powerpc: Don't change the section in _GLOBAL()

Currently the _GLOBAL() macro unilaterally sets the assembler section to
".text" at the start of the macro. This is rude as the caller may be
using a different section.

So let the caller decide which section to emit the code into. On big
endian we do need to switch to the ".opd" section to emit the OPD, but
do that with pushsection/popsection, thereby leaving the original
section intact.

I verified that the order of all entries in System.map is unchanged
after this patch. The actual addresses shift around slightly so you
can't just diff the System.map.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/ppc_asm.h

@@ -201,14 +201,12 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
 #ifdef PPC64_ELF_ABI_v2
 
 #define _GLOBAL(name) \
-	.section ".text"; \
 	.align 2 ; \
 	.type name,@function; \
 	.globl name; \
 name:
 
 #define _GLOBAL_TOC(name) \
-	.section ".text"; \
 	.align 2 ; \
 	.type name,@function; \
 	.globl name; \
@@ -225,16 +223,15 @@ name: \
 #define GLUE(a,b) XGLUE(a,b)
 
 #define _GLOBAL(name) \
-	.section ".text"; \
 	.align 2 ; \
 	.globl name; \
 	.globl GLUE(.,name); \
-	.section ".opd","aw"; \
+	.pushsection ".opd","aw"; \
 name: \
 	.quad GLUE(.,name); \
 	.quad .TOC.@tocbase; \
 	.quad 0; \
-	.previous; \
+	.popsection; \
 	.type GLUE(.,name),@function; \
 GLUE(.,name):
 
@@ -251,7 +248,6 @@ GLUE(.,name):
 n:
 
 #define _GLOBAL(n)	\
-	.text;		\
 	.stabs __stringify(n:F-1),N_FUN,0,0,n;\
 	.globl n;	\
 n: