From nobody Sun Apr 5 13:24:56 2026 Received: from mail-ed1-f73.google.com (mail-ed1-f73.google.com [209.85.208.73]) (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 31E4B34252D for ; Thu, 19 Feb 2026 15:03:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771513422; cv=none; b=ubWZWG5mthYbxrXQnMQmIhpsolvVJJO+4NDJQQM690axKelmx+F80U/hsIZvGiy3Iphe4NxEjvlOj/T3Ei6x5VJ8K6zBXWHYAFM1WkC1Gf1D5wKe5mZznRqgoX3VKEej92eFopFL09J1EID+0ZG9qUKNaLoYlFVE8PM3IgHipJk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771513422; c=relaxed/simple; bh=BmyUpW0RSpMZX5HCFKFhPYwEBbQil/y0rGG2CIvyIiQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=qa/G7qwJaivEl40kfV57JJBmCX9xPaCdmDwC4ECJH0UTaEfKQAhcSn+V4ukW5RxwI/s+I6iSRnem0lZcsu3959zCwF/BkUVoeqo2lnjCyEYBvpwO/1L+nWfE2CQ1mbR153jJQ68jDN4Jr9GWmM9eJdVdaSXrBTs6ZLUAanuMLUA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=cn5tmX8D; arc=none smtp.client-ip=209.85.208.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cn5tmX8D" Received: by mail-ed1-f73.google.com with SMTP id 4fb4d7f45d1cf-65a43295689so966361a12.3 for ; Thu, 19 Feb 2026 07:03:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1771513419; x=1772118219; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=M9+ARIgqsEga7ypKxJEyYbrKnJKwPy+BmaCOQYOBhWM=; b=cn5tmX8DuB2Cmj4SHjOyYpgntdwLBQRagtXHJbwAJGCHNha+uYRT3C5N8lXVPWRf/6 lzKNjSQpp9ixCAJWDHTr6uknEvkTKWq27FzkNLrIsXRAzTCKU3ZA6PeqzRoJlz/HzTGt zGrk2c6FJkgxXBfjUFVYpppuOU90QDGpBPqWjUYGnubUTSrbWA8uQlWqxWXBl42yDM7F zQyCngC7qwOY5zIOYZF3ZuemOfE5284Y+21BXy+ezTLaYhcESRWzG1JugNasx7OTnFNM oCNZwhOYho1QiYO0K9nc3Nqr6WHx2rePMPc39iJtlJeH6doe6TngMhyFMwMbTe8qG7d5 43sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771513419; x=1772118219; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=M9+ARIgqsEga7ypKxJEyYbrKnJKwPy+BmaCOQYOBhWM=; b=A2tcFw+mAp3FpP8WL3dQmUBdlgrZblv7oyDubj0D/alGI74kEajSf5y42sn35BqpFq hm4M12Mqyzx3RMuXRVNg9xD853ppPQDELKpILjlCLIvxC5PQ2KkF3/aq8I7SEsD5ORMb SwA5DCRa9J88LSyGlgMNSZGfbbnscDzxI9dv+p/ZcpbHcSfKottql4E8iS+9uo4qt/od uVjhqn73GAQ+MSAghakfASA1X+WQR/8frswCTVvJ3KbmkeO35SKgTJLqdN3YPReK84tJ KXjRoFIv7ZvXWlEec2T74qF15MSTQYjFghAiQb4hSibxk3CLIhu1/RexjlK2vXG9ek15 /usA== X-Forwarded-Encrypted: i=1; AJvYcCW5jPbKT2Z5x0wxGg1rvr3+59Hu3HUHlURe7M//4Fm0dFYf31PvfdGJPoYYznLNI1w+7DBG1srowl2iUe4=@vger.kernel.org X-Gm-Message-State: AOJu0YxX5/Q17wj5fqtPVlwB29OA8iR4n231oQJca7UyPPEQO/rvToG7 Wea3Pb6824E1PElKU+9K11XRDrjt16oVJ8piRcbFRecYiLTKlbKZ2ojr4g/CI6LeGesr/NnkFRC P70jzMJEPdLOWjS8hzdOU1w== X-Received: from edzd2.prod.google.com ([2002:a05:6402:8c2:b0:65a:3686:71b9]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:5188:b0:659:329a:bc10 with SMTP id 4fb4d7f45d1cf-65bc7a7622bmr9740227a12.18.1771513418420; Thu, 19 Feb 2026 07:03:38 -0800 (PST) Date: Thu, 19 Feb 2026 15:02:54 +0000 In-Reply-To: <20260219150307.14538-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260219150307.14538-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.335.g19a08e0c02-goog Message-ID: <20260219150307.14538-18-vdonnefort@google.com> Subject: [PATCH v12 17/30] tracing: load/unload page callbacks for simple_ring_buffer From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add load/unload callback used for each admitted page in the ring-buffer. This will be later useful for the pKVM hypervisor which uses a different VA space and need to dynamically map/unmap the ring-buffer pages. Reviewed-by: Steven Rostedt (Google) Signed-off-by: Vincent Donnefort diff --git a/include/linux/simple_ring_buffer.h b/include/linux/simple_ring= _buffer.h index 2c4c0ae336bc..21aec556293e 100644 --- a/include/linux/simple_ring_buffer.h +++ b/include/linux/simple_ring_buffer.h @@ -54,4 +54,12 @@ int simple_ring_buffer_reset(struct simple_rb_per_cpu *c= pu_buffer); =20 int simple_ring_buffer_swap_reader_page(struct simple_rb_per_cpu *cpu_buff= er); =20 +int simple_ring_buffer_init_mm(struct simple_rb_per_cpu *cpu_buffer, + struct simple_buffer_page *bpages, + const struct ring_buffer_desc *desc, + void *(*load_page)(unsigned long va), + void (*unload_page)(void *va)); + +void simple_ring_buffer_unload_mm(struct simple_rb_per_cpu *cpu_buffer, + void (*unload_page)(void *)); #endif diff --git a/kernel/trace/simple_ring_buffer.c b/kernel/trace/simple_ring_b= uffer.c index 15df9781411b..02af2297ae5a 100644 --- a/kernel/trace/simple_ring_buffer.c +++ b/kernel/trace/simple_ring_buffer.c @@ -71,7 +71,7 @@ static void simple_bpage_reset(struct simple_buffer_page = *bpage) local_set(&bpage->page->commit, 0); } =20 -static void simple_bpage_init(struct simple_buffer_page *bpage, unsigned l= ong page) +static void simple_bpage_init(struct simple_buffer_page *bpage, void *page) { INIT_LIST_HEAD(&bpage->link); bpage->page =3D (struct buffer_data_page *)page; @@ -372,18 +372,15 @@ int simple_ring_buffer_reset(struct simple_rb_per_cpu= *cpu_buffer) } EXPORT_SYMBOL_GPL(simple_ring_buffer_reset); =20 -/** - * simple_ring_buffer_init - Init @cpu_buffer based on @desc - * @cpu_buffer: A simple_rb_per_cpu buffer to init, allocated by the calle= r. - * @bpages: Array of simple_buffer_pages, with as many elements as @desc->= nr_page_va - * @desc: A ring_buffer_desc - * - * Returns 0 on success or -EINVAL if the content of @desc is invalid - */ -int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct s= imple_buffer_page *bpages, - const struct ring_buffer_desc *desc) +int simple_ring_buffer_init_mm(struct simple_rb_per_cpu *cpu_buffer, + struct simple_buffer_page *bpages, + const struct ring_buffer_desc *desc, + void *(*load_page)(unsigned long va), + void (*unload_page)(void *va)) { struct simple_buffer_page *bpage =3D bpages; + int ret =3D 0; + void *page; int i; =20 /* At least 1 reader page and two pages in the ring-buffer */ @@ -392,15 +389,22 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu = *cpu_buffer, struct simple_ =20 memset(cpu_buffer, 0, sizeof(*cpu_buffer)); =20 - cpu_buffer->bpages =3D bpages; + cpu_buffer->meta =3D load_page(desc->meta_va); + if (!cpu_buffer->meta) + return -EINVAL; =20 - cpu_buffer->meta =3D (void *)desc->meta_va; memset(cpu_buffer->meta, 0, sizeof(*cpu_buffer->meta)); cpu_buffer->meta->meta_page_size =3D PAGE_SIZE; cpu_buffer->meta->nr_subbufs =3D cpu_buffer->nr_pages; =20 /* The reader page is not part of the ring initially */ - simple_bpage_init(bpage, desc->page_va[0]); + page =3D load_page(desc->page_va[0]); + if (!page) { + unload_page(cpu_buffer->meta); + return -EINVAL; + } + + simple_bpage_init(bpage, page); bpage->id =3D 0; =20 cpu_buffer->nr_pages =3D 1; @@ -410,7 +414,13 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *= cpu_buffer, struct simple_ cpu_buffer->head_page =3D bpage + 1; =20 for (i =3D 1; i < desc->nr_page_va; i++) { - simple_bpage_init(++bpage, desc->page_va[i]); + page =3D load_page(desc->page_va[i]); + if (!page) { + ret =3D -EINVAL; + break; + } + + simple_bpage_init(++bpage, page); =20 bpage->link.next =3D &(bpage + 1)->link; bpage->link.prev =3D &(bpage - 1)->link; @@ -419,6 +429,14 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *= cpu_buffer, struct simple_ cpu_buffer->nr_pages =3D i + 1; } =20 + if (ret) { + for (i--; i >=3D 0; i--) + unload_page((void *)desc->page_va[i]); + unload_page(cpu_buffer->meta); + + return ret; + } + /* Close the ring */ bpage->link.next =3D &cpu_buffer->tail_page->link; cpu_buffer->tail_page->link.prev =3D &bpage->link; @@ -426,23 +444,58 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu = *cpu_buffer, struct simple_ /* The last init'ed page points to the head page */ simple_bpage_set_head_link(bpage); =20 + cpu_buffer->bpages =3D bpages; + return 0; } -EXPORT_SYMBOL_GPL(simple_ring_buffer_init); + +static void *__load_page(unsigned long page) +{ + return (void *)page; +} + +static void __unload_page(void *page) { } =20 /** - * simple_ring_buffer_unload - Prepare @cpu_buffer for deletion - * @cpu_buffer: A simple_rb_per_cpu that will be deleted. + * simple_ring_buffer_init - Init @cpu_buffer based on @desc + * @cpu_buffer: A simple_rb_per_cpu buffer to init, allocated by the calle= r. + * @bpages: Array of simple_buffer_pages, with as many elements as @desc->= nr_page_va + * @desc: A ring_buffer_desc + * + * Returns 0 on success or -EINVAL if the content of @desc is invalid */ -void simple_ring_buffer_unload(struct simple_rb_per_cpu *cpu_buffer) +int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct s= imple_buffer_page *bpages, + const struct ring_buffer_desc *desc) +{ + return simple_ring_buffer_init_mm(cpu_buffer, bpages, desc, __load_page, = __unload_page); +} +EXPORT_SYMBOL_GPL(simple_ring_buffer_init); + +void simple_ring_buffer_unload_mm(struct simple_rb_per_cpu *cpu_buffer, + void (*unload_page)(void *)) { + int p; + if (!simple_rb_loaded(cpu_buffer)) return; =20 simple_rb_enable_tracing(cpu_buffer, false); =20 + unload_page(cpu_buffer->meta); + for (p =3D 0; p < cpu_buffer->nr_pages; p++) + unload_page(cpu_buffer->bpages[p].page); + cpu_buffer->bpages =3D NULL; } + +/** + * simple_ring_buffer_unload - Prepare @cpu_buffer for deletion + * @cpu_buffer: A simple_rb_per_cpu that will be deleted. + */ +void simple_ring_buffer_unload(struct simple_rb_per_cpu *cpu_buffer) +{ + return simple_ring_buffer_unload_mm(cpu_buffer, __unload_page); +} EXPORT_SYMBOL_GPL(simple_ring_buffer_unload); =20 /** --=20 2.53.0.335.g19a08e0c02-goog