powerpc: Move cache line size to rtld_global_ro

GCC 10.0 enabled -fno-common by default and this started to point that
__cache_line_size had been implemented in 2 different places: loader and
libc.

In order to avoid this duplication, the libc variable has been removed
and the loader variable is moved to rtld_global_ro.

File sysdeps/unix/sysv/linux/powerpc/dl-auxv.h has been added in order
to reuse code for both static and dynamic linking scenarios.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

3 files changed, 39 insertions, 9 deletions

diff --git a/sysdeps/powerpc/powerpc64/a2/memcpy.S b/sysdeps/powerpc/powerpc64/a2/memcpy.S
index 0e3c435f3c..1162cc2207 100644
--- a/sysdeps/powerpc/powerpc64/a2/memcpy.S
+++ b/sysdeps/powerpc/powerpc64/a2/memcpy.S
@@ -18,6 +18,7 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sysdep.h>
+#include <rtld-global-offsets.h>
 
 #ifndef MEMCPY
 # define MEMCPY memcpy
@@ -27,8 +28,9 @@
 #define ZERO_AHEAD 2            /* no cache lines DST zeroing ahead  */
 
 	.section        ".toc","aw"
-.LC0:
-	.tc __cache_line_size[TC],__cache_line_size
+__GLRO_DEF(dl_cache_line_size)
+
+
 	.section        ".text"
 	.align 2
 
@@ -55,10 +57,11 @@ ENTRY (MEMCPY, 5)
 	*/
 
 	neg     r8,r3           /* LS 4 bits = # bytes to 8-byte dest bdry  */
-	ld      r9,.LC0@toc(r2) /* Get cache line size (part 1) */
+	/* Get the cache line size.  */
+	__GLRO (r9, dl_cache_line_size,
+		RTLD_GLOBAL_RO_DL_CACHE_LINE_SIZE_OFFSET)
 	clrldi  r8,r8,64-4      /* align to 16byte boundary  */
 	sub     r7,r4,r3        /* compute offset to src from dest */
-	lwz     r9,0(r9)        /* Get cache line size (part 2) */
 	cmpldi  cr0,r8,0        /* Were we aligned on a 16 byte bdy? */
 	addi    r10,r9,-1       /* Cache line mask */
 	beq+    L(dst_aligned)
@@ -121,7 +124,7 @@ L(dst_aligned):
 	cmpdi	cr0,r9,0	/* Cache line size set? */
 	bne+	cr0,L(cachelineset)
 
-/* __cache_line_size not set: generic byte copy without much optimization */
+/* Cache line size not set: generic byte copy without much optimization */
 	clrldi.	r0,r5,63	/* If length is odd copy one byte */
 	beq	L(cachelinenotset_align)
 	lbz	r7,0(r4)	/* Read one byte from source */
diff --git a/sysdeps/powerpc/powerpc64/memset.S b/sysdeps/powerpc/powerpc64/memset.S
index 857c023755..2fa98e6e2d 100644
--- a/sysdeps/powerpc/powerpc64/memset.S
+++ b/sysdeps/powerpc/powerpc64/memset.S
@@ -17,10 +17,11 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sysdep.h>
+#include <rtld-global-offsets.h>
 
 	.section	".toc","aw"
-.LC0:
-	.tc __cache_line_size[TC],__cache_line_size
+__GLRO_DEF(dl_cache_line_size)
+
 	.section	".text"
 	.align 2
 
@@ -146,8 +147,10 @@ L(zloopstart):
 /* If the remaining length is less the 32 bytes, don't bother getting
 	 the cache line size.  */
 	beq	L(medium)
-	ld	rCLS,.LC0@toc(r2)
-	lwz	rCLS,0(rCLS)
+	/* Read the cache line size.  */
+	__GLRO (rCLS, dl_cache_line_size,
+		RTLD_GLOBAL_RO_DL_CACHE_LINE_SIZE_OFFSET)
+
 /* If the cache line size was not set just goto to L(nondcbz) which is
 	 safe for any cache line size.  */
 	cmpldi	cr1,rCLS,0
diff --git a/sysdeps/powerpc/powerpc64/sysdep.h b/sysdeps/powerpc/powerpc64/sysdep.h
index aefd29a14d..d6616ac905 100644
--- a/sysdeps/powerpc/powerpc64/sysdep.h
+++ b/sysdeps/powerpc/powerpc64/sysdep.h
@@ -342,6 +342,30 @@ LT_LABELSUFFIX(name,_name_end): ; \
 #define	PSEUDO_END_ERRVAL(name) \
   END (name)
 
+#ifdef SHARED
+# if IS_IN (rtld)
+	 /* Inside ld.so we use the local alias to avoid runtime GOT
+	    relocations.  */
+#  define __GLRO_DEF(var)				\
+.LC__ ## var:						\
+	.tc _rtld_local_ro[TC],_rtld_local_ro
+# else
+#  define __GLRO_DEF(var)				\
+.LC__ ## var:						\
+	.tc _rtld_global_ro[TC],_rtld_global_ro
+# endif
+# define __GLRO(rOUT, var, offset)		\
+	ld	rOUT,.LC__ ## var@toc(r2);	\
+	lwz	rOUT,offset(rOUT)
+#else
+# define __GLRO_DEF(var)			\
+.LC__ ## var:					\
+	.tc _ ## var[TC],_ ## var
+# define __GLRO(rOUT, var, offset)		\
+	ld	rOUT,.LC__ ## var@toc(r2);	\
+	lwz	rOUT,0(rOUT)
+#endif
+
 #else /* !__ASSEMBLER__ */
 
 #if _CALL_ELF != 2