From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7C80CDB465 for ; Mon, 16 Oct 2023 14:47:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232341AbjJPOrt (ORCPT ); Mon, 16 Oct 2023 10:47:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233266AbjJPOrs (ORCPT ); Mon, 16 Oct 2023 10:47:48 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB552B4 for ; Mon, 16 Oct 2023 07:47:44 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D851C433C7; Mon, 16 Oct 2023 14:47:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1697467664; bh=34wtwRPGKzKN8HfO5lu25lbtyl48QQm4K8aenixk9PI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wDpWZFZCgi3J8tk4+SEbKn87tOavf5SOJJbLOBfPyMn8KCDJ/l2yvqqC6A6mqULcq 674MupsCdzmXju9jWxDK9IN85kyAy75JJriyGl9W7K6PmVn8pfn5ddPAi00CYRtWol V2qrg+w6wdK10I9e8CI0pGF0/G5ZhlyrZoWtQMBE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Daniel Borkmann , Sasha Levin Subject: [PATCH 6.5 066/191] riscv, bpf: Track both a0 (RISC-V ABI) and a5 (BPF) return values Date: Mon, 16 Oct 2023 10:40:51 +0200 Message-ID: <20231016084016.945165178@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231016084015.400031271@linuxfoundation.org> References: <20231016084015.400031271@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Björn Töpel [ Upstream commit 7112cd26e606c7ba51f9cc5c1905f06039f6f379 ] The RISC-V BPF uses a5 for BPF return values, which are zero-extended, whereas the RISC-V ABI uses a0 which is sign-extended. In other words, a5 and a0 can differ, and are used in different context. The BPF trampoline are used for both BPF programs, and regular kernel functions. Make sure that the RISC-V BPF trampoline saves, and restores both a0 and a5. Fixes: 49b5e77ae3e2 ("riscv, bpf: Add bpf trampoline support for RV64") Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20231004120706.52848-3-bjorn@kernel.org Signed-off-by: Sasha Levin --- arch/riscv/net/bpf_jit_comp64.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 3a3631bae05c1..3b4cb713e3684 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -757,8 +757,10 @@ static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_of if (ret) return ret; - if (save_ret) - emit_sd(RV_REG_FP, -retval_off, regmap[BPF_REG_0], ctx); + if (save_ret) { + emit_sd(RV_REG_FP, -retval_off, RV_REG_A0, ctx); + emit_sd(RV_REG_FP, -(retval_off - 8), regmap[BPF_REG_0], ctx); + } /* update branch with beqz */ if (ctx->insns) { @@ -844,7 +846,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET); if (save_ret) { - stack_size += 8; + stack_size += 16; /* Save both A5 (BPF R0) and A0 */ retval_off = stack_size; } @@ -931,6 +933,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, if (ret) goto out; emit_sd(RV_REG_FP, -retval_off, RV_REG_A0, ctx); + emit_sd(RV_REG_FP, -(retval_off - 8), regmap[BPF_REG_0], ctx); im->ip_after_call = ctx->insns + ctx->ninsns; /* 2 nops reserved for auipc+jalr pair */ emit(rv_nop(), ctx); @@ -962,8 +965,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, if (flags & BPF_TRAMP_F_RESTORE_REGS) restore_args(nregs, args_off, ctx); - if (save_ret) + if (save_ret) { emit_ld(RV_REG_A0, -retval_off, RV_REG_FP, ctx); + emit_ld(regmap[BPF_REG_0], -(retval_off - 8), RV_REG_FP, ctx); + } emit_ld(RV_REG_S1, -sreg_off, RV_REG_FP, ctx); -- 2.40.1