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AJvYcCWsEOxNoICvWK9PsyrivK4dDuoreTrlYXV7VwJkaXE4NtojmA3Z8RJSxn7zYgQPZ/I34m3IeU1I6H2a+Pc=@vger.kernel.org X-Gm-Message-State: AOJu0YyuPWD/NpNFHDACd2vtdJv/RPpEsEdaKCaMg6AaoPFG0kFPjNBb jApcPXxioziB3nP+oQMXYiroJbpsVdDyoGF0ejVuuMZPg7M6M40/lFsiT/sx1nw4opkHC9VVvHr 9RdImKygRyQyuhpN6pVJ0JA== X-Google-Smtp-Source: AGHT+IF6GiKCqwKfjKEeuxZgNsXAZSGVRxvCwcB1YwHTIPjTMo5AijDWEtVQrQi9EZhBvqgSIyLZKQ4QheeyH+xU X-Received: from wmby13.prod.google.com ([2002:a05:600c:c04d:b0:46e:3771:b9c9]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:18a9:b0:404:ac77:6598 with SMTP id ffacd0b85a97d-4256713ac9dmr2185339f8f.11.1759498753278; Fri, 03 Oct 2025 06:39:13 -0700 (PDT) Date: Fri, 3 Oct 2025 14:38:14 +0100 In-Reply-To: <20251003133825.2068970-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251003133825.2068970-1-vdonnefort@google.com> X-Mailer: git-send-email 2.51.0.618.g983fd99d29-goog Message-ID: <20251003133825.2068970-18-vdonnefort@google.com> Subject: [PATCH v7 17/28] 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. Signed-off-by: Vincent Donnefort diff --git a/include/linux/simple_ring_buffer.h b/include/linux/simple_ring= _buffer.h index f324df2f875b..ecd0e988c699 100644 --- a/include/linux/simple_ring_buffer.h +++ b/include/linux/simple_ring_buffer.h @@ -110,4 +110,11 @@ int simple_ring_buffer_reset(struct simple_rb_per_cpu = *cpu_buffer); */ int simple_ring_buffer_swap_reader_page(struct simple_rb_per_cpu *cpu_buff= er); =20 +int __simple_ring_buffer_init(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(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 20e3cd6071a2..c2ec6017c37c 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; @@ -338,10 +338,15 @@ int simple_ring_buffer_reset(struct simple_rb_per_cpu= *cpu_buffer) return 0; } =20 -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(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 */ @@ -350,15 +355,22 @@ 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; @@ -368,7 +380,13 @@ 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; @@ -377,6 +395,14 @@ 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; @@ -384,19 +410,46 @@ 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; } =20 -void simple_ring_buffer_unload(struct simple_rb_per_cpu *cpu_buffer) +static void *__load_page(unsigned long page) { + return (void *)page; +} + +static void __unload_page(void *page) { } + +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(cpu_buffer, bpages, desc, __load_page, _= _unload_page); +} + +void __simple_ring_buffer_unload(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; } =20 +void simple_ring_buffer_unload(struct simple_rb_per_cpu *cpu_buffer) +{ + return __simple_ring_buffer_unload(cpu_buffer, __unload_page); +} + int simple_ring_buffer_enable_tracing(struct simple_rb_per_cpu *cpu_buffer= , bool enable) { if (!simple_rb_loaded(cpu_buffer)) --=20 2.51.0.618.g983fd99d29-goog