Commit 61319d15 authored by Chenghao Duan's avatar Chenghao Duan Committed by Huacai Chen
Browse files

LoongArch: BPF: Adjust the jump offset of tail calls 



Call the next bpf prog and skip the first instruction of TCC
initialization.

A total of 7 instructions are skipped:
'move t0, ra'			1 inst
'move_imm + jirl'		5 inst
'addid REG_TCC, zero, 0'	1 inst

Relevant test cases: the tailcalls test item in selftests/bpf.

Cc: stable@vger.kernel.org
Fixes: 677e6123 ("LoongArch: BPF: Disable trampoline for kernel module function trace")
Signed-off-by: default avatarChenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent d314e1f4

arch/loongarch/net/bpf_jit.c

+1 −1
Original line number Diff line number Diff line
@@ -239,7 +239,7 @@ static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call) 
		 * Call the next bpf prog and skip the first instruction

		 * of TCC initialization.

		 */

		emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T3, 6);

		emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T3, 7);

	}

}