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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 20:08:10 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 20:08:10 +0300
commit288321a9c65192878446a00acaa9f6c3ca9bb1f5 (patch)
treed61bceb24d7438de2c965af7883bcfd0ffd828a6 /Documentation
parent7e4910b9acea9fb9575f6506f76dd465259ad8d9 (diff)
parent9d843e8fafc7c0b15d8f511d146c0c3d7c816634 (diff)
downloadlinux-288321a9c65192878446a00acaa9f6c3ca9bb1f5.tar.xz
Merge tag 'pstore-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull pstore update from Kees Cook: - Add mem_type property to expand support for >2 memory types (Mukesh Ojha) * tag 'pstore-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: pstore: Add mem_type property DT parsing support
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/ramoops.rst4
-rw-r--r--Documentation/devicetree/bindings/reserved-memory/ramoops.txt10
2 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/admin-guide/ramoops.rst b/Documentation/admin-guide/ramoops.rst
index b0a1ae7df13b..8f107d8c9261 100644
--- a/Documentation/admin-guide/ramoops.rst
+++ b/Documentation/admin-guide/ramoops.rst
@@ -3,7 +3,7 @@ Ramoops oops/panic logger
Sergiu Iordache <sergiu@chromium.org>
-Updated: 17 November 2011
+Updated: 10 Feb 2021
Introduction
------------
@@ -30,6 +30,8 @@ mapping to pgprot_writecombine. Setting ``mem_type=1`` attempts to use
depends on atomic operations. At least on ARM, pgprot_noncached causes the
memory to be mapped strongly ordered, and atomic operations on strongly ordered
memory are implementation defined, and won't work on many ARMs such as omaps.
+Setting ``mem_type=2`` attempts to treat the memory region as normal memory,
+which enables full cache on it. This can improve the performance.
The memory area is divided into ``record_size`` chunks (also rounded down to
power of two) and each kmesg dump writes a ``record_size`` chunk of
diff --git a/Documentation/devicetree/bindings/reserved-memory/ramoops.txt b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
index b7886fea368c..b571ef6dab0f 100644
--- a/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
+++ b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
@@ -42,8 +42,14 @@ Optional properties:
- pmsg-size: size in bytes of log buffer reserved for userspace messages
(defaults to 0: disabled)
-- unbuffered: if present, use unbuffered mappings to map the reserved region
- (defaults to buffered mappings)
+- mem-type: if present, sets the type of mapping is to be used to map the
+ reserved region. mem-type: 0 = write-combined (default), 1 = unbuffered,
+ 2 = cached.
+
+- unbuffered: deprecated, use mem_type instead. If present, and mem_type is
+ not specified, it is equivalent to mem_type = 1 and uses unbuffered mappings
+ to map the reserved region (defaults to buffered mappings mem_type = 0). If
+ both are specified -- "mem_type" overrides "unbuffered".
- max-reason: if present, sets maximum type of kmsg dump reasons to store
(defaults to 2: log Oopses and Panics). This can be set to INT_MAX to