From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) (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 950CD3090C5 for ; Wed, 6 May 2026 22:23:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778106199; cv=none; b=H8HJqseM2v11NO/uqomSTPpsgpfmVSdSzFfczHcfB26ZzE8ZMQfTkRB3YcHpWrS8+o7uw/YAWTox8ucgtrQmrzroACS80B11Gv3sVpDT4qK11yr6SjFK8+SbF2qsrYjU0E8eFvT7dz39BOJ6GfVTlBqzQjHw83DA2+AbKPWDqgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778106199; c=relaxed/simple; bh=Cfq6nPRfkbbJmLb+gIU5oSKoY3tnjcfiBK3Gbgz0qdg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Sm/yTFGtaQFJFx0Abknln8Xfd32SNgXZkoZTaC67eXIzrIU/8s6R2Nj+FE8zYbfim2SyxA4vnoQfV/THcNuCuBueWRNRZ7nvasK9RTGVeJoPbtgkl7kTnQrYtskZSCqyZ1Zi1dsfgAkDbVRcg73P2a78cWutSvq1C1DUPjpP+NE= 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=WNCuROvt; arc=none smtp.client-ip=209.85.128.47 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="WNCuROvt" Received: by mail-wm1-f47.google.com with SMTP id 5b1f17b1804b1-4891e86fabeso1974675e9.1 for ; Wed, 06 May 2026 15:23:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778106196; x=1778710996; 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=YKiIsHsvorfmkWjWxVhsMnyuw9niDeJiHULsuxkpGE8=; b=WNCuROvtcRJejsk0PEEwmOfleAJ2ZoDyBTDGl4qS/mUFkpuq5EtoAC38ItY3MXiV1/ 5MjBBDPBv9zKgZBJmH1ObNDyDmWDrUheikp87apLkeb6l2HxwyLQh1O9sYsqBSqNPgd+ 6QK9Yb5wtHkDIyCF1Kwtsw/vKR0SyL/9/uJz5SYjVgJwWgcDluVj6h7OFaQEFGc4Ex4X 13C0rqmL+o5mmeSYGonn4cyczgRHFLvzmZeiyjcsT47Yj2CXRF4YSAmA4cAH/C0kqKA6 6Iu42fFuAPZio+1mFFZ/h7rTBpWYuYisA7vSuonmMAWzYwj9EmADsAHwB08FTr9P8Bz3 VuMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778106196; x=1778710996; 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=YKiIsHsvorfmkWjWxVhsMnyuw9niDeJiHULsuxkpGE8=; b=JAOyP3llqKrYm8jE9froHtvxqP5uZWHFIU2W/Jwis1avsoXxtVAq5/wR8iZfi8XUoA Y07jHmzKlFZiPEB5eAxjfVbJ4Zp+4QV9uI7pmacKasI0HP2SyO6iKpecZBzhMklTLFKG 65r/qec6GRSNwWx1V+6FkP0vKRPCfw9AeE0yBGs3xocXuzzKF5661Ei3L7oExyPBlJzL 9CltCi+pyBS1QcwGxTXlRtGEFKMEQMigyNG+xVCNPwem0zAAIIBYAmUquAzpD6YGc87L rhDDAohjfwp00hNvwQGe8yzknBt4IjFe5aG2SQ1xAvu1MEQcBWk74zefiSQncvAbtdy+ SDNw== X-Forwarded-Encrypted: i=1; AFNElJ//l5uN0ZlL3jvyKIrLu+dvtGqVQbI3v4pw32H1XmnUKzvl9DPAsKD4F0RND7+NXfrRvAkdsLMCjIK4j38=@vger.kernel.org X-Gm-Message-State: AOJu0YwvNVNr3+Ei2L7qy3b7p4IWzuPNtVNqHzWHnGQm9RddpdpSu3ZJ DLRK9XaYAu8FIwDpksgIL1wq7HuMoe9yW8GtZWIvJ2qWIag/xO6CYi1zRfeT7Q== X-Gm-Gg: AeBDieugi+eso4nq4mJpxYqIBmIZVG6tVGNzAi5mWG86HgGNaHzMWsCiavLuOyFlMst SfhugjZGf7IjNkpLWYOw09xj2TAz+2T6KiOMKOazzyKzpOt2/rV+rR6SdhYtpkAOUwFav3i2guv XuuG4/HJXZd2YnY0Jk2XSUAlFwIqkMorzy/3gtMWCNIjB/74+NpNHhXsOhGM2ltdOlyLAUKxOOB ezWaAPd02vAFtTtRVpcANvx9gcfWDn7bltWTCZPfqxHvj2RK1KCXQ4/X8Cs1CvjvDX4w8TZxxQ0 rWnlWbmjq8SkAo6MHkd2/Em6k81sWlrGmxP0IAzIx+S6/zOzz1ljqDjnKEFbsw/mn1Mz98NDxwP 4CvF6etUG+v0RVirTchBvC4dln5IpTNDc9ZqWqbVKm7Yyc5YbRs3Sx58yhpKbWc93muuOhwBGXv si1cXJvDFJKvWckoyRpJ/d+IoirJSVcL05GnctXJCuif1AjUA6Z1ygn5cJT5I03Kd/U9w3fQUZn eDe7L0n5FSplTdpPZUWEfjw2JUH4Ezd0ZXXr7bDg2xf X-Received: by 2002:a05:600c:a305:b0:48a:5970:2005 with SMTP id 5b1f17b1804b1-48e51e08362mr58841715e9.2.1778106195632; Wed, 06 May 2026 15:23:15 -0700 (PDT) Received: from dev.homenet.telecomitalia.it (host-82-48-38-157.retail.telecomitalia.it. [82.48.38.157]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48e530d2d06sm25229295e9.16.2026.05.06.15.23.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 May 2026 15:23:15 -0700 (PDT) From: Adriano Vero To: maddy@linux.ibm.com, mpe@ellerman.id.au, sourabhjain@linux.ibm.com Cc: npiggin@gmail.com, chleroy@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Adriano Vero Subject: [PATCH v3] powerpc/fadump: Add timeout to RTAS busy-wait loops Date: Thu, 7 May 2026 00:20:23 +0200 Message-ID: <20260506222024.30352-1-adri.vero.dev@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260419065039.23495-1-adri.vero.dev@gmail.com> References: <20260419065039.23495-1-adri.vero.dev@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The ibm,configure-kernel-dump RTAS call sites in rtas_fadump_register(), rtas_fadump_unregister(), and rtas_fadump_invalidate() polled indefinitely while firmware returned a busy status. A misbehaving or hung firmware could stall these paths forever, blocking fadump registration at boot or preventing clean teardown. Introduce rtas_fadump_call(), a helper that wraps the common busy-wait pattern shared by all three sites. The helper accumulates the total delay and returns -ETIMEDOUT if firmware keeps returning a busy status beyond RTAS_FADUMP_MAX_WAIT_MS (60 seconds). A pr_debug() message is emitted on each busy iteration to aid diagnosis when the timeout is hit. Signed-off-by: Adriano Vero Reviewed-by: Sourabh Jain --- arch/powerpc/platforms/pseries/rtas-fadump.c | 80 ++++++++++++-------- arch/powerpc/platforms/pseries/rtas-fadump.h | 6 ++ 2 files changed, 53 insertions(+), 33 deletions(-) diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.c b/arch/powerpc/platforms/pseries/rtas-fadump.c index eceb3289383e..3bb4ac2ab6cc 100644 --- a/arch/powerpc/platforms/pseries/rtas-fadump.c +++ b/arch/powerpc/platforms/pseries/rtas-fadump.c @@ -179,9 +179,42 @@ static u64 rtas_fadump_get_bootmem_min(void) return RTAS_FADUMP_MIN_BOOT_MEM; } +/* + * Helper to make an ibm,configure-kernel-dump RTAS call with a bounded + * busy-wait loop. Returns the RTAS return code on completion, or + * -ETIMEDOUT if firmware keeps returning a busy status beyond + * RTAS_FADUMP_MAX_WAIT_MS milliseconds. + */ +static int rtas_fadump_call(struct fw_dump *fadump_conf, int operation, + void *fdm_ptr, unsigned int fdm_size, + const char *op_name) +{ + unsigned int wait_time, total_wait = 0; + int rc; + + do { + rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, + NULL, operation, fdm_ptr, fdm_size); + wait_time = rtas_busy_delay_time(rc); + if (wait_time) { + pr_debug("Firmware busy during fadump %s, waiting %ums (total %ums)\n", + op_name, wait_time, total_wait); + if (total_wait >= RTAS_FADUMP_MAX_WAIT_MS) { + pr_err("Timed out waiting for firmware to complete fadump %s\n", + op_name); + return -ETIMEDOUT; + } + total_wait += wait_time; + mdelay(wait_time); + } + } while (wait_time); + + return rc; +} + static int rtas_fadump_register(struct fw_dump *fadump_conf) { - unsigned int wait_time, fdm_size; + unsigned int fdm_size; int rc, err = -EIO; /* @@ -192,16 +225,10 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf) fdm_size = sizeof(struct rtas_fadump_section_header); fdm_size += be16_to_cpu(fdm.header.dump_num_sections) * sizeof(struct rtas_fadump_section); - /* TODO: Add upper time limit for the delay */ - do { - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, - NULL, FADUMP_REGISTER, &fdm, fdm_size); - - wait_time = rtas_busy_delay_time(rc); - if (wait_time) - mdelay(wait_time); - - } while (wait_time); + rc = rtas_fadump_call(fadump_conf, FADUMP_REGISTER, &fdm, fdm_size, + "register"); + if (rc == -ETIMEDOUT) + return -ETIMEDOUT; switch (rc) { case 0: @@ -234,19 +261,12 @@ static int rtas_fadump_register(struct fw_dump *fadump_conf) static int rtas_fadump_unregister(struct fw_dump *fadump_conf) { - unsigned int wait_time; int rc; - /* TODO: Add upper time limit for the delay */ - do { - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, - NULL, FADUMP_UNREGISTER, &fdm, - sizeof(struct rtas_fadump_mem_struct)); - - wait_time = rtas_busy_delay_time(rc); - if (wait_time) - mdelay(wait_time); - } while (wait_time); + rc = rtas_fadump_call(fadump_conf, FADUMP_UNREGISTER, &fdm, + sizeof(struct rtas_fadump_mem_struct), "unregister"); + if (rc == -ETIMEDOUT) + return -ETIMEDOUT; if (rc) { pr_err("Failed to un-register - unexpected error(%d).\n", rc); @@ -259,19 +279,13 @@ static int rtas_fadump_unregister(struct fw_dump *fadump_conf) static int rtas_fadump_invalidate(struct fw_dump *fadump_conf) { - unsigned int wait_time; int rc; - /* TODO: Add upper time limit for the delay */ - do { - rc = rtas_call(fadump_conf->ibm_configure_kernel_dump, 3, 1, - NULL, FADUMP_INVALIDATE, fdm_active, - sizeof(struct rtas_fadump_mem_struct)); - - wait_time = rtas_busy_delay_time(rc); - if (wait_time) - mdelay(wait_time); - } while (wait_time); + rc = rtas_fadump_call(fadump_conf, FADUMP_INVALIDATE, + (void *)fdm_active, + sizeof(struct rtas_fadump_mem_struct), "invalidate"); + if (rc == -ETIMEDOUT) + return -ETIMEDOUT; if (rc) { pr_err("Failed to invalidate - unexpected error (%d).\n", rc); diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.h b/arch/powerpc/platforms/pseries/rtas-fadump.h index c109abf6befd..65fdab7b5b8d 100644 --- a/arch/powerpc/platforms/pseries/rtas-fadump.h +++ b/arch/powerpc/platforms/pseries/rtas-fadump.h @@ -41,6 +41,12 @@ #define MAX_SECTIONS 10 #define RTAS_FADUMP_MAX_BOOT_MEM_REGS 7 +/* + * Maximum time to wait for firmware to respond to an + * ibm,configure-kernel-dump RTAS call before giving up. + */ +#define RTAS_FADUMP_MAX_WAIT_MS 60000U + /* Kernel Dump section info */ struct rtas_fadump_section { __be32 request_flag; -- 2.54.0