From dd642ccb45ecce1402eb2550f5284fc6bb9ed7b8 Mon Sep 17 00:00:00 2001 From: Pu Lehui Date: Sun, 10 Apr 2022 18:12:46 +0800 Subject: riscv, bpf: Implement more atomic operations for RV64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch implement more BPF atomic operations for RV64. The newly added operations are shown below: atomic[64]_[fetch_]add atomic[64]_[fetch_]and atomic[64]_[fetch_]or atomic[64]_xchg atomic[64]_cmpxchg Since riscv specification does not provide AMO instruction for CAS operation, we use lr/sc instruction for cmpxchg operation, and AMO instructions for the rest ops. Tests "test_bpf.ko" and "test_progs -t atomic" have passed, as well as "test_verifier" with no new failure cases. Signed-off-by: Pu Lehui Signed-off-by: Daniel Borkmann Acked-by: Song Liu Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20220410101246.232875-1-pulehui@huawei.com --- arch/riscv/net/bpf_jit.h | 67 ++++++++++++++++++++++++ arch/riscv/net/bpf_jit_comp64.c | 110 +++++++++++++++++++++++++++++++--------- 2 files changed, 153 insertions(+), 24 deletions(-) (limited to 'arch/riscv/net') diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h index f42d9cd3b64d..2a3715bf29fe 100644 --- a/arch/riscv/net/bpf_jit.h +++ b/arch/riscv/net/bpf_jit.h @@ -535,6 +535,43 @@ static inline u32 rv_amoadd_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) return rv_amo_insn(0, aq, rl, rs2, rs1, 2, rd, 0x2f); } +static inline u32 rv_amoand_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0xc, aq, rl, rs2, rs1, 2, rd, 0x2f); +} + +static inline u32 rv_amoor_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x8, aq, rl, rs2, rs1, 2, rd, 0x2f); +} + +static inline u32 rv_amoxor_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x4, aq, rl, rs2, rs1, 2, rd, 0x2f); +} + +static inline u32 rv_amoswap_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x1, aq, rl, rs2, rs1, 2, rd, 0x2f); +} + +static inline u32 rv_lr_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x2, aq, rl, rs2, rs1, 2, rd, 0x2f); +} + +static inline u32 rv_sc_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x3, aq, rl, rs2, rs1, 2, rd, 0x2f); +} + +static inline u32 rv_fence(u8 pred, u8 succ) +{ + u16 imm11_0 = pred << 4 | succ; + + return rv_i_insn(imm11_0, 0, 0, 0, 0xf); +} + /* RVC instrutions. */ static inline u16 rvc_addi4spn(u8 rd, u32 imm10) @@ -753,6 +790,36 @@ static inline u32 rv_amoadd_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) return rv_amo_insn(0, aq, rl, rs2, rs1, 3, rd, 0x2f); } +static inline u32 rv_amoand_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0xc, aq, rl, rs2, rs1, 3, rd, 0x2f); +} + +static inline u32 rv_amoor_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x8, aq, rl, rs2, rs1, 3, rd, 0x2f); +} + +static inline u32 rv_amoxor_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x4, aq, rl, rs2, rs1, 3, rd, 0x2f); +} + +static inline u32 rv_amoswap_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x1, aq, rl, rs2, rs1, 3, rd, 0x2f); +} + +static inline u32 rv_lr_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x2, aq, rl, rs2, rs1, 3, rd, 0x2f); +} + +static inline u32 rv_sc_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl) +{ + return rv_amo_insn(0x3, aq, rl, rs2, rs1, 3, rd, 0x2f); +} + /* RV64-only RVC instructions. */ static inline u16 rvc_ld(u8 rd, u32 imm8, u8 rs1) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 0bcda99d1d68..00df3a8f92ac 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -455,6 +455,90 @@ static int emit_call(bool fixed, u64 addr, struct rv_jit_context *ctx) return 0; } +static void emit_atomic(u8 rd, u8 rs, s16 off, s32 imm, bool is64, + struct rv_jit_context *ctx) +{ + u8 r0; + int jmp_offset; + + if (off) { + if (is_12b_int(off)) { + emit_addi(RV_REG_T1, rd, off, ctx); + } else { + emit_imm(RV_REG_T1, off, ctx); + emit_add(RV_REG_T1, RV_REG_T1, rd, ctx); + } + rd = RV_REG_T1; + } + + switch (imm) { + /* lock *(u32/u64 *)(dst_reg + off16) = src_reg */ + case BPF_ADD: + emit(is64 ? rv_amoadd_d(RV_REG_ZERO, rs, rd, 0, 0) : + rv_amoadd_w(RV_REG_ZERO, rs, rd, 0, 0), ctx); + break; + case BPF_AND: + emit(is64 ? rv_amoand_d(RV_REG_ZERO, rs, rd, 0, 0) : + rv_amoand_w(RV_REG_ZERO, rs, rd, 0, 0), ctx); + break; + case BPF_OR: + emit(is64 ? rv_amoor_d(RV_REG_ZERO, rs, rd, 0, 0) : + rv_amoor_w(RV_REG_ZERO, rs, rd, 0, 0), ctx); + break; + case BPF_XOR: + emit(is64 ? rv_amoxor_d(RV_REG_ZERO, rs, rd, 0, 0) : + rv_amoxor_w(RV_REG_ZERO, rs, rd, 0, 0), ctx); + break; + /* src_reg = atomic_fetch_(dst_reg + off16, src_reg) */ + case BPF_ADD | BPF_FETCH: + emit(is64 ? rv_amoadd_d(rs, rs, rd, 0, 0) : + rv_amoadd_w(rs, rs, rd, 0, 0), ctx); + if (!is64) + emit_zext_32(rs, ctx); + break; + case BPF_AND | BPF_FETCH: + emit(is64 ? rv_amoand_d(rs, rs, rd, 0, 0) : + rv_amoand_w(rs, rs, rd, 0, 0), ctx); + if (!is64) + emit_zext_32(rs, ctx); + break; + case BPF_OR | BPF_FETCH: + emit(is64 ? rv_amoor_d(rs, rs, rd, 0, 0) : + rv_amoor_w(rs, rs, rd, 0, 0), ctx); + if (!is64) + emit_zext_32(rs, ctx); + break; + case BPF_XOR | BPF_FETCH: + emit(is64 ? rv_amoxor_d(rs, rs, rd, 0, 0) : + rv_amoxor_w(rs, rs, rd, 0, 0), ctx); + if (!is64) + emit_zext_32(rs, ctx); + break; + /* src_reg = atomic_xchg(dst_reg + off16, src_reg); */ + case BPF_XCHG: + emit(is64 ? rv_amoswap_d(rs, rs, rd, 0, 0) : + rv_amoswap_w(rs, rs, rd, 0, 0), ctx); + if (!is64) + emit_zext_32(rs, ctx); + break; + /* r0 = atomic_cmpxchg(dst_reg + off16, r0, src_reg); */ + case BPF_CMPXCHG: + r0 = bpf_to_rv_reg(BPF_REG_0, ctx); + emit(is64 ? rv_addi(RV_REG_T2, r0, 0) : + rv_addiw(RV_REG_T2, r0, 0), ctx); + emit(is64 ? rv_lr_d(r0, 0, rd, 0, 0) : + rv_lr_w(r0, 0, rd, 0, 0), ctx); + jmp_offset = ninsns_rvoff(8); + emit(rv_bne(RV_REG_T2, r0, jmp_offset >> 1), ctx); + emit(is64 ? rv_sc_d(RV_REG_T3, rs, rd, 0, 0) : + rv_sc_w(RV_REG_T3, rs, rd, 0, 0), ctx); + jmp_offset = ninsns_rvoff(-6); + emit(rv_bne(RV_REG_T3, 0, jmp_offset >> 1), ctx); + emit(rv_fence(0x3, 0x3), ctx); + break; + } +} + #define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0) #define BPF_FIXUP_REG_MASK GENMASK(31, 27) @@ -1146,30 +1230,8 @@ out_be: break; case BPF_STX | BPF_ATOMIC | BPF_W: case BPF_STX | BPF_ATOMIC | BPF_DW: - if (insn->imm != BPF_ADD) { - pr_err("bpf-jit: not supported: atomic operation %02x ***\n", - insn->imm); - return -EINVAL; - } - - /* atomic_add: lock *(u32 *)(dst + off) += src - * atomic_add: lock *(u64 *)(dst + off) += src - */ - - if (off) { - if (is_12b_int(off)) { - emit_addi(RV_REG_T1, rd, off, ctx); - } else { - emit_imm(RV_REG_T1, off, ctx); - emit_add(RV_REG_T1, RV_REG_T1, rd, ctx); - } - - rd = RV_REG_T1; - } - - emit(BPF_SIZE(code) == BPF_W ? - rv_amoadd_w(RV_REG_ZERO, rs, rd, 0, 0) : - rv_amoadd_d(RV_REG_ZERO, rs, rd, 0, 0), ctx); + emit_atomic(rd, rs, off, imm, + BPF_SIZE(code) == BPF_DW, ctx); break; default: pr_err("bpf-jit: unknown opcode %02x\n", code); -- cgit v1.2.3