arm64: mm: fold alternatives into .init
Currently we treat the alternatives separately from other data that's
only used during initialisation, using separate .altinstructions and
.altinstr_replacement linker sections. These are freed for general
allocation separately from .init*. This is problematic as:
* We do not remove execute permissions, as we do for .init, leaving the
memory executable.
* We pad between them, making the kernel Image bianry up to PAGE_SIZE
bytes larger than necessary.
This patch moves the two sections into the contiguous region used for
.init*. This saves some memory, ensures that we remove execute
permissions, and allows us to remove some code made redundant by this
reorganisation.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index a64340d..f943a84 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -140,9 +140,6 @@
PERCPU_SECTION(64)
- . = ALIGN(PAGE_SIZE);
- __init_end = .;
-
. = ALIGN(4);
.altinstructions : {
__alt_instructions = .;
@@ -154,6 +151,8 @@
}
. = ALIGN(PAGE_SIZE);
+ __init_end = .;
+
_data = .;
_sdata = .;
RW_DATA_SECTION(64, PAGE_SIZE, THREAD_SIZE)