lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20250506164820.515876-13-vdonnefort@google.com>
Date: Tue,  6 May 2025 17:48:08 +0100
From: Vincent Donnefort <vdonnefort@...gle.com>
To: rostedt@...dmis.org, mhiramat@...nel.org, mathieu.desnoyers@...icios.com, 
	linux-trace-kernel@...r.kernel.org, maz@...nel.org, oliver.upton@...ux.dev, 
	joey.gouly@....com, suzuki.poulose@....com, yuzenghui@...wei.com
Cc: kvmarm@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
	jstultz@...gle.com, qperret@...gle.com, will@...nel.org, 
	kernel-team@...roid.com, linux-kernel@...r.kernel.org, 
	Vincent Donnefort <vdonnefort@...gle.com>
Subject: [PATCH v4 12/24] tracing: load/unload page callbacks for simple_ring_buffer

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 <vdonnefort@...gle.com>

diff --git a/include/linux/simple_ring_buffer.h b/include/linux/simple_ring_buffer.h
index 6cf8486d46e2..10e385d347a0 100644
--- a/include/linux/simple_ring_buffer.h
+++ b/include/linux/simple_ring_buffer.h
@@ -46,4 +46,12 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct simple_
 int simple_ring_buffer_enable_tracing(struct simple_rb_per_cpu *cpu_buffer, bool enable);
 int simple_ring_buffer_swap_reader_page(struct simple_rb_per_cpu *cpu_buffer);
 int simple_ring_buffer_reset(struct simple_rb_per_cpu *cpu_buffer);
+
+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_buffer.c
index da9ea42b9926..54c8f221f693 100644
--- a/kernel/trace/simple_ring_buffer.c
+++ b/kernel/trace/simple_ring_buffer.c
@@ -55,7 +55,7 @@ static void simple_bpage_reset(struct simple_buffer_page *bpage)
 	local_set(&bpage->page->commit, 0);
 }
 
-static void simple_bpage_init(struct simple_buffer_page *bpage, unsigned long page)
+static void simple_bpage_init(struct simple_buffer_page *bpage, void *page)
 {
 	INIT_LIST_HEAD(&bpage->list);
 	bpage->page = (struct buffer_data_page *)page;
@@ -282,10 +282,14 @@ int simple_ring_buffer_reset(struct simple_rb_per_cpu *cpu_buffer)
 	return 0;
 }
 
-int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct simple_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 = bpages;
+	int ret = 0;
+	void *page;
 	int i;
 
 	/* At least 1 reader page and one head */
@@ -294,15 +298,22 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct simple_
 
 	memset(cpu_buffer, 0, sizeof(*cpu_buffer));
 
-	cpu_buffer->bpages = bpages;
+	cpu_buffer->meta = load_page(desc->meta_va);
+	if (!cpu_buffer->meta)
+		return -EINVAL;
 
-	cpu_buffer->meta = (void *)desc->meta_va;
 	memset(cpu_buffer->meta, 0, sizeof(*cpu_buffer->meta));
 	cpu_buffer->meta->meta_page_size = PAGE_SIZE;
 	cpu_buffer->meta->nr_subbufs = cpu_buffer->nr_pages;
 
 	/* The reader page is not part of the ring initially */
-	simple_bpage_init(bpage, desc->page_va[0]);
+	page = load_page(desc->page_va[0]);
+	if (!page) {
+		unload_page(cpu_buffer->meta);
+		return -EINVAL;
+	}
+
+	simple_bpage_init(bpage, page);
 	bpage->id = 0;
 
 	cpu_buffer->nr_pages = 1;
@@ -312,7 +323,13 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct simple_
 	cpu_buffer->head_page = bpage + 1;
 
 	for (i = 1; i < desc->nr_page_va; i++) {
-		simple_bpage_init(++bpage, desc->page_va[i]);
+		page = load_page(desc->page_va[i]);
+		if (!page) {
+			ret = -EINVAL;
+			break;
+		}
+
+		simple_bpage_init(++bpage, page);
 
 		bpage->list.next = &(bpage + 1)->list;
 		bpage->list.prev = &(bpage - 1)->list;
@@ -321,6 +338,14 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct simple_
 		cpu_buffer->nr_pages = i + 1;
 	}
 
+	if (ret) {
+		for (i--; i >= 0; i--)
+			unload_page((void *)desc->page_va[i]);
+		unload_page(cpu_buffer->meta);
+
+		return ret;
+	}
+
 	/* Close the ring */
 	bpage->list.next = &cpu_buffer->tail_page->list;
 	cpu_buffer->tail_page->list.prev = &bpage->list;
@@ -328,19 +353,46 @@ 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_link_flag(bpage, SIMPLE_RB_LINK_HEAD);
 
+	cpu_buffer->bpages = bpages;
+
 	return 0;
 }
 
-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 simple_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;
 
 	simple_rb_enable_tracing(cpu_buffer, false);
 
+	unload_page(cpu_buffer->meta);
+	for (p = 0; p < cpu_buffer->nr_pages; p++)
+		unload_page(cpu_buffer->bpages[p].page);
+
 	cpu_buffer->bpages = 0;
 }
 
+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))
-- 
2.49.0.967.g6a0df3ecc3-goog


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ