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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@google.com>, Tejun Heo <tj@kernel.org>,
	Li Zefan <lizefan@huawei.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	kernel-team@android.com
Subject: [PATCH v3 05/14] arm64: Advertise CPUs capable of running 32-bit applications in sysfs
Date: Fri, 13 Nov 2020 09:37:10 +0000	[thread overview]
Message-ID: <20201113093720.21106-6-will@kernel.org> (raw)
In-Reply-To: <20201113093720.21106-1-will@kernel.org>

Since 32-bit applications will be killed if they are caught trying to
execute on a 64-bit-only CPU in a mismatched system, advertise the set
of 32-bit capable CPUs to userspace in sysfs.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
 .../ABI/testing/sysfs-devices-system-cpu      |  9 +++++++++
 arch/arm64/kernel/cpufeature.c                | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 1a04ca8162ad..8a2e377b0dde 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -493,6 +493,15 @@ Description:	AArch64 CPU registers
 		'identification' directory exposes the CPU ID registers for
 		identifying model and revision of the CPU.
 
+What:		/sys/devices/system/cpu/aarch32_el0
+Date:		November 2020
+Contact:	Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
+Description:	Identifies the subset of CPUs in the system that can execute
+		AArch32 (32-bit ARM) applications. If present, the same format as
+		/sys/devices/system/cpu/{offline,online,possible,present} is used.
+		If absent, then all or none of the CPUs can execute AArch32
+		applications and execve() will behave accordingly.
+
 What:		/sys/devices/system/cpu/cpu#/cpu_capacity
 Date:		December 2016
 Contact:	Linux kernel mailing list <linux-kernel@vger.kernel.org>
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 1aa01ecc133f..a7a9b7bffc49 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -67,6 +67,7 @@
 #include <linux/crash_dump.h>
 #include <linux/sort.h>
 #include <linux/stop_machine.h>
+#include <linux/sysfs.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/cpu.h>
@@ -1272,6 +1273,24 @@ const struct cpumask *system_32bit_el0_cpumask(void)
 	return cpu_present_mask;
 }
 
+static ssize_t aarch32_el0_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	const struct cpumask *mask = system_32bit_el0_cpumask();
+
+	return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(mask));
+}
+static const DEVICE_ATTR_RO(aarch32_el0);
+
+static int __init aarch32_el0_sysfs_init(void)
+{
+	if (!allow_mismatched_32bit_el0)
+		return 0;
+
+	return device_create_file(cpu_subsys.dev_root, &dev_attr_aarch32_el0);
+}
+device_initcall(aarch32_el0_sysfs_init);
+
 static bool has_32bit_el0(const struct arm64_cpu_capabilities *entry, int scope)
 {
 	if (!has_cpuid_feature(entry, scope))
-- 
2.29.2.299.gdc1121823c-goog


WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	kernel-team@android.com,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Quentin Perret <qperret@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	linux-kernel@vger.kernel.org, Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Ingo Molnar <mingo@redhat.com>, Li Zefan <lizefan@huawei.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>, Will Deacon <will@kernel.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>
Subject: [PATCH v3 05/14] arm64: Advertise CPUs capable of running 32-bit applications in sysfs
Date: Fri, 13 Nov 2020 09:37:10 +0000	[thread overview]
Message-ID: <20201113093720.21106-6-will@kernel.org> (raw)
In-Reply-To: <20201113093720.21106-1-will@kernel.org>

Since 32-bit applications will be killed if they are caught trying to
execute on a 64-bit-only CPU in a mismatched system, advertise the set
of 32-bit capable CPUs to userspace in sysfs.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
 .../ABI/testing/sysfs-devices-system-cpu      |  9 +++++++++
 arch/arm64/kernel/cpufeature.c                | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index 1a04ca8162ad..8a2e377b0dde 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -493,6 +493,15 @@ Description:	AArch64 CPU registers
 		'identification' directory exposes the CPU ID registers for
 		identifying model and revision of the CPU.
 
+What:		/sys/devices/system/cpu/aarch32_el0
+Date:		November 2020
+Contact:	Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
+Description:	Identifies the subset of CPUs in the system that can execute
+		AArch32 (32-bit ARM) applications. If present, the same format as
+		/sys/devices/system/cpu/{offline,online,possible,present} is used.
+		If absent, then all or none of the CPUs can execute AArch32
+		applications and execve() will behave accordingly.
+
 What:		/sys/devices/system/cpu/cpu#/cpu_capacity
 Date:		December 2016
 Contact:	Linux kernel mailing list <linux-kernel@vger.kernel.org>
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 1aa01ecc133f..a7a9b7bffc49 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -67,6 +67,7 @@
 #include <linux/crash_dump.h>
 #include <linux/sort.h>
 #include <linux/stop_machine.h>
+#include <linux/sysfs.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/cpu.h>
@@ -1272,6 +1273,24 @@ const struct cpumask *system_32bit_el0_cpumask(void)
 	return cpu_present_mask;
 }
 
+static ssize_t aarch32_el0_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	const struct cpumask *mask = system_32bit_el0_cpumask();
+
+	return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(mask));
+}
+static const DEVICE_ATTR_RO(aarch32_el0);
+
+static int __init aarch32_el0_sysfs_init(void)
+{
+	if (!allow_mismatched_32bit_el0)
+		return 0;
+
+	return device_create_file(cpu_subsys.dev_root, &dev_attr_aarch32_el0);
+}
+device_initcall(aarch32_el0_sysfs_init);
+
 static bool has_32bit_el0(const struct arm64_cpu_capabilities *entry, int scope)
 {
 	if (!has_cpuid_feature(entry, scope))
-- 
2.29.2.299.gdc1121823c-goog


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  parent reply	other threads:[~2020-11-13  9:38 UTC|newest]

Thread overview: 104+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-13  9:37 [PATCH v3 00/14] An alternative series for asymmetric AArch32 systems Will Deacon
2020-11-13  9:37 ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 01/14] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 02/14] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-19 11:27   ` Valentin Schneider
2020-11-19 11:27     ` Valentin Schneider
2020-11-19 13:12     ` Will Deacon
2020-11-19 13:12       ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 03/14] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 04/14] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-13  9:37 ` Will Deacon [this message]
2020-11-13  9:37   ` [PATCH v3 05/14] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2020-11-13  9:37 ` [PATCH v3 06/14] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 07/14] sched: Introduce restrict_cpus_allowed_ptr() to limit task CPU affinity Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-19  9:18   ` Quentin Perret
2020-11-19  9:18     ` Quentin Perret
2020-11-19 11:03     ` Quentin Perret
2020-11-19 11:03       ` Quentin Perret
2020-11-19 11:05     ` Will Deacon
2020-11-19 11:05       ` Will Deacon
2020-11-19 11:27       ` Valentin Schneider
2020-11-19 11:27         ` Valentin Schneider
2020-11-19 13:13         ` Will Deacon
2020-11-19 13:13           ` Will Deacon
2020-11-19 14:54           ` Valentin Schneider
2020-11-19 14:54             ` Valentin Schneider
2020-11-19 16:41             ` Will Deacon
2020-11-19 16:41               ` Will Deacon
2020-11-19 12:47   ` Valentin Schneider
2020-11-19 12:47     ` Valentin Schneider
2020-11-19 13:13     ` Will Deacon
2020-11-19 13:13       ` Will Deacon
2020-11-19 14:54       ` Valentin Schneider
2020-11-19 14:54         ` Valentin Schneider
2020-11-19 16:09       ` Peter Zijlstra
2020-11-19 16:09         ` Peter Zijlstra
2020-11-19 16:57         ` Valentin Schneider
2020-11-19 16:57           ` Valentin Schneider
2020-11-19 19:25           ` Will Deacon
2020-11-19 19:25             ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 08/14] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-19  9:24   ` Quentin Perret
2020-11-19  9:24     ` Quentin Perret
2020-11-19 11:06     ` Will Deacon
2020-11-19 11:06       ` Will Deacon
2020-11-19 16:19       ` Peter Zijlstra
2020-11-19 16:19         ` Peter Zijlstra
2020-11-19 16:30         ` Will Deacon
2020-11-19 16:30           ` Will Deacon
2020-11-19 16:44           ` Peter Zijlstra
2020-11-19 16:44             ` Peter Zijlstra
2020-11-19 16:51             ` Will Deacon
2020-11-19 16:51               ` Will Deacon
2020-11-19 16:14   ` Peter Zijlstra
2020-11-19 16:14     ` Peter Zijlstra
2020-11-19 16:28     ` Will Deacon
2020-11-19 16:28       ` Will Deacon
2020-11-19 16:42       ` Peter Zijlstra
2020-11-19 16:42         ` Peter Zijlstra
2020-11-19 16:48         ` Will Deacon
2020-11-19 16:48           ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-19  9:29   ` Quentin Perret
2020-11-19  9:29     ` Quentin Perret
2020-11-19 11:06     ` Will Deacon
2020-11-19 11:06       ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 10/14] sched: Introduce arch_cpu_allowed_mask() to limit fallback rq selection Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-19  9:38   ` Quentin Perret
2020-11-19  9:38     ` Quentin Perret
2020-11-19 11:07     ` Will Deacon
2020-11-19 11:07       ` Will Deacon
2020-11-19 20:39       ` Will Deacon
2020-11-19 20:39         ` Will Deacon
2020-11-23 14:48         ` Quentin Perret
2020-11-23 14:48           ` Quentin Perret
2020-11-13  9:37 ` [PATCH v3 11/14] sched: Reject CPU affinity changes based on arch_cpu_allowed_mask() Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-19  9:47   ` Quentin Perret
2020-11-19  9:47     ` Quentin Perret
2020-11-19 11:07     ` Will Deacon
2020-11-19 11:07       ` Will Deacon
2020-11-19 14:30       ` Quentin Perret
2020-11-19 14:30         ` Quentin Perret
2020-11-19 16:44         ` Will Deacon
2020-11-19 16:44           ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 12/14] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 13/14] arm64: Implement arch_cpu_allowed_mask() Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-13  9:37 ` [PATCH v3 14/14] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2020-11-13  9:37   ` Will Deacon
2020-11-19 16:11 ` [PATCH v3 00/14] An alternative series for asymmetric AArch32 systems Peter Zijlstra
2020-11-19 16:11   ` Peter Zijlstra
2020-11-19 16:39   ` Will Deacon
2020-11-19 16:39     ` Will Deacon

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