Revert "arm64/alternatives: use subsections for replacement sequences"

This reverts commit d6d9145866 which is
commit f7b93d4294 upstream as it makes
clang go boom in the build systems :(

Cc: Will Deacon <willdeacon@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I082c05e3d9cc00fd7173897a7c89c56aecf7facb

arch/arm64/include/asm/alternative.h

@@ -73,11 +73,11 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
 	".pushsection .altinstructions,\"a\"\n"				\
 	ALTINSTR_ENTRY(feature)						\
 	".popsection\n"							\
-	".subsection 1\n"						\
+	".pushsection .altinstr_replacement, \"a\"\n"			\
 	"663:\n\t"							\
 	newinstr "\n"							\
 	"664:\n\t"							\
-	".previous\n\t"							\
+	".popsection\n\t"						\
 	".org	. - (664b-663b) + (662b-661b)\n\t"			\
 	".org	. - (662b-661b) + (664b-663b)\n"			\
 	".endif\n"
@@ -117,9 +117,9 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
 662:	.pushsection .altinstructions, "a"
 	altinstruction_entry 661b, 663f, \cap, 662b-661b, 664f-663f
 	.popsection
-	.subsection 1
+	.pushsection .altinstr_replacement, "ax"
 663:	\insn2
-664:	.previous
+664:	.popsection
 	.org	. - (664b-663b) + (662b-661b)
 	.org	. - (662b-661b) + (664b-663b)
 	.endif
@@ -160,7 +160,7 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
 	.pushsection .altinstructions, "a"
 	altinstruction_entry 663f, 661f, \cap, 664f-663f, 662f-661f
 	.popsection
-	.subsection 1
+	.pushsection .altinstr_replacement, "ax"
 	.align 2	/* So GAS knows label 661 is suitably aligned */
 661:
 .endm
@@ -179,9 +179,9 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
 .macro alternative_else
 662:
 	.if .Lasm_alt_mode==0
-	.subsection 1
+	.pushsection .altinstr_replacement, "ax"
 	.else
-	.previous
+	.popsection
 	.endif
 663:
 .endm
@@ -192,7 +192,7 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
 .macro alternative_endif
 664:
 	.if .Lasm_alt_mode==0
-	.previous
+	.popsection
 	.endif
 	.org	. - (664b-663b) + (662b-661b)
 	.org	. - (662b-661b) + (664b-663b)

arch/arm64/kernel/vmlinux.lds.S

@@ -154,6 +154,9 @@ SECTIONS
 		*(.altinstructions)
 		__alt_instructions_end = .;
 	}
+	.altinstr_replacement : {
+		*(.altinstr_replacement)
+	}
 
 	. = ALIGN(PAGE_SIZE);
 	__inittext_end = .;