[PATCH bpf-next 06/10] riscv, bpf: Add Zacas instructions

From: Pu Lehui
Date: Sat Jul 19 2025 - 05:15:04 EST


From: Pu Lehui <pulehui@xxxxxxxxxx>

Add Zacas instructions introduced by [0] to reduce code size and
improve performance of RV64 JIT.

Link: https://github.com/riscvarchive/riscv-zacas/releases/download/v1.0/riscv-zacas.pdf [0]
Signed-off-by: Pu Lehui <pulehui@xxxxxxxxxx>
---
arch/riscv/net/bpf_jit.h | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h
index 0964df48c25e..2351fba5d3e7 100644
--- a/arch/riscv/net/bpf_jit.h
+++ b/arch/riscv/net/bpf_jit.h
@@ -751,6 +751,17 @@ static inline u16 rvc_swsp(u32 imm8, u8 rs2)
return rv_css_insn(0x6, imm, rs2, 0x2);
}

+/* RVZACAS instructions. */
+static inline u32 rvzacas_amocas_w(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl)
+{
+ return rv_amo_insn(0x5, aq, rl, rs2, rs1, 2, rd, 0x2f);
+}
+
+static inline u32 rvzacas_amocas_d(u8 rd, u8 rs2, u8 rs1, u8 aq, u8 rl)
+{
+ return rv_amo_insn(0x5, aq, rl, rs2, rs1, 3, rd, 0x2f);
+}
+
/* RVZBA instructions. */
static inline u32 rvzba_sh2add(u8 rd, u8 rs1, u8 rs2)
{
--
2.34.1