[PATCH v2] pstore: use DT reserved-memory bindings
From: Kees Cook
Date: Mon Aug 01 2016 - 15:06:44 EST
Instead of a ramoops-specific node, use a child node of /reserved-memory.
This requires that of_platform_device_create() be explicitly called
for the node, though, since "/reserved-memory" does not have its own
"compatible" property.
Suggested-by: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
v2:
- rebase to 4.8, use of_platform_default_populate_init(), robh
- use platform device resources instead of node directly, robh
---
.../bindings/{misc => reserved-memory}/ramoops.txt | 8 ++---
Documentation/ramoops.txt | 38 +++++++++++++++-------
drivers/of/platform.c | 20 ++++++++++--
fs/pstore/ram.c | 23 ++++---------
4 files changed, 56 insertions(+), 33 deletions(-)
rename Documentation/devicetree/bindings/{misc => reserved-memory}/ramoops.txt (86%)
diff --git a/Documentation/devicetree/bindings/misc/ramoops.txt b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
similarity index 86%
rename from Documentation/devicetree/bindings/misc/ramoops.txt
rename to Documentation/devicetree/bindings/reserved-memory/ramoops.txt
index cd02cec67d38..e81f821a2135 100644
--- a/Documentation/devicetree/bindings/misc/ramoops.txt
+++ b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
@@ -2,8 +2,9 @@ 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.
+recovered after a reboot. This is a child-node of "/reserved-memory", and
+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
@@ -21,8 +22,7 @@ Required properties:
- compatible: must be "ramoops"
-- memory-region: phandle to a region of memory that is preserved between
- reboots
+- reg: region of memory that is preserved between reboots
Optional properties:
diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt
index 9264bcab4099..26b9f31cf65a 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -45,18 +45,34 @@ corrupt, but usually it is restorable.
2. Setting the parameters
-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
- and then use the reserved memory for ramoops. For example, assuming a machine
- with > 128 MB of memory, the following kernel command line will tell the
- kernel to use only the first 128 MB of memory, and place ECC-protected ramoops
- region at 128 MB boundary:
+Setting the ramoops parameters can be done in several different manners:
+
+ A. 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 and then use the reserved memory for ramoops. For example, assuming a
+ machine with > 128 MB of memory, the following kernel command line will tell
+ the 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 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
+
+ B. Use Device Tree bindings, as described in
+ Documentation/device-tree/bindings/reserved-memory/ramoops.txt.
+ For example:
+
+ reserved-memory {
+ #address-cells = <2>;
+ #size-cells = <2>;
+ ranges;
+
+ ramoops@8f000000 {
+ compatible = "ramoops";
+ reg = <0 0x8f000000 0 0x100000>;
+ record-size = <0x4000>;
+ console-size = <0x4000>;
+ };
+ };
+
+ C. 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/drivers/of/platform.c b/drivers/of/platform.c
index 765390e3ed8d..8aa197691074 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -499,8 +499,24 @@ EXPORT_SYMBOL_GPL(of_platform_default_populate);
static int __init of_platform_default_populate_init(void)
{
- if (of_have_populated_dt())
- of_platform_default_populate(NULL, NULL, NULL);
+ struct device_node *node;
+
+ if (!of_have_populated_dt())
+ return -ENODEV;
+
+ /*
+ * Handle ramoops explicitly, since it is inside /reserved-memory,
+ * which lacks a "compatible" property.
+ */
+ node = of_find_node_by_path("/reserved-memory");
+ if (node) {
+ node = of_find_compatible_node(node, NULL, "ramoops");
+ if (node)
+ of_platform_device_create(node, NULL, NULL);
+ }
+
+ /* Populate everything else. */
+ of_platform_default_populate(NULL, NULL, NULL);
return 0;
}
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 47516a794011..427eee7570bb 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -486,30 +486,21 @@ 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;
+ 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) {
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
dev_err(&pdev->dev,
- "failed to translate memory-region to resource: %d\n",
- ret);
- return ret;
+ "failed to locate DT /reserved-memory resource\n");
+ return -EINVAL;
}
- pdata->mem_size = resource_size(&res);
- pdata->mem_address = res.start;
+ 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");
--
2.7.4
--
Kees Cook
Brillo & Chrome OS Security