From: Heiko Carstens <hca@linux.ibm.com>
To: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
David Hildenbrand <david@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
kvm@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-s390@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Shuah Khan <shuah@kernel.org>,
Sven Schnelle <svens@linux.ibm.com>
Subject: Re: [PATCH 5/5] s390/uaccess: add cmpxchg_user_key()
Date: Wed, 9 Nov 2022 23:24:24 +0100 [thread overview]
Message-ID: <Y2womHanaMzETfwU@osiris> (raw)
In-Reply-To: <f604b6038c4a8bad5123e1f1f14b15c2190f28e9.camel@linux.ibm.com>
On Wed, Nov 09, 2022 at 04:46:29PM +0100, Janis Schoetterl-Glausch wrote:
> On Wed, 2022-11-02 at 15:19 +0100, Heiko Carstens wrote:
> > + case 1: {
> > + unsigned int prev, tmp, shift;
> > +
> > + shift = (3 ^ (address & 3)) << 3;
> > + address ^= address & 3;
> > + asm volatile(
> > + " spka 0(%[key])\n"
> > + " sacf 256\n"
> > + "0: l %[prev],%[address]\n"
> > + "1: nr %[prev],%[mask]\n"
> > + " lr %[tmp],%[prev]\n"
> > + " or %[prev],%[old]\n"
> > + " or %[tmp],%[new]\n"
> > + "2: cs %[prev],%[tmp],%[address]\n"
> > + "3: jnl 4f\n"
> > + " xr %[tmp],%[prev]\n"
> > + " nr %[tmp],%[mask]\n"
>
> Are you only entertaining cosmetic changes to cmpxchg.h?
I fail to parse what you are trying to say. Please elaborate.
> The loop condition being imprecise seems non-ideal.
What exactly is imprecise?
> > + [key] "a" (key),
>
> Why did you get rid of the << 4 shift?
> That's inconsistent with the other uaccess functions that take an access key.
That's not only inconsistent, but also a bug.
Thank you for pointing this out. Will be fixed.
next prev parent reply other threads:[~2022-11-09 22:24 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-12 20:56 [PATCH v2 0/9] KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg Janis Schoetterl-Glausch
2022-10-12 20:56 ` [PATCH v2 1/9] s390/uaccess: Add storage key checked cmpxchg access to user space Janis Schoetterl-Glausch
2022-10-20 11:18 ` Heiko Carstens
2022-10-20 13:40 ` Nico Boehr
2022-10-21 19:22 ` Heiko Carstens
2022-11-02 14:12 ` Heiko Carstens
2022-11-02 14:16 ` [PATCH 1/5] s390/cmpxchg: use symbolic names for inline assembly operands Heiko Carstens
2022-11-02 14:17 ` [PATCH 2/5] s390/cmpxchg: make variables local to each case label Heiko Carstens
2022-11-02 14:18 ` [PATCH 3/5] s390/cmpxchg: remove digits from input constraints Heiko Carstens
2022-11-02 14:18 ` [PATCH 4/5] s390/extable: add EX_TABLE_UA_LOAD_REGPAIR() macro Heiko Carstens
2022-11-02 14:19 ` [PATCH 5/5] s390/uaccess: add cmpxchg_user_key() Heiko Carstens
2022-11-09 15:46 ` Janis Schoetterl-Glausch
2022-11-09 22:24 ` Heiko Carstens [this message]
2022-11-10 11:01 ` Janis Schoetterl-Glausch
2022-11-10 11:32 ` Heiko Carstens
2022-11-13 18:20 ` Heiko Carstens
2022-11-16 19:36 ` [PATCH v2 1/9] s390/uaccess: Add storage key checked cmpxchg access to user space Janis Schoetterl-Glausch
2022-11-17 8:42 ` Nico Boehr
2022-10-12 20:56 ` [PATCH v2 2/9] KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg Janis Schoetterl-Glausch
2022-10-13 13:48 ` kernel test robot
2022-10-12 20:56 ` [PATCH v2 3/9] Documentation: KVM: s390: Describe KVM_S390_MEMOP_F_CMPXCHG Janis Schoetterl-Glausch
2022-10-12 20:56 ` [PATCH v2 4/9] KVM: s390: selftest: memop: Pass mop_desc via pointer Janis Schoetterl-Glausch
2022-10-12 20:56 ` [PATCH v2 5/9] KVM: s390: selftest: memop: Replace macros by functions Janis Schoetterl-Glausch
2022-10-12 20:56 ` [PATCH v2 6/9] KVM: s390: selftest: memop: Add cmpxchg tests Janis Schoetterl-Glausch
2022-10-12 20:56 ` [PATCH v2 7/9] KVM: s390: selftest: memop: Add bad address test Janis Schoetterl-Glausch
2022-10-13 13:17 ` Nico Boehr
2022-10-12 20:56 ` [PATCH v2 8/9] KVM: s390: selftest: memop: Fix typo Janis Schoetterl-Glausch
2022-10-13 13:16 ` Nico Boehr
2022-10-12 20:56 ` [PATCH v2 9/9] KVM: s390: selftest: memop: Fix wrong address being used in test Janis Schoetterl-Glausch
2022-10-13 13:15 ` Nico Boehr
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