arm64: add module support for alternatives fixups

Currently the kernel patches all necessary instructions once at boot
time, so modules are not covered by this.
Change the apply_alternatives() function to take a beginning and an
end pointer and introduce a new variant (apply_alternatives_all()) to
cover the existing use case for the static kernel image section.
Add a module_finalize() function to arm64 to check for an
alternatives section in a module and patch only the instructions from
that specific area.
Since that module code is not touched before the module
initialization has ended, we don't need to halt the machine before
doing the patching in the module's code.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h
index f6d206e7f9e9..d261f01e2bae 100644
--- a/arch/arm64/include/asm/alternative.h
+++ b/arch/arm64/include/asm/alternative.h
@@ -13,7 +13,8 @@ struct alt_instr {
         u8  alt_len;            /* size of new instruction(s), <= orig_len */
 };
 
-void apply_alternatives(void);
+void apply_alternatives_all(void);
+void apply_alternatives(void *start, size_t length);
 void free_alternatives_memory(void);
 
 #define ALTINSTR_ENTRY(feature)                                               \