From f5cf70d9d1dc7f4cbeffb7fb75cbbe08720e3873 Mon Sep 17 00:00:00 2001
From: Gustavo Romero <gromero@br.ibm.com>
Date: Sun, 26 Mar 2017 15:08:15 +0000
Subject: [PATCH] Remove dependency on glibc on PPC

Remove dependency on glibc by using gcc builtin function and no glibc
wrappers.

Currently there are no surrogates in musl for:

  __ppc_get_timebase()
  __ppc_set_ppr_low()
  __ppc_set_ppr_med()

however glibc __ppc_get_timebase() is just a wrapper for GCC builtin
__builtin_get_timebase() available since GCC 4.8 [1], so assuming that
aports on ppc64le will never be built using GCC < 4.8 we can just
switch directly to the GCC builtin function.

Also __ppc_set_ppr_{low,med}() are not available on musl but both
are simple glibc wrappers on a single asm instruction, hence there
is no harm in using asm directly instead. Actually, using asm
directly was the first solution adopted in MariaDB [2].

[1] https://goo.gl/jxLV6O
[2] https://goo.gl/9bjuVC

--- a/storage/xtradb/include/ut0ut.h
+++ b/storage/xtradb/include/ut0ut.h
@@ -85,9 +85,8 @@
    the YieldProcessor macro defined in WinNT.h. It is a CPU architecture-
    independent way by using YieldProcessor. */
 #  define UT_RELAX_CPU() YieldProcessor()
-# elif defined(__powerpc__) && defined __GLIBC__
-#include <sys/platform/ppc.h>
-#  define UT_RELAX_CPU() __ppc_get_timebase()
+# elif defined(__powerpc__)
+#  define UT_RELAX_CPU() __builtin_ppc_get_timebase()
 # else
 #  define UT_RELAX_CPU() ((void)0) /* avoid warning for an empty statement */
 # endif
@@ -101,9 +100,8 @@
 #endif
 
 # if defined(HAVE_HMT_PRIORITY_INSTRUCTION)
-#include <sys/platform/ppc.h>
-#  define UT_LOW_PRIORITY_CPU() __ppc_set_ppr_low()
-#  define UT_RESUME_PRIORITY_CPU() __ppc_set_ppr_med()
+#  define UT_LOW_PRIORITY_CPU() __asm__ __volatile__ ("or 1,1,1")
+#  define UT_RESUME_PRIORITY_CPU() __asm__ __volatile__ ("or 2,2,2")
 # else
 #  define UT_LOW_PRIORITY_CPU() ((void)0)
 #  define UT_RESUME_PRIORITY_CPU() ((void)0)
--- a/storage/innobase/include/ut0ut.h
+++ b/storage/innobase/include/ut0ut.h
@@ -70,9 +70,8 @@
    the YieldProcessor macro defined in WinNT.h. It is a CPU architecture-
    independent way by using YieldProcessor. */
 # define UT_RELAX_CPU() YieldProcessor()
-#elif defined(__powerpc__) && defined __GLIBC__
-# include <sys/platform/ppc.h>
-# define UT_RELAX_CPU() __ppc_get_timebase()
+#elif defined(__powerpc__)
+# define UT_RELAX_CPU() __builtin_ppc_get_timebase()
 #else
 # define UT_RELAX_CPU() do { \
      volatile int32	volatile_var; \
@@ -90,9 +89,8 @@
 #endif
 
 #if defined(HAVE_HMT_PRIORITY_INSTRUCTION)
-# include <sys/platform/ppc.h>
-# define UT_LOW_PRIORITY_CPU() __ppc_set_ppr_low()
-# define UT_RESUME_PRIORITY_CPU() __ppc_set_ppr_med()
+# define UT_LOW_PRIORITY_CPU() __asm__  __volatile__ ("or 1,1,1")
+# define UT_RESUME_PRIORITY_CPU() __asm__ __volatile__ ("or 2,2,2")
 #else
 # define UT_LOW_PRIORITY_CPU() ((void)0)
 # define UT_RESUME_PRIORITY_CPU() ((void)0)