diff --git a/libexec/rtld-elf/powerpc/rtld_machdep.h b/libexec/rtld-elf/powerpc/rtld_machdep.h
index c89ec4817401..4e7854d34661 100644
--- a/libexec/rtld-elf/powerpc/rtld_machdep.h
+++ b/libexec/rtld-elf/powerpc/rtld_machdep.h
@@ -69,12 +69,12 @@ void _rtld_powerpc_pltcall(void);
 
 #define TLS_TP_OFFSET	0x7000
 #define TLS_DTV_OFFSET	0x8000
-#define TLS_TCB_SIZE	8
+#define TLS_TCB_SIZE	16
 
 #define round(size, align) \
     (((size) + (align) - 1) & ~((align) - 1))
 #define calculate_first_tls_offset(size, align) \
-    TLS_TCB_SIZE
+    round(8, align)
 #define calculate_tls_offset(prev_offset, prev_size, size, align) \
     round(prev_offset + prev_size, align)
 #define calculate_tls_end(off, size)    ((off) + (size))