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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 10:08:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 10:08:10 -0700
commit288321a9c65192878446a00acaa9f6c3ca9bb1f5 (patch)
treed61bceb24d7438de2c965af7883bcfd0ffd828a6 /Documentation
parent7e4910b9acea9fb9575f6506f76dd465259ad8d9 (diff)
parent9d843e8fafc7c0b15d8f511d146c0c3d7c816634 (diff)
downloadlinux-288321a9c65192878446a00acaa9f6c3ca9bb1f5.tar.gz
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