ramoops: use DT reserved-memory bindings

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@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Kees Cook 2016-07-29 18:11:32 -07:00
parent f38d2e5313
commit 529182e204
4 changed files with 56 additions and 33 deletions

View File

@ -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:

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@ -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>

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@ -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;
}

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@ -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");