Merge branches 'for-next/gcs', 'for-next/probes', 'for-next/asm-offsets', 'for-next...

[linux.git] / Documentation / arch / arm64 / booting.rst

diff --git a/Documentation/arch/arm64/booting.rst b/Documentation/arch/arm64/booting.rst
index b57776a68f156d0be28a73c6036073494f3961e0..938781f59468c8e3364621722510af3fe4f4182e 100644 (file)
--- a/Documentation/arch/arm64/booting.rst
+++ b/Documentation/arch/arm64/booting.rst
@@ -41,6 +41,9 @@ to automatically locate and size all RAM, or it may use knowledge of
 the RAM in the machine, or any other method the boot loader designer
 sees fit.)
 
+For Arm Confidential Compute Realms this includes ensuring that all
+protected RAM has a Realm IPA state (RIPAS) of "RAM".
+
 
 2. Setup the device tree
 -------------------------
@@ -411,6 +414,38 @@ Before jumping into the kernel, the following conditions must be met:
 
     - HFGRWR_EL2.nPIRE0_EL1 (bit 57) must be initialised to 0b1.
 
+ - For CPUs with Guarded Control Stacks (FEAT_GCS):
+
+  - GCSCR_EL1 must be initialised to 0.
+
+  - GCSCRE0_EL1 must be initialised to 0.
+
+  - If EL3 is present:
+
+    - SCR_EL3.GCSEn (bit 39) must be initialised to 0b1.
+
+  - If EL2 is present:
+
+    - GCSCR_EL2 must be initialised to 0.
+
+ - If the kernel is entered at EL1 and EL2 is present:
+
+    - HCRX_EL2.GCSEn must be initialised to 0b1.
+
+    - HFGITR_EL2.nGCSEPP (bit 59) must be initialised to 0b1.
+
+    - HFGITR_EL2.nGCSSTR_EL1 (bit 58) must be initialised to 0b1.
+
+    - HFGITR_EL2.nGCSPUSHM_EL1 (bit 57) must be initialised to 0b1.
+
+    - HFGRTR_EL2.nGCS_EL1 (bit 53) must be initialised to 0b1.
+
+    - HFGRTR_EL2.nGCS_EL0 (bit 52) must be initialised to 0b1.
+
+    - HFGWTR_EL2.nGCS_EL1 (bit 53) must be initialised to 0b1.
+
+    - HFGWTR_EL2.nGCS_EL0 (bit 52) must be initialised to 0b1.
+
 The requirements described above for CPU mode, caches, MMUs, architected
 timers, coherency and system registers apply to all CPUs.  All CPUs must
 enter the kernel in the same exception level.  Where the values documented