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>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
kernel-team@android.com
Subject: [PATCH v6 20/21] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores
Date: Tue, 18 May 2021 10:47:24 +0100 [thread overview]
Message-ID: <20210518094725.7701-21-will@kernel.org> (raw)
In-Reply-To: <20210518094725.7701-1-will@kernel.org>
The scheduler now knows enough about these braindead systems to place
32-bit tasks accordingly, so throw out the safety checks and allow the
ret-to-user path to avoid do_notify_resume() if there is nothing to do.
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/process.c | 14 +-------------
arch/arm64/kernel/signal.c | 26 --------------------------
2 files changed, 1 insertion(+), 39 deletions(-)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 8e0da06c4e77..de9833f08742 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -527,15 +527,6 @@ static void erratum_1418040_thread_switch(struct task_struct *prev,
write_sysreg(val, cntkctl_el1);
}
-static void compat_thread_switch(struct task_struct *next)
-{
- if (!is_compat_thread(task_thread_info(next)))
- return;
-
- if (static_branch_unlikely(&arm64_mismatched_32bit_el0))
- set_tsk_thread_flag(next, TIF_NOTIFY_RESUME);
-}
-
static void update_sctlr_el1(u64 sctlr)
{
/*
@@ -577,7 +568,6 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
ssbs_thread_switch(next);
erratum_1418040_thread_switch(prev, next);
ptrauth_thread_switch_user(next);
- compat_thread_switch(next);
/*
* Complete any pending TLB or cache maintenance on this CPU in case
@@ -657,10 +647,8 @@ void arch_setup_new_exec(void)
* at the point of execve(), although we try a bit harder to
* honour the cpuset hierarchy.
*/
- if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) {
+ if (static_branch_unlikely(&arm64_mismatched_32bit_el0))
force_compatible_cpus_allowed_ptr(current);
- set_tsk_thread_flag(current, TIF_NOTIFY_RESUME);
- }
} else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) {
relax_compatible_cpus_allowed_ptr(current);
}
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index f8192f4ae0b8..6237486ff6bb 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -911,19 +911,6 @@ static void do_signal(struct pt_regs *regs)
restore_saved_sigmask();
}
-static bool cpu_affinity_invalid(struct pt_regs *regs)
-{
- if (!compat_user_mode(regs))
- return false;
-
- /*
- * We're preemptible, but a reschedule will cause us to check the
- * affinity again.
- */
- return !cpumask_test_cpu(raw_smp_processor_id(),
- system_32bit_el0_cpumask());
-}
-
asmlinkage void do_notify_resume(struct pt_regs *regs,
unsigned long thread_flags)
{
@@ -951,19 +938,6 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
if (thread_flags & _TIF_NOTIFY_RESUME) {
tracehook_notify_resume(regs);
rseq_handle_notify_resume(NULL, regs);
-
- /*
- * If we reschedule after checking the affinity
- * then we must ensure that TIF_NOTIFY_RESUME
- * is set so that we check the affinity again.
- * Since tracehook_notify_resume() clears the
- * flag, ensure that the compiler doesn't move
- * it after the affinity check.
- */
- barrier();
-
- if (cpu_affinity_invalid(regs))
- force_sig(SIGKILL);
}
if (thread_flags & _TIF_FOREIGN_FPSTATE)
--
2.31.1.751.gd2f1c929bd-goog
next prev parent reply other threads:[~2021-05-18 9:49 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-18 9:47 [PATCH v6 00/21] Add support for 32-bit tasks on asymmetric AArch32 systems Will Deacon
2021-05-18 9:47 ` [PATCH v6 01/21] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2021-05-21 10:47 ` Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 02/21] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2021-05-21 10:25 ` Catalin Marinas
2021-05-24 12:05 ` Will Deacon
2021-05-24 13:49 ` Catalin Marinas
2021-05-21 10:41 ` Catalin Marinas
2021-05-24 12:09 ` Will Deacon
2021-05-24 13:46 ` Catalin Marinas
2021-05-21 15:22 ` Qais Yousef
2021-05-24 20:21 ` Will Deacon
2021-05-18 9:47 ` [PATCH v6 03/21] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2021-05-21 10:47 ` Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 04/21] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2021-05-21 10:55 ` Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 05/21] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2021-05-21 11:00 ` Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 06/21] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2021-05-21 16:03 ` Peter Zijlstra
2021-05-24 12:17 ` Will Deacon
2021-05-18 9:47 ` [PATCH v6 07/21] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2021-05-21 17:39 ` Qais Yousef
2021-05-24 20:21 ` Will Deacon
2021-05-18 9:47 ` [PATCH v6 08/21] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Will Deacon
2021-05-21 16:25 ` Qais Yousef
2021-05-24 21:09 ` Will Deacon
2021-05-18 9:47 ` [PATCH v6 09/21] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Will Deacon
2021-05-18 9:47 ` [PATCH v6 10/21] sched: Introduce task_struct::user_cpus_ptr to track requested affinity Will Deacon
2021-05-18 9:47 ` [PATCH v6 11/21] sched: Split the guts of sched_setaffinity() into a helper function Will Deacon
2021-05-21 16:41 ` Qais Yousef
2021-05-24 21:16 ` Will Deacon
2021-05-18 9:47 ` [PATCH v6 12/21] sched: Allow task CPU affinity to be restricted on asymmetric systems Will Deacon
2021-05-21 17:11 ` Qais Yousef
2021-05-24 21:43 ` Will Deacon
2021-05-18 9:47 ` [PATCH v6 13/21] sched: Admit forcefully-affined tasks into SCHED_DEADLINE Will Deacon
2021-05-18 10:20 ` Quentin Perret
2021-05-18 10:28 ` Will Deacon
2021-05-18 10:48 ` Quentin Perret
2021-05-18 10:59 ` Will Deacon
2021-05-18 13:19 ` Quentin Perret
2021-05-20 9:13 ` Juri Lelli
2021-05-20 10:16 ` Will Deacon
2021-05-20 10:33 ` Quentin Perret
2021-05-20 12:38 ` Juri Lelli
2021-05-20 12:38 ` Daniel Bristot de Oliveira
2021-05-20 15:06 ` Dietmar Eggemann
2021-05-20 16:00 ` Daniel Bristot de Oliveira
2021-05-20 17:55 ` Dietmar Eggemann
2021-05-20 18:03 ` Will Deacon
2021-05-21 11:26 ` Dietmar Eggemann
2021-05-20 18:01 ` Will Deacon
2021-05-21 5:25 ` Juri Lelli
2021-05-21 8:15 ` Quentin Perret
2021-05-21 8:39 ` Juri Lelli
2021-05-21 10:37 ` Will Deacon
2021-05-21 11:23 ` Dietmar Eggemann
2021-05-21 13:02 ` Quentin Perret
2021-05-21 14:04 ` Juri Lelli
2021-05-21 17:47 ` Dietmar Eggemann
2021-05-21 13:00 ` Daniel Bristot de Oliveira
2021-05-21 13:12 ` Quentin Perret
2021-05-24 20:47 ` Will Deacon
2021-05-18 9:47 ` [PATCH v6 14/21] freezer: Add frozen_or_skipped() helper function Will Deacon
2021-05-18 9:47 ` [PATCH v6 15/21] sched: Defer wakeup in ttwu() for unschedulable frozen tasks Will Deacon
2021-05-18 9:47 ` [PATCH v6 16/21] arm64: Implement task_cpu_possible_mask() Will Deacon
2021-05-24 14:57 ` Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 17/21] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2021-05-24 15:02 ` Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 18/21] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2021-05-24 15:46 ` Catalin Marinas
2021-05-24 20:32 ` Will Deacon
2021-05-25 9:43 ` Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 19/21] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2021-05-24 15:47 ` Catalin Marinas
2021-05-18 9:47 ` Will Deacon [this message]
2021-05-24 15:47 ` [PATCH v6 20/21] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Catalin Marinas
2021-05-18 9:47 ` [PATCH v6 21/21] Documentation: arm64: describe asymmetric 32-bit support Will Deacon
2021-05-21 17:37 ` Qais Yousef
2021-05-24 21:46 ` Will Deacon
2021-05-24 16:22 ` Catalin Marinas
2021-05-21 17:45 ` [PATCH v6 00/21] Add support for 32-bit tasks on asymmetric AArch32 systems Qais Yousef
2021-05-24 22:08 ` Will Deacon
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