arm64: add alternative runtime patching

With a blatant copy of some x86 bits we introduce the alternative
runtime patching "framework" to arm64.
This is quite basic for now and we only provide the functions we need
at this time.
This is connected to the newly introduced feature bits.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 4596f46d0244..3236727be2b9 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -116,6 +116,17 @@ SECTIONS
         . = ALIGN(PAGE_SIZE);
         __init_end = .;
 
+        . = ALIGN(4);
+        .altinstructions : {
+                __alt_instructions = .;
+                *(.altinstructions)
+                __alt_instructions_end = .;
+        }
+        .altinstr_replacement : {
+                *(.altinstr_replacement)
+        }
+
+        . = ALIGN(PAGE_SIZE);
         _data = .;
         _sdata = .;
         RW_DATA_SECTION(64, PAGE_SIZE, THREAD_SIZE)