linux/arch/x86/kernel
Li Zhong 9b132fbe54 Add rcu user eqs exception hooks for async page fault
This patch adds user eqs exception hooks for async page fault page not
present code path, to exit the user eqs and re-enter it as necessary.

Async page fault is different from other exceptions that it may be
triggered from idle process, so we still need rcu_irq_enter() and
rcu_irq_exit() to exit cpu idle eqs when needed, to protect the code
that needs use rcu.

As Frederic pointed out it would be safest and simplest to protect the
whole kvm_async_pf_task_wait(). Otherwise, "we need to check all the
code there deeply for potential RCU uses and ensure it will never be
extended later to use RCU.".

However, We'd better re-enter the cpu idle eqs if we get the exception
in cpu idle eqs, by calling rcu_irq_exit() before native_safe_halt().

So the patch does what Frederic suggested for rcu_irq_*() API usage
here, except that I moved the rcu_irq_*() pair originally in
do_async_page_fault() into kvm_async_pf_task_wait().

That's because, I think it's better to have rcu_irq_*() pairs to be in
one function ( rcu_irq_exit() after rcu_irq_enter() ), especially here,
kvm_async_pf_task_wait() has other callers, which might cause
rcu_irq_exit() be called without a matching rcu_irq_enter() before it,
which is illegal if the cpu happens to be in rcu idle state.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
2012-12-18 15:15:41 +02:00
..
acpi Merge branch 'acpi-general' 2012-11-29 21:43:06 +01:00
apic PCI changes for the v3.8 merge window: 2012-12-13 12:14:47 -08:00
cpu Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-12-13 12:00:02 -08:00
.gitignore
alternative.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-10-01 10:47:45 -07:00
amd_gart_64.c X86 & IA64: adapt for dma_map_ops changes 2012-03-28 16:36:31 +02:00
amd_nb.c Merge branch 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-22 16:07:45 -07:00
apb_timer.c Merge branch 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-07-23 10:34:47 -07:00
aperture_64.c x86/gart: Fix kmemleak warning 2012-06-06 11:58:38 +02:00
apm_32.c x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level> 2012-06-06 09:17:22 +02:00
asm-offsets.c x86, um/x86: switch to generic sys_execve and kernel_execve 2012-09-30 22:53:32 -04:00
asm-offsets_32.c x86: Generate system call tables and unistd_*.h from tables 2011-11-17 13:35:37 -08:00
asm-offsets_64.c x32: If configured, add x32 system calls to system call tables 2012-02-20 12:52:06 -08:00
audit_64.c
bootflag.c
check.c x86: kernel/check.c simple_strtoul cleanup 2012-05-15 15:36:41 -07:00
cpuid.c Use get_online_cpus to avoid races involving CPU hotplug 2012-09-23 07:43:56 -07:00
crash.c x86/kexec: crash_vmclear_local_vmcss needs __rcu 2012-12-11 19:55:23 -02:00
crash_dump_32.c x86: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:15 +08:00
crash_dump_64.c
devicetree.c x86: dt: Use linear irq domain for ioapic(s) 2012-08-21 22:16:57 +02:00
doublefault_32.c
dumpstack.c x86: Move call to print_modules() out of show_regs() 2012-06-20 14:33:48 +02:00
dumpstack_32.c x86: Move call to print_modules() out of show_regs() 2012-06-20 14:33:48 +02:00
dumpstack_64.c x86: Move call to print_modules() out of show_regs() 2012-06-20 14:33:48 +02:00
e820.c x86, mm: Trim memory in memblock to be page aligned 2012-10-24 11:52:21 -07:00
early-quirks.c
early_printk.c Revert "x86/early_printk: Replace obsolete simple_strtoul() usage with kstrtoint()" 2012-07-22 15:47:52 +02:00
entry_32.S x86, um: switch to generic fork/vfork/clone 2012-11-28 22:13:44 -05:00
entry_64.S Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-12-12 12:22:13 -08:00
ftrace.c ftrace/x86: Add save_regs for i386 function calls 2012-07-19 13:20:37 -04:00
head.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
head32.c x86, realmode: Move ACPI wakeup to unified realmode code 2012-05-08 11:46:05 -07:00
head64.c x86, realmode: Move ACPI wakeup to unified realmode code 2012-05-08 11:46:05 -07:00
head_32.S Merge branch 'x86-bsp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-12-11 19:56:33 -08:00
head_64.S x86-64, hotplug: Add start_cpu0() entry point to head_64.S 2012-11-14 09:39:51 -08:00
hpet.c x86: hpet: Fix masking of MSI interrupts 2012-11-02 22:53:27 +01:00
hw_breakpoint.c
i386_ksyms_32.c
i387.c x86/i387.c: Initialize thread xstate only on CPU0 only once 2012-11-14 15:28:11 -08:00
i8237.c
i8253.c x86: Use common i8253 clockevent 2011-07-01 10:37:14 +02:00
i8259.c x86/irq/i8259: Fix incorrect comment 2012-08-22 09:34:24 +02:00
io_delay.c
ioport.c
irq.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-10-01 11:13:33 -07:00
irq_32.c x86: Use common threadinfo allocator 2012-05-08 14:08:44 +02:00
irq_64.c x86: Add stack top margin for stack overflow checking 2011-12-07 09:27:11 +01:00
irq_work.c
irqinit.c x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR 2012-06-27 19:29:13 -07:00
jump_label.c jump_label, x86: Fix section mismatch 2011-12-06 20:41:02 +01:00
kdebugfs.c arch/x86/kernel/kdebugfs.c: Ensure a consistent return value in error case 2012-07-26 15:07:20 +02:00
kgdb.c kgdb,x86: fix warning about unused variable 2012-10-12 06:37:34 -05:00
kprobes-common.h x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
kprobes-opt.c x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
kprobes.c kprobes/x86: Move skip_singlestep up 2012-09-20 14:48:16 +02:00
kvm.c Add rcu user eqs exception hooks for async page fault 2012-12-18 15:15:41 +02:00
kvmclock.c x86: kvm guest: pvclock vsyscall support 2012-11-27 23:29:10 -02:00
ldt.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
machine_kexec_32.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
machine_kexec_64.c
Makefile tracing,x86: Add a TSC trace_clock 2012-11-13 15:48:27 -05:00
microcode_amd.c x86, microcode, AMD: Add support for family 16h processors 2012-11-20 22:23:28 -08:00
microcode_core.c Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-10-01 11:15:17 -07:00
microcode_intel.c x86, microcode: Add a refresh firmware flag to ->request_microcode_fw 2012-08-22 16:15:58 -07:00
mmconf-fam10h_64.c
module.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-07-24 13:34:56 -07:00
mpparse.c Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-05-29 20:14:53 -07:00
msr.c Use get_online_cpus to avoid races involving CPU hotplug 2012-09-23 07:43:56 -07:00
nmi.c x86: Save cr2 in NMI in case NMIs take a page fault (for i386) 2012-06-08 18:51:12 -04:00
nmi_selftest.c x86/nmi: Clean up register_nmi_handler() usage 2012-06-20 14:23:17 +02:00
paravirt-spinlocks.c
paravirt.c x86, pvops: Remove hooks for {rd,wr}msr_safe_regs 2012-06-07 11:41:08 -07:00
paravirt_patch_32.c
paravirt_patch_64.c
pci-calgary_64.c x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level> 2012-06-06 09:17:22 +02:00
pci-dma.c iommu: Remove group_mf 2012-06-25 13:48:30 +02:00
pci-iommu_table.c arch/x86/kernel/pci-iommu_table.c: Convert sprintf_symbol to %pS 2011-05-10 10:21:35 +02:00
pci-nommu.c X86: integrate CMA with DMA-mapping subsystem 2012-05-21 15:09:38 +02:00
pci-swiotlb.c X86 & IA64: adapt for dma_map_ops changes 2012-03-28 16:36:31 +02:00
pcspeaker.c
perf_regs.c perf: Fix off by one test in perf_reg_value() 2012-09-19 17:08:40 +02:00
probe_roms.c x86/pci/probe_roms: Add missing __iomem annotation to pci_map_biosrom() 2012-09-05 10:52:25 +02:00
process.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-12-12 12:22:13 -08:00
process_32.c flagday: don't pass regs to copy_thread() 2012-11-28 23:43:42 -05:00
process_64.c flagday: don't pass regs to copy_thread() 2012-11-28 23:43:42 -05:00
ptrace.c Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 2012-12-03 06:27:05 +01:00
pvclock.c x86: pvclock: generic pvclock vsyscall initialization 2012-11-27 23:29:09 -02:00
quirks.c x86/PCI: move fixup hooks from __init to __devinit 2012-06-12 09:10:54 -06:00
reboot.c x86/reboot: Remove quirk entry for SBC FITPC 2012-10-04 12:22:32 +02:00
reboot_fixups_32.c
relocate_kernel_32.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
relocate_kernel_64.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
resource.c
rtc.c x86: Allow tracing of functions in arch/x86/kernel/rtc.c 2012-10-24 13:14:22 +02:00
setup.c x86: Use PCI setup data 2012-12-05 14:38:26 -07:00
setup_percpu.c x86: Add read_mostly declaration/definition to variables from smp.h 2012-06-14 12:42:11 +02:00
signal.c Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 2012-12-03 06:27:05 +01:00
smp.c x86/reboot: Update nonmi_ipi parameter 2012-05-14 11:49:38 +02:00
smpboot.c Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-12-11 19:58:29 -08:00
stacktrace.c x86: Swap save_stack_trace_regs parameters 2011-06-14 22:48:51 -04:00
step.c uprobes/x86: Do not (ab)use TIF_SINGLESTEP/user_*_single_step() for single-stepping 2012-09-15 17:37:30 +02:00
sys_x86_64.c mm: fix cache coloring on x86_64 architecture 2012-12-11 17:22:25 -08:00
syscall_32.c x86, syscall: Re-fix typo in comment 2011-11-18 16:25:07 -08:00
syscall_64.c x32: If configured, add x32 system calls to system call tables 2012-02-20 12:52:06 -08:00
tboot.c x86, realmode: fixes compilation issue in tboot.c 2012-05-08 15:04:27 -07:00
tce_64.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
test_nx.c x86: Eliminate various 'set but not used' warnings 2011-05-21 19:10:33 +02:00
test_rodata.c x86, extable: Remove open-coded exception table entries in arch/x86/kernel/test_rodata.c 2012-04-20 13:51:38 -07:00
time.c MCA: delete all remaining traces of microchannel bus support. 2012-05-17 19:06:13 -04:00
tls.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 14:28:26 -07:00
tls.h
topology.c x86, topology: Debug CPU0 hotplug 2012-11-14 15:28:11 -08:00
trace_clock.c tracing,x86: Add a TSC trace_clock 2012-11-13 15:48:27 -05:00
traps.c context_tracking: New context tracking susbsystem 2012-11-30 11:40:07 -08:00
tsc.c x86: Allow tracing of functions in arch/x86/kernel/rtc.c 2012-10-24 13:14:22 +02:00
tsc_sync.c x86/tsc: Reduce the TSC sync check time for core-siblings 2012-02-22 11:49:40 +01:00
uprobes.c uprobes/x86: Cleanup the single-stepping code 2012-11-03 17:15:12 +01:00
verify_cpu.S
vm86_32.c thp: change split_huge_page_pmd() interface 2012-12-12 17:38:31 -08:00
vmlinux.lds.S x86, realmode: Move ACPI wakeup to unified realmode code 2012-05-08 11:46:05 -07:00
vsmp_64.c x86/apic/x2apic: Limit the vector reservation to the user specified mask 2012-07-06 11:00:22 +02:00
vsyscall_64.c time: Convert x86_64 to using new update_vsyscall 2012-09-24 12:38:09 -04:00
vsyscall_emu_64.S x86-64: Rework vsyscall emulation and add vsyscall= parameter 2011-08-10 19:26:46 -05:00
vsyscall_trace.h x86-64: Add vsyscall:emulate_vsyscall trace event 2011-08-04 16:13:53 -07:00
x86_init.c x86: xen: Cleanup and remove x86_init.paging.pagetable_setup_done() 2012-09-12 15:33:06 +02:00
x8664_ksyms_64.c ftrace/x86: Add support for -mfentry to x86_64 2012-08-23 11:26:36 -04:00
xsave.c x86, smap: Do not abuse the [f][x]rstor_checking() functions for user space 2012-09-25 15:42:18 -07:00