Revision 7f680d7ec3153dffc4d37aea517ead2b9fb9b8e9 authored by Linus Torvalds on 20 August 2017, 16:36:52 UTC, committed by Linus Torvalds on 20 August 2017, 16:36:52 UTC
Pull x86 fixes from Thomas Gleixner: "Another pile of small fixes and updates for x86: - Plug a hole in the SMAP implementation which misses to clear AC on NMI entry - Fix the norandmaps/ADDR_NO_RANDOMIZE logic so the command line parameter works correctly again - Use the proper accessor in the startup64 code for next_early_pgt to prevent accessing of invalid addresses and faulting in the early boot code. - Prevent CPU hotplug lock recursion in the MTRR code - Unbreak CPU0 hotplugging - Rename overly long CPUID bits which got introduced in this cycle - Two commits which mark data 'const' and restrict the scope of data and functions to file scope by making them 'static'" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86: Constify attribute_group structures x86/boot/64/clang: Use fixup_pointer() to access 'next_early_pgt' x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checks x86: Fix norandmaps/ADDR_NO_RANDOMIZE x86/mtrr: Prevent CPU hotplug lock recursion x86: Mark various structures and functions as 'static' x86/cpufeature, kvm/svm: Rename (shorten) the new "virtualized VMSAVE/VMLOAD" CPUID flag x86/smpboot: Unbreak CPU0 hotplug x86/asm/64: Clear AC on NMI entries
preempt.c
/*
* Preemptible hypercalls
*
* Copyright (C) 2014 Citrix Systems R&D ltd.
*
* This source code is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <xen/xen-ops.h>
#ifndef CONFIG_PREEMPT
/*
* Some hypercalls issued by the toolstack can take many 10s of
* seconds. Allow tasks running hypercalls via the privcmd driver to
* be voluntarily preempted even if full kernel preemption is
* disabled.
*
* Such preemptible hypercalls are bracketed by
* xen_preemptible_hcall_begin() and xen_preemptible_hcall_end()
* calls.
*/
DEFINE_PER_CPU(bool, xen_in_preemptible_hcall);
EXPORT_SYMBOL_GPL(xen_in_preemptible_hcall);
asmlinkage __visible void xen_maybe_preempt_hcall(void)
{
if (unlikely(__this_cpu_read(xen_in_preemptible_hcall)
&& need_resched())) {
/*
* Clear flag as we may be rescheduled on a different
* cpu.
*/
__this_cpu_write(xen_in_preemptible_hcall, false);
_cond_resched();
__this_cpu_write(xen_in_preemptible_hcall, true);
}
}
#endif /* CONFIG_PREEMPT */
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