From nobody Fri Jun 12 15:49:38 2026 Received: from cstnet.cn (smtp21.cstnet.cn [159.226.251.21]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9829B39C00B for ; Mon, 11 May 2026 12:41:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.21 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778503292; cv=none; b=Gv0sKoJiX2Jpaouo3B6pu55o1/HB6uqp+D4P018SH8mH5YD5P6+QFb2L8++c8hVdwJHhMxaAa/kkEZ2WnQwQauogkB5O4N6mbwsGXdCU0SJm2H9UDfIJZoAJgzFIfzxWe9J1t6rdgxwuNLKgWb5eO7x4FzoK8AF2Kr78eLkX450= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778503292; c=relaxed/simple; bh=foYYboCVvu/RzGE43jY7RWPtmSrQzeVeze74R29Us3I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BJuG912etN5w2rRSlqlXGjvvT0GsbvQCT3b51hdvrdbjaws2/xXdV5TR+ogyqXawAqn7E/3xtx0efgR40zbW2QfyfjIePr84dzE2JaNucHNsM1gWX14LDrvhVxoW95pBERkEvlzh7+niKOLcfY8EsxPSyhb3dXcu3FmqtAyjXGE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from yzs (unknown [183.156.89.125]) by APP-01 (Coremail) with SMTP id qwCowADXf2tfzgFqB9bmDw--.5197S2; Mon, 11 May 2026 20:41:04 +0800 (CST) From: Zishun Yi To: Andreas Schwab Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Andrew Jones , =?UTF-8?q?Cl=C3=A9ment=20L=C3=A9ger?= , Charlie Jenkins , Nam Cao , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Zishun Yi Subject: [PATCH v3] riscv: misaligned: Restore epc in error path Date: Mon, 11 May 2026 20:41:01 +0800 Message-ID: <20260511124101.3202094-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.51.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qwCowADXf2tfzgFqB9bmDw--.5197S2 X-Coremail-Antispam: 1UD129KBjvJXoWxurWxCr1rZFyDKFy8ZF1DZFb_yoW5Zr1rpF 4UJ3s09rW2y3Z2gFWS9F4qgFyrZwn3JryxGrsrG34SkFWjqryFqFyft3WYqFy5XrWkXr48 KFW2qrs8W3ZxAwUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9014x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxa n2IY04v7MxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4 AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE 17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMI IF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4l IxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIda VFxhVjvjDU0xZFpf9x0JUqeHgUUUUU= X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiBwoEA2oBuvNICQABso Content-Type: text/plain; charset="utf-8" In handle_scalar_misaligned_store/load, regs->epc is temporarily set to 0. And be restored in the first error path. But it not restore for the rest of the error path. This cause the epc corrupted. Fix this by restore epc in fp error and copy_from_user error. Fixes: 7c586a555a48 ("riscv: add floating point insn support to misaligned = access emulation") Fixes: 441381506ba7 ("riscv: misaligned: remove CONFIG_RISCV_M_MODE specifi= c code") Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Zishun Yi --- Change in v3: - Refactored error handling to use a centralized common error exit (goto out_restore_epc). Change in v2: - add Assisted-by tag arch/riscv/kernel/traps_misaligned.c | 32 +++++++++++++++++++--------- 1 file changed, 22 insertions(+), 10 deletions(-) diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps= _misaligned.c index 2a27d3ff4ac6..21a3ceb1fae8 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -224,6 +224,7 @@ static int handle_scalar_misaligned_load(struct pt_regs= *regs) unsigned long insn; unsigned long addr =3D regs->badaddr; int fp =3D 0, shift =3D 0, len =3D 0; + int ret =3D -1; =20 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr); =20 @@ -303,17 +304,18 @@ static int handle_scalar_misaligned_load(struct pt_re= gs *regs) shift =3D 8 * (sizeof(ulong) - len); insn =3D RVC_RS2S(insn) << SH_RD; } else { - regs->epc =3D epc; - return -1; + goto out_restore_epc; } =20 - if (!IS_ENABLED(CONFIG_FPU) && fp) - return -EOPNOTSUPP; + if (!IS_ENABLED(CONFIG_FPU) && fp) { + ret =3D -EOPNOTSUPP; + goto out_restore_epc; + } =20 val.data_u64 =3D 0; if (user_mode(regs)) { if (copy_from_user(&val, (u8 __user *)addr, len)) - return -1; + goto out_restore_epc; } else { memcpy(&val, (u8 *)addr, len); } @@ -328,6 +330,10 @@ static int handle_scalar_misaligned_load(struct pt_reg= s *regs) regs->epc =3D epc + INSN_LEN(insn); =20 return 0; + +out_restore_epc: + regs->epc =3D epc; + return ret; } =20 static int handle_scalar_misaligned_store(struct pt_regs *regs) @@ -337,6 +343,7 @@ static int handle_scalar_misaligned_store(struct pt_reg= s *regs) unsigned long insn; unsigned long addr =3D regs->badaddr; int len =3D 0, fp =3D 0; + int ret =3D -1; =20 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr); =20 @@ -405,16 +412,17 @@ static int handle_scalar_misaligned_store(struct pt_r= egs *regs) len =3D 2; val.data_ulong =3D GET_RS2S(insn, regs); } else { - regs->epc =3D epc; - return -1; + goto out_restore_epc; } =20 - if (!IS_ENABLED(CONFIG_FPU) && fp) - return -EOPNOTSUPP; + if (!IS_ENABLED(CONFIG_FPU) && fp) { + ret =3D -EOPNOTSUPP; + goto out_restore_epc; + } =20 if (user_mode(regs)) { if (copy_to_user((u8 __user *)addr, &val, len)) - return -1; + goto out_restore_epc; } else { memcpy((u8 *)addr, &val, len); } @@ -422,6 +430,10 @@ static int handle_scalar_misaligned_store(struct pt_re= gs *regs) regs->epc =3D epc + INSN_LEN(insn); =20 return 0; + +out_restore_epc: + regs->epc =3D epc; + return ret; } =20 int handle_misaligned_load(struct pt_regs *regs) --=20 2.51.2