From: Peter Zijlstra <peterz@infradead.org>
To: ira.weiny@intel.com
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Subject: Re: [RFC PATCH 11/15] memremap: Add zone device access protection
Date: Tue, 14 Jul 2020 10:40:57 +0200 [thread overview]
Message-ID: <20200714084057.GP10769@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200714070220.3500839-12-ira.weiny@intel.com>
On Tue, Jul 14, 2020 at 12:02:16AM -0700, ira.weiny@intel.com wrote:
> +static pgprot_t dev_protection_enable_get(struct dev_pagemap *pgmap, pgprot_t prot)
> +{
> + if (pgmap->flags & PGMAP_PROT_ENABLED && dev_page_pkey != PKEY_INVALID) {
> + pgprotval_t val = pgprot_val(prot);
> +
> + mutex_lock(&dev_prot_enable_lock);
> + dev_protection_enable++;
> + /* Only enable the static branch 1 time */
> + if (dev_protection_enable == 1)
> + static_branch_enable(&dev_protection_static_key);
> + mutex_unlock(&dev_prot_enable_lock);
> +
> + prot = __pgprot(val | _PAGE_PKEY(dev_page_pkey));
> + }
> + return prot;
> +}
> +
> +static void dev_protection_enable_put(struct dev_pagemap *pgmap)
> +{
> + if (pgmap->flags & PGMAP_PROT_ENABLED && dev_page_pkey != PKEY_INVALID) {
> + mutex_lock(&dev_prot_enable_lock);
> + dev_protection_enable--;
> + if (dev_protection_enable == 0)
> + static_branch_disable(&dev_protection_static_key);
> + mutex_unlock(&dev_prot_enable_lock);
> + }
> +}
That's an anti-pattern vs static_keys, I'm thinking you actually want
static_key_slow_{inc,dec}() instead of {enable,disable}().
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WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: ira.weiny@intel.com
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Subject: Re: [RFC PATCH 11/15] memremap: Add zone device access protection
Date: Tue, 14 Jul 2020 10:40:57 +0200 [thread overview]
Message-ID: <20200714084057.GP10769@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200714070220.3500839-12-ira.weiny@intel.com>
On Tue, Jul 14, 2020 at 12:02:16AM -0700, ira.weiny@intel.com wrote:
> +static pgprot_t dev_protection_enable_get(struct dev_pagemap *pgmap, pgprot_t prot)
> +{
> + if (pgmap->flags & PGMAP_PROT_ENABLED && dev_page_pkey != PKEY_INVALID) {
> + pgprotval_t val = pgprot_val(prot);
> +
> + mutex_lock(&dev_prot_enable_lock);
> + dev_protection_enable++;
> + /* Only enable the static branch 1 time */
> + if (dev_protection_enable == 1)
> + static_branch_enable(&dev_protection_static_key);
> + mutex_unlock(&dev_prot_enable_lock);
> +
> + prot = __pgprot(val | _PAGE_PKEY(dev_page_pkey));
> + }
> + return prot;
> +}
> +
> +static void dev_protection_enable_put(struct dev_pagemap *pgmap)
> +{
> + if (pgmap->flags & PGMAP_PROT_ENABLED && dev_page_pkey != PKEY_INVALID) {
> + mutex_lock(&dev_prot_enable_lock);
> + dev_protection_enable--;
> + if (dev_protection_enable == 0)
> + static_branch_disable(&dev_protection_static_key);
> + mutex_unlock(&dev_prot_enable_lock);
> + }
> +}
That's an anti-pattern vs static_keys, I'm thinking you actually want
static_key_slow_{inc,dec}() instead of {enable,disable}().
next prev parent reply other threads:[~2020-07-14 8:41 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 7:02 [RFC PATCH 00/15] PKS: Add Protection Keys Supervisor (PKS) support ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 01/15] x86/pkeys: Create pkeys_internal.h ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 02/15] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 03/15] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 04/15] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 8:27 ` Peter Zijlstra
2020-07-14 8:27 ` Peter Zijlstra
2020-07-14 18:53 ` Ira Weiny
2020-07-14 18:53 ` Ira Weiny
2020-07-14 18:56 ` Dave Hansen
2020-07-14 18:56 ` Dave Hansen
2020-07-14 19:05 ` Peter Zijlstra
2020-07-14 19:05 ` Peter Zijlstra
2020-07-14 19:09 ` Ira Weiny
2020-07-14 19:09 ` Ira Weiny
2020-07-16 8:37 ` [x86/pks] 061e3e0b92: leaking-addresses.dmesg.uncheckedMSRaccesserror:WRMSRto0x6e1(triedtowrite0x0000000055555554)atrIP:(write_pkrs+0x15/0x2b) kernel test robot
2020-07-16 8:37 ` kernel test robot
2020-07-14 7:02 ` [RFC PATCH 05/15] x86/pks: Add PKS kernel API ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 06/15] x86/pks: Add a debugfs file for allocated PKS keys ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 07/15] Documentation/pkeys: Update documentation for kernel pkeys ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 08/15] x86/pks: Add PKS Test code ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 09/15] fs/dax: Remove unused size parameter ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 10/15] drivers/dax: Expand lock scope to cover the use of addresses ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 11/15] memremap: Add zone device access protection ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 8:40 ` Peter Zijlstra [this message]
2020-07-14 8:40 ` Peter Zijlstra
2020-07-14 19:10 ` Ira Weiny
2020-07-14 19:10 ` Ira Weiny
2020-07-14 19:40 ` Peter Zijlstra
2020-07-14 19:40 ` Peter Zijlstra
2020-07-14 7:02 ` [RFC PATCH 12/15] kmap: Add stray write protection for device pages ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 8:44 ` Peter Zijlstra
2020-07-14 8:44 ` Peter Zijlstra
2020-07-14 19:06 ` Ira Weiny
2020-07-14 19:06 ` Ira Weiny
2020-07-14 19:29 ` Peter Zijlstra
2020-07-14 19:29 ` Peter Zijlstra
2020-07-14 19:42 ` Dave Hansen
2020-07-14 19:42 ` Dave Hansen
2020-07-14 19:49 ` Peter Zijlstra
2020-07-14 19:49 ` Peter Zijlstra
2020-07-14 20:00 ` Ira Weiny
2020-07-14 20:00 ` Ira Weiny
2020-07-14 7:02 ` [RFC PATCH 13/15] dax: Stray write protection for dax_direct_access() ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 14/15] nvdimm/pmem: Stray write protection for pmem->virt_addr ira.weiny
2020-07-14 7:02 ` ira.weiny
2020-07-14 7:02 ` [RFC PATCH 15/15] [dax|pmem]: Enable stray write protection ira.weiny
2020-07-14 7:02 ` ira.weiny
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