Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide

[karo-tx-linux.git] / Documentation / arm64 / booting.txt

diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt
index 1690350f16e77beb441efee1d797576087edd612..369a4f48eb0dac3c80d5f22054fc4b02f1006f28 100644 (file)
--- a/Documentation/arm64/booting.txt
+++ b/Documentation/arm64/booting.txt
@@ -81,7 +81,7 @@ The decompressed kernel image contains a 64-byte header as follows:
   u64 res3     = 0;            /* reserved */
   u64 res4     = 0;            /* reserved */
   u32 magic    = 0x644d5241;   /* Magic number, little endian, "ARM\x64" */
-  u32 res5;                    /* reserved (used for PE COFF offset) */
+  u32 res5;                    /* reserved (used for PE COFF offset) */
 
 
 Header notes:
@@ -103,7 +103,7 @@ Header notes:
 
 - The flags field (introduced in v3.17) is a little-endian 64-bit field
   composed as follows:
-  Bit 0:       Kernel endianness.  1 if BE, 0 if LE.
+  Bit 0:       Kernel endianness.  1 if BE, 0 if LE.
   Bits 1-63:   Reserved.
 
 - When image_size is zero, a bootloader should attempt to keep as much
@@ -115,11 +115,14 @@ The Image must be placed text_offset bytes from a 2MB aligned base
 address near the start of usable system RAM and called there. Memory
 below that base address is currently unusable by Linux, and therefore it
 is strongly recommended that this location is the start of system RAM.
+The region between the 2 MB aligned base address and the start of the
+image has no special significance to the kernel, and may be used for
+other purposes.
 At least image_size bytes from the start of the image must be free for
 use by the kernel.
 
-Any memory described to the kernel (even that below the 2MB aligned base
-address) which is not marked as reserved from the kernel e.g. with a
+Any memory described to the kernel (even that below the start of the
+image) which is not marked as reserved from the kernel (e.g., with a
 memreserve region in the device tree) will be considered as available to
 the kernel.
 
@@ -170,13 +173,22 @@ Before jumping into the kernel, the following conditions must be met:
   the kernel image will be entered must be initialised by software at a
   higher exception level to prevent execution in an UNKNOWN state.
 
-  For systems with a GICv3 interrupt controller:
+  For systems with a GICv3 interrupt controller to be used in v3 mode:
   - If EL3 is present:
     ICC_SRE_EL3.Enable (bit 3) must be initialiased to 0b1.
     ICC_SRE_EL3.SRE (bit 0) must be initialised to 0b1.
   - If the kernel is entered at EL1:
     ICC.SRE_EL2.Enable (bit 3) must be initialised to 0b1
     ICC_SRE_EL2.SRE (bit 0) must be initialised to 0b1.
+  - The DT or ACPI tables must describe a GICv3 interrupt controller.
+
+  For systems with a GICv3 interrupt controller to be used in
+  compatibility (v2) mode:
+  - If EL3 is present:
+    ICC_SRE_EL3.SRE (bit 0) must be initialised to 0b0.
+  - If the kernel is entered at EL1:
+    ICC_SRE_EL2.SRE (bit 0) must be initialised to 0b0.
+  - The DT or ACPI tables must describe a GICv2 interrupt controller.
 
 The requirements described above for CPU mode, caches, MMUs, architected
 timers, coherency and system registers apply to all CPUs.  All CPUs must