_call for kernel and bpf context riscv, bpf: Add bpf_arch_text_poke support for RV64 riscv, bpf: Add bpf trampoline support for RV64 arch/riscv/include/asm/patch.h | 2 +- arch/riscv/kernel/patch.c | 19 +- arch/riscv/kernel/probes/kprobes.c | 15 +- arch/riscv/net/bpf_jit.h | 5 + arch/riscv/net/bpf_jit_comp64.c | 437 +++++++++++++++++++++++++++-- 5 files changed, 444 insertions(+), 34 deletions(-) -- 2.25.1
