Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

5 files changed, 779 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sram/allwinner,sun4i-a10-system-control.yaml b/Documentation/devicetree/bindings/sram/allwinner,sun4i-a10-system-control.yaml
new file mode 100644
index 000000000..6e6ab2168
--- /dev/null
+++ b/Documentation/devicetree/bindings/sram/allwinner,sun4i-a10-system-control.yaml
@@ -0,0 +1,166 @@
+# SPDX-License-Identifier: GPL-2.0+
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sram/allwinner,sun4i-a10-system-control.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner A10 System Control
+
+maintainers:
+  - Chen-Yu Tsai <wens@csie.org>
+  - Maxime Ripard <mripard@kernel.org>
+
+description:
+  The SRAM controller found on most Allwinner devices is represented
+  by a regular node for the SRAM controller itself, with sub-nodes
+  representing the SRAM handled by the SRAM controller.
+
+properties:
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 1
+
+  compatible:
+    oneOf:
+      - enum:
+          - allwinner,sun4i-a10-sram-controller
+          - allwinner,sun50i-a64-sram-controller
+        deprecated: true
+      - enum:
+          - allwinner,sun4i-a10-system-control
+          - allwinner,sun5i-a13-system-control
+          - allwinner,sun8i-a23-system-control
+          - allwinner,sun8i-h3-system-control
+          - allwinner,sun20i-d1-system-control
+          - allwinner,sun50i-a64-system-control
+          - allwinner,sun50i-h5-system-control
+          - allwinner,sun50i-h616-system-control
+      - items:
+          - enum:
+              - allwinner,suniv-f1c100s-system-control
+              - allwinner,sun7i-a20-system-control
+              - allwinner,sun8i-r40-system-control
+          - const: allwinner,sun4i-a10-system-control
+      - items:
+          - const: allwinner,sun8i-v3s-system-control
+          - const: allwinner,sun8i-h3-system-control
+      - items:
+          - enum:
+              - allwinner,sun50i-a100-system-control
+              - allwinner,sun50i-h6-system-control
+              - allwinner,sun55i-a523-system-control
+          - const: allwinner,sun50i-a64-system-control
+
+  reg:
+    maxItems: 1
+
+  ranges: true
+
+patternProperties:
+  "^regulators@[0-9a-f]+$":
+    $ref: /schemas/regulator/allwinner,sun20i-d1-system-ldos.yaml#
+
+  "^sram@[a-f0-9]+":
+    $ref: /schemas/sram/sram.yaml#
+    unevaluatedProperties: false
+
+    patternProperties:
+      "^sram-section?@[a-f0-9]+$":
+        type: object
+        additionalProperties: false
+
+        properties:
+          reg: true
+
+          compatible:
+            oneOf:
+              - const: allwinner,sun4i-a10-sram-a3-a4
+              - const: allwinner,sun4i-a10-sram-c1
+              - const: allwinner,sun4i-a10-sram-d
+              - const: allwinner,sun50i-a64-sram-c
+              - const: allwinner,sun50i-h616-ve-sram
+              - items:
+                  - enum:
+                      - allwinner,sun5i-a13-sram-a3-a4
+                      - allwinner,sun7i-a20-sram-a3-a4
+                  - const: allwinner,sun4i-a10-sram-a3-a4
+              - items:
+                  - enum:
+                      - allwinner,sun5i-a13-sram-c1
+                      - allwinner,sun7i-a20-sram-c1
+                      - allwinner,sun8i-a23-sram-c1
+                      - allwinner,sun8i-h3-sram-c1
+                      - allwinner,sun8i-r40-sram-c1
+                      - allwinner,sun50i-a64-sram-c1
+                      - allwinner,sun50i-h5-sram-c1
+                      - allwinner,sun50i-h6-sram-c1
+                  - const: allwinner,sun4i-a10-sram-c1
+              - items:
+                  - enum:
+                      - allwinner,suniv-f1c100s-sram-d
+                      - allwinner,sun5i-a13-sram-d
+                      - allwinner,sun7i-a20-sram-d
+                  - const: allwinner,sun4i-a10-sram-d
+              - items:
+                  - enum:
+                      - allwinner,sun50i-h6-sram-c
+                      - allwinner,sun50i-h616-sram-c
+                  - const: allwinner,sun50i-a64-sram-c
+
+required:
+  - "#address-cells"
+  - "#size-cells"
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    system-control@1c00000 {
+      compatible = "allwinner,sun4i-a10-system-control";
+      reg = <0x01c00000 0x30>;
+      #address-cells = <1>;
+      #size-cells = <1>;
+      ranges;
+
+      sram_a: sram@0 {
+        compatible = "mmio-sram";
+        reg = <0x00000000 0xc000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0x00000000 0xc000>;
+
+        emac_sram: sram-section@8000 {
+          compatible = "allwinner,sun4i-a10-sram-a3-a4";
+          reg = <0x8000 0x4000>;
+        };
+      };
+    };
+
+  - |
+    syscon@3000000 {
+      compatible = "allwinner,sun20i-d1-system-control";
+      reg = <0x3000000 0x1000>;
+      ranges;
+      #address-cells = <1>;
+      #size-cells = <1>;
+
+      regulators@3000150 {
+        compatible = "allwinner,sun20i-d1-system-ldos";
+        reg = <0x3000150 0x4>;
+
+        reg_ldoa: ldoa {
+          regulator-min-microvolt = <1800000>;
+          regulator-max-microvolt = <1800000>;
+        };
+
+        reg_ldob: ldob {
+          regulator-name = "vcc-dram";
+          regulator-min-microvolt = <1500000>;
+          regulator-max-microvolt = <1500000>;
+        };
+      };
+    };
diff --git a/Documentation/devicetree/bindings/sram/qcom,imem.yaml b/Documentation/devicetree/bindings/sram/qcom,imem.yaml
new file mode 100644
index 000000000..b4f082f2a
--- /dev/null
+++ b/Documentation/devicetree/bindings/sram/qcom,imem.yaml
@@ -0,0 +1,149 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sram/qcom,imem.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm IMEM memory region
+
+maintainers:
+  - Bjorn Andersson <bjorn.andersson@linaro.org>
+
+description:
+  Qualcomm IMEM is dedicated memory region for various debug features and DMA
+  transactions.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - qcom,apq8064-imem
+          - qcom,ipq5424-imem
+          - qcom,msm8226-imem
+          - qcom,msm8974-imem
+          - qcom,msm8976-imem
+          - qcom,qcs404-imem
+          - qcom,qcs615-imem
+          - qcom,qcs8300-imem
+          - qcom,qdu1000-imem
+          - qcom,sa8775p-imem
+          - qcom,sar2130p-imem
+          - qcom,sc7180-imem
+          - qcom,sc7280-imem
+          - qcom,sc8280xp-imem
+          - qcom,sdm630-imem
+          - qcom,sdm845-imem
+          - qcom,sdx55-imem
+          - qcom,sdx65-imem
+          - qcom,sdx75-imem
+          - qcom,sm6115-imem
+          - qcom,sm6125-imem
+          - qcom,sm6350-imem
+          - qcom,sm6375-imem
+          - qcom,sm7150-imem
+          - qcom,sm8150-imem
+          - qcom,sm8250-imem
+          - qcom,sm8350-imem
+          - qcom,sm8450-imem
+          - qcom,sm8550-imem
+          - qcom,sm8650-imem
+          - qcom,sm8750-imem
+          - qcom,x1e80100-imem
+      - const: syscon
+      - const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+  ranges: true
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+  reboot-mode:
+    $ref: /schemas/power/reset/syscon-reboot-mode.yaml#
+
+patternProperties:
+  "^minidump-sram@[0-9a-f]+$":
+    type: object
+    description:
+      A word in always-on SRAM shared between the kernel and boot firmware.
+      Before DDR is initialised on the warm reset following a crash, firmware
+      reads this word to decide where to deliver the minidump (USB or storage).
+
+    properties:
+      reg:
+        maxItems: 1
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+  "^modem-tables@[0-9a-f]+$":
+    type: object
+    description:
+      Region containing packet processing configuration for the IP Accelerator.
+
+    properties:
+      reg:
+        maxItems: 1
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+  "^pil-reloc@[0-9a-f]+$":
+    $ref: /schemas/remoteproc/qcom,pil-info.yaml#
+    description: Peripheral image loader relocation region
+
+required:
+  - compatible
+  - reg
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - qcom,apq8064-imem
+              - qcom,msm8226-imem
+              - qcom,msm8974-imem
+    then:
+      properties:
+        reboot-mode:
+          patternProperties:
+            # Negative look-ahead to disallow unsupported modes. The '$' has to be
+            # part of lookahead group to work, instead of trailing outside of ().
+            "^mode-(?!(bootloader$|normal$|recovery$))": false
+    else:
+      properties:
+        reboot-mode: false
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        sram@146bf000 {
+            compatible = "qcom,sdm845-imem", "syscon", "simple-mfd";
+            reg = <0 0x146bf000 0 0x1000>;
+            ranges = <0 0 0x146bf000 0x1000>;
+
+            #address-cells = <1>;
+            #size-cells = <1>;
+
+            pil-reloc@94c {
+                compatible = "qcom,pil-reloc-info";
+                reg = <0x94c 0xc8>;
+            };
+        };
+    };
diff --git a/Documentation/devicetree/bindings/sram/qcom,ocmem.yaml b/Documentation/devicetree/bindings/sram/qcom,ocmem.yaml
new file mode 100644
index 000000000..61c784ef7
--- /dev/null
+++ b/Documentation/devicetree/bindings/sram/qcom,ocmem.yaml
@@ -0,0 +1,123 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sram/qcom,ocmem.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: On Chip Memory (OCMEM) that is present on some Qualcomm Snapdragon SoCs.
+
+maintainers:
+  - Brian Masney <masneyb@onstation.org>
+
+description: |
+  The On Chip Memory (OCMEM) is typically used by the GPU, camera/video, and
+  audio components on some Snapdragon SoCs.
+
+properties:
+  compatible:
+    enum:
+      - qcom,msm8226-ocmem  # v1.1.0
+      - qcom,msm8974-ocmem  # v1.4.0
+
+  reg:
+    items:
+      - description: Control registers
+      - description: OCMEM address range
+
+  reg-names:
+    items:
+      - const: ctrl
+      - const: mem
+
+  clocks:
+    minItems: 1
+    items:
+      - description: Core clock
+      - description: Interface clock
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: core
+      - const: iface
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+  ranges:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - clock-names
+  - '#address-cells'
+  - '#size-cells'
+  - ranges
+
+additionalProperties: false
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - qcom,msm8974-ocmem
+    then:
+      properties:
+        clocks:
+          minItems: 2
+        clock-names:
+          minItems: 2
+    else:
+      properties:
+        clocks:
+          minItems: 1
+        clock-names:
+          minItems: 1
+
+patternProperties:
+  "-sram@[0-9a-f]+$":
+    type: object
+    additionalProperties: false
+    description: A region of reserved memory.
+
+    properties:
+      reg:
+        maxItems: 1
+
+    required:
+      - reg
+
+examples:
+  - |
+    #include <dt-bindings/clock/qcom,rpmcc.h>
+    #include <dt-bindings/clock/qcom,mmcc-msm8974.h>
+
+    sram@fdd00000 {
+        compatible = "qcom,msm8974-ocmem";
+
+        reg = <0xfdd00000 0x2000>,
+              <0xfec00000 0x180000>;
+        reg-names = "ctrl",
+                    "mem";
+
+        clocks = <&rpmcc RPM_SMD_OCMEMGX_CLK>,
+                 <&mmcc OCMEMCX_OCMEMNOC_CLK>;
+        clock-names = "core",
+                      "iface";
+
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0xfec00000 0x100000>;
+
+        gmu-sram@0 {
+            reg = <0x0 0x100000>;
+        };
+    };
diff --git a/Documentation/devicetree/bindings/sram/sram-consumer.yaml b/Documentation/devicetree/bindings/sram/sram-consumer.yaml
new file mode 100644
index 000000000..f00087bd2
--- /dev/null
+++ b/Documentation/devicetree/bindings/sram/sram-consumer.yaml
@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sram/sram-consumer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SRAM Consumers
+
+maintainers:
+  - Rob Herring <robh@kernel.org>
+
+select: true
+
+properties:
+  sram:
+    description:
+      Phandles to one or more reserved on-chip SRAM regions. The regions
+      should be defined as child nodes of the respective SRAM node, and
+      should be defined as per the generic bindings in,
+      Documentation/devicetree/bindings/sram/sram.yaml
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      maxItems: 1
+
+additionalProperties: true
+...
diff --git a/Documentation/devicetree/bindings/sram/sram.yaml b/Documentation/devicetree/bindings/sram/sram.yaml
new file mode 100644
index 000000000..b83fc6831
--- /dev/null
+++ b/Documentation/devicetree/bindings/sram/sram.yaml
@@ -0,0 +1,315 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sram/sram.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic on-chip SRAM
+
+maintainers:
+  - Rob Herring <robh@kernel.org>
+
+description: |+
+  Simple IO memory regions to be managed by the genalloc API.
+
+  Each child of the sram node specifies a region of reserved memory. Each
+  child node should use a 'reg' property to specify a specific range of
+  reserved memory.
+
+  Following the generic-names recommended practice, node names should
+  reflect the purpose of the node. Unit address (@<address>) should be
+  appended to the name.
+
+properties:
+  $nodename:
+    pattern: "^sram(@.*)?"
+
+  compatible:
+    contains:
+      enum:
+        - mmio-sram
+        - amlogic,meson-gxbb-sram
+        - arm,juno-sram-ns
+        - atmel,sama5d2-securam
+        - nvidia,tegra186-sysram
+        - nvidia,tegra194-sysram
+        - nvidia,tegra234-sysram
+        - qcom,eliza-imem
+        - qcom,glymur-imem
+        - qcom,hawi-imem
+        - qcom,kaanapali-imem
+        - qcom,maili-imem
+        - qcom,milos-imem
+        - qcom,rpm-msg-ram
+        - qcom,shikra-imem
+        - rockchip,rk3288-pmu-sram
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+    description:
+      A list of phandle and clock specifier pair that controls the single
+      SRAM clock.
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 1
+
+  ranges:
+    maxItems: 1
+    description:
+      Should translate from local addresses within the sram to bus addresses.
+
+  no-memory-wc:
+    description:
+      The flag indicating, that SRAM memory region has not to be remapped
+      as write combining. WC is used by default.
+    type: boolean
+
+patternProperties:
+  "^([a-z0-9]+-)*sram(-section)?@[a-f0-9]+$":
+    type: object
+    description:
+      Each child of the sram node specifies a region of reserved memory.
+    properties:
+      compatible:
+        description:
+          Should contain a vendor specific string in the form
+          <vendor>,[<device>-]<usage>
+        contains:
+          enum:
+            - allwinner,sun4i-a10-sram-a3-a4
+            - allwinner,sun4i-a10-sram-c1
+            - allwinner,sun4i-a10-sram-d
+            - allwinner,sun9i-a80-smp-sram
+            - allwinner,sun50i-a64-sram-c
+            - allwinner,sun50i-h616-ve-sram
+            - amlogic,meson8-ao-arc-sram
+            - amlogic,meson8b-ao-arc-sram
+            - amlogic,meson8-smp-sram
+            - amlogic,meson8b-smp-sram
+            - amlogic,meson-gxbb-scp-shmem
+            - amlogic,meson-axg-scp-shmem
+            - arm,juno-scp-shmem
+            - arm,scmi-shmem
+            - arm,scp-shmem
+            - qcom,pil-reloc-info
+            - renesas,smp-sram
+            - rockchip,rk3066-smp-sram
+            - samsung,exynos4210-sysram
+            - samsung,exynos4210-sysram-ns
+            - socionext,milbeaut-smp-sram
+            - stericsson,u8500-esram
+
+      reg:
+        description:
+          IO mem address range, relative to the SRAM range.
+        maxItems: 1
+
+      reg-io-width:
+        description:
+          The size (in bytes) of the IO accesses that should be performed on the
+          SRAM.
+        enum: [1, 2, 4, 8]
+
+      pool:
+        description:
+          Indicates that the particular reserved SRAM area is addressable
+          and in use by another device or devices.
+        type: boolean
+
+      export:
+        description:
+          Indicates that the reserved SRAM area may be accessed outside
+          of the kernel, e.g. by bootloader or userspace.
+        type: boolean
+
+      protect-exec:
+        description: |
+          Same as 'pool' above but with the additional constraint that code
+          will be run from the region and that the memory is maintained as
+          read-only, executable during code execution. NOTE: This region must
+          be page aligned on start and end in order to properly allow
+          manipulation of the page attributes.
+        type: boolean
+
+      label:
+        description:
+          The name for the reserved partition, if omitted, the label is taken
+          from the node name excluding the unit address.
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+if:
+  not:
+    properties:
+      compatible:
+        contains:
+          enum:
+            - qcom,rpm-msg-ram
+            - rockchip,rk3288-pmu-sram
+then:
+  required:
+    - "#address-cells"
+    - "#size-cells"
+    - ranges
+
+additionalProperties: false
+
+examples:
+  - |
+    sram@5c000000 {
+        compatible = "mmio-sram";
+        reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
+
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0x5c000000 0x40000>;
+
+        smp-sram@100 {
+            reg = <0x100 0x50>;
+        };
+
+        device-sram@1000 {
+            reg = <0x1000 0x1000>;
+            pool;
+        };
+
+        exported-sram@20000 {
+            reg = <0x20000 0x20000>;
+            export;
+        };
+    };
+
+  - |
+    // Samsung SMP-capable Exynos SoCs use part of the SYSRAM for the bringup
+    // of the secondary cores. Once the core gets powered up it executes the
+    // code that is residing at some specific location of the SYSRAM.
+    //
+    // Therefore reserved section sub-nodes have to be added to the mmio-sram
+    // declaration. These nodes are of two types depending upon secure or
+    // non-secure execution environment.
+    sram@2020000 {
+        compatible = "mmio-sram";
+        reg = <0x02020000 0x54000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0x02020000 0x54000>;
+
+        smp-sram@0 {
+            compatible = "samsung,exynos4210-sysram";
+            reg = <0x0 0x1000>;
+        };
+
+        smp-sram@53000 {
+            compatible = "samsung,exynos4210-sysram-ns";
+            reg = <0x53000 0x1000>;
+        };
+    };
+
+  - |
+    // Amlogic's SMP-capable SoCs use part of the sram for the bringup of the cores.
+    // Once the core gets powered up it executes the code that is residing at a
+    // specific location.
+    //
+    // Therefore a reserved section sub-node has to be added to the mmio-sram
+    // declaration.
+    sram@d9000000 {
+        compatible = "mmio-sram";
+        reg = <0xd9000000 0x20000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0xd9000000 0x20000>;
+
+        smp-sram@1ff80 {
+            compatible = "amlogic,meson8b-smp-sram";
+            reg = <0x1ff80 0x8>;
+        };
+    };
+
+  - |
+    sram@e63c0000 {
+        compatible = "mmio-sram";
+        reg = <0xe63c0000 0x1000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0xe63c0000 0x1000>;
+
+        smp-sram@0 {
+            compatible = "renesas,smp-sram";
+            reg = <0 0x10>;
+        };
+    };
+
+  - |
+    sram@10080000 {
+        compatible = "mmio-sram";
+        reg = <0x10080000 0x10000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges;
+
+        smp-sram@10080000 {
+            compatible = "rockchip,rk3066-smp-sram";
+            reg = <0x10080000 0x50>;
+        };
+    };
+
+  - |
+    // Rockchip's rk3288 SoC uses the sram of pmu to store the function of
+    // resume from maskrom(the 1st level loader). This is a common use of
+    // the "pmu-sram" because it keeps power even in low power states
+    // in the system.
+    sram@ff720000 {
+      compatible = "rockchip,rk3288-pmu-sram", "mmio-sram";
+      reg = <0xff720000 0x1000>;
+    };
+
+  - |
+    // Allwinner's A80 SoC uses part of the secure sram for hotplugging of the
+    // primary core (cpu0). Once the core gets powered up it checks if a magic
+    // value is set at a specific location. If it is then the BROM will jump
+    // to the software entry address, instead of executing a standard boot.
+    //
+    // Also there are no "secure-only" properties. The implementation should
+    // check if this SRAM is usable first.
+    sram@20000 {
+        // 256 KiB secure SRAM at 0x20000
+        compatible = "mmio-sram";
+        reg = <0x00020000 0x40000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0x00020000 0x40000>;
+
+        smp-sram@1000 {
+            // This is checked by BROM to determine if
+            // cpu0 should jump to SMP entry vector
+            compatible = "allwinner,sun9i-a80-smp-sram";
+            reg = <0x1000 0x8>;
+        };
+    };
+
+  - |
+    sram@0 {
+        compatible = "mmio-sram";
+        reg = <0x0 0x10000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0x0 0x10000>;
+
+        smp-sram@f100 {
+            compatible = "socionext,milbeaut-smp-sram";
+            reg = <0xf100 0x20>;
+        };
+    };