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[PATCH v2] Remove TLS_MULTIPLE_THREADS_IN_TCB define
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Mon, 30 Oct 2017 17:25:34 -0200
- Subject: [PATCH v2] Remove TLS_MULTIPLE_THREADS_IN_TCB define
- Authentication-results: sourceware.org; auth=none
Changes from previous version [1]:
- Removed TLS_MULTIPLE_THREADS_IN_TCB define.
---
GLIBC current uses the TLS_MULTIPLE_THREADS_IN_TCB define to declare and set
the single thread optimization (STO) access by either a global variable
or a field in TCB. However STO refactor (09c76a740998) added a new variable,
SINGLE_THREAD_BY_GLOBAL, which essentially provides the same semantic.
This patch remove the TLS_MULTIPLE_THREADS_IN_TCB and uses
SINGLE_THREAD_BY_GLOBAL instead. It also adds some macros to access and
modify the STO field depending of the prefered architecture way.
It also make the archictures that actually use the global variable to
include them on final lib{c,pthread}.so. For instance m68k lib{c,pthread}.so
defines {__{pthread,libc}_multiple threads even though its STO is implemented
by TCB access.
Checked on x86_64-linux-gnu and on a build with major touched
ABIs (aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf,
hppa-linux-gnu, i686-linux-gnu, m68k-linux-gnu, microblaze-linux-gnu,
mips-linux-gnu, mips64-linux-gnu, powerpc-linux-gnu,
powerpc64le-linux-gnu, s390-linux-gnu, s390x-linux-gnu, sh4-linux-gnu,
sparcv9-linux-gnu, sparc64-linux-gnu, tilegx-linux-gnu).
* nptl/allocatestack.c (allocate_state): Use
SET_SINGLE_THREAD_PTHREAD macro.
* nptl/pthread_cancel.c (__pthread_cancel): Likewise.
* nptl/libc_multiple_threads.c (__libc_multiple_threads): Define for
libc and SINGLE_THREAD_BY_GLOBAL.
* nptl/libc_pthread_init.c (__libc_pthread_init): Use same
signature whether SINGLE_THREAD_BY_GLOBAL is set or not.
* nptl/pthreadP.h (__libc_pthread_init): Likewise.
* nptl/nptl-init.c (__libc_multiple_threads_ptr): Use
MULTIPLE_THREADS_PTR_DEF.
(__pthread_initialize_minimal_internal): Use MULTIPLE_THREADS_PTR_SET
macro.
* nptl/vars.c (__pthread_multiple_threads): Define for libpthread
and SINGLE_THREAD_BY_GLOBAL.
* sysdeps/unix/sysv/linux/sysdep-cancel.h (MULTIPLE_THREADS_PTR_DEF):
Define.
(MULTIPLE_THREADS_PTR_SET): Likewise.
(SET_SINGLE_THREAD_PTHREAD): Likewise.
* sysdeps/i386/nptl/tls.h (TLS_MULTIPLE_THREADS_IN_TCB): Remove.
* sysdeps/ia64/nptl/tls.h (TLS_MULTIPLE_THREADS_IN_TCB): Likewise.
* sysdeps/powerpc/nptl/tls.h (TLS_MULTIPLE_THREADS_IN_TCB): Likewise.
* sysdeps/s390/nptl/tls.h (TLS_MULTIPLE_THREADS_IN_TCB): Likewise.
* sysdeps/sh/nptl/tls.h (TLS_MULTIPLE_THREADS_IN_TCB): Likewise.
* sysdeps/tile/nptl/tls.h (TLS_MULTIPLE_THREADS_IN_TCB): Likewise.
* sysdeps/powerpc/nptl/tcb-offsets.sym (TLS_MULTIPLE_THREADS_IN_TCB):
Likewise.
[1] https://sourceware.org/ml/libc-alpha/2017-08/msg00238.html
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
ChangeLog | 29 +++++++++++++++++++++++++++++
nptl/allocatestack.c | 9 +++------
nptl/libc_multiple_threads.c | 4 +---
nptl/libc_pthread_init.c | 12 ++++--------
nptl/nptl-init.c | 14 +++++---------
nptl/pthreadP.h | 13 -------------
nptl/pthread_cancel.c | 7 +++----
nptl/vars.c | 2 +-
sysdeps/i386/nptl/tls.h | 2 --
sysdeps/ia64/nptl/tls.h | 2 --
sysdeps/powerpc/nptl/tcb-offsets.sym | 2 --
sysdeps/powerpc/nptl/tls.h | 3 ---
sysdeps/s390/nptl/tls.h | 4 ----
sysdeps/sh/nptl/tls.h | 2 --
sysdeps/tile/nptl/tls.h | 3 ---
sysdeps/unix/sysv/linux/sysdep-cancel.h | 27 +++++++++++++++++++++++++--
16 files changed, 71 insertions(+), 64 deletions(-)
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index ad9add8..b85767d 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -32,6 +32,7 @@
#include <futex-internal.h>
#include <kernel-features.h>
#include <stack-aliasing.h>
+#include <sysdep-cancel.h>
#ifndef NEED_SEPARATE_REGISTER_STACK
@@ -482,9 +483,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
/* This is at least the second thread. */
pd->header.multiple_threads = 1;
-#ifndef TLS_MULTIPLE_THREADS_IN_TCB
- __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
-#endif
+ SET_SINGLE_THREAD_PTHREAD (1);
#ifndef __ASSUME_PRIVATE_FUTEX
/* The thread must know when private futexes are supported. */
@@ -602,9 +601,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
/* This is at least the second thread. */
pd->header.multiple_threads = 1;
-#ifndef TLS_MULTIPLE_THREADS_IN_TCB
- __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
-#endif
+ SET_SINGLE_THREAD_PTHREAD (1);
#ifndef __ASSUME_PRIVATE_FUTEX
/* The thread must know when private futexes are supported. */
diff --git a/nptl/libc_multiple_threads.c b/nptl/libc_multiple_threads.c
index ef6a4be..1ae23e2 100644
--- a/nptl/libc_multiple_threads.c
+++ b/nptl/libc_multiple_threads.c
@@ -18,11 +18,9 @@
#include <pthreadP.h>
-#if IS_IN (libc)
-# ifndef TLS_MULTIPLE_THREADS_IN_TCB
+#if IS_IN (libc) && defined (SINGLE_THREAD_BY_GLOBAL)
/* 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
nptl/descr.h for more context on the single-threaded process case. */
int __libc_multiple_threads attribute_hidden;
-# endif
#endif
diff --git a/nptl/libc_pthread_init.c b/nptl/libc_pthread_init.c
index 875b27e..8bac037 100644
--- a/nptl/libc_pthread_init.c
+++ b/nptl/libc_pthread_init.c
@@ -26,18 +26,12 @@
#include <libc-lock.h>
#include <sysdep.h>
#include <ldsodefs.h>
-
+#include <sysdep-cancel.h>
unsigned long int *__fork_generation_pointer;
-#ifdef TLS_MULTIPLE_THREADS_IN_TCB
-void
-#else
-extern int __libc_multiple_threads attribute_hidden;
-
int *
-#endif
__libc_pthread_init (unsigned long int *ptr, void (*reclaim) (void),
const struct pthread_functions *functions)
{
@@ -73,8 +67,10 @@ __libc_pthread_init (unsigned long int *ptr, void (*reclaim) (void),
__libc_pthread_functions_init = 1;
#endif
-#ifndef TLS_MULTIPLE_THREADS_IN_TCB
+#ifdef SINGLE_THREAD_BY_GLOBAL
return &__libc_multiple_threads;
+# else
+ return NULL;
#endif
}
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 2921607..a1320f3 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -38,11 +38,9 @@
#include <kernel-features.h>
#include <libc-pointer-arith.h>
#include <pthread-pids.h>
+#include <sysdep-cancel.h>
-#ifndef TLS_MULTIPLE_THREADS_IN_TCB
-/* Pointer to the corresponding variable in libc. */
-int *__libc_multiple_threads_ptr attribute_hidden;
-#endif
+MULTIPLE_THREADS_PTR_DEF;
/* Size and alignment of static TLS block. */
size_t __static_tls_size;
@@ -457,11 +455,9 @@ __pthread_initialize_minimal_internal (void)
GL(dl_wait_lookup_done) = &__wait_lookup_done;
/* Register the fork generation counter with the libc. */
-#ifndef TLS_MULTIPLE_THREADS_IN_TCB
- __libc_multiple_threads_ptr =
-#endif
- __libc_pthread_init (&__fork_generation, __reclaim_stacks,
- ptr_pthread_functions);
+ MULTIPLE_THREADS_PTR_SET (__libc_pthread_init (&__fork_generation,
+ __reclaim_stacks,
+ ptr_pthread_functions));
/* Determine whether the machine is SMP or not. */
__is_smp = is_smp_system ();
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index dbf46b0..d89fdca 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -382,23 +382,10 @@ hidden_proto (__nptl_create_event)
hidden_proto (__nptl_death_event)
/* Register the generation counter in the libpthread with the libc. */
-#ifdef TLS_MULTIPLE_THREADS_IN_TCB
-extern void __libc_pthread_init (unsigned long int *ptr,
- void (*reclaim) (void),
- const struct pthread_functions *functions);
-#else
extern int *__libc_pthread_init (unsigned long int *ptr,
void (*reclaim) (void),
const struct pthread_functions *functions);
-/* 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
- nptl/descr.h for more context on the single-threaded process case. */
-extern int __pthread_multiple_threads attribute_hidden;
-/* Pointer to the corresponding variable in libc. */
-extern int *__libc_multiple_threads_ptr attribute_hidden;
-#endif
-
/* Find a thread given its TID. */
extern struct pthread *__find_thread_by_id (pid_t tid) attribute_hidden
#ifdef SHARED
diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c
index 742dfe6..f52ea08 100644
--- a/nptl/pthread_cancel.c
+++ b/nptl/pthread_cancel.c
@@ -19,10 +19,11 @@
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
-#include "pthreadP.h"
#include <atomic.h>
#include <sysdep.h>
#include <unistd.h>
+#include <pthreadP.h>
+#include <sysdep-cancel.h>
int
__pthread_cancel (pthread_t th)
@@ -88,9 +89,7 @@ __pthread_cancel (pthread_t th)
cannot. So we set multiple_threads to true so that cancellation
points get executed. */
THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
-#ifndef TLS_MULTIPLE_THREADS_IN_TCB
- __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
-#endif
+ SET_SINGLE_THREAD_PTHREAD (1);
}
/* Mark the thread as canceled. This has to be done
atomically since other bits could be modified as well. */
diff --git a/nptl/vars.c b/nptl/vars.c
index 198f463..42b8db9 100644
--- a/nptl/vars.c
+++ b/nptl/vars.c
@@ -30,7 +30,7 @@ int __default_pthread_attr_lock = LLL_LOCK_INITIALIZER;
/* Flag whether the machine is SMP or not. */
int __is_smp attribute_hidden;
-#ifndef TLS_MULTIPLE_THREADS_IN_TCB
+#if IS_IN (libpthread) && defined (SINGLE_THREAD_BY_GLOBAL)
/* 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
nptl/descr.h for more context on the single-threaded process case. */
diff --git a/sysdeps/i386/nptl/tls.h b/sysdeps/i386/nptl/tls.h
index f9a6b11..e0fd6f9 100644
--- a/sysdeps/i386/nptl/tls.h
+++ b/sysdeps/i386/nptl/tls.h
@@ -52,8 +52,6 @@ typedef struct
void *__private_ss;
} tcbhead_t;
-# define TLS_MULTIPLE_THREADS_IN_TCB 1
-
#else /* __ASSEMBLER__ */
# include <tcb-offsets.h>
#endif
diff --git a/sysdeps/ia64/nptl/tls.h b/sysdeps/ia64/nptl/tls.h
index 400caf3..9b0cc3d 100644
--- a/sysdeps/ia64/nptl/tls.h
+++ b/sysdeps/ia64/nptl/tls.h
@@ -36,8 +36,6 @@ typedef struct
register struct pthread *__thread_self __asm__("r13");
-# define TLS_MULTIPLE_THREADS_IN_TCB 1
-
#else /* __ASSEMBLER__ */
# include <tcb-offsets.h>
#endif
diff --git a/sysdeps/powerpc/nptl/tcb-offsets.sym b/sysdeps/powerpc/nptl/tcb-offsets.sym
index 7c9fd33..77c9a4f 100644
--- a/sysdeps/powerpc/nptl/tcb-offsets.sym
+++ b/sysdeps/powerpc/nptl/tcb-offsets.sym
@@ -10,9 +10,7 @@
# define thread_offsetof(mem) ((ptrdiff_t) THREAD_SELF + offsetof (struct pthread, mem))
-#if TLS_MULTIPLE_THREADS_IN_TCB
MULTIPLE_THREADS_OFFSET thread_offsetof (header.multiple_threads)
-#endif
TID thread_offsetof (tid)
POINTER_GUARD (offsetof (tcbhead_t, pointer_guard) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
TAR_SAVE (offsetof (tcbhead_t, tar_save) - TLS_TCB_OFFSET - sizeof (tcbhead_t))
diff --git a/sysdeps/powerpc/nptl/tls.h b/sysdeps/powerpc/nptl/tls.h
index 7556e7c..01dc520 100644
--- a/sysdeps/powerpc/nptl/tls.h
+++ b/sysdeps/powerpc/nptl/tls.h
@@ -43,9 +43,6 @@
# define TLS_DTV_AT_TP 1
# define TLS_TCB_AT_TP 0
-/* We use the multiple_threads field in the pthread struct */
-#define TLS_MULTIPLE_THREADS_IN_TCB 1
-
/* Get the thread descriptor definition. */
# include <nptl/descr.h>
diff --git a/sysdeps/s390/nptl/tls.h b/sysdeps/s390/nptl/tls.h
index 7bc6c89..c3adf3c 100644
--- a/sysdeps/s390/nptl/tls.h
+++ b/sysdeps/s390/nptl/tls.h
@@ -48,10 +48,6 @@ typedef struct
void *__private_ss;
} tcbhead_t;
-# ifndef __s390x__
-# define TLS_MULTIPLE_THREADS_IN_TCB 1
-# endif
-
#else /* __ASSEMBLER__ */
# include <tcb-offsets.h>
#endif
diff --git a/sysdeps/sh/nptl/tls.h b/sysdeps/sh/nptl/tls.h
index 547cff1..064ba93 100644
--- a/sysdeps/sh/nptl/tls.h
+++ b/sysdeps/sh/nptl/tls.h
@@ -36,8 +36,6 @@ typedef struct
uintptr_t pointer_guard;
} tcbhead_t;
-# define TLS_MULTIPLE_THREADS_IN_TCB 1
-
#else /* __ASSEMBLER__ */
# include <tcb-offsets.h>
#endif /* __ASSEMBLER__ */
diff --git a/sysdeps/tile/nptl/tls.h b/sysdeps/tile/nptl/tls.h
index 7314843..ec64154 100644
--- a/sysdeps/tile/nptl/tls.h
+++ b/sysdeps/tile/nptl/tls.h
@@ -41,9 +41,6 @@
# define TLS_DTV_AT_TP 1
# define TLS_TCB_AT_TP 0
-/* We use the multiple_threads field in the pthread struct */
-#define TLS_MULTIPLE_THREADS_IN_TCB 1
-
/* Get the thread descriptor definition. */
# include <nptl/descr.h>
diff --git a/sysdeps/unix/sysv/linux/sysdep-cancel.h b/sysdeps/unix/sysv/linux/sysdep-cancel.h
index 57bd093..b5a9b29 100644
--- a/sysdeps/unix/sysv/linux/sysdep-cancel.h
+++ b/sysdeps/unix/sysv/linux/sysdep-cancel.h
@@ -32,12 +32,24 @@
field. */
#ifdef SINGLE_THREAD_BY_GLOBAL
+
+extern int __pthread_multiple_threads attribute_hidden;
+
+/* 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
+ nptl/descr.h for more context on the single-threaded process case. */
+# define MULTIPLE_THREADS_PTR_DEF \
+ int *__libc_multiple_threads_ptr attribute_hidden
+
+# define MULTIPLE_THREADS_PTR_SET(__ptr) \
+ __libc_multiple_threads_ptr = (__ptr)
+
# if IS_IN (libc)
-extern int __libc_multiple_threads;
+extern int __libc_multiple_threads attribute_hidden;
# define SINGLE_THREAD_P \
__glibc_likely (__libc_multiple_threads == 0)
# elif IS_IN (libpthread)
-extern int __pthread_multiple_threads;
+extern int *__libc_multiple_threads_ptr attribute_hidden;
# define SINGLE_THREAD_P \
__glibc_likely (__pthread_multiple_threads == 0)
# elif IS_IN (librt)
@@ -48,7 +60,16 @@ extern int __pthread_multiple_threads;
/* For rtld, et cetera. */
# define SINGLE_THREAD_P (1)
# endif
+
+# define SET_SINGLE_THREAD_PTHREAD(__value) \
+ *__libc_multiple_threads_ptr = __pthread_multiple_threads = (__value)
+
#else /* SINGLE_THREAD_BY_GLOBAL */
+
+# define MULTIPLE_THREADS_PTR_DEF
+
+# define MULTIPLE_THREADS_PTR_SET(__ptr) __ptr
+
# if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
# define SINGLE_THREAD_P \
__glibc_likely (THREAD_GETMEM (THREAD_SELF, \
@@ -57,6 +78,8 @@ extern int __pthread_multiple_threads;
/* For rtld, et cetera. */
# define SINGLE_THREAD_P (1)
# endif
+
+# define SET_SINGLE_THREAD_PTHREAD(__value)
#endif /* SINGLE_THREAD_BY_GLOBAL */
#define RTLD_SINGLE_THREAD_P \
--
2.7.4