From nobody Wed Dec 17 01:13:11 2025 Received: from mail.valinux.co.jp (mail.valinux.co.jp [210.128.90.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B185325634 for ; Thu, 18 Jul 2024 09:37:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.128.90.3 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721295430; cv=none; b=jcbykHcvIHiDNYboKsLzUFciZjMZIOLzDE+dJz4orASohw8KhU2uFhxOF4wtyvON34Z7sqAqndHOGqQqmu3FefzmqhuIUDnc1O7tv8yx1DiCE67iFzpF0CCauFtoUvtqQBI/xuAp5c6+qdT7roJ6HVkUhtWWNPEOOS1CFaRImm8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721295430; c=relaxed/simple; bh=sJbPNxK5gRhIDyjMLN+0i8DFfx8g3MhG6j4IptBLT8s=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=NC/34UV3RZazCFGUOJbJQtfVwVm7fhQ6eO34GPXiikXwIjJ/ZXogLJs0R6z1UQhMdCsEfiSG9ISGcjSY23GPG3WZgulF5XW2Q/kAByzcxckysnv/FW6d+xXtGISOuQl04hNtkWfZ//zuDHcmdhKbf6CVFI6lf6zZEqqHTwL+ai0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=valinux.co.jp; spf=pass smtp.mailfrom=valinux.co.jp; arc=none smtp.client-ip=210.128.90.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=valinux.co.jp Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=valinux.co.jp Received: from localhost (localhost [127.0.0.1]) by mail.valinux.co.jp (Postfix) with ESMTP id F07ACA9D5E; Thu, 18 Jul 2024 18:37:06 +0900 (JST) X-Virus-Scanned: Debian amavisd-new at valinux.co.jp Received: from mail.valinux.co.jp ([127.0.0.1]) by localhost (mail.valinux.co.jp [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UzITp37JSzLc; Thu, 18 Jul 2024 18:37:06 +0900 (JST) Received: from DESKTOP-NBGHJ1C.local.valinux.co.jp (vagw.valinux.co.jp [210.128.90.14]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by mail.valinux.co.jp (Postfix) with ESMTPSA id C2B36A9606; Thu, 18 Jul 2024 18:37:06 +0900 (JST) From: takakura@valinux.co.jp To: palmer@dabbelt.com, bjorn@kernel.org, paul.walmsley@sifive.com, akpm@linux-foundation.org, aou@eecs.berkeley.edu, apatel@ventanamicro.com, arnd@arndb.de, atishp@rivosinc.com, bmeng.cn@gmail.com, conor.dooley@microchip.com, daniel.thompson@linaro.org, samuel.holland@sifive.com, sfr@canb.auug.org.au Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, taka@valinux.co.jp, Ryo Takakura Subject: [PATCH v2] RISC-V: Enable IPI CPU Backtrace Date: Thu, 18 Jul 2024 18:36:59 +0900 Message-Id: <20240718093659.158912-1-takakura@valinux.co.jp> X-Mailer: git-send-email 2.34.1 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 Content-Type: text/plain; charset="utf-8" From: Ryo Takakura Add arch_trigger_cpumask_backtrace() which is a generic infrastructure=20 for sampling other CPUs' backtrace using IPI. The feature is used when lockups are detected or in case of oops/panic=20 if parameters are set accordingly. Below is the case of oops with the oops_all_cpu_backtrace enabled. $ sysctl kernel.oops_all_cpu_backtrace=3D1 triggering oops shows: [ 212.214237] NMI backtrace for cpu 1 [ 212.214390] CPU: 1 PID: 610 Comm: in:imklog Tainted: G OE = 6.10.0-rc6 #1 [ 212.214570] Hardware name: riscv-virtio,qemu (DT) [ 212.214690] epc : fallback_scalar_usercopy+0x8/0xdc [ 212.214809] ra : _copy_to_user+0x20/0x40 [ 212.214913] epc : ffffffff80c3a930 ra : ffffffff8059ba7e sp : ff20000000= eabb50 [ 212.215061] gp : ffffffff82066f90 tp : ff6000008e958000 t0 : 3463303866= 660000 [ 212.215210] t1 : 000000000000005b t2 : 3463303866666666 s0 : ff20000000= eabb60 [ 212.215358] s1 : 0000000000000386 a0 : 00007ff6e81df926 a1 : ff60000082= 4df800 [ 212.215505] a2 : 000000000000003f a3 : 7fffffffffffffc0 a4 : 0000000000= 000000 [ 212.215651] a5 : 000000000000003f a6 : 0000000000000000 a7 : 0000000000= 000000 [ 212.215857] s2 : ff600000824df800 s3 : ffffffff82066cc0 s4 : 0000000000= 001c1a [ 212.216074] s5 : ffffffff8206a5a8 s6 : 00007ff6e81df926 s7 : ffffffff82= 06a5a0 [ 212.216278] s8 : ff600000824df800 s9 : ffffffff81e25de0 s10: 0000000000= 00003f [ 212.216471] s11: ffffffff8206a59d t3 : ff600000824df812 t4 : ff60000082= 4df812 [ 212.216651] t5 : ff600000824df818 t6 : 0000000000040000 [ 212.216796] status: 0000000000040120 badaddr: 0000000000000000 cause: 80= 00000000000001 [ 212.217035] [] fallback_scalar_usercopy+0x8/0xdc [ 212.217207] [] syslog_print+0x1f4/0x2b2 [ 212.217362] [] do_syslog.part.0+0x94/0x2d8 [ 212.217502] [] do_syslog+0x66/0x88 [ 212.217636] [] kmsg_read+0x44/0x5c [ 212.217764] [] proc_reg_read+0x7a/0xa8 [ 212.217952] [] vfs_read+0xb0/0x24e [ 212.218090] [] ksys_read+0x64/0xe4 [ 212.218264] [] __riscv_sys_read+0x20/0x2c [ 212.218453] [] do_trap_ecall_u+0x60/0x1d4 [ 212.218664] [] ret_from_exception+0x0/0x64 Signed-off-by: Ryo Takakura --- Changes since V1: https://lore.kernel.org/lkml/20240417050711.41930-1-takakura@valinux.co.jp/ - fix build failure when SMP=3Dn as @Palmer pointed out --- arch/riscv/include/asm/irq.h | 5 +++++ arch/riscv/kernel/smp.c | 16 ++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h index 8e10a9443..8330d16b0 100644 --- a/arch/riscv/include/asm/irq.h +++ b/arch/riscv/include/asm/irq.h @@ -12,6 +12,11 @@ =20 #include =20 +#ifdef CONFIG_SMP +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu= ); +#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace +#endif + void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void)); =20 struct fwnode_handle *riscv_get_intc_hwnode(void); diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 8e6eb6445..9b0478997 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -21,6 +21,7 @@ #include #include #include +#include =20 #include #include @@ -33,6 +34,7 @@ enum ipi_message_type { IPI_CPU_CRASH_STOP, IPI_IRQ_WORK, IPI_TIMER, + IPI_CPU_BACKTRACE, IPI_MAX }; =20 @@ -136,6 +138,9 @@ static irqreturn_t handle_IPI(int irq, void *data) tick_receive_broadcast(); break; #endif + case IPI_CPU_BACKTRACE: + nmi_cpu_backtrace(get_irq_regs()); + break; default: pr_warn("CPU%d: unhandled IPI%d\n", smp_processor_id(), ipi); break; @@ -203,6 +208,7 @@ static const char * const ipi_names[] =3D { [IPI_CPU_CRASH_STOP] =3D "CPU stop (for crash dump) interrupts", [IPI_IRQ_WORK] =3D "IRQ work interrupts", [IPI_TIMER] =3D "Timer broadcast interrupts", + [IPI_CPU_BACKTRACE] =3D "CPU backtrace interrupts", }; =20 void show_ipi_stats(struct seq_file *p, int prec) @@ -323,3 +329,13 @@ void arch_smp_send_reschedule(int cpu) send_ipi_single(cpu, IPI_RESCHEDULE); } EXPORT_SYMBOL_GPL(arch_smp_send_reschedule); + +static void riscv_backtrace_ipi(cpumask_t *mask) +{ + send_ipi_mask(mask, IPI_CPU_BACKTRACE); +} + +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) +{ + nmi_trigger_cpumask_backtrace(mask, exclude_cpu, riscv_backtrace_ipi); +} --=20 2.34.1