path: root/Documentation/ramoops.txt
diff options
Diffstat (limited to 'Documentation/ramoops.txt')
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt
index 4ba7db231cb2..59a74a8ee2e5 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -40,6 +40,12 @@ corrupt, but usually it is restorable.
Setting the ramoops parameters can be done in 2 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:
+ "mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1"
2. 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:
@@ -70,6 +76,14 @@ if (ret) {
return ret;
+You can specify either RAM memory or peripheral devices' memory. However, when
+specifying RAM, be sure to reserve the memory by issuing memblock_reserve()
+very early in the architecture code, e.g.:
+#include <linux/memblock.h>
+memblock_reserve(ramoops_data.mem_address, ramoops_data.mem_size);
3. Dump format
The data dump begins with a header, currently defined as "====" followed by a

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