From 72ae139546333304dc6dd1c840fec4fc8bbc6fed Mon Sep 17 00:00:00 2001 From: Pu Lehui Date: Wed, 15 Feb 2023 21:52:03 +0800 Subject: [PATCH] riscv, bpf: Factor out emit_call for kernel and bpf context MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ Upstream commit 0fd1fd0104954380477353aea29c347e85dff16d ] The current emit_call function is not suitable for kernel function call as it store return value to bpf R0 register. We can separate it out for common use. Meanwhile, simplify judgment logic, that is, fixed function address can use jal or auipc+jalr, while the unfixed can use only auipc+jalr. Signed-off-by: Pu Lehui Signed-off-by: Daniel Borkmann Tested-by: Björn Töpel Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20230215135205.1411105-3-pulehui@huaweicloud.com Stable-dep-of: 2f1b0d3d7331 ("riscv, bpf: Sign-extend return values") Signed-off-by: Sasha Levin --- arch/riscv/net/bpf_jit_comp64.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index f2417ac54edd6..69ebab81d9352 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -428,12 +428,12 @@ static void emit_sext_32_rd(u8 *rd, struct rv_jit_context *ctx) *rd = RV_REG_T2; } -static int emit_jump_and_link(u8 rd, s64 rvoff, bool force_jalr, +static int emit_jump_and_link(u8 rd, s64 rvoff, bool fixed_addr, struct rv_jit_context *ctx) { s64 upper, lower; - if (rvoff && is_21b_int(rvoff) && !force_jalr) { + if (rvoff && fixed_addr && is_21b_int(rvoff)) { emit(rv_jal(rd, rvoff >> 1), ctx); return 0; } else if (in_auipc_jalr_range(rvoff)) { @@ -454,24 +454,17 @@ static bool is_signed_bpf_cond(u8 cond) cond == BPF_JSGE || cond == BPF_JSLE; } -static int emit_call(bool fixed, u64 addr, struct rv_jit_context *ctx) +static int emit_call(u64 addr, bool fixed_addr, struct rv_jit_context *ctx) { s64 off = 0; u64 ip; - u8 rd; - int ret; if (addr && ctx->insns) { ip = (u64)(long)(ctx->insns + ctx->ninsns); off = addr - ip; } - ret = emit_jump_and_link(RV_REG_RA, off, !fixed, ctx); - if (ret) - return ret; - rd = bpf_to_rv_reg(BPF_REG_0, ctx); - emit_mv(rd, RV_REG_A0, ctx); - return 0; + return emit_jump_and_link(RV_REG_RA, off, fixed_addr, ctx); } static void emit_atomic(u8 rd, u8 rs, s16 off, s32 imm, bool is64, @@ -913,7 +906,7 @@ out_be: /* JUMP off */ case BPF_JMP | BPF_JA: rvoff = rv_offset(i, off, ctx); - ret = emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx); + ret = emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx); if (ret) return ret; break; @@ -1032,17 +1025,20 @@ out_be: /* function call */ case BPF_JMP | BPF_CALL: { - bool fixed; + bool fixed_addr; u64 addr; mark_call(ctx); - ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, &addr, - &fixed); + ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, + &addr, &fixed_addr); if (ret < 0) return ret; - ret = emit_call(fixed, addr, ctx); + + ret = emit_call(addr, fixed_addr, ctx); if (ret) return ret; + + emit_mv(bpf_to_rv_reg(BPF_REG_0, ctx), RV_REG_A0, ctx); break; } /* tail call */ @@ -1057,7 +1053,7 @@ out_be: break; rvoff = epilogue_offset(ctx); - ret = emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx); + ret = emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx); if (ret) return ret; break; -- 2.39.5