Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "Mostly refactoring/clean-up:

   - CPU ops and PSCI (Power State Coordination Interface) refactoring
     following the merging of the arm64 ACPI support, together with
     handling of Trusted (secure) OS instances

   - Using fixmap for permanent FDT mapping, removing the initial dtb
     placement requirements (within 512MB from the start of the kernel
     image).  This required moving the FDT self reservation out of the
     memreserve processing

   - Idmap (1:1 mapping used for MMU on/off) handling clean-up

   - Removing flush_cache_all() - not safe on ARM unless the MMU is off.
     Last stages of CPU power down/up are handled by firmware already

   - "Alternatives" (run-time code patching) refactoring and support for
     immediate branch patching, GICv3 CPU interface access

   - User faults handling clean-up

  And some fixes:

   - Fix for VDSO building with broken ELF toolchains

   - Fix another case of init_mm.pgd usage for user mappings (during
     ASID roll-over broadcasting)

   - Fix for FPSIMD reloading after CPU hotplug

   - Fix for missing syscall trace exit

   - Workaround for .inst asm bug

   - Compat fix for switching the user tls tpidr_el0 register"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (42 commits)
  arm64: use private ratelimit state along with show_unhandled_signals
  arm64: show unhandled SP/PC alignment faults
  arm64: vdso: work-around broken ELF toolchains in Makefile
  arm64: kernel: rename __cpu_suspend to keep it aligned with arm
  arm64: compat: print compat_sp instead of sp
  arm64: mm: Fix freeing of the wrong memmap entries with !SPARSEMEM_VMEMMAP
  arm64: entry: fix context tracking for el0_sp_pc
  arm64: defconfig: enable memtest
  arm64: mm: remove reference to tlb.S from comment block
  arm64: Do not attempt to use init_mm in reset_context()
  arm64: KVM: Switch vgic save/restore to alternative_insn
  arm64: alternative: Introduce feature for GICv3 CPU interface
  arm64: psci: fix !CONFIG_HOTPLUG_CPU build warning
  arm64: fix bug for reloading FPSIMD state after CPU hotplug.
  arm64: kernel thread don't need to save fpsimd context.
  arm64: fix missing syscall trace exit
  arm64: alternative: Work around .inst assembler bugs
  arm64: alternative: Merge alternative-asm.h into alternative.h
  arm64: alternative: Allow immediate branch as alternative instruction
  arm64: Rework alternate sequence for ARM erratum 845719
  ...

1 files changed, 6 insertions, 4 deletions

diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt
index f3c05b5f9f08..1690350f16e7 100644
--- a/Documentation/arm64/booting.txt
+++ b/Documentation/arm64/booting.txt
@@ -45,11 +45,13 @@ sees fit.)
 
 Requirement: MANDATORY
 
-The device tree blob (dtb) must be placed on an 8-byte boundary within
-the first 512 megabytes from the start of the kernel image and must not
-cross a 2-megabyte boundary. This is to allow the kernel to map the
-blob using a single section mapping in the initial page tables.
+The device tree blob (dtb) must be placed on an 8-byte boundary and must
+not exceed 2 megabytes in size. Since the dtb will be mapped cacheable
+using blocks of up to 2 megabytes in size, it must not be placed within
+any 2M region which must be mapped with any specific attributes.
 
+NOTE: versions prior to v4.2 also require that the DTB be placed within
+the 512 MB region starting at text_offset bytes below the kernel Image.
 
 3. Decompress the kernel image
 ------------------------------