path: root/Documentation/kdump
diff options
authorRussell King <>2016-03-14 19:34:37 +0000
committerRussell King <>2016-05-03 11:13:45 +0100
commit61603016e2122bf95328321b2f1a64277202b6e3 (patch)
tree02a04c1043bca3f4872ef8b2374f8516e7cba64e /Documentation/kdump
parentf55532a0c0b8bb6148f4e07853b876ef73bc69ca (diff)
ARM: kexec: fix crashkernel= handling
When the kernel crashkernel parameter is specified with just a size, we are supposed to allocate a region from RAM to store the crashkernel. However, ARM merely reserves physical address zero with no checking that there is even RAM there. Fix this by lifting similar code from x86, importing it to ARM with the ARM specific parameters added. In the absence of any platform specific information, we allocate the crashkernel region from the first 512MB of physical memory. Update the kdump documentation to reflect this change. Signed-off-by: Russell King <> Reviewed-by: Pratyush Anand <>
Diffstat (limited to 'Documentation/kdump')
1 files changed, 3 insertions, 10 deletions
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index bc4bd5a44b88..88ff63d5fde3 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -263,12 +263,6 @@ The syntax is:
-Please note, on arm, the offset is required.
- crashkernel=<range1>:<size1>[,<range2>:<size2>,...]@offset
- range=start-[end]
- 'start' is inclusive and 'end' is exclusive.
For example:
@@ -307,10 +301,9 @@ Boot into System Kernel
on the memory consumption of the kdump system. In general this is not
dependent on the memory size of the production system.
- On arm, use "crashkernel=Y@X". Note that the start address of the kernel
- will be aligned to 128MiB (0x08000000), so if the start address is not then
- any space below the alignment point may be overwritten by the dump-capture kernel,
- which means it is possible that the vmcore is not that precise as expected.
+ On arm, the use of "crashkernel=Y@X" is no longer necessary; the
+ kernel will automatically locate the crash kernel image within the
+ first 512MB of RAM if X is not given.
Load the Dump-capture Kernel