diff mbox

Correct robust mutex / PI futex kernel assumptions (bug 9894)

Message ID Pine.LNX.4.64.1403252334530.10779@digraph.polyomino.org.uk
State Committed
Headers

Commit Message

Joseph Myers March 25, 2014, 11:36 p.m. UTC 
  On Tue, 25 Mar 2014, David Miller wrote:

> From: "Joseph S. Myers" <joseph@codesourcery.com>
> Date: Tue, 25 Mar 2014 23:20:00 +0000
> 
> > On Tue, 25 Mar 2014, David Miller wrote:
> > 
> >> Actually, it turns out you can simply test for the CPP macro __sparc_v9__
> > 
> > In that case, here is a revised patch using __sparc_v9__ in place of 
> > __arch64__.
> 
> It only get's set for 32-bit v9, you'll need to keep the
> (__sparc__ && __arch64__) in an "||" conditional branch.
> 
> Something like (__sparc__ && (__arch64__ || __sparc_v9__))

Here's a third patch version.

2014-03-25  Joseph Myers  <joseph@codesourcery.com>

	[BZ #9894]
	* sysdeps/unix/sysv/linux/kernel-features.h
	[__sparc__ && !__arch64__ && !__sparc_v9__]
	(__ASSUME_SET_ROBUST_LIST): Do not define.
	[__sparc__ && !__arch64__ && !__sparc_v9__]
	(__ASSUME_FUTEX_LOCK_PI): Likewise.
	[__sparc__ && !__arch64__ && !__sparc_v9__] (__ASSUME_REQUEUE_PI):
	Likewise.
	* sysdeps/unix/sysv/linux/arm/kernel-features.h
	(__ASSUME_FUTEX_LOCK_PI): Undefine.
	(__ASSUME_REQUEUE_PI): Likewise.
	(__ASSUME_SET_ROBUST_LIST): Likewise.
	* sysdeps/unix/sysv/linux/m68k/kernel-features.h
	[__LINUX_KERNEL_VERSION < 0x030a00] (__ASSUME_FUTEX_LOCK_PI):
	Undefine.
	* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
	[__LINUX_KERNEL_VERSION < 0x020621] (__ASSUME_FUTEX_LOCK_PI):
	Likewise.
	[__LINUX_KERNEL_VERSION < 0x020621] (__ASSUME_REQUEUE_PI):
	Likewise.
	[__LINUX_KERNEL_VERSION < 0x020621] (__ASSUME_SET_ROBUST_LIST):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/kernel-features.h
	[__mips == 1 || _MIPS_ARCH_R5900] (__ASSUME_FUTEX_LOCK_PI):
	Undefine.
	[__mips == 1 || _MIPS_ARCH_R5900] (__ASSUME_REQUEUE_PI): Likewise.
	[__mips == 1 || _MIPS_ARCH_R5900] (__ASSUME_SET_ROBUST_LIST):
	Likewise.

Comments

David Miller March 26, 2014, 12:21 a.m. UTC | #1 
From: "Joseph S. Myers" <joseph@codesourcery.com>
Date: Tue, 25 Mar 2014 23:36:36 +0000

> On Tue, 25 Mar 2014, David Miller wrote:
> 
>> From: "Joseph S. Myers" <joseph@codesourcery.com>
>> Date: Tue, 25 Mar 2014 23:20:00 +0000
>> 
>> > On Tue, 25 Mar 2014, David Miller wrote:
>> > 
>> >> Actually, it turns out you can simply test for the CPP macro __sparc_v9__
>> > 
>> > In that case, here is a revised patch using __sparc_v9__ in place of 
>> > __arch64__.
>> 
>> It only get's set for 32-bit v9, you'll need to keep the
>> (__sparc__ && __arch64__) in an "||" conditional branch.
>> 
>> Something like (__sparc__ && (__arch64__ || __sparc_v9__))
> 
> Here's a third patch version.

Looks good to me.
David Holsgrove March 31, 2014, 1:20 a.m. UTC | #2 
> -----Original Message-----

> From: David Miller [mailto:davem@davemloft.net]

> Sent: Wednesday, 26 March 2014 10:21 am

> To: joseph@codesourcery.com

> Cc: libc-alpha@sourceware.org; schwab@linux-m68k.org; David Holsgrove;

> aurel32@debian.org

> Subject: Re: Correct robust mutex / PI futex kernel assumptions (bug 9894)

> 

> From: "Joseph S. Myers" <joseph@codesourcery.com>

> Date: Tue, 25 Mar 2014 23:36:36 +0000

> 

> > On Tue, 25 Mar 2014, David Miller wrote:

> >

> >> From: "Joseph S. Myers" <joseph@codesourcery.com>

> >> Date: Tue, 25 Mar 2014 23:20:00 +0000

> >>

> >> > On Tue, 25 Mar 2014, David Miller wrote:

> >> >

> >> >> Actually, it turns out you can simply test for the CPP macro __sparc_v9__

> >> >

> >> > In that case, here is a revised patch using __sparc_v9__ in place of

> >> > __arch64__.

> >>

> >> It only get's set for 32-bit v9, you'll need to keep the

> >> (__sparc__ && __arch64__) in an "||" conditional branch.

> >>

> >> Something like (__sparc__ && (__arch64__ || __sparc_v9__))

> >

> > Here's a third patch version.

> 

> Looks good to me.


Good for MicroBlaze too - thanks Joseph,

David
diff mbox

Patch

diff --git a/sysdeps/unix/sysv/linux/arm/kernel-features.h b/sysdeps/unix/sysv/linux/arm/kernel-features.h
index 401343b..96b7350 100644
--- a/sysdeps/unix/sysv/linux/arm/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/arm/kernel-features.h
@@ -53,3 +53,10 @@ 
 # undef __ASSUME_PSELECT
 # undef __ASSUME_PPOLL
 #endif
+
+/* The ARM kernel may or may not support
+   futex_atomic_cmpxchg_inatomic, depending on kernel
+   configuration.  */
+#undef __ASSUME_FUTEX_LOCK_PI
+#undef __ASSUME_REQUEUE_PI
+#undef __ASSUME_SET_ROBUST_LIST
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 555b82c..db6af35 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -106,9 +106,12 @@ 
 # define __ASSUME_ATFCTS	1
 #endif
 
-/* Support for inter-process robust mutexes was added in 2.6.17.  */
+/* Support for inter-process robust mutexes was added in 2.6.17 (but
+   some architectures lack futex_atomic_cmpxchg_inatomic in some
+   configurations).  */
 #if __LINUX_KERNEL_VERSION >= 0x020611 \
-    && (!defined __sh__ || __LINUX_KERNEL_VERSION >= 0x020613)
+    && (!defined __sh__ || __LINUX_KERNEL_VERSION >= 0x020613) \
+    && !(defined __sparc__ && !defined __arch64__ && !defined __sparc_v9__)
 # define __ASSUME_SET_ROBUST_LIST	1
 #endif
 
@@ -119,8 +122,10 @@ 
 # define __ASSUME_COMPLETE_READV_WRITEV	1
 #endif
 
-/* Support for PI futexes was added in 2.6.18.  */
-#if __LINUX_KERNEL_VERSION >= 0x020612
+/* Support for PI futexes was added in 2.6.18 (but some architectures
+   lack futex_atomic_cmpxchg_inatomic in some configurations).  */
+#if __LINUX_KERNEL_VERSION >= 0x020612 \
+    && !(defined __sparc__ && !defined __arch64__ && !defined __sparc_v9__)
 # define __ASSUME_FUTEX_LOCK_PI	1
 #endif
 
@@ -223,8 +228,11 @@ 
 # define __ASSUME_PWRITEV	1
 #endif
 
-/* Support for FUTEX_*_REQUEUE_PI was added in 2.6.31.  */
-#if __LINUX_KERNEL_VERSION >= 0x02061f
+/* Support for FUTEX_*_REQUEUE_PI was added in 2.6.31 (but some
+   architectures lack futex_atomic_cmpxchg_inatomic in some
+   configurations).  */
+#if __LINUX_KERNEL_VERSION >= 0x02061f \
+    && !(defined __sparc__ && !defined __arch64__ && !defined __sparc_v9__)
 # define __ASSUME_REQUEUE_PI	1
 #endif
 
diff --git a/sysdeps/unix/sysv/linux/m68k/kernel-features.h b/sysdeps/unix/sysv/linux/m68k/kernel-features.h
index cb8915f..bc340bd 100644
--- a/sysdeps/unix/sysv/linux/m68k/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/m68k/kernel-features.h
@@ -48,6 +48,7 @@ 
 
 /* No support for PI futexes or robust mutexes before 3.10 for m68k.  */
 #if __LINUX_KERNEL_VERSION < 0x030a00
+# undef __ASSUME_FUTEX_LOCK_PI
 # undef __ASSUME_REQUEUE_PI
 # undef __ASSUME_SET_ROBUST_LIST
 #endif
diff --git a/sysdeps/unix/sysv/linux/microblaze/kernel-features.h b/sysdeps/unix/sysv/linux/microblaze/kernel-features.h
index f9a61a9..a62b839 100644
--- a/sysdeps/unix/sysv/linux/microblaze/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/microblaze/kernel-features.h
@@ -43,6 +43,13 @@ 
 
 #include_next <kernel-features.h>
 
+/* Support for futex_atomic_cmpxchg_inatomic was added in 2.6.33.  */
+#if __LINUX_KERNEL_VERSION < 0x020621
+# undef __ASSUME_FUTEX_LOCK_PI
+# undef __ASSUME_REQUEUE_PI
+# undef __ASSUME_SET_ROBUST_LIST
+#endif
+
 /* The MicroBlaze kernel does not support the pselect6, preadv and
    pwritev syscalls.  */
 #undef __ASSUME_PSELECT
diff --git a/sysdeps/unix/sysv/linux/mips/kernel-features.h b/sysdeps/unix/sysv/linux/mips/kernel-features.h
index 52cbf3a..19d3cba 100644
--- a/sysdeps/unix/sysv/linux/mips/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/mips/kernel-features.h
@@ -53,3 +53,11 @@ 
 #if _MIPS_SIM == _ABIN32 && __LINUX_KERNEL_VERSION < 0x020623
 # undef __ASSUME_GETDENTS64_SYSCALL
 #endif
+
+/* The MIPS kernel does not support futex_atomic_cmpxchg_inatomic if
+   emulating LL/SC.  */
+#if __mips == 1 || defined _MIPS_ARCH_R5900
+# undef __ASSUME_FUTEX_LOCK_PI
+# undef __ASSUME_REQUEUE_PI
+# undef __ASSUME_SET_ROBUST_LIST
+#endif