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 v5 05/15] arm64: Advertise CPUs capable of running 32-bit applications in sysfs
Date: Tue, 8 Dec 2020 13:28:25 +0000 [thread overview]
Message-ID: <20201208132835.6151-6-will@kernel.org> (raw)
In-Reply-To: <20201208132835.6151-1-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 bb53af53ce8d..088bf668cbe7 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_possible_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))
--
2.29.2.576.ga3fc446d84-goog
next prev parent reply other threads:[~2020-12-08 13:30 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-08 13:28 [PATCH v5 00/15] An alternative series for asymmetric AArch32 systems Will Deacon
2020-12-08 13:28 ` [PATCH v5 01/15] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2020-12-08 13:28 ` [PATCH v5 02/15] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-12-08 13:28 ` [PATCH v5 03/15] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-12-08 13:28 ` [PATCH v5 04/15] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-12-08 13:28 ` Will Deacon [this message]
2020-12-08 13:28 ` [PATCH v5 06/15] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2020-12-08 13:28 ` [PATCH v5 07/15] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2020-12-17 12:15 ` Qais Yousef
2020-12-17 13:44 ` Peter Zijlstra
2020-12-17 14:59 ` Will Deacon
2020-12-17 15:00 ` Qais Yousef
2020-12-08 13:28 ` [PATCH v5 08/15] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Will Deacon
2020-12-28 3:54 ` Suren Baghdasaryan
2020-12-08 13:28 ` [PATCH v5 09/15] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Will Deacon
2020-12-08 13:28 ` [PATCH v5 10/15] sched: Introduce force_compatible_cpus_allowed_ptr() to limit CPU affinity Will Deacon
2020-12-28 4:29 ` Suren Baghdasaryan
2020-12-08 13:28 ` [PATCH v5 11/15] arm64: Implement task_cpu_possible_mask() Will Deacon
2020-12-08 13:28 ` [PATCH v5 12/15] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2020-12-08 13:28 ` [PATCH v5 13/15] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2020-12-08 13:28 ` [PATCH v5 14/15] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-12-08 13:28 ` [PATCH v5 15/15] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2020-12-15 17:36 ` [PATCH v5 00/15] An alternative series for asymmetric AArch32 systems Peter Zijlstra
2020-12-15 18:50 ` Will Deacon
2020-12-17 10:55 ` Peter Zijlstra
2020-12-16 11:16 ` Qais Yousef
2020-12-16 14:14 ` Will Deacon
2020-12-16 16:48 ` Qais Yousef
2020-12-16 18:21 ` Suren Baghdasaryan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201208132835.6151-6-will@kernel.org \
--to=will@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=gregkh@linuxfoundation.org \
--cc=hannes@cmpxchg.org \
--cc=juri.lelli@redhat.com \
--cc=kernel-team@android.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lizefan@huawei.com \
--cc=maz@kernel.org \
--cc=mingo@redhat.com \
--cc=morten.rasmussen@arm.com \
--cc=peterz@infradead.org \
--cc=qais.yousef@arm.com \
--cc=qperret@google.com \
--cc=surenb@google.com \
--cc=tj@kernel.org \
--cc=vincent.guittot@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).