Add private_function for private functions within glibc [BZ #21598]

USE_REGPARMS in config.h.in is only used to control how parameters are
passed for internal functions on i386.  On i386, we define

 #define internal_function __attribute__ ((regparm (3), stdcall))

so that we pass up to 3 integer parameters in registers for internal
functuons on i386.  i386 has

_dl_runtime_resolve:

        movl (%esp), %ecx
        movl %eax, (%esp)       # Store the function address.
        movl 4(%esp), %eax
        ret $12                 # Jump to function address.

which is incompatible with Shadow Stack in Intel Control-flow Enforcement
Technology (CET) instructions:

https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf

since shadow stack doesn't match return stack.  We need to use register
indirect branch via %ecx.  That means only 2 parameters can be passed
in registers for external function calls with lazy binding when shadow
stack is enabled.  However, internal_function, which should be used only
with hidden function within libc.so, are also used with private function
calls between different shared objects of glibc.

This patch removes USE_REGPARMS and internal_function from config.h.in.
It adds a new header file, function-attrs.h, to define internal_function
and private_function, which is for private function calls between
different shared objects.  Currently, sysdeps/i386/function-attrs.h
defines private_function as

 #define private_function __attribute__ ((regparm (3), stdcall))

There is no change in shared objects on Linux/i686 nor Linux/x86_64.

When shadow stack is enabled, private_function will be defined as

 #define private_function __attribute__ ((regparm (2), stdcall))

so that %ecx can be used as scratch register by _dl_runtime_resolve.

	[BZ #21598]
	* config.h.in (USE_REGPARMS): Removed.
	(internal_function): Likewise.
	* debug/fortify_fail.c (__fortify_fail): Replace internal_function
	with private_function.
	* elf/dl-addr.c (_dl_addr): Likewise.
	* elf/dl-error-skeleton.c (_dl_signal_error): Likewise.
	(_dl_catch_error): Likewise.
	* elf/dl-execstack.c (_dl_make_stack_executable): Likewise.
	* elf/dl-load.c (_dl_rtld_di_serinfo): Likewise.
	* elf/dl-open.c (_dl_find_dso_for_object): Likewise.
	* elf/dl-support.c (_dl_make_stack_executable_hook): Likewise.
	* elf/dl-sym.c (_dl_vsym): Likewise.
	(_dl_sym): Likewise.
	* elf/dl-tls.c (_dl_get_tls_static_info): Likewise.
	(_dl_allocate_tls_init): Likewise.
	(_dl_allocate_tls): Likewise.
	(_dl_deallocate_tls): Likewise.
	* grp/grp-merge.c (__copy_grp): Likewise.
	(__merge_grp): Likewise.
	* grp/grp-merge.h (__copy_grp): Likewise.
	(__merge_grp): Likewise.
	* include/dlfcn.h (_dl_addr): Likewise.
	(_dl_sym): Likewise.
	(_dl_vsym): Likewise.
	* include/rpc/pmap_clnt.h (__libc_rpc_getport): Likewise.
	* include/stdio.h (__fortify_fail): Likewise.
	* include/stdlib.h (__strtof_nan): Likewise.
	(__strtod_nan): Likewise.
	(__strtold_nan): Likewise.
	(__wcstof_nan): Likewise.
	(__wcstod_nan): Likewise.
	(__wcstold_nan): Likewise.
	(__strtof128_nan): Likewise.
	(__wcstof128_nan): Likewise.
	* nptl/allocatestack.c (__make_stacks_executable): Likewise.
	* nptl/libc_pthread_init.c (__libc_pthread_init): Likewise.
	* nptl/pthreadP.h (__make_stacks_executable): Likewise.
	(__libc_pthread_init): Likewise.
	* nss/XXX-lookup.c (DB_LOOKUP_FCT): Likewise.
	(DB_COMPAT_FCT): Likewise.
	* nss/getXXbyYY_r.c (DB_LOOKUP_FCT): Likewise.
	* nss/getXXent_r.c (DB_LOOKUP_FCT): Likewise.
	* nss/nsswitch.h (db_lookup_function): Likewise.
	* resolv/gai_misc.h (__gai_sigqueue): Likewise.
	* resolv/gai_sigqueue.c (__gai_sigqueue): Likewise.
	* stdlib/strtod_nan_main.c (STRTOD_NAN): Likewise.
	* sunrpc/pm_getport.c (__libc_rpc_getport): Likewise.
	* sysdeps/generic/ldsodefs.h (_dl_make_stack_executable_hook):
	Likewise.
	(_dl_make_stack_executable): Likewise.
	(_dl_signal_error): Likewise.
	(_dl_catch_error): Likewise.
	(_dl_rtld_di_serinfo): Likewise.
	(_dl_allocate_tls): Likewise.
	(_dl_get_tls_static_info): Likewise.
	(_dl_allocate_tls_init): Likewise.
	(_dl_deallocate_tls): Likewise.
	(_dl_find_dso_for_object): Likewise.
	* sysdeps/unix/sysv/linux/dl-execstack.c
	(_dl_make_stack_executable): Likewise.
	* sysdeps/unix/sysv/linux/gai_sigqueue.c (__gai_sigqueue):
	Likewise.
	* sysdeps/unix/sysv/linux/netlink_assert_response.c
	(__netlink_assert_response): Likewise.
	* sysdeps/unix/sysv/linux/netlinkaccess.h
	(__netlink_assert_response): Likewise.
	* include/libc-symbols.h (internal_function): Removed.
	Include <function-attrs.h>.
	* sysdeps/generic/function-attrs.h: New file.
	* sysdeps/i386/function-attrs.h: Likewise.
	* sysdeps/i386/configure.ac (USE_REGPARMS): Removed.
	* sysdeps/i386/configure: Regenerated.

37 files changed, 120 insertions, 83 deletions

diff --git a/config.h.in b/config.h.in
index 22418576a0..31343ab8df 100644
--- a/config.h.in
+++ b/config.h.in
@@ -47,10 +47,6 @@
 #undef	STACK_PROTECTOR_LEVEL
 #endif
 
-/* Define if the regparm attribute shall be used for local functions
-   (gcc on ix86 only).  */
-#undef	USE_REGPARMS
-
 /* Defined on SPARC if GCC emits GOTDATA relocations.  */
 #undef  HAVE_GCC_GOTDATA
 
@@ -99,13 +95,6 @@
 /* AArch64 big endian ABI */
 #undef HAVE_AARCH64_BE
 
-
-/* Defined to some form of __attribute__ ((...)) if the compiler supports
-   a different, more efficient calling convention.  */
-#if defined USE_REGPARMS && !defined PROF
-# define internal_function __attribute__ ((regparm (3), stdcall))
-#endif
-
 /* Linux specific: minimum supported kernel version.  */
 #undef	__LINUX_KERNEL_VERSION
 
diff --git a/debug/fortify_fail.c b/debug/fortify_fail.c
index a0777ae570..0987269bf8 100644
--- a/debug/fortify_fail.c
+++ b/debug/fortify_fail.c
@@ -38,7 +38,7 @@ __fortify_fail_abort (_Bool need_backtrace, const char *msg)
 }
 
 void
-__attribute__ ((noreturn)) internal_function
+__attribute__ ((noreturn)) private_function
 __fortify_fail (const char *msg)
 {
   __fortify_fail_abort (true, msg);
diff --git a/elf/dl-addr.c b/elf/dl-addr.c
index 1fac63d1a9..edd42be629 100644
--- a/elf/dl-addr.c
+++ b/elf/dl-addr.c
@@ -121,7 +121,7 @@ determine_info (const ElfW(Addr) addr, struct link_map *match, Dl_info *info,
 
 
 int
-internal_function
+private_function
 _dl_addr (const void *address, Dl_info *info,
 	  struct link_map **mapp, const ElfW(Sym) **symbolp)
 {
diff --git a/elf/dl-error-skeleton.c b/elf/dl-error-skeleton.c
index 8de6c87abf..f0be41795a 100644
--- a/elf/dl-error-skeleton.c
+++ b/elf/dl-error-skeleton.c
@@ -104,7 +104,7 @@ _dl_signal_exception (int errcode, struct dl_exception *exception,
 libc_hidden_def (_dl_signal_exception)
 
 void
-internal_function
+private_function
 _dl_signal_error (int errcode, const char *objname, const char *occation,
 		  const char *errstring)
 {
@@ -210,7 +210,7 @@ _dl_catch_exception (struct dl_exception *exception,
 libc_hidden_def (_dl_catch_exception)
 
 int
-internal_function
+private_function
 _dl_catch_error (const char **objname, const char **errstring,
 		 bool *mallocedp, void (*operate) (void *), void *args)
 {
diff --git a/elf/dl-execstack.c b/elf/dl-execstack.c
index 875338bea5..c83de345a1 100644
--- a/elf/dl-execstack.c
+++ b/elf/dl-execstack.c
@@ -23,7 +23,7 @@
    so as to mprotect it.  */
 
 int
-internal_function
+private_function
 _dl_make_stack_executable (void **stack_endp)
 {
   return ENOSYS;
diff --git a/elf/dl-load.c b/elf/dl-load.c
index c1b6d4ba0f..14cf164bd2 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -2241,7 +2241,7 @@ add_path (struct add_path_state *p, const struct r_search_path_struct *sps,
 }
 
 void
-internal_function
+private_function
 _dl_rtld_di_serinfo (struct link_map *loader, Dl_serinfo *si, bool counting)
 {
   if (counting)
diff --git a/elf/dl-open.c b/elf/dl-open.c
index 91a1d1a4f8..6d3de83e5a 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -162,7 +162,7 @@ add_to_global (struct link_map *new)
    address ADDR.  Returns the pointer to the link map of the matching DSO, or
    NULL if a match is not found.  */
 struct link_map *
-internal_function
+private_function
 _dl_find_dso_for_object (const ElfW(Addr) addr)
 {
   struct link_map *l;
diff --git a/elf/dl-support.c b/elf/dl-support.c
index c22be854f4..b98cc4e9df 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -181,7 +181,7 @@ ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS;
 /* If loading a shared object requires that we make the stack executable
    when it was not, we do it by calling this function.
    It returns an errno code or zero on success.  */
-int (*_dl_make_stack_executable_hook) (void **) internal_function
+int (*_dl_make_stack_executable_hook) (void **) private_function
   = _dl_make_stack_executable;
 
 
diff --git a/elf/dl-sym.c b/elf/dl-sym.c
index fb54a91858..71f534de42 100644
--- a/elf/dl-sym.c
+++ b/elf/dl-sym.c
@@ -235,7 +235,7 @@ RTLD_NEXT used in code not dynamically loaded"));
 
 
 void *
-internal_function
+private_function
 _dl_vsym (void *handle, const char *name, const char *version, void *who)
 {
   struct r_found_version vers;
@@ -252,7 +252,7 @@ _dl_vsym (void *handle, const char *name, const char *version, void *who)
 
 
 void *
-internal_function
+private_function
 _dl_sym (void *handle, const char *name, void *who)
 {
   return do_sym (handle, name, who, NULL, DL_LOOKUP_RETURN_NEWEST);
diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index 5aba33b3fa..49af79d254 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -308,7 +308,7 @@ allocate_dtv (void *result)
 
 /* Get size and alignment requirements of the static TLS block.  */
 void
-internal_function
+private_function
 _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
 {
   *sizep = GL(dl_tls_static_size);
@@ -439,7 +439,7 @@ _dl_resize_dtv (dtv_t *dtv)
 
 
 void *
-internal_function
+private_function
 _dl_allocate_tls_init (void *result)
 {
   if (result == NULL)
@@ -532,7 +532,7 @@ _dl_allocate_tls_init (void *result)
 rtld_hidden_def (_dl_allocate_tls_init)
 
 void *
-internal_function
+private_function
 _dl_allocate_tls (void *mem)
 {
   return _dl_allocate_tls_init (mem == NULL
@@ -543,7 +543,7 @@ rtld_hidden_def (_dl_allocate_tls)
 
 
 void
-internal_function
+private_function
 _dl_deallocate_tls (void *tcb, bool dealloc_tcb)
 {
   dtv_t *dtv = GET_DTV (tcb);
diff --git a/grp/grp-merge.c b/grp/grp-merge.c
index 035e7a604b..1cd7774694 100644
--- a/grp/grp-merge.c
+++ b/grp/grp-merge.c
@@ -36,7 +36,7 @@
   })
 
 int
-internal_function
+private_function
 __copy_grp (const struct group srcgrp, const size_t buflen,
 	    struct group *destgrp, char *destbuf, char **endptr)
 {
@@ -117,7 +117,7 @@ libc_hidden_def (__copy_grp)
 /* Check that the name, GID and passwd fields match, then
    copy in the gr_mem array.  */
 int
-internal_function
+private_function
 __merge_grp (struct group *savedgrp, char *savedbuf, char *savedend,
 	     size_t buflen, struct group *mergegrp, char *mergebuf)
 {
diff --git a/grp/grp-merge.h b/grp/grp-merge.h
index 1ad9b9a539..180beff55b 100644
--- a/grp/grp-merge.h
+++ b/grp/grp-merge.h
@@ -26,12 +26,12 @@
 int
 __copy_grp (const struct group srcgrp, const size_t buflen,
 	    struct group *destgrp, char *destbuf, char **endptr)
-	    internal_function;
+	    private_function;
 
 /* Merge the member lists of two grp structs together.  */
 int
 __merge_grp (struct group *savedgrp, char *savedbuf, char *savedend,
 	     size_t buflen, struct group *mergegrp, char *mergebuf)
-	     internal_function;
+	     private_function;
 
 #endif /* _GRP_MERGE_H */
diff --git a/include/dlfcn.h b/include/dlfcn.h
index 2524292ebc..8fcd1727d5 100644
--- a/include/dlfcn.h
+++ b/include/dlfcn.h
@@ -44,7 +44,7 @@ libc_hidden_proto (__libc_dlclose)
 #ifdef ElfW
 extern int _dl_addr (const void *address, Dl_info *info,
 		     struct link_map **mapp, const ElfW(Sym) **symbolp)
-     internal_function;
+     private_function;
 libc_hidden_proto (_dl_addr)
 #endif
 
@@ -61,7 +61,7 @@ extern void _dl_close_worker (struct link_map *map, bool force)
    RTLD_NEXT).  WHO is the calling function, for RTLD_NEXT.  Returns
    the symbol value, which may be NULL.  */
 extern void *_dl_sym (void *handle, const char *name, void *who)
-    internal_function;
+    private_function;
 
 /* Look up version VERSION of symbol NAME in shared object HANDLE
    (which may be RTLD_DEFAULT or RTLD_NEXT).  WHO is the calling
@@ -69,7 +69,7 @@ extern void *_dl_sym (void *handle, const char *name, void *who)
    NULL.  */
 extern void *_dl_vsym (void *handle, const char *name, const char *version,
 		       void *who)
-    internal_function;
+    private_function;
 
 /* Helper function for <dlfcn.h> functions.  Runs the OPERATE function via
    _dl_catch_error.  Returns zero for success, nonzero for failure; and
diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index fe3ab81c51..c539b3443e 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -195,12 +195,7 @@
 
 #endif /* __ASSEMBLER__ */
 
-/* On some platforms we can make internal function calls (i.e., calls of
-   functions not exported) a bit faster by using a different calling
-   convention.  */
-#ifndef internal_function
-# define internal_function	/* empty */
-#endif
+#include <function-attrs.h>
 
 /* Determine the return address.  */
 #define RETURN_ADDRESS(nr) \
diff --git a/include/rpc/pmap_clnt.h b/include/rpc/pmap_clnt.h
index ec907c28cc..6a60d4442f 100644
--- a/include/rpc/pmap_clnt.h
+++ b/include/rpc/pmap_clnt.h
@@ -13,7 +13,7 @@ extern int __get_socket (struct sockaddr_in *saddr)
 extern u_short __libc_rpc_getport (struct sockaddr_in *address, u_long program,
 				   u_long version, u_int protocol,
 				   time_t timeout_sec, time_t tottimeout_sec)
-     internal_function;
+     private_function;
 libc_hidden_proto (__libc_rpc_getport)
 
 libc_hidden_proto (clnt_broadcast)
diff --git a/include/stdio.h b/include/stdio.h
index 215f919990..e02d56ddbf 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -99,7 +99,7 @@ extern void __libc_fatal (const char *__message)
 extern void __libc_message (enum __libc_message_action action,
 			    const char *__fnt, ...);
 extern void __fortify_fail (const char *msg)
-     __attribute__ ((__noreturn__)) internal_function;
+     __attribute__ ((__noreturn__)) private_function;
 extern void __fortify_fail_abort (_Bool, const char *msg)
      __attribute__ ((__noreturn__)) internal_function;
 libc_hidden_proto (__fortify_fail)
diff --git a/include/stdlib.h b/include/stdlib.h
index 6fd868828b..670134b1f5 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -201,16 +201,18 @@ libc_hidden_proto (strtoll)
 libc_hidden_proto (strtoul)
 libc_hidden_proto (strtoull)
 
-extern float __strtof_nan (const char *, char **, char) internal_function;
-extern double __strtod_nan (const char *, char **, char) internal_function;
+extern float __strtof_nan (const char *, char **, char)
+     private_function;
+extern double __strtod_nan (const char *, char **, char)
+     private_function;
 extern long double __strtold_nan (const char *, char **, char)
-     internal_function;
+     private_function;
 extern float __wcstof_nan (const wchar_t *, wchar_t **, wchar_t)
-     internal_function;
+     private_function;
 extern double __wcstod_nan (const wchar_t *, wchar_t **, wchar_t)
-     internal_function;
+     private_function;
 extern long double __wcstold_nan (const wchar_t *, wchar_t **, wchar_t)
-     internal_function;
+     private_function;
 
 libc_hidden_proto (__strtof_nan)
 libc_hidden_proto (__strtod_nan)
@@ -229,9 +231,9 @@ libc_hidden_proto (__strtof128_l)
 libc_hidden_proto (strtof128)
 
 extern _Float128 __strtof128_nan (const char *, char **, char)
-     internal_function;
+     private_function;
 extern _Float128 __wcstof128_nan (const wchar_t *, wchar_t **, wchar_t)
-     internal_function;
+     private_function;
 
 libc_hidden_proto (__strtof128_nan)
 libc_hidden_proto (__wcstof128_nan)
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index ce2e24af95..e81008f358 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -784,7 +784,7 @@ __deallocate_stack (struct pthread *pd)
 
 
 int
-internal_function
+private_function
 __make_stacks_executable (void **stack_endp)
 {
   /* First the main thread's stack.  */
diff --git a/nptl/libc_pthread_init.c b/nptl/libc_pthread_init.c
index 0db7a10893..5c00161e26 100644
--- a/nptl/libc_pthread_init.c
+++ b/nptl/libc_pthread_init.c
@@ -38,7 +38,7 @@ extern int __libc_multiple_threads attribute_hidden;
 
 int *
 #endif
-internal_function
+private_function
 __libc_pthread_init (unsigned long int *ptr, void (*reclaim) (void),
 		     const struct pthread_functions *functions)
 {
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index 6e7d6ff09e..3e376494f8 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -357,7 +357,7 @@ extern void __reclaim_stacks (void) attribute_hidden;
 
 /* Make all threads's stacks executable.  */
 extern int __make_stacks_executable (void **stack_endp)
-     internal_function attribute_hidden;
+     private_function attribute_hidden;
 
 /* longjmp handling.  */
 extern void __pthread_cleanup_upto (__jmp_buf target, char *targetframe);
@@ -388,12 +388,12 @@ hidden_proto (__nptl_death_event)
 extern void __libc_pthread_init (unsigned long int *ptr,
 				 void (*reclaim) (void),
 				 const struct pthread_functions *functions)
-     internal_function;
+     private_function;
 #else
 extern int *__libc_pthread_init (unsigned long int *ptr,
 				 void (*reclaim) (void),
 				 const struct pthread_functions *functions)
-     internal_function;
+     private_function;
 
 /* Variable set to a nonzero value either if more than one thread runs or ran,
    or if a single-threaded process is trying to cancel itself.  See
diff --git a/nss/XXX-lookup.c b/nss/XXX-lookup.c
index 5a37fdae08..84c3f525f9 100644
--- a/nss/XXX-lookup.c
+++ b/nss/XXX-lookup.c
@@ -57,11 +57,11 @@ service_user *DATABASE_NAME_SYMBOL attribute_hidden;
 
 extern int DB_LOOKUP_FCT (service_user **ni, const char *fct_name,
 			  const char *fct2_name, void **fctp)
-  internal_function;
+  private_function;
 libc_hidden_proto (DB_LOOKUP_FCT)
 
 int
-internal_function
+private_function
 DB_LOOKUP_FCT (service_user **ni, const char *fct_name, const char *fct2_name,
 	       void **fctp)
 {
@@ -79,7 +79,7 @@ libc_hidden_def (DB_LOOKUP_FCT)
 
 #ifndef NO_COMPAT
 int
-internal_function attribute_compat_text_section
+private_function attribute_compat_text_section
 DB_COMPAT_FCT (service_user **ni, const char *fct_name, void **fctp)
 {
   return DB_LOOKUP_FCT (ni, fct_name, NULL, fctp);
diff --git a/nss/getXXbyYY_r.c b/nss/getXXbyYY_r.c
index bce80e05dd..2304d9d924 100644
--- a/nss/getXXbyYY_r.c
+++ b/nss/getXXbyYY_r.c
@@ -181,7 +181,7 @@ typedef enum nss_status (*lookup_function) (ADD_PARAMS, LOOKUP_TYPE *, char *,
 /* The lookup function for the first entry of this service.  */
 extern int DB_LOOKUP_FCT (service_user **nip, const char *name,
 			  const char *name2, void **fctp)
-     internal_function;
+     private_function;
 libc_hidden_proto (DB_LOOKUP_FCT)
 
 
diff --git a/nss/getXXent_r.c b/nss/getXXent_r.c
index 2710c1cd51..9066d47e20 100644
--- a/nss/getXXent_r.c
+++ b/nss/getXXent_r.c
@@ -114,7 +114,7 @@ __libc_lock_define_initialized (static, lock)
 /* The lookup function for the first entry of this service.  */
 extern int DB_LOOKUP_FCT (service_user **nip, const char *name,
 			  const char *name2, void **fctp)
-     internal_function;
+     private_function;
 libc_hidden_proto (DB_LOOKUP_FCT)
 
 void
diff --git a/nss/nsswitch.h b/nss/nsswitch.h
index bd3fbcb082..b5e7ca14c7 100644
--- a/nss/nsswitch.h
+++ b/nss/nsswitch.h
@@ -169,7 +169,7 @@ extern void __nss_disable_nscd (void (*) (size_t, struct traced_file *));
 
 typedef int (*db_lookup_function) (service_user **, const char *, const char *,
 				   void **)
-     internal_function;
+     private_function;
 typedef enum nss_status (*setent_function) (int);
 typedef enum nss_status (*endent_function) (void);
 typedef enum nss_status (*getent_function) (void *, char *, size_t,
diff --git a/resolv/gai_misc.h b/resolv/gai_misc.h
index 6679d2b7d5..6f686c0bc7 100644
--- a/resolv/gai_misc.h
+++ b/resolv/gai_misc.h
@@ -96,6 +96,6 @@ extern int __gai_notify_only (struct sigevent *sigev, pid_t caller_pid)
 
 /* Send the signal.  */
 extern int __gai_sigqueue (int sig, const union sigval val, pid_t caller_pid)
-     internal_function;
+     private_function;
 
 #endif /* gai_misc.h */
diff --git a/resolv/gai_sigqueue.c b/resolv/gai_sigqueue.c
index ebc1e5ed46..ddec42c743 100644
--- a/resolv/gai_sigqueue.c
+++ b/resolv/gai_sigqueue.c
@@ -22,7 +22,7 @@
 #include <gai_misc.h>
 
 int
-internal_function
+private_function
 __gai_sigqueue (int sig, const union sigval val, pid_t caller_pid)
 {
   __set_errno (ENOSYS);
diff --git a/stdlib/strtod_nan_main.c b/stdlib/strtod_nan_main.c
index 96b788cb1e..f002abeb5d 100644
--- a/stdlib/strtod_nan_main.c
+++ b/stdlib/strtod_nan_main.c
@@ -29,7 +29,7 @@
    return a default NAN.  If ENDPTR is not NULL, set *ENDPTR to point
    to the character after the initial n-char-sequence.  */
 
-internal_function
+private_function
 FLOAT
 STRTOD_NAN (const STRING_TYPE *str, STRING_TYPE **endptr, STRING_TYPE endc)
 {
diff --git a/sunrpc/pm_getport.c b/sunrpc/pm_getport.c
index 54d2e439d2..0883abc663 100644
--- a/sunrpc/pm_getport.c
+++ b/sunrpc/pm_getport.c
@@ -82,7 +82,7 @@ __get_socket (struct sockaddr_in *saddr)
  * Returns 0 if no map exists.
  */
 u_short
-internal_function
+private_function
 __libc_rpc_getport (struct sockaddr_in *address, u_long program,
 		    u_long version, u_int protocol, time_t timeout_sec,
 		    time_t tottimeout_sec)
diff --git a/sysdeps/generic/function-attrs.h b/sysdeps/generic/function-attrs.h
new file mode 100644
index 0000000000..979f0bf014
--- /dev/null
+++ b/sysdeps/generic/function-attrs.h
@@ -0,0 +1,24 @@
+/* Define internal_function and private_function.  Generic version.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* On some platforms we can make internal function calls (i.e., calls of
+   functions within the same shared object) or private function calls
+   (i.e., calls of functions between different shared objects of glibc)
+   a bit faster by using a different calling convention.  */
+#define internal_function	/* empty */
+#define private_function	/* empty */
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 1c0b9cb32e..6d5ee24d73 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -377,7 +377,7 @@ struct rtld_global
   /* If loading a shared object requires that we make the stack executable
      when it was not, we do it by calling this function.
      It returns an errno code or zero on success.  */
-  EXTERN int (*_dl_make_stack_executable_hook) (void **) internal_function;
+  EXTERN int (*_dl_make_stack_executable_hook) (void **) private_function;
 
   /* Prevailing state of the stack, PF_X indicating it's executable.  */
   EXTERN ElfW(Word) _dl_stack_flags;
@@ -632,7 +632,7 @@ extern size_t _dl_phnum;
 
 /* This is the initial value of GL(dl_make_stack_executable_hook).
    A threads library can change it.  */
-extern int _dl_make_stack_executable (void **stack_endp) internal_function;
+extern int _dl_make_stack_executable (void **stack_endp) private_function;
 rtld_hidden_proto (_dl_make_stack_executable)
 
 /* Variable pointing to the end of the stack (or close to it).  This value
@@ -782,7 +782,7 @@ libc_hidden_proto (_dl_signal_exception)
 /* Like _dl_signal_exception, but creates the exception first.  */
 extern void _dl_signal_error (int errcode, const char *object,
 			      const char *occasion, const char *errstring)
-     internal_function __attribute__ ((__noreturn__));
+     private_function __attribute__ ((__noreturn__));
 libc_hidden_proto (_dl_signal_error)
 
 /* Like _dl_signal_exception, but may return when called in the
@@ -837,7 +837,7 @@ extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
 extern int _dl_catch_error (const char **objname, const char **errstring,
 			    bool *mallocedp, void (*operate) (void *),
 			    void *args)
-     internal_function;
+     private_function;
 libc_hidden_proto (_dl_catch_error)
 
 /* Call OPERATE (ARGS).  If no error occurs, set *EXCEPTION to zero.
@@ -878,7 +878,7 @@ extern void _dl_setup_hash (struct link_map *map)
    bytes to be used in filling in the result.  */
 extern void _dl_rtld_di_serinfo (struct link_map *loader,
 				 Dl_serinfo *si, bool counting)
-     internal_function;
+     private_function;
 
 
 /* Search loaded objects' symbol tables for a definition of the symbol
@@ -1077,12 +1077,12 @@ void __pthread_initialize_minimal (void) weak_function;
 #endif
 
 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv.  */
-extern void *_dl_allocate_tls (void *mem) internal_function;
+extern void *_dl_allocate_tls (void *mem) private_function;
 rtld_hidden_proto (_dl_allocate_tls)
 
 /* Get size and alignment requirements of the static TLS block.  */
 extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
-     internal_function;
+     private_function;
 
 extern void _dl_allocate_static_tls (struct link_map *map)
      internal_function attribute_hidden;
@@ -1091,11 +1091,11 @@ extern void _dl_allocate_static_tls (struct link_map *map)
    only used within rtld.c itself at startup time.  */
 extern void *_dl_allocate_tls_storage (void)
      internal_function attribute_hidden;
-extern void *_dl_allocate_tls_init (void *) internal_function;
+extern void *_dl_allocate_tls_init (void *) private_function;
 rtld_hidden_proto (_dl_allocate_tls_init)
 
 /* Deallocate memory allocated with _dl_allocate_tls.  */
-extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
+extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) private_function;
 rtld_hidden_proto (_dl_deallocate_tls)
 
 extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
@@ -1146,7 +1146,7 @@ extern void _dl_show_scope (struct link_map *new, int from)
      attribute_hidden;
 
 extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr)
-     internal_function;
+     private_function;
 rtld_hidden_proto (_dl_find_dso_for_object)
 
 /* Initialization which is normally done by the dynamic linker.  */
diff --git a/sysdeps/i386/configure b/sysdeps/i386/configure
index 5b55c5affe..3dbc23a610 100644
--- a/sysdeps/i386/configure
+++ b/sysdeps/i386/configure
@@ -26,7 +26,7 @@ libc_compiler_builtin_inlined=no
 cat > conftest.c <<EOF
 int _start (void) { int a, b, c; __sync_val_compare_and_swap (&a, b, c); return 0; }
 EOF
-if ! { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
+if ! { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp
 		     -O0 -nostdlib -nostartfiles
 		     -S conftest.c -o - | fgrep "__sync_val_compare_and_swap"
 		     1>&5'
@@ -77,8 +77,5 @@ if test $libc_cv_asm_mpx = yes; then
 
 fi
 
-$as_echo "#define USE_REGPARMS 1" >>confdefs.h
-
-
 $as_echo "#define PI_STATIC_AND_HIDDEN 1" >>confdefs.h
 
diff --git a/sysdeps/i386/configure.ac b/sysdeps/i386/configure.ac
index 19ef33f34a..f7766ad2b8 100644
--- a/sysdeps/i386/configure.ac
+++ b/sysdeps/i386/configure.ac
@@ -45,8 +45,6 @@ if test $libc_cv_asm_mpx = yes; then
   AC_DEFINE(HAVE_MPX_SUPPORT)
 fi
 
-AC_DEFINE(USE_REGPARMS)
-
 dnl It is always possible to access static and hidden symbols in an
 dnl position independent way.
 AC_DEFINE(PI_STATIC_AND_HIDDEN)
diff --git a/sysdeps/i386/function-attrs.h b/sysdeps/i386/function-attrs.h
new file mode 100644
index 0000000000..708647bf9b
--- /dev/null
+++ b/sysdeps/i386/function-attrs.h
@@ -0,0 +1,32 @@
+/* Define internal_function and private_function.  i386 version.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* On i386, we can make internal function calls (i.e., calls of functions
+   within the same shared object) or private function calls (i.e., calls
+   of functions between different shared objects of glibc) a bit faster
+   by passing function parameters in registers.  */
+
+#ifdef PROF
+/* The mcount code relies on a normal frame pointer being on the stack
+   to locate its caller.  */
+# define internal_function	/* empty */
+# define private_function	/* empty */
+#else
+# define internal_function	__attribute__ ((regparm (3), stdcall))
+# define private_function	__attribute__ ((regparm (3), stdcall))
+#endif
diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c
index 3c4de1cb46..913af76a75 100644
--- a/sysdeps/unix/sysv/linux/dl-execstack.c
+++ b/sysdeps/unix/sysv/linux/dl-execstack.c
@@ -30,7 +30,7 @@ extern int __stack_prot attribute_relro attribute_hidden;
 
 
 int
-internal_function
+private_function
 _dl_make_stack_executable (void **stack_endp)
 {
   /* This gives us the highest/lowest page that needs to be changed.  */
diff --git a/sysdeps/unix/sysv/linux/gai_sigqueue.c b/sysdeps/unix/sysv/linux/gai_sigqueue.c
index 0f7b459b5e..04c8d5008a 100644
--- a/sysdeps/unix/sysv/linux/gai_sigqueue.c
+++ b/sysdeps/unix/sysv/linux/gai_sigqueue.c
@@ -30,7 +30,7 @@
 
 /* Return any pending signal or wait for one for the given time.  */
 int
-internal_function
+private_function
 __gai_sigqueue (int sig, const union sigval val, pid_t caller_pid)
 {
   siginfo_t info;
diff --git a/sysdeps/unix/sysv/linux/netlink_assert_response.c b/sysdeps/unix/sysv/linux/netlink_assert_response.c
index d60eb1515e..963c879e71 100644
--- a/sysdeps/unix/sysv/linux/netlink_assert_response.c
+++ b/sysdeps/unix/sysv/linux/netlink_assert_response.c
@@ -39,7 +39,7 @@ get_address_family (int fd)
 }
 
 void
-internal_function
+private_function
 __netlink_assert_response (int fd, ssize_t result)
 {
   if (result < 0)
diff --git a/sysdeps/unix/sysv/linux/netlinkaccess.h b/sysdeps/unix/sysv/linux/netlinkaccess.h
index 6cffb65b14..bcbcc23abb 100644
--- a/sysdeps/unix/sysv/linux/netlinkaccess.h
+++ b/sysdeps/unix/sysv/linux/netlinkaccess.h
@@ -52,7 +52,7 @@ extern int __netlink_request (struct netlink_handle *h, int type);
 /* Terminate the process if RESULT is an invalid recvmsg result for
    the netlink socket FD.  */
 void __netlink_assert_response (int fd, ssize_t result)
-  internal_function;
+  private_function;
 libc_hidden_proto (__netlink_assert_response)
 
 #endif /* netlinkaccess.h */