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Subject[RFC][PATCH] pstore: use DT reserved-memory bindings
Instead of a ramoops-specific node, use a child node of /reserved-memory.
This requires that of_platform_populate() be called for the node, though,
since it does not have its own "compatible" property.

Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Here's what I've got for moving ramoops under /reserved-memory... still
feels like a bit of a hack.
---
Documentation/devicetree/bindings/misc/ramoops.txt | 48 ----------------------
.../bindings/reserved-memory/ramoops.txt | 48 ++++++++++++++++++++++
Documentation/ramoops.txt | 2 +-
drivers/of/platform.c | 5 +++
fs/pstore/ram.c | 12 +-----
5 files changed, 56 insertions(+), 59 deletions(-)
delete mode 100644 Documentation/devicetree/bindings/misc/ramoops.txt
create mode 100644 Documentation/devicetree/bindings/reserved-memory/ramoops.txt

diff --git a/Documentation/devicetree/bindings/misc/ramoops.txt b/Documentation/devicetree/bindings/misc/ramoops.txt
deleted file mode 100644
index cd02cec67d38..000000000000
--- a/Documentation/devicetree/bindings/misc/ramoops.txt
+++ /dev/null
@@ -1,48 +0,0 @@
-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/devicetree/bindings/reserved-memory/ramoops.txt b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
new file mode 100644
index 000000000000..e81f821a2135
--- /dev/null
+++ b/Documentation/devicetree/bindings/reserved-memory/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. 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
+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"
+
+- reg: 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 9264bcab4099..deaf07cbf484 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -55,7 +55,7 @@ Setting the ramoops parameters can be done in 3 different manners:
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.
+ Documentation/device-tree/bindings/reserved-memory/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:

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 16e8daffac06..c07adf72bb8e 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -356,6 +356,11 @@ static int of_platform_bus_create(struct device_node *bus,
void *platform_data = NULL;
int rc = 0;

+ /* Always populate reserved-memory nodes. */
+ if (strict && strcmp(bus->full_name, "/reserved-memory") == 0) {
+ return of_platform_populate(bus, matches, lookup, parent);
+ }
+
/* Make sure it has a compatible property */
if (strict && (!of_get_property(bus, "compatible", NULL))) {
pr_debug("%s() - skipping %s, no compatible prop\n",
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 47516a794011..af5cee0c2156 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -486,24 +486,16 @@ 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);
+ ret = of_address_to_resource(of_node, 0, &res);
if (ret) {
dev_err(&pdev->dev,
- "failed to translate memory-region to resource: %d\n",
+ "failed to translate reserved-memory to resource: %d\n",
ret);
return ret;
}
--
2.7.4

--
Kees Cook
Brillo & Chrome OS Security

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