From: Hengqi Chen hengqi.chen@gmail.com
[ Upstream commit 64f50f6575721ef03d001e907455cbe3baa2a5b1 ]
This patch fixes the following issue of function calls in JIT, like:
[ 29.346981] multi-func JIT bug 105 != 103
The issus can be reproduced by running the "inline simple bpf_loop call" verifier test.
This is because we are emiting 2-4 instructions for 64-bit immediate moves. During the first pass of JIT, the placeholder address is zero, emiting two instructions for it. In the extra pass, the function address is in XKVRANGE, emiting four instructions for it. This change the instruction index in JIT context. Let's always use 4 instructions for function address in JIT. So that the instruction sequences don't change between the first pass and the extra pass for function calls.
Fixes: 5dc615520c4d ("LoongArch: Add BPF JIT support") Signed-off-by: Hengqi Chen hengqi.chen@gmail.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Tested-by: Tiezhu Yang yangtiezhu@loongson.cn Link: https://lore.kernel.org/bpf/20230214152633.2265699-1-hengqi.chen@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/loongarch/net/bpf_jit.c | 2 +- arch/loongarch/net/bpf_jit.h | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index bdcd0c7719a9e..2467bfb8889a9 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -782,7 +782,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext if (ret < 0) return ret;
- move_imm(ctx, t1, func_addr, is32); + move_addr(ctx, t1, func_addr); emit_insn(ctx, jirl, t1, LOONGARCH_GPR_RA, 0); move_reg(ctx, regmap[BPF_REG_0], LOONGARCH_GPR_A0); break; diff --git a/arch/loongarch/net/bpf_jit.h b/arch/loongarch/net/bpf_jit.h index e665ddb0aeb85..093885539e701 100644 --- a/arch/loongarch/net/bpf_jit.h +++ b/arch/loongarch/net/bpf_jit.h @@ -80,6 +80,27 @@ static inline void emit_sext_32(struct jit_ctx *ctx, enum loongarch_gpr reg, boo emit_insn(ctx, addiw, reg, reg, 0); }
+static inline void move_addr(struct jit_ctx *ctx, enum loongarch_gpr rd, u64 addr) +{ + u64 imm_11_0, imm_31_12, imm_51_32, imm_63_52; + + /* lu12iw rd, imm_31_12 */ + imm_31_12 = (addr >> 12) & 0xfffff; + emit_insn(ctx, lu12iw, rd, imm_31_12); + + /* ori rd, rd, imm_11_0 */ + imm_11_0 = addr & 0xfff; + emit_insn(ctx, ori, rd, rd, imm_11_0); + + /* lu32id rd, imm_51_32 */ + imm_51_32 = (addr >> 32) & 0xfffff; + emit_insn(ctx, lu32id, rd, imm_51_32); + + /* lu52id rd, rd, imm_63_52 */ + imm_63_52 = (addr >> 52) & 0xfff; + emit_insn(ctx, lu52id, rd, rd, imm_63_52); +} + static inline void move_imm(struct jit_ctx *ctx, enum loongarch_gpr rd, long imm, bool is32) { long imm_11_0, imm_31_12, imm_51_32, imm_63_52, imm_51_0, imm_51_31;