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Message-Id: <1465599059-22665-2-git-send-email-keescook@chromium.org>
Date: Fri, 10 Jun 2016 15:50:59 -0700
From: Kees Cook <keescook@...omium.org>
To: linux-kernel@...r.kernel.org
Cc: Kees Cook <keescook@...omium.org>,
Greg Hackmann <ghackmann@...gle.com>,
Arnd Bergmann <arnd@...db.de>,
Rob Herring <robh+dt@...nel.org>,
Markus Pargmann <mpa@...gutronix.de>,
Olof Johansson <olof@...om.net>,
Brian Norris <computersforpeace@...il.com>,
Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Lee Campbell <leecam@...gle.com>,
Tony Luck <tony.luck@...el.com>, devicetree@...r.kernel.org,
linux-doc@...r.kernel.org
Subject: [PATCH v4] pstore/ram: add Device Tree bindings
From: Greg Hackmann <ghackmann@...gle.com>
ramoops is one of the remaining places where ARM vendors still rely on
board-specific shims. Device Tree lets us replace those shims with
generic code.
These bindings mirror the ramoops module parameters, with two small
differences:
(1) dump_oops becomes an optional "no-dump-oops" property, since ramoops
sets dump_oops=1 by default.
(2) mem_type=1 becomes the more self-explanatory "unbuffered" property.
Signed-off-by: Greg Hackmann <ghackmann@...gle.com>
[fixed platform_get_drvdata() crash, thanks to Brian Norris]
[switched from u64 to u32 to simplify code, various whitespace fixes]
[use dev_of_node() to gain code-elimination for CONFIG_OF=n]
Signed-off-by: Kees Cook <keescook@...omium.org>
---
Documentation/devicetree/bindings/misc/ramoops.txt | 48 +++++++++++
Documentation/ramoops.txt | 6 +-
fs/pstore/ram.c | 95 +++++++++++++++++++++-
3 files changed, 145 insertions(+), 4 deletions(-)
create mode 100644 Documentation/devicetree/bindings/misc/ramoops.txt
diff --git a/Documentation/devicetree/bindings/misc/ramoops.txt b/Documentation/devicetree/bindings/misc/ramoops.txt
new file mode 100644
index 000000000000..cd02cec67d38
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/ramoops.txt
@@ -0,0 +1,48 @@
+Ramoops oops/panic logger
+=========================
+
+ramoops provides persistent RAM storage for oops and panics, so they can be
+recovered after a reboot. It is a backend to pstore, so this node is named
+"ramoops" after the backend, rather than "pstore" which is the subsystem.
+
+Parts of this storage may be set aside for other persistent log buffers, such
+as kernel log messages, or for optional ECC error-correction data. The total
+size of these optional buffers must fit in the reserved region.
+
+Any remaining space will be used for a circular buffer of oops and panic
+records. These records have a configurable size, with a size of 0 indicating
+that they should be disabled.
+
+At least one of "record-size", "console-size", "ftrace-size", or "pmsg-size"
+must be set non-zero, but are otherwise optional as listed below.
+
+
+Required properties:
+
+- compatible: must be "ramoops"
+
+- memory-region: phandle to a region of memory that is preserved between
+ reboots
+
+
+Optional properties:
+
+- ecc-size: enables ECC support and specifies ECC buffer size in bytes
+ (defaults to 0: no ECC)
+
+- record-size: maximum size in bytes of each dump done on oops/panic
+ (defaults to 0: disabled)
+
+- console-size: size in bytes of log buffer reserved for kernel messages
+ (defaults to 0: disabled)
+
+- ftrace-size: size in bytes of log buffer reserved for function tracing and
+ profiling (defaults to 0: disabled)
+
+- pmsg-size: size in bytes of log buffer reserved for userspace messages
+ (defaults to 0: disabled)
+
+- unbuffered: if present, use unbuffered mappings to map the reserved region
+ (defaults to buffered mappings)
+
+- no-dump-oops: if present, only dump panics (defaults to panics and oops)
diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt
index 5d8675615e59..9264bcab4099 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -45,7 +45,7 @@ corrupt, but usually it is restorable.
2. Setting the parameters
-Setting the ramoops parameters can be done in 2 different manners:
+Setting the ramoops parameters can be done in 3 different manners:
1. Use the module parameters (which have the names of the variables described
as before).
For quick debugging, you can also reserve parts of memory during boot
@@ -54,7 +54,9 @@ Setting the ramoops parameters can be done in 2 different manners:
kernel to use only the first 128 MB of memory, and place ECC-protected ramoops
region at 128 MB boundary:
"mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1"
- 2. Use a platform device and set the platform data. The parameters can then
+ 2. Use Device Tree bindings, as described in
+ Documentation/device-tree/bindings/misc/ramoops.txt.
+ 3. Use a platform device and set the platform data. The parameters can then
be set through that platform data. An example of doing that is:
#include <linux/pstore_ram.h>
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index d9668c2b43cb..47516a794011 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -34,6 +34,8 @@
#include <linux/slab.h>
#include <linux/compiler.h>
#include <linux/pstore_ram.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
#define RAMOOPS_KERNMSG_HDR "===="
#define MIN_MEM_SIZE 4096UL
@@ -458,15 +460,98 @@ static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
return 0;
}
+static int ramoops_parse_dt_size(struct platform_device *pdev,
+ const char *propname, u32 *value)
+{
+ u32 val32 = 0;
+ int ret;
+
+ ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
+ if (ret < 0 && ret != -EINVAL) {
+ dev_err(&pdev->dev, "failed to parse property %s: %d\n",
+ propname, ret);
+ return ret;
+ }
+
+ if (val32 > INT_MAX) {
+ dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
+ return -EOVERFLOW;
+ }
+
+ *value = val32;
+ return 0;
+}
+
+static int ramoops_parse_dt(struct platform_device *pdev,
+ struct ramoops_platform_data *pdata)
+{
+ struct device_node *of_node = pdev->dev.of_node;
+ struct device_node *mem_region;
+ struct resource res;
+ u32 value;
+ int ret;
+
+ dev_dbg(&pdev->dev, "using Device Tree\n");
+
+ mem_region = of_parse_phandle(of_node, "memory-region", 0);
+ if (!mem_region) {
+ dev_err(&pdev->dev, "no memory-region phandle\n");
+ return -ENODEV;
+ }
+
+ ret = of_address_to_resource(mem_region, 0, &res);
+ of_node_put(mem_region);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to translate memory-region to resource: %d\n",
+ ret);
+ return ret;
+ }
+
+ pdata->mem_size = resource_size(&res);
+ pdata->mem_address = res.start;
+ pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
+ pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
+
+#define parse_size(name, field) { \
+ ret = ramoops_parse_dt_size(pdev, name, &value); \
+ if (ret < 0) \
+ return ret; \
+ field = value; \
+ }
+
+ parse_size("record-size", pdata->record_size);
+ parse_size("console-size", pdata->console_size);
+ parse_size("ftrace-size", pdata->ftrace_size);
+ parse_size("pmsg-size", pdata->pmsg_size);
+ parse_size("ecc-size", pdata->ecc_info.ecc_size);
+
+#undef parse_size
+
+ return 0;
+}
+
static int ramoops_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
- struct ramoops_platform_data *pdata = pdev->dev.platform_data;
+ struct ramoops_platform_data *pdata = dev->platform_data;
struct ramoops_context *cxt = &oops_cxt;
size_t dump_mem_sz;
phys_addr_t paddr;
int err = -EINVAL;
+ if (dev_of_node(dev) && !pdata) {
+ pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata) {
+ err = -ENOMEM;
+ goto fail_out;
+ }
+
+ err = ramoops_parse_dt(pdev, pdata);
+ if (err < 0)
+ goto fail_out;
+ }
+
/* Only a single ramoops area allowed at a time, so fail extra
* probes.
*/
@@ -596,11 +681,17 @@ static int ramoops_remove(struct platform_device *pdev)
return 0;
}
+static const struct of_device_id dt_match[] = {
+ { .compatible = "ramoops" },
+ {}
+};
+
static struct platform_driver ramoops_driver = {
.probe = ramoops_probe,
.remove = ramoops_remove,
.driver = {
- .name = "ramoops",
+ .name = "ramoops",
+ .of_match_table = dt_match,
},
};
--
2.7.4
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