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 v4 08/14] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0
Date: Tue, 24 Nov 2020 15:50:33 +0000 [thread overview]
Message-ID: <20201124155039.13804-9-will@kernel.org> (raw)
In-Reply-To: <20201124155039.13804-1-will@kernel.org>
When exec'ing a 32-bit task on a system with mismatched support for
32-bit EL0, try to ensure that it starts life on a CPU that can actually
run it.
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/process.c | 42 ++++++++++++++++++++++++++++++++++++-
1 file changed, 41 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 1540ab0fbf23..72116b0c7c73 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -31,6 +31,7 @@
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/cpu.h>
+#include <linux/cpuset.h>
#include <linux/elfcore.h>
#include <linux/pm.h>
#include <linux/tick.h>
@@ -625,6 +626,45 @@ unsigned long arch_align_stack(unsigned long sp)
return sp & ~0xf;
}
+static void adjust_compat_task_affinity(struct task_struct *p)
+{
+ cpumask_var_t cpuset_mask;
+ const struct cpumask *possible_mask = system_32bit_el0_cpumask();
+ const struct cpumask *newmask = possible_mask;
+
+ /*
+ * Restrict the CPU affinity mask for a 32-bit task so that it contains
+ * only the 32-bit-capable subset of its original CPU mask. If this is
+ * empty, then try again with the cpuset allowed mask. If that fails,
+ * forcefully override it with the set of all 32-bit-capable CPUs that
+ * we know about.
+ *
+ * From the perspective of the task, this looks similar to what would
+ * happen if the 64-bit-only CPUs were hot-unplugged at the point of
+ * execve().
+ */
+ if (!restrict_cpus_allowed_ptr(p, possible_mask))
+ goto out;
+
+ if (alloc_cpumask_var(&cpuset_mask, GFP_KERNEL)) {
+ cpuset_cpus_allowed(p, cpuset_mask);
+ if (cpumask_and(cpuset_mask, cpuset_mask, possible_mask)) {
+ newmask = cpuset_mask;
+ goto out_set_mask;
+ }
+ }
+
+ if (printk_ratelimit()) {
+ printk_deferred("Overriding affinity for 32-bit process %d (%s) to CPUs %*pbl\n",
+ task_pid_nr(p), p->comm, cpumask_pr_args(newmask));
+ }
+out_set_mask:
+ set_cpus_allowed_ptr(p, newmask);
+ free_cpumask_var(cpuset_mask);
+out:
+ set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
+}
+
/*
* Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY.
*/
@@ -635,7 +675,7 @@ void arch_setup_new_exec(void)
if (is_compat_task()) {
mmflags = MMCF_AARCH32;
if (static_branch_unlikely(&arm64_mismatched_32bit_el0))
- set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
+ adjust_compat_task_affinity(current);
}
current->mm->context.flags = mmflags;
--
2.29.2.454.gaff20da3a2-goog
next prev parent reply other threads:[~2020-11-24 15:51 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 15:50 [PATCH v4 00/14] An alternative series for asymmetric AArch32 systems Will Deacon
2020-11-24 15:50 ` [PATCH v4 01/14] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2020-11-24 15:50 ` [PATCH v4 02/14] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-11-27 10:25 ` Marc Zyngier
2020-11-27 11:50 ` Will Deacon
2020-11-27 13:09 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-12-02 13:16 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 03/14] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-11-27 10:26 ` Marc Zyngier
2020-11-27 11:53 ` Will Deacon
2020-11-27 17:14 ` Marc Zyngier
2020-11-27 17:24 ` Quentin Perret
2020-11-27 18:16 ` Marc Zyngier
2020-12-01 16:57 ` Will Deacon
2020-12-02 8:18 ` Marc Zyngier
2020-12-02 17:27 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 04/14] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-11-27 13:12 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-12-02 13:52 ` Qais Yousef
2020-12-02 17:42 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 05/14] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2020-11-24 15:50 ` [PATCH v4 06/14] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-11-27 13:17 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 07/14] sched: Introduce restrict_cpus_allowed_ptr() to limit task CPU affinity Will Deacon
2020-11-27 9:49 ` Quentin Perret
2020-11-27 13:19 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-12-02 13:06 ` Qais Yousef
2020-11-24 15:50 ` Will Deacon [this message]
2020-11-27 10:01 ` [PATCH v4 08/14] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Quentin Perret
2020-11-27 13:23 ` Qais Yousef
2020-12-01 16:55 ` Will Deacon
2020-12-02 14:07 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2020-11-27 13:32 ` Qais Yousef
2020-11-30 17:05 ` Qais Yousef
2020-11-30 17:36 ` Quentin Perret
2020-12-01 11:58 ` Qais Yousef
2020-12-01 12:37 ` Quentin Perret
2020-12-01 14:11 ` Qais Yousef
2020-12-01 15:56 ` Quentin Perret
2020-12-01 22:30 ` Will Deacon
2020-12-02 11:34 ` Qais Yousef
2020-12-02 11:33 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 10/14] sched: Introduce arch_task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2020-11-24 15:50 ` [PATCH v4 11/14] sched: Reject CPU affinity changes based on arch_task_cpu_possible_mask() Will Deacon
2020-11-27 9:54 ` Quentin Perret
2020-11-24 15:50 ` [PATCH v4 12/14] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2020-11-27 13:41 ` Qais Yousef
2020-12-01 22:13 ` Will Deacon
2020-12-02 12:59 ` Qais Yousef
2020-12-02 17:42 ` Will Deacon
2020-12-02 18:08 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 13/14] arm64: Implement arch_task_cpu_possible_mask() Will Deacon
2020-11-27 13:41 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 14/14] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2020-11-27 13:58 ` [PATCH v4 00/14] An alternative series for asymmetric AArch32 systems Qais Yousef
2020-12-05 20:43 ` Pavel Machek
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=20201124155039.13804-9-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).