From patchwork Mon Jun 6 12:37:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xianting Tian X-Patchwork-Id: 12870304 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E7CBACCA473 for ; Mon, 6 Jun 2022 12:38:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date:Subject:Cc:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=j0VsKLNtDGBDRD1lbTGRv13IHOd/eYfFjmuCfnBxEYQ=; b=bQLQlBm0T7CGIi IqCu7ceEEJ9UNQlFV0goZwLOdzmLpZwl+FjHYO3ZitTBdB1yxqrcah591wr2HaZoc60ZFXEzJHBGJ mQT09wwy0FAjplBGvJECIkZ6S7+K4h/7RrxGXlXTkTosqmOWATOCudRj/klfcwiQsb7wlOJnP6FLN 0PbnBcpL8MgXkiIQ7Jf2dCxuTm3xabJxQt4v9BptOjY9zFou4PEcyPIukv99abfjPGu+qYP9UgSdM q4J+AZcI4p+X7AK0sB6fTQCXc9XRpninMLoatySMCsdSN3b7q8+lzS1CmA7j5aU/CUQId2ulUr3Kg g9R2kOZl5lWwqTDaJzaQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nyBzj-001CdN-8I; Mon, 06 Jun 2022 12:38:07 +0000 Received: from out199-14.us.a.mail.aliyun.com ([47.90.199.14]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nyBzf-001Cbf-PU for linux-riscv@lists.infradead.org; Mon, 06 Jun 2022 12:38:06 +0000 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=xianting.tian@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0VFYRvQg_1654519072; Received: from localhost(mailfrom:xianting.tian@linux.alibaba.com fp:SMTPD_---0VFYRvQg_1654519072) by smtp.aliyun-inc.com(127.0.0.1); Mon, 06 Jun 2022 20:37:53 +0800 From: Xianting Tian To: paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, wangkefeng.wang@huawei.com, philipp.tomsich@vrull.eu, ebiederm@xmission.com, heiko@sntech.de, vitaly.wool@konsulko.com, tongtiangen@huawei.com, guoren@kernel.org Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Xianting Tian Subject: [PATCH v3] RISC-V: Add fixup to support fast call of crash_kexec() Date: Mon, 6 Jun 2022 20:37:50 +0800 Message-Id: <20220606123750.2884245-1-xianting.tian@linux.alibaba.com> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220606_053804_145451_D560E6A8 X-CRM114-Status: UNSURE ( 8.64 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Currently, almost all archs (x86, arm64, mips...) support fast call of crash_kexec() when "regs && kexec_should_crash()" is true. But RISC-V not, it can only enter crash system via panic(). However panic() doesn't pass the regs of the real accident scene to crash_kexec(), it caused we can't get accurate backtrace via gdb, $ riscv64-linux-gnu-gdb vmlinux vmcore Reading symbols from vmlinux... [New LWP 95] #0 console_unlock () at kernel/printk/printk.c:2557 2557 if (do_cond_resched) (gdb) bt #0 console_unlock () at kernel/printk/printk.c:2557 #1 0x0000000000000000 in ?? () With the patch we can get the accurate backtrace, $ riscv64-linux-gnu-gdb vmlinux vmcore Reading symbols from vmlinux... [New LWP 95] #0 0xffffffe00063a4e0 in test_thread (data=) at drivers/test_crash.c:81 81 *(int *)p = 0xdead; (gdb) (gdb) bt #0 0xffffffe00064d5c0 in test_thread (data=) at drivers/test_crash.c:81 #1 0x0000000000000000 in ?? () Test code to produce NULL address dereference in test_crash.c, void *p = NULL; *(int *)p = 0xdead; Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code") Reviewed-by: Guo Ren Signed-off-by: Xianting Tian Reviewed-by: Kefeng Wang --- Changes from v1: - simplify the commit message Changes from v2: - add fixup in title --- arch/riscv/kernel/traps.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index b40426509244..39d0f8bba4b4 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -44,6 +45,9 @@ void die(struct pt_regs *regs, const char *str) ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); + if (regs && kexec_should_crash(current)) + crash_kexec(regs); + bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); spin_unlock_irq(&die_lock);