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[PATCH 2/3] Remove __ASSUME_SET_ROBUST_LIST
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Wed, 18 May 2016 18:57:17 -0300
- Subject: [PATCH 2/3] Remove __ASSUME_SET_ROBUST_LIST
- Authentication-results: sourceware.org; auth=none
- References: <1463608638-7215-1-git-send-email-adhemerval dot zanella at linaro dot org>
This patch removes __ASSUME_SET_ROBUST_LIST usage and assumes that
kernel will correctly return if it supports or not
futex_atomic_cmpxchg_inatomic.
On minimum supported kernel (v3.2 and v2.6.32 for x86) kernel has:
2418 SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
2419 size_t, len)
2420 {
2421 if (!futex_cmpxchg_enabled)
2422 return -ENOSYS;
The patch also adds the __set_robust_list_avail runtime check for all
architectures, since for some the syscall may still return ENOSYS if
futex_atomic_cmpxchg_inatomic is not supported (for instance ARM).
Tested on armhf (with 3.8 kernel) and x86_64.
* nptl/nptl-init.c [__ASSUME_SET_ROBUST_LIST]
(__set_robust_list_avail): Remove define.
[__NR_set_robust_list] (__pthread_initialize_minimal_internal):
Likewise.
* nptl/pthreadP.h [__ASSUME_SET_ROBUST_LIST]
(__set_robust_list_avail): Likewise.
* nptl/pthread_create.c
[__NR_set_robust_list && !__ASSUME_SET_ROBUST_LIST]
(START_THREAD_DEFN): Likewise.
* nptl/pthread_mutex_init.c [!__ASSUME_SET_ROBUST_LIST]
(__pthread_mutex_init): Likewise.
* sysdeps/unix/sysv/linux/arm/kernel-features.h
(__ASSUME_SET_ROBUST_LIST): Likewise.
* sysdeps/unix/sysv/linux/kernel-features.h:
(__ASSUME_SET_ROBUST_LIST): Likewise.
* sysdeps/unix/sysv/linux/m68k/kernel-features.h:
(__ASSUME_SET_ROBUST_LIST): Likewise.
* sysdeps/unix/sysv/linux/mips/kernel-features.h:
(__ASSUME_SET_ROBUST_LIST): Likewise.
* sysdeps/unix/sysv/linux/sparc/kernel-features.h:
(__ASSUME_SET_ROBUST_LIST): Likewise.
---
ChangeLog | 22 ++++++++++++++++++++++
nptl/nptl-init.c | 11 ++---------
nptl/pthreadP.h | 2 --
nptl/pthread_create.c | 8 +-------
nptl/pthread_mutex_init.c | 2 --
sysdeps/unix/sysv/linux/arm/kernel-features.h | 1 -
sysdeps/unix/sysv/linux/kernel-features.h | 5 -----
sysdeps/unix/sysv/linux/m68k/kernel-features.h | 1 -
sysdeps/unix/sysv/linux/mips/kernel-features.h | 1 -
sysdeps/unix/sysv/linux/sparc/kernel-features.h | 1 -
10 files changed, 25 insertions(+), 29 deletions(-)
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index bdbdfed..cad14c7 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -48,14 +48,8 @@ int *__libc_multiple_threads_ptr attribute_hidden;
size_t __static_tls_size;
size_t __static_tls_align_m1;
-#ifndef __ASSUME_SET_ROBUST_LIST
/* Negative if we do not have the system call and we can use it. */
int __set_robust_list_avail;
-# define set_robust_list_not_avail() \
- __set_robust_list_avail = -1
-#else
-# define set_robust_list_not_avail() do { } while (0)
-#endif
#ifndef __ASSUME_FUTEX_CLOCK_REALTIME
/* Nonzero if we do not have FUTEX_CLOCK_REALTIME. */
@@ -328,7 +322,7 @@ __pthread_initialize_minimal_internal (void)
pd->robust_prev = &pd->robust_head;
#endif
pd->robust_head.list = &pd->robust_head;
-#ifdef __NR_set_robust_list
+
pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
- offsetof (pthread_mutex_t,
__data.__list.__next));
@@ -336,8 +330,7 @@ __pthread_initialize_minimal_internal (void)
int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
sizeof (struct robust_list_head));
if (INTERNAL_SYSCALL_ERROR_P (res, err))
-#endif
- set_robust_list_not_avail ();
+ __set_robust_list_avail = -1;
}
#ifdef __NR_futex
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index 4edc74b..d479a3e 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -199,10 +199,8 @@ hidden_proto (__pthread_keys)
/* Number of threads running. */
extern unsigned int __nptl_nthreads attribute_hidden;
-#ifndef __ASSUME_SET_ROBUST_LIST
/* Negative if we do not have the system call and we can use it. */
extern int __set_robust_list_avail attribute_hidden;
-#endif
/* Thread Priority Protection. */
extern int __sched_fifo_min_prio attribute_hidden;
diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
index a834063..c3f4087 100644
--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -271,10 +271,7 @@ START_THREAD_DEFN
if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0) == -2))
futex_wake (&pd->setxid_futex, 1, FUTEX_PRIVATE);
-#ifdef __NR_set_robust_list
-# ifndef __ASSUME_SET_ROBUST_LIST
- if (__set_robust_list_avail >= 0)
-# endif
+ if (__glibc_likely (__set_robust_list_avail >= 0))
{
INTERNAL_SYSCALL_DECL (err);
/* This call should never fail because the initial call in init.c
@@ -282,7 +279,6 @@ START_THREAD_DEFN
INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
sizeof (struct robust_list_head));
}
-#endif
#ifdef SIGCANCEL
/* If the parent was running cancellation handlers while creating
@@ -388,7 +384,6 @@ START_THREAD_DEFN
the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE. */
atomic_bit_set (&pd->cancelhandling, EXITING_BIT);
-#ifndef __ASSUME_SET_ROBUST_LIST
/* If this thread has any robust mutexes locked, handle them now. */
# ifdef __PTHREAD_MUTEX_HAVE_PREV
void *robust = pd->robust_head.list;
@@ -419,7 +414,6 @@ START_THREAD_DEFN
}
while (robust != (void *) &pd->robust_head);
}
-#endif
/* Mark the memory of the stack as usable to the kernel. We free
everything except for the space used for the TCB itself. */
diff --git a/nptl/pthread_mutex_init.c b/nptl/pthread_mutex_init.c
index 6e5acb6..6aef890 100644
--- a/nptl/pthread_mutex_init.c
+++ b/nptl/pthread_mutex_init.c
@@ -91,11 +91,9 @@ __pthread_mutex_init (pthread_mutex_t *mutex,
if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) != 0)
{
-#ifndef __ASSUME_SET_ROBUST_LIST
if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_PSHARED) != 0
&& __set_robust_list_avail < 0)
return ENOTSUP;
-#endif
mutex->__data.__kind |= PTHREAD_MUTEX_ROBUST_NORMAL_NP;
}
diff --git a/sysdeps/unix/sysv/linux/arm/kernel-features.h b/sysdeps/unix/sysv/linux/arm/kernel-features.h
index 6ca607e..4012751 100644
--- a/sysdeps/unix/sysv/linux/arm/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/arm/kernel-features.h
@@ -24,7 +24,6 @@
configuration. */
#if __LINUX_KERNEL_VERSION < 0x030E03
# undef __ASSUME_REQUEUE_PI
-# undef __ASSUME_SET_ROBUST_LIST
#endif
/* Define this if your 32-bit syscall API requires 64-bit register
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 43b72b1..45edad5 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -59,11 +59,6 @@
they were introduced in 2.6.17-rc1, on SH in 2.6.19-rc1. */
#define __ASSUME_ATFCTS 1
-/* Support for inter-process robust mutexes was added in 2.6.17 (but
- some architectures lack futex_atomic_cmpxchg_inatomic in some
- configurations). */
-#define __ASSUME_SET_ROBUST_LIST 1
-
/* Support for private futexes was added in 2.6.22. */
#define __ASSUME_PRIVATE_FUTEX 1
diff --git a/sysdeps/unix/sysv/linux/m68k/kernel-features.h b/sysdeps/unix/sysv/linux/m68k/kernel-features.h
index 9e7f0e1..bec9539 100644
--- a/sysdeps/unix/sysv/linux/m68k/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/m68k/kernel-features.h
@@ -52,5 +52,4 @@
/* No support for PI futexes or robust mutexes before 3.10 for m68k. */
#if __LINUX_KERNEL_VERSION < 0x030a00
# undef __ASSUME_REQUEUE_PI
-# undef __ASSUME_SET_ROBUST_LIST
#endif
diff --git a/sysdeps/unix/sysv/linux/mips/kernel-features.h b/sysdeps/unix/sysv/linux/mips/kernel-features.h
index 09d5ece..3640b5f 100644
--- a/sysdeps/unix/sysv/linux/mips/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/mips/kernel-features.h
@@ -25,7 +25,6 @@
emulating LL/SC. */
#if __mips == 1 || defined _MIPS_ARCH_R5900
# undef __ASSUME_REQUEUE_PI
-# undef __ASSUME_SET_ROBUST_LIST
#endif
/* Define this if your 32-bit syscall API requires 64-bit register
diff --git a/sysdeps/unix/sysv/linux/sparc/kernel-features.h b/sysdeps/unix/sysv/linux/sparc/kernel-features.h
index 69c9c7c..dc7c4aa 100644
--- a/sysdeps/unix/sysv/linux/sparc/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/sparc/kernel-features.h
@@ -35,5 +35,4 @@
futex_atomic_cmpxchg_inatomic. */
#if !defined __arch64__ && !defined __sparc_v9__
# undef __ASSUME_REQUEUE_PI
-# undef __ASSUME_SET_ROBUST_LIST
#endif
--
2.7.4