From: Hengqi Chen <hengqi.chen@gmail.com>
Date: Tue, 14 Feb 2023 15:26:33 +0000
Subject: [PATCH] LoongArch, bpf: Use 4 instructions for function address in
JIT
References: bsc#1012628
Patch-mainline: 6.2.3
Git-commit: 64f50f6575721ef03d001e907455cbe3baa2a5b1
[ 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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 c4b1947e..288003a9 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -841,7 +841,7 @@ 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 ca708024..c335dc4e 100644
--- a/arch/loongarch/net/bpf_jit.h
+++ b/arch/loongarch/net/bpf_jit.h
@@ -82,6 +82,27 @@ 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;
--
2.35.3