From patchwork Sat Jul 27 06:34:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinjie Ruan X-Patchwork-Id: 13743620 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 B277BC3DA61 for ; Sat, 27 Jul 2024 06:29:57 +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:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version: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=m+QheDNgjwGu5+jGddqCSVG9441BUx/37QKRBTY8Rg0=; b=h00c5auHv9yEQC 18/7uyfI7CAEk1ghmtAvhfrvNaOgSvP3FbU0oXyrWFh6zjyIW6z7mT/m/ay+LNoH4Fcc9K9QQpr8v q2qx/MvLFno2KiOVEGC1MW1ofue2oZtM5VCFzuoLdDESSWoDkBdMK7KjuDX22S7mAQhZC563welk7 SaMcybamk9fEV949U944E6zKUwRnB2yua40WVUacd/buGUcBxS6hL25Oe466EdOc7mIR8iUgOrbEu yuMcuGgT6CyVaEMLbVwphhAEziIQw518J/oW20ysE4NnPxQmDKBK/Yqbd9N9rQwnlGye5y70GaJ3g Xu6Y/fQCyOmCVQVnPYgg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sXavm-00000006BxH-3YEj; Sat, 27 Jul 2024 06:29:26 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sXavj-00000006Bv1-29XG for linux-riscv@lists.infradead.org; Sat, 27 Jul 2024 06:29:25 +0000 Received: from mail.maildlp.com (unknown [172.19.162.112]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4WWF4v4Bczz1HFR4; Sat, 27 Jul 2024 14:26:23 +0800 (CST) Received: from kwepemi100008.china.huawei.com (unknown [7.221.188.57]) by mail.maildlp.com (Postfix) with ESMTPS id DF1721402CF; Sat, 27 Jul 2024 14:29:07 +0800 (CST) Received: from huawei.com (10.90.53.73) by kwepemi100008.china.huawei.com (7.221.188.57) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Sat, 27 Jul 2024 14:29:07 +0800 From: Jinjie Ruan To: , , , , , , , CC: Subject: [PATCH v2] RISC-V: Implement kgdb_roundup_cpus() to enable future NMI Roundup Date: Sat, 27 Jul 2024 14:34:38 +0800 Message-ID: <20240727063438.886155-1-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemi100008.china.huawei.com (7.221.188.57) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240726_232923_967675_A1765AFA X-CRM114-Status: GOOD ( 14.25 ) 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: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Until now, the generic weak kgdb_roundup_cpus() has been used for kgdb on RISCV. A custom one allows to debug CPUs that are stuck with interrupts disabled with NMI support in the future. And using an IPI is better than the generic one since it avoids the potential situation described in the generic kgdb_call_nmi_hook(). As Andrew pointed out, once there is NMI support, we can easily extend this and the CPU backtrace support to use NMIs. After this patch, the kgdb test show that: # echo g > /proc/sysrq-trigger [2]kdb> btc btc: cpu status: Currently on cpu 2 Available cpus: 0-1(-), 2, 3(-) Stack traceback for pid 0 0xffffffff81c13a40 0 0 1 0 - 0xffffffff81c14510 swapper/0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.10.0-g3120273055b6-dirty #51 Hardware name: riscv-virtio,qemu (DT) Call Trace: [] dump_backtrace+0x28/0x30 [] show_stack+0x38/0x44 [] dump_stack_lvl+0x58/0x7a [] dump_stack+0x18/0x20 [] kgdb_cpu_enter+0x682/0x6b2 [] kgdb_nmicallback+0xa0/0xac [] handle_IPI+0x9c/0x120 [] handle_percpu_devid_irq+0xa4/0x1e4 [] generic_handle_domain_irq+0x28/0x36 [] ipi_mux_process+0xe8/0x110 [] imsic_handle_irq+0xf8/0x13a [] generic_handle_domain_irq+0x28/0x36 [] riscv_intc_aia_irq+0x2e/0x40 [] handle_riscv_irq+0x54/0x86 [] call_on_irq_stack+0x32/0x40 Rebased on Ryo Takakura's "RISC-V: Enable IPI CPU Backtrace" patch. Signed-off-by: Jinjie Ruan Reviewed-by: Andrew Jones --- v2: - Update the commit title and message. - Add Reviewed-by. --- arch/riscv/kernel/smp.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 9b047899791c..c180a647a30e 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -35,6 +36,7 @@ enum ipi_message_type { IPI_IRQ_WORK, IPI_TIMER, IPI_CPU_BACKTRACE, + IPI_KGDB_ROUNDUP, IPI_MAX }; @@ -115,6 +117,7 @@ void arch_irq_work_raise(void) static irqreturn_t handle_IPI(int irq, void *data) { + unsigned int cpu = smp_processor_id(); int ipi = irq - ipi_virq_base; switch (ipi) { @@ -128,7 +131,7 @@ static irqreturn_t handle_IPI(int irq, void *data) ipi_stop(); break; case IPI_CPU_CRASH_STOP: - ipi_cpu_crash_stop(smp_processor_id(), get_irq_regs()); + ipi_cpu_crash_stop(cpu, get_irq_regs()); break; case IPI_IRQ_WORK: irq_work_run(); @@ -141,8 +144,11 @@ static irqreturn_t handle_IPI(int irq, void *data) case IPI_CPU_BACKTRACE: nmi_cpu_backtrace(get_irq_regs()); break; + case IPI_KGDB_ROUNDUP: + kgdb_nmicallback(cpu, get_irq_regs()); + break; default: - pr_warn("CPU%d: unhandled IPI%d\n", smp_processor_id(), ipi); + pr_warn("CPU%d: unhandled IPI%d\n", cpu, ipi); break; } @@ -209,6 +215,7 @@ static const char * const ipi_names[] = { [IPI_IRQ_WORK] = "IRQ work interrupts", [IPI_TIMER] = "Timer broadcast interrupts", [IPI_CPU_BACKTRACE] = "CPU backtrace interrupts", + [IPI_KGDB_ROUNDUP] = "KGDB roundup interrupts", }; void show_ipi_stats(struct seq_file *p, int prec) @@ -339,3 +346,19 @@ void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) { nmi_trigger_cpumask_backtrace(mask, exclude_cpu, riscv_backtrace_ipi); } + +#ifdef CONFIG_KGDB +void kgdb_roundup_cpus(void) +{ + int this_cpu = raw_smp_processor_id(); + int cpu; + + for_each_online_cpu(cpu) { + /* No need to roundup ourselves */ + if (cpu == this_cpu) + continue; + + send_ipi_single(cpu, IPI_KGDB_ROUNDUP); + } +} +#endif