From: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
This patch adds arch specific descriptions about kdump usage on arm64
to kdump.txt.
Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
Documentation/kdump/kdump.txt | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index bc4bd5a..36cf978 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -18,7 +18,7 @@ memory image to a dump file on the local disk, or across the network to
a remote system.
Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64,
-s390x and arm architectures.
+s390x, arm and arm64 architectures.
When the system kernel boots, it reserves a small section of memory for
the dump-capture kernel. This ensures that ongoing Direct Memory Access
@@ -249,6 +249,20 @@ Dump-capture kernel config options (Arch Dependent, arm)
AUTO_ZRELADDR=y
+Dump-capture kernel config options (Arch Dependent, arm64)
+----------------------------------------------------------
+
+1) The maximum memory size on the dump-capture kernel must be limited by
+ specifying:
+
+ mem=X[MG]
+
+ where X should be less than or equal to the size in "crashkernel="
+ boot parameter. Kexec-tools will automatically add this.
+
+2) Currently, kvm will not be enabled on the dump-capture kernel even
+ if it is configured.
+
Extended crashkernel syntax
===========================
@@ -312,6 +326,8 @@ Boot into System Kernel
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 arm64, use "crashkernel=Y[@X]". Note that the start address of
+ the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
Load the Dump-capture Kernel
============================
@@ -334,6 +350,8 @@ For s390x:
- Use image or bzImage
For arm:
- Use zImage
+For arm64:
+ - Use vmlinux or Image
If you are using a uncompressed vmlinux image then use following command
to load dump-capture kernel.
@@ -377,6 +395,9 @@ For s390x:
For arm:
"1 maxcpus=1 reset_devices"
+For arm64:
+ "1 mem=X[MG] maxcpus=1 reset_devices"
+
Notes on loading the dump-capture kernel:
* By default, the ELF headers are stored in ELF64 format to support
--
2.5.0
