path: root/Documentation/ramoops.txt
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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-05-26 06:20:25 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-06-13 16:59:28 -0700
commit958502d836cf18c6f39bdb787b76d53839e4d8aa (patch)
treeaee5d5c7301e5219c2f3637cee7afef638d4880d /Documentation/ramoops.txt
parent602b5be4f14cabd5b751c340919958549475ab62 (diff)
pstore/ram: Add some more documentation and examples
Suggested-by: Shuah Khan <shuahkhan@gmail.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Colin Cross <ccross@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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