Now we support crashkernel=X,[low] on arm64, update the Documentation.

Signed-off-by: Chen Zhou <chenzho...@huawei.com>
---
 Documentation/admin-guide/kdump/kdump.rst       | 13 +++++++++++--
 Documentation/admin-guide/kernel-parameters.txt | 12 +++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/kdump/kdump.rst 
b/Documentation/admin-guide/kdump/kdump.rst
index ac7e131..e55173e 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst
@@ -299,7 +299,13 @@ Boot into System Kernel
    "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
    starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
 
-   On x86 and x86_64, use "crashkernel=64M@16M".
+   On x86 use "crashkernel=64M@16M".
+
+   On x86_64, use "crashkernel=Y[@X]" to select a region under 4G first, and
+   fall back to reserve region above 4G when '@offset' hasn't been specified.
+   We can also use "crashkernel=X,high" to select a region above 4G, which
+   also tries to allocate at least 256M below 4G automatically and
+   "crashkernel=Y,low" can be used to allocate specified size low memory.
 
    On ppc64, use "crashkernel=128M@32M".
 
@@ -316,8 +322,11 @@ Boot into System Kernel
    kernel will automatically locate the crash kernel image within the
    first 512MB of RAM if X is not given.
 
-   On arm64, use "crashkernel=Y[@X]".  Note that the start address of
+   On arm64, use "crashkernel=Y[@X]". Note that the start address of
    the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000).
+   If crashkernel=Z,low is specified simultaneously, reserve spcified size
+   low memory for crash kdump kernel devices firstly and then reserve memory
+   above 4G.
 
 Load the Dump-capture Kernel
 ============================
diff --git a/Documentation/admin-guide/kernel-parameters.txt 
b/Documentation/admin-guide/kernel-parameters.txt
index ade4e6e..bde3ab4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -706,6 +706,9 @@
                        [KNL, x86_64] select a region under 4G first, and
                        fall back to reserve region above 4G when '@offset'
                        hasn't been specified.
+                       [KNL, arm64] If crashkernel=X,low is specified, reserve
+                       spcified size low memory for crash kdump kernel devices
+                       firstly, and then reserve memory above 4G.
                        See Documentation/admin-guide/kdump/kdump.rst for 
further details.
 
        crashkernel=range1:size1[,range2:size2,...][@offset]
@@ -730,12 +733,19 @@
                        requires at least 64M+32K low memory, also enough extra
                        low memory is needed to make sure DMA buffers for 32-bit
                        devices won't run out. Kernel would try to allocate at
-                       at least 256M below 4G automatically.
+                       least 256M below 4G automatically.
                        This one let user to specify own low range under 4G
                        for second kernel instead.
                        0: to disable low allocation.
                        It will be ignored when crashkernel=X,high is not used
                        or memory reserved is below 4G.
+                       [KNL, arm64] range under 4G.
+                       This one let user to specify own low range under 4G
+                       for crash dump kernel instead.
+                       Different with x86_64, kernel allocates specified size
+                       physical memory region only when this parameter is 
specified
+                       instead of trying to allocate at least 256M below 4G
+                       automatically.
 
        cryptomgr.notests
                        [KNL] Disable crypto self-tests
-- 
2.7.4


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Reply via email to