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CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the preempt anand xen-ops code over to use CONFIG_PREEMPTION. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Juergen Gross <jgross@suse.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: xen-devel@lists.xenproject.org Link: https://lore.kernel.org/r/20191015191821.11479-23-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
41 lines
1,022 B
C
41 lines
1,022 B
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Preemptible hypercalls
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*
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* Copyright (C) 2014 Citrix Systems R&D ltd.
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*/
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#include <linux/sched.h>
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#include <xen/xen-ops.h>
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#ifndef CONFIG_PREEMPTION
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/*
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* Some hypercalls issued by the toolstack can take many 10s of
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* seconds. Allow tasks running hypercalls via the privcmd driver to
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* be voluntarily preempted even if full kernel preemption is
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* disabled.
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*
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* Such preemptible hypercalls are bracketed by
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* xen_preemptible_hcall_begin() and xen_preemptible_hcall_end()
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* calls.
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*/
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DEFINE_PER_CPU(bool, xen_in_preemptible_hcall);
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EXPORT_SYMBOL_GPL(xen_in_preemptible_hcall);
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asmlinkage __visible void xen_maybe_preempt_hcall(void)
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{
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if (unlikely(__this_cpu_read(xen_in_preemptible_hcall)
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&& need_resched())) {
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/*
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* Clear flag as we may be rescheduled on a different
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* cpu.
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*/
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__this_cpu_write(xen_in_preemptible_hcall, false);
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_cond_resched();
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__this_cpu_write(xen_in_preemptible_hcall, true);
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}
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}
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#endif /* CONFIG_PREEMPTION */
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