From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f175.google.com (mail-lj1-f175.google.com [209.85.208.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ED84132D0F5 for ; Fri, 12 Jun 2026 20:33:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781296409; cv=none; b=CqPQ9Ls66BGQDs3D4ww3vSTRKsS/eP6URsWNNNzAhRSZYcpXNfiaO1Yx+kXpSIZtjWXjxROJgyCZUp7r9C793G+Hb9gmq+1Qcp2CN2neE+nzeNyvzvZuMMCgXi0btdSgWJ3qiXz48MK1frYwXQPkmBKcI5eEFoS7RzqTxAbwxis= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781296409; c=relaxed/simple; bh=sxmyOWeTHHxi3XZ7/n/lZPH/SI1SxJQvJMP+vMzWDwo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RofY5uanFbp6jus6mju6p4LIh1q6HLW5IqZXQI40OUgBpGre8TPsf6v5wWVL9dVU2Z3OXsQlvMrfKFr8tdmwuzhMfDnBxFOmKWQIq1t/h7gFnZCBasRQs5OwztdCu2wyZF/wUe+Wcc/0DO1Ciaqdh6SdaEy9il82NVyPRIdLASM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=DqtpGKEU; arc=none smtp.client-ip=209.85.208.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="DqtpGKEU" Received: by mail-lj1-f175.google.com with SMTP id 38308e7fff4ca-3965bc493caso12084321fa.2 for ; Fri, 12 Jun 2026 13:33:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1781296406; x=1781901206; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=zyvz3ufjy6ivfzF2sNltt0RdDD9Xm6yL7j4zOBoOGug=; b=DqtpGKEUR87VegX358PhWsR9tL9oBrQqOp1nyDecpw0xpXixxcmrcec0Y9P0gYRW3q Oy3GSSYwAXzczYEpXoOKmF3v2/FGA7dgSsuL7VEBL+Z/P7IU61rudQe9mbUYEG+HsQx1 UbQfrkfdVFh0kl8pQqe6g8ukK9SPM6KfBq+RkpydNWbgEIUAJglO1yIvvsVFInRXb0uu NIaA3LgMWPaT0sMDzTnN/wVmQui+P6fD2Vzx6ND2hQ9doSFEUbfETQh783QqUpvk1voM Vq90ULaSWzxEOMqeOelUW59EQU+7jR76675jxFoWRdCP8Iouo9w1kKkZJTWTpLc9Rh1v enAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781296406; x=1781901206; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=zyvz3ufjy6ivfzF2sNltt0RdDD9Xm6yL7j4zOBoOGug=; b=K7jbJugJFr0dxk+wtHdbpoo1ISDYMauddOPV919SjS5iJLyTho1E9wMCAHSwzTz2UU KUr3uIEh71SK6ojsla70B5tfibw7vE30EuG5ZDln1g2QWYtB8SJ1vtIpUvQhnAW8EpP1 y693H4Y6ldPMYkInYCM447HrojqqkDJu1+WaYutmCCVVUsYleWnRiRZDcBgyF8W8cAgt Qxt5atrxTRNUDKaG9jB8W4yEfa9jHvvOjP4WAOa80XSWW2GNk9rVp6mEG6wt1jTgsyvx wTtEfI9pU/m3mZ703LGAX9EohUNlPnN+Ym4s6qNvPONZsf3y0KgBJ6ZaYwKWPb3EefRW mv+g== X-Forwarded-Encrypted: i=1; AFNElJ+xpRpINCbkpefopg3mz/J51H903AhTIBWOCy62CfIsHgojRVzqVnwpQCG8DJPHccTaBXp3J1WT2gx15A==@vger.kernel.org X-Gm-Message-State: AOJu0YyuYnmkg+KMUWq5ZEOlVAtI/iBzxOxA5AI8/lCtm9igGb51VeIl JlSEuF2eVss6Snxz+dy0y8lwFdTuqGcRYqt0o8Dwta6FUKAT7F4llEbm X-Gm-Gg: Acq92OHm9SNkD99KmCfBtHTnP8dysLTX/gVNjt0XnOojnblHTH8ID1w/sUvdq3iCVnu gkwRuyTdysAiP3EeGAepOYoVFPGuD5DdSqquD+fNmKf4NdUEX0yFml6aHifN4boFsQSWYJXvDLo ch/GcRFTse/PP4OQW2r04YFYZlqfAHs787l3dtKidQjhHwRbuaq+8tcBJiLnEyQAElnSd1pV25E 6Q2jku5fojEHbFGBO+9TXhfGxtEVl8I4pIMRgnt9Szie9swWKWLszdW7QJ4Avt7ucYEy5CV61ZG pajt3LzqX7SdXfPnpOa1YfWfbmK2BIfBERgzoM9X++BoYzlrC1g8BfWb4fjnEKlhRNkGuMpAY6D sLscheieEcIaJlDNAgStZMFecBueAPkAWNQWr/b94JzTi4DpkxofwcL8YJ2XWPOFPeCW4llbRUf kthpZUOb2IXsk3qTIofS3wMLu/BJi2x1tYssEsSWzFIX+WHgoONV4XYydKjEOUgrJe+y3M7jijt 58iZ6tP6SDtLf0664ZN98vut8GQd05A X-Received: by 2002:a05:6512:acc:b0:5aa:6d0f:d765 with SMTP id 2adb3069b0e04-5ad2db2b0b1mr1339855e87.20.1781296406022; Fri, 12 Jun 2026 13:33:26 -0700 (PDT) Received: from buildhost.darklands.se (h-37-123-143-144.NA.cust.bahnhof.se. [37.123.143.144]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5ad2e161e70sm788949e87.5.2026.06.12.13.33.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Jun 2026 13:33:25 -0700 (PDT) From: Magnus Lindholm To: richard.henderson@linaro.org, mattst88@gmail.com, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org Cc: glaubitz@physik.fu-berlin.de, mcree@orcon.net.nz, ink@unseen.parts, macro@orcam.me.uk, Magnus Lindholm Subject: [PATCH v3 2/8] alpha: add ARCH_STACKWALK-based stacktrace support Date: Fri, 12 Jun 2026 22:26:50 +0200 Message-ID: <20260612203006.2265557-3-linmag7@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260612203006.2265557-1-linmag7@gmail.com> References: <20260612203006.2265557-1-linmag7@gmail.com> Precedence: bulk X-Mailing-List: linux-alpha@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Implement arch_stack_walk() for Alpha using a simple kernel stack scanning walker. Start from regs+1 for current tasks to skip pt_regs and use pcb.ksp for blocked tasks. Filter candidates with __kernel_text_address() and stop at stack bounds via kstack_end(). Enable CONFIG_STACKTRACE_SUPPORT and CONFIG_ARCH_STACKWALK so generic stacktrace users (dump_stack(), /proc/*/stack, SysRq backtraces, etc.) work on Alpha. This provides functional in-kernel stack traces without requiring frame pointer unwinding. Reviewed-by: Matt Turner Tested-by: Matt Turner Signed-off-by: Magnus Lindholm --- arch/alpha/Kconfig | 4 +++ arch/alpha/kernel/Makefile | 3 +- arch/alpha/kernel/stacktrace.c | 61 +++++++++++++++++++++++++++++++++ arch/alpha/kernel/vmlinux.lds.S | 2 ++ 4 files changed, 69 insertions(+), 1 deletion(-) create mode 100644 arch/alpha/kernel/stacktrace.c diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index f3b882835617..7ac435c56845 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -39,6 +39,7 @@ config ALPHA select MODULES_USE_ELF_RELA select ODD_RT_SIGACTION select OLD_SIGSUSPEND + select ARCH_STACKWALK select CPU_NO_EFFICIENT_FFS if !ALPHA_EV67 select MMU_GATHER_NO_RANGE select MMU_GATHER_RCU_TABLE_FREE @@ -80,6 +81,9 @@ config PGTABLE_LEVELS config AUDIT_ARCH bool +config STACKTRACE_SUPPORT + def_bool y + menu "System setup" choice diff --git a/arch/alpha/kernel/Makefile b/arch/alpha/kernel/Makefile index 187cd8df2faf..4ea5c189e60e 100644 --- a/arch/alpha/kernel/Makefile +++ b/arch/alpha/kernel/Makefile @@ -9,7 +9,8 @@ ccflags-y := -Wno-sign-compare obj-y := head.o entry.o traps.o process.o osf_sys.o irq.o \ irq_alpha.o signal.o setup.o ptrace.o time.o \ - systbls.o err_common.o io.o bugs.o termios.o + systbls.o err_common.o io.o bugs.o termios.o \ + stacktrace.o obj-$(CONFIG_VGA_HOSE) += console.o obj-$(CONFIG_SMP) += smp.o diff --git a/arch/alpha/kernel/stacktrace.c b/arch/alpha/kernel/stacktrace.c new file mode 100644 index 000000000000..74d95f591039 --- /dev/null +++ b/arch/alpha/kernel/stacktrace.c @@ -0,0 +1,61 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include + +#include +#include + +static __always_inline unsigned long alpha_get_current_ksp(void) +{ + unsigned long sp; + + asm volatile("mov $30, %0" : "=r"(sp)); + return sp; +} + +static void alpha_scan_kernel_stack(unsigned long ksp, + stack_trace_consume_fn consume_entry, + void *cookie) +{ + unsigned long *p = (unsigned long *)ksp; + + if (unlikely(ksp & (sizeof(unsigned long) - 1))) + return; + + while (!kstack_end(p)) { + unsigned long addr = READ_ONCE_NOCHECK(*p++); + + if (!__kernel_text_address(addr)) + continue; + + if (!consume_entry(cookie, addr)) + break; + } +} + +noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, + void *cookie, + struct task_struct *task, + struct pt_regs *regs) +{ + unsigned long ksp; + + if (!task) + task = current; + + if (regs && task == current) { + /* + * pt_regs is stored on the kernel stack; regs+1 matches + * what arch/alpha/kernel/traps.c uses as the trace start. + */ + ksp = (unsigned long)(regs + 1); + } else if (task == current) { + ksp = alpha_get_current_ksp(); + } else { + ksp = task_thread_info(task)->pcb.ksp; + } + + alpha_scan_kernel_stack(ksp, consume_entry, cookie); +} diff --git a/arch/alpha/kernel/vmlinux.lds.S b/arch/alpha/kernel/vmlinux.lds.S index 2d136c63db16..95704e64b6a6 100644 --- a/arch/alpha/kernel/vmlinux.lds.S +++ b/arch/alpha/kernel/vmlinux.lds.S @@ -28,6 +28,8 @@ SECTIONS TEXT_TEXT SCHED_TEXT LOCK_TEXT + IRQENTRY_TEXT + SOFTIRQENTRY_TEXT *(.fixup) *(.gnu.warning) } :text -- 2.53.0