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RE: [PATCH] Fix the atomic_compare_and_exchange_*_rel definitions.
- From: Lei Xu <lei dot xu at nxp dot com>
- To: "munroesj at linux dot vnet dot ibm dot com" <munroesj at linux dot vnet dot ibm dot com>, "Tulio Magno Quites Machado Filho" <tuliom at linux dot vnet dot ibm dot com>
- Cc: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>, Scott Wood <scott dot wood at nxp dot com>, "carlos at systemhalted dot org" <carlos at systemhalted dot org>, "sjmunroe at us dot ibm dot com" <sjmunroe at us dot ibm dot com>
- Date: Tue, 14 Jun 2016 06:00:34 +0000
- Subject: RE: [PATCH] Fix the atomic_compare_and_exchange_*_rel definitions.
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Hello, Steven, Tulio
Thank you and please see my comments below~
-----Original Message-----
From: Steven Munroe [mailto:munroesj@linux.vnet.ibm.com]
Sent: Monday, June 13, 2016 10:33 PM
To: Tulio Magno Quites Machado Filho; Lei Xu
Cc: libc-alpha@sourceware.org; Scott Wood; carlos@systemhalted.org; sjmunroe@us.ibm.com
Subject: Re: [PATCH] Fix the atomic_compare_and_exchange_*_rel definitions.
On Mon, 2016-06-13 at 11:19 -0300, Tulio Magno Quites Machado Filho
wrote:
> Hi Lei,
>
> Lei Xu <lei.xu@nxp.com> writes:
>
> > In current code, atomic_compare_and_exchange_*_rel is defined as
> > atomic_compare_and_exchange_*_acq, however this is wrong on power
> > arch, especially __arch_*_rel has been defined on power arch.
> > This has caused segmentation fault issue when doing
> > pthread_mutex_lock/unlock operations on PowerPC E6500.
>
> I didn't expect the generic code to affect a PowerPC E6500 build.
> It should be using both of the files:
> sysdeps/powerpc/atomic-machine.h
> sysdeps/powerpc/powerpc32/atomic-machine.h
>
E6500 is a 64-bit part which unfortunately follows the Embedded profile and so can not blindly use the power* server profile definitions and overrides.
I suspect he needs a sysdeps/powerpc/powerpc64/e6500/ with overrides and Implies to pick up common powerpc definitions
[XuLei]
[XuLei] If we would not like to modify the generic files, another solution is to add the definitions directly in "sysdeps/powerpc/bits/atomic.h" file:
I am very happy to have all your comments, thanks.
[PATCH] Define "atomic_compare_and_exchange_bool_rel" for powerpc
Define the "atomic_compare_and_exchange_bool_rel" for powerpc,
otherwise it will use "atomic_compare_and_exchange_bool_acq" by default.
---
sysdeps/powerpc/bits/atomic.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/sysdeps/powerpc/bits/atomic.h b/sysdeps/powerpc/bits/atomic.h
index d71f64e..d2b91ba 100644
--- a/sysdeps/powerpc/bits/atomic.h
+++ b/sysdeps/powerpc/bits/atomic.h
@@ -80,6 +80,12 @@ typedef uintmax_t uatomic_max_t;
#define atomic_full_barrier() __asm ("sync" ::: "memory")
#define atomic_write_barrier() __asm ("eieio" ::: "memory")
+#ifdef __arch_compare_and_exchange_bool_32_rel
+#define atomic_compare_and_exchange_bool_rel(mem, newval, oldval) \
+ __atomic_bool_bysize (__arch_compare_and_exchange_bool,rel, \
+ mem, newval, oldval)
+#endif
+
#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
({ \
__typeof (*(mem)) __tmp; \
--------------------------------------[Xulei]
> These files define atomic_compare_and_exchange_val_rel(), which should
> prevent from defining the atomic_compare_and_exchange_val_rel() as
> atomic_compare_and_exchange_val_acq() in the generic file.
>
> So, there is a chance your build didn't use these files...
> How are you configuring your glibc build?
>