From nobody Wed Apr 24 01:03:11 2024 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 3A03DC433EF for ; Sat, 14 May 2022 03:35:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231504AbiENDfU (ORCPT ); Fri, 13 May 2022 23:35:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231463AbiENDe7 (ORCPT ); Fri, 13 May 2022 23:34:59 -0400 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5389B95DCE for ; Fri, 13 May 2022 20:34:58 -0700 (PDT) Received: by mail-wr1-x430.google.com with SMTP id a5so9786411wrp.7 for ; Fri, 13 May 2022 20:34:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=AvxCAVhEBFSALzFW5QU4eqtsfJ+K74cWo1IjNe8gKhU=; b=hhjaEh4q933w6AuKifPXLtD2S7TfCNdCj8QpH8AO9IxW5szpex5NDjVkBj7Rnfup8Y kPiGnYL2/ahfl9LkZjZc2Scb28RQpXCFJjj9hcSbwaEoV3xlvXxPDdnzC91OTJbsBmmX eYuJqs2MR2qvuvb84xdzKd0tWp51YGkHRcCsAtiX7DBDg5WjIEwlQBLZc5f8cBRDXcdP jG+nLWhoeNXCrZ/xcYN/BMPl8kB5NPX+vy78YnAfiSZhQbXG9LvLdI+N1TBEQGvW00Q5 6PmOcdeC8zQ0PWsQ78nCQA11C1oy6OXj+mLTgE4oVQz+CjxwbcKnglv3TzQu4kynXVfE JQbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=AvxCAVhEBFSALzFW5QU4eqtsfJ+K74cWo1IjNe8gKhU=; b=JPeAooJRCNWYwMOKAUA3Ko7wVM3hY6hvi1qsKfJ2qM6owH27wFynwV75SmG4Zoakp2 x6+O4h3aP9Jdz4MLcg3b0rnTpwjmUOz//VVhCM0hOoxDceFjZ3PKBIYMMFz/OzhGnixQ rQ9oaROui13JeFB3E2G1jFpjm4jB29LPCRXwX/CUqTaAUM0684IK0TDx77TqVsvuwu5E jzbe2qQF4Jnsag5Dr8XRdSUG3hV8wID1Ui6pdOMZOLb5+BrCGKblEMGV19vYUFjtp57x SenLGfRGxLwsUHDhnV7ur74IjtOqpRKA6e4auGPu9mtxzfjB//qo8IxbZWpSdhjGMDh0 IQ5w== X-Gm-Message-State: AOAM532rKCyPznUwvdrwiDdxnUwB/QdaCpCB1Z9loqxN26mEOP0rIkAA uLz7C87D38kBykfh2TfM1K4= X-Google-Smtp-Source: ABdhPJwfMSYLdMz16J88+j7WK3C7LzuI8Xgae1g0LeGemd94qEf2RxkJ/dd5rCMRDloHLwtJFZjppg== X-Received: by 2002:a05:6000:81c:b0:20c:d4e7:400d with SMTP id bt28-20020a056000081c00b0020cd4e7400dmr6032737wrb.459.1652499296894; Fri, 13 May 2022 20:34:56 -0700 (PDT) Received: from octofox.metropolis ([178.134.103.46]) by smtp.gmail.com with ESMTPSA id h1-20020adfaa81000000b0020c66310845sm3542638wrc.55.2022.05.13.20.34.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 May 2022 20:34:56 -0700 (PDT) From: Max Filippov To: linux-xtensa@linux-xtensa.org Cc: Chris Zankel , linux-kernel@vger.kernel.org, Max Filippov Subject: [PATCH v2 3/3] xtensa: improve call0 ABI probing Date: Fri, 13 May 2022 20:34:37 -0700 Message-Id: <20220514033437.4182899-4-jcmvbkbc@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220514033437.4182899-1-jcmvbkbc@gmail.com> References: <20220514033437.4182899-1-jcmvbkbc@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When call0 userspace ABI support by probing is enabled instructions that cause illegal instruction exception when PS.WOE is clear are retried with PS.WOE set before calling c-level exception handler. Record user pc at which PS.WOE was set in the fast exception handler and clear PS.WOE in the c-level exception handler if we get there from the same address. Signed-off-by: Max Filippov --- Changes v1->v2: - split ABI probing improvement from the artificial division by 0 arch/xtensa/include/asm/thread_info.h | 4 ++++ arch/xtensa/kernel/asm-offsets.c | 3 +++ arch/xtensa/kernel/entry.S | 5 +++++ arch/xtensa/kernel/traps.c | 12 ++++++++++++ 4 files changed, 24 insertions(+) diff --git a/arch/xtensa/include/asm/thread_info.h b/arch/xtensa/include/as= m/thread_info.h index 52974317a6b6..326db1c1d5d8 100644 --- a/arch/xtensa/include/asm/thread_info.h +++ b/arch/xtensa/include/asm/thread_info.h @@ -56,6 +56,10 @@ struct thread_info { /* result of the most recent exclusive store */ unsigned long atomctl8; #endif +#ifdef CONFIG_USER_ABI_CALL0_PROBE + /* Address where PS.WOE was enabled by the ABI probing code */ + unsigned long ps_woe_fix_addr; +#endif =20 /* * If i-th bit is set then coprocessor state is loaded into the diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offs= ets.c index 9a1db6ffcbf4..da38de20ae59 100644 --- a/arch/xtensa/kernel/asm-offsets.c +++ b/arch/xtensa/kernel/asm-offsets.c @@ -88,6 +88,9 @@ int main(void) OFFSET(TI_STSTUS, thread_info, status); OFFSET(TI_CPU, thread_info, cpu); OFFSET(TI_PRE_COUNT, thread_info, preempt_count); +#ifdef CONFIG_USER_ABI_CALL0_PROBE + OFFSET(TI_PS_WOE_FIX_ADDR, thread_info, ps_woe_fix_addr); +#endif =20 /* struct thread_info (offset from start_struct) */ DEFINE(THREAD_RA, offsetof (struct task_struct, thread.ra)); diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 3224b4ceca34..e3eae648ba2e 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1056,6 +1056,11 @@ ENTRY(fast_illegal_instruction_user) movi a3, PS_WOE_MASK or a0, a0, a3 wsr a0, ps +#ifdef CONFIG_USER_ABI_CALL0_PROBE + GET_THREAD_INFO(a3, a2) + rsr a0, epc1 + s32i a0, a3, TI_PS_WOE_FIX_ADDR +#endif l32i a3, a2, PT_AREG3 l32i a0, a2, PT_AREG0 rsr a2, depc diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index 47445b2d4217..21c2c30baf69 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -324,6 +324,18 @@ static int check_div0(struct pt_regs *regs) =20 static void do_illegal_instruction(struct pt_regs *regs) { +#ifdef CONFIG_USER_ABI_CALL0_PROBE + /* + * When call0 application encounters an illegal instruction fast + * exception handler will attempt to set PS.WOE and retry failing + * instruction. + * If we get here we know that that instruction is also illegal + * with PS.WOE set, so it's not related to the windowed option + * hence PS.WOE may be cleared. + */ + if (regs->pc =3D=3D current_thread_info()->ps_woe_fix_addr) + regs->ps &=3D ~PS_WOE_MASK; +#endif if (check_div0(regs)) { do_div0(regs); return; --=20 2.30.2