linux-kernel - [PATCH] LoongArch: BPF: Adjust the parameter of emit

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20241128061110.5204-1-yangtiezhu@loongson.cn>
Date: Thu, 28 Nov 2024 14:11:10 +0800
From: Tiezhu Yang <yangtiezhu@...ngson.cn>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: loongarch@...ts.linux.dev,
	bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] LoongArch: BPF: Adjust the parameter of emit_jirl()

The branch instructions beq, bne, blt, bge, bltu, bgeu and jirl belong
to the format reg2i16, but the sequence of oprand is different for the
instruction jirl, adjust the parameter of emit_jirl() to make it more
readable correspond with the Instruction Set Architecture manual.

Here are the instruction formats:

  beq     rj, rd, offs16
  bne     rj, rd, offs16
  blt     rj, rd, offs16
  bge     rj, rd, offs16
  bltu    rj, rd, offs16
  bgeu    rj, rd, offs16
  jirl    rd, rj, offs16

Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#branch-instructions
Suggested-by: Huacai Chen <chenhuacai@...ngson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---

This patch is based on the following commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=73c359d1d356

 arch/loongarch/include/asm/inst.h | 12 +++++++++++-
 arch/loongarch/kernel/inst.c      |  2 +-
 arch/loongarch/net/bpf_jit.c      |  6 +++---
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index 944482063f14..3089785ca97e 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -683,7 +683,17 @@ DEF_EMIT_REG2I16_FORMAT(blt, blt_op)
 DEF_EMIT_REG2I16_FORMAT(bge, bge_op)
 DEF_EMIT_REG2I16_FORMAT(bltu, bltu_op)
 DEF_EMIT_REG2I16_FORMAT(bgeu, bgeu_op)
-DEF_EMIT_REG2I16_FORMAT(jirl, jirl_op)
+
+static inline void emit_jirl(union loongarch_instruction *insn,
+			     enum loongarch_gpr rd,
+			     enum loongarch_gpr rj,
+			     int offset)
+{
+	insn->reg2i16_format.opcode = jirl_op;
+	insn->reg2i16_format.immediate = offset;
+	insn->reg2i16_format.rd = rd;
+	insn->reg2i16_format.rj = rj;
+}
 
 #define DEF_EMIT_REG2BSTRD_FORMAT(NAME, OP)				\
 static inline void emit_##NAME(union loongarch_instruction *insn,	\
diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c
index 3050329556d1..14d7d700bcb9 100644
--- a/arch/loongarch/kernel/inst.c
+++ b/arch/loongarch/kernel/inst.c
@@ -332,7 +332,7 @@ u32 larch_insn_gen_jirl(enum loongarch_gpr rd, enum loongarch_gpr rj, int imm)
 		return INSN_BREAK;
 	}
 
-	emit_jirl(&insn, rj, rd, imm >> 2);
+	emit_jirl(&insn, rd, rj, imm >> 2);
 
 	return insn.word;
 }
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index dd350cba1252..ea357a3edc09 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -181,13 +181,13 @@ static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call)
 		/* Set return value */
 		emit_insn(ctx, addiw, LOONGARCH_GPR_A0, regmap[BPF_REG_0], 0);
 		/* Return to the caller */
-		emit_insn(ctx, jirl, LOONGARCH_GPR_RA, LOONGARCH_GPR_ZERO, 0);
+		emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_RA, 0);
 	} else {
 		/*
 		 * Call the next bpf prog and skip the first instruction
 		 * of TCC initialization.
 		 */
-		emit_insn(ctx, jirl, LOONGARCH_GPR_T3, LOONGARCH_GPR_ZERO, 1);
+		emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T3, 1);
 	}
 }
 
@@ -904,7 +904,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
 			return ret;
 
 		move_addr(ctx, t1, func_addr);
-		emit_insn(ctx, jirl, t1, LOONGARCH_GPR_RA, 0);
+		emit_insn(ctx, jirl, LOONGARCH_GPR_RA, t1, 0);
 		move_reg(ctx, regmap[BPF_REG_0], LOONGARCH_GPR_A0);
 		break;
 
-- 
2.42.0