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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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b239fb2501
This patch introduces paravirt_ops hooks to control how the kernel's initial pagetable is set up. In the case of a native boot, the very early bootstrap code creates a simple non-PAE pagetable to map the kernel and physical memory. When the VM subsystem is initialized, it creates a proper pagetable which respects the PAE mode, large pages, etc. When booting under a hypervisor, there are many possibilities for what paging environment the hypervisor establishes for the guest kernel, so the constructon of the kernel's pagetable depends on the hypervisor. In the case of Xen, the hypervisor boots the kernel with a fully constructed pagetable, which is already using PAE if necessary. Also, Xen requires particular care when constructing pagetables to make sure all pagetables are always mapped read-only. In order to make this easier, kernel's initial pagetable construction has been changed to only allocate and initialize a pagetable page if there's no page already present in the pagetable. This allows the Xen paravirt backend to make a copy of the hypervisor-provided pagetable, allowing the kernel to establish any more mappings it needs while keeping the existing ones. A slightly subtle point which is worth highlighting here is that Xen requires all kernel mappings to share the same pte_t pages between all pagetables, so that updating a kernel page's mapping in one pagetable is reflected in all other pagetables. This makes it possible to allocate a page and attach it to a pagetable without having to explicitly enumerate that page's mapping in all pagetables. And: +From: "Eric W. Biederman" <ebiederm@xmission.com> If we don't set the leaf page table entries it is quite possible that will inherit and incorrect page table entry from the initial boot page table setup in head.S. So we need to redo the effort here, so we pick up PSE, PGE and the like. Hypervisors like Xen require that their page tables be read-only, which is slightly incompatible with our low identity mappings, however I discussed this with Jeremy he has modified the Xen early set_pte function to avoid problems in this area. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: William Irwin <bill.irwin@oracle.com> Cc: Ingo Molnar <mingo@elte.hu>
248 lines
6.7 KiB
C
248 lines
6.7 KiB
C
/* Paravirtualization interfaces
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Copyright (C) 2006 Rusty Russell IBM Corporation
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/efi.h>
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#include <linux/bcd.h>
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#include <linux/start_kernel.h>
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#include <asm/bug.h>
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#include <asm/paravirt.h>
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#include <asm/desc.h>
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#include <asm/setup.h>
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#include <asm/arch_hooks.h>
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#include <asm/time.h>
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#include <asm/irq.h>
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#include <asm/delay.h>
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#include <asm/fixmap.h>
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#include <asm/apic.h>
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#include <asm/tlbflush.h>
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#include <asm/timer.h>
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/* nop stub */
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void _paravirt_nop(void)
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{
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}
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static void __init default_banner(void)
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{
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printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
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paravirt_ops.name);
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}
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char *memory_setup(void)
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{
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return paravirt_ops.memory_setup();
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}
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/* Simple instruction patching code. */
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#define DEF_NATIVE(name, code) \
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extern const char start_##name[], end_##name[]; \
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asm("start_" #name ": " code "; end_" #name ":")
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DEF_NATIVE(cli, "cli");
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DEF_NATIVE(sti, "sti");
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DEF_NATIVE(popf, "push %eax; popf");
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DEF_NATIVE(pushf, "pushf; pop %eax");
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DEF_NATIVE(pushf_cli, "pushf; pop %eax; cli");
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DEF_NATIVE(iret, "iret");
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DEF_NATIVE(sti_sysexit, "sti; sysexit");
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static const struct native_insns
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{
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const char *start, *end;
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} native_insns[] = {
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[PARAVIRT_IRQ_DISABLE] = { start_cli, end_cli },
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[PARAVIRT_IRQ_ENABLE] = { start_sti, end_sti },
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[PARAVIRT_RESTORE_FLAGS] = { start_popf, end_popf },
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[PARAVIRT_SAVE_FLAGS] = { start_pushf, end_pushf },
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[PARAVIRT_SAVE_FLAGS_IRQ_DISABLE] = { start_pushf_cli, end_pushf_cli },
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[PARAVIRT_INTERRUPT_RETURN] = { start_iret, end_iret },
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[PARAVIRT_STI_SYSEXIT] = { start_sti_sysexit, end_sti_sysexit },
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};
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static unsigned native_patch(u8 type, u16 clobbers, void *insns, unsigned len)
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{
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unsigned int insn_len;
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/* Don't touch it if we don't have a replacement */
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if (type >= ARRAY_SIZE(native_insns) || !native_insns[type].start)
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return len;
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insn_len = native_insns[type].end - native_insns[type].start;
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/* Similarly if we can't fit replacement. */
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if (len < insn_len)
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return len;
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memcpy(insns, native_insns[type].start, insn_len);
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return insn_len;
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}
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void init_IRQ(void)
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{
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paravirt_ops.init_IRQ();
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}
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static void native_flush_tlb(void)
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{
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__native_flush_tlb();
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}
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/*
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* Global pages have to be flushed a bit differently. Not a real
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* performance problem because this does not happen often.
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*/
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static void native_flush_tlb_global(void)
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{
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__native_flush_tlb_global();
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}
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static void native_flush_tlb_single(u32 addr)
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{
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__native_flush_tlb_single(addr);
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}
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/* These are in entry.S */
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extern void native_iret(void);
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extern void native_irq_enable_sysexit(void);
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static int __init print_banner(void)
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{
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paravirt_ops.banner();
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return 0;
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}
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core_initcall(print_banner);
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struct paravirt_ops paravirt_ops = {
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.name = "bare hardware",
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.paravirt_enabled = 0,
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.kernel_rpl = 0,
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.patch = native_patch,
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.banner = default_banner,
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.arch_setup = paravirt_nop,
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.memory_setup = machine_specific_memory_setup,
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.get_wallclock = native_get_wallclock,
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.set_wallclock = native_set_wallclock,
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.time_init = hpet_time_init,
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.init_IRQ = native_init_IRQ,
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.cpuid = native_cpuid,
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.get_debugreg = native_get_debugreg,
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.set_debugreg = native_set_debugreg,
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.clts = native_clts,
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.read_cr0 = native_read_cr0,
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.write_cr0 = native_write_cr0,
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.read_cr2 = native_read_cr2,
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.write_cr2 = native_write_cr2,
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.read_cr3 = native_read_cr3,
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.write_cr3 = native_write_cr3,
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.read_cr4 = native_read_cr4,
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.read_cr4_safe = native_read_cr4_safe,
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.write_cr4 = native_write_cr4,
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.save_fl = native_save_fl,
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.restore_fl = native_restore_fl,
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.irq_disable = native_irq_disable,
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.irq_enable = native_irq_enable,
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.safe_halt = native_safe_halt,
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.halt = native_halt,
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.wbinvd = native_wbinvd,
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.read_msr = native_read_msr_safe,
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.write_msr = native_write_msr_safe,
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.read_tsc = native_read_tsc,
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.read_pmc = native_read_pmc,
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.get_scheduled_cycles = native_read_tsc,
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.get_cpu_khz = native_calculate_cpu_khz,
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.load_tr_desc = native_load_tr_desc,
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.set_ldt = native_set_ldt,
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.load_gdt = native_load_gdt,
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.load_idt = native_load_idt,
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.store_gdt = native_store_gdt,
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.store_idt = native_store_idt,
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.store_tr = native_store_tr,
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.load_tls = native_load_tls,
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.write_ldt_entry = write_dt_entry,
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.write_gdt_entry = write_dt_entry,
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.write_idt_entry = write_dt_entry,
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.load_esp0 = native_load_esp0,
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.set_iopl_mask = native_set_iopl_mask,
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.io_delay = native_io_delay,
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#ifdef CONFIG_X86_LOCAL_APIC
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.apic_write = native_apic_write,
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.apic_write_atomic = native_apic_write_atomic,
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.apic_read = native_apic_read,
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.setup_boot_clock = setup_boot_APIC_clock,
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.setup_secondary_clock = setup_secondary_APIC_clock,
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#endif
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.set_lazy_mode = paravirt_nop,
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.pagetable_setup_start = native_pagetable_setup_start,
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.pagetable_setup_done = native_pagetable_setup_done,
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.flush_tlb_user = native_flush_tlb,
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.flush_tlb_kernel = native_flush_tlb_global,
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.flush_tlb_single = native_flush_tlb_single,
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.map_pt_hook = paravirt_nop,
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.alloc_pt = paravirt_nop,
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.alloc_pd = paravirt_nop,
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.alloc_pd_clone = paravirt_nop,
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.release_pt = paravirt_nop,
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.release_pd = paravirt_nop,
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.set_pte = native_set_pte,
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.set_pte_at = native_set_pte_at,
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.set_pmd = native_set_pmd,
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.pte_update = paravirt_nop,
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.pte_update_defer = paravirt_nop,
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.ptep_get_and_clear = native_ptep_get_and_clear,
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#ifdef CONFIG_X86_PAE
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.set_pte_atomic = native_set_pte_atomic,
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.set_pte_present = native_set_pte_present,
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.set_pud = native_set_pud,
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.pte_clear = native_pte_clear,
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.pmd_clear = native_pmd_clear,
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.pmd_val = native_pmd_val,
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.make_pmd = native_make_pmd,
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#endif
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.pte_val = native_pte_val,
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.pgd_val = native_pgd_val,
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.make_pte = native_make_pte,
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.make_pgd = native_make_pgd,
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.irq_enable_sysexit = native_irq_enable_sysexit,
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.iret = native_iret,
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.startup_ipi_hook = paravirt_nop,
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};
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/*
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* NOTE: CONFIG_PARAVIRT is experimental and the paravirt_ops
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* semantics are subject to change. Hence we only do this
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* internal-only export of this, until it gets sorted out and
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* all lowlevel CPU ops used by modules are separately exported.
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*/
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EXPORT_SYMBOL_GPL(paravirt_ops);
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