426 lines
11 KiB
C
426 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Paravirtualization interfaces
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Copyright (C) 2006 Rusty Russell IBM Corporation
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2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
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*/
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/export.h>
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#include <linux/efi.h>
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#include <linux/bcd.h>
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#include <linux/highmem.h>
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#include <linux/kprobes.h>
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#include <linux/pgtable.h>
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#include <asm/bug.h>
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#include <asm/paravirt.h>
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#include <asm/debugreg.h>
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#include <asm/desc.h>
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#include <asm/setup.h>
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#include <asm/time.h>
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#include <asm/pgalloc.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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#include <asm/special_insns.h>
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#include <asm/tlb.h>
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#include <asm/io_bitmap.h>
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/*
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* nop stub, which must not clobber anything *including the stack* to
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* avoid confusing the entry prologues.
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*/
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extern void _paravirt_nop(void);
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asm (".pushsection .entry.text, \"ax\"\n"
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".global _paravirt_nop\n"
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"_paravirt_nop:\n\t"
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"ret\n\t"
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".size _paravirt_nop, . - _paravirt_nop\n\t"
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".type _paravirt_nop, @function\n\t"
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".popsection");
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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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pv_info.name);
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}
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/* Undefined instruction for dealing with missing ops pointers. */
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static const unsigned char ud2a[] = { 0x0f, 0x0b };
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struct branch {
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unsigned char opcode;
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u32 delta;
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} __attribute__((packed));
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static unsigned paravirt_patch_call(void *insn_buff, const void *target,
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unsigned long addr, unsigned len)
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{
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const int call_len = 5;
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struct branch *b = insn_buff;
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unsigned long delta = (unsigned long)target - (addr+call_len);
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if (len < call_len) {
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pr_warn("paravirt: Failed to patch indirect CALL at %ps\n", (void *)addr);
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/* Kernel might not be viable if patching fails, bail out: */
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BUG_ON(1);
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}
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b->opcode = 0xe8; /* call */
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b->delta = delta;
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BUILD_BUG_ON(sizeof(*b) != call_len);
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return call_len;
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}
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#ifdef CONFIG_PARAVIRT_XXL
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/* identity function, which can be inlined */
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u64 notrace _paravirt_ident_64(u64 x)
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{
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return x;
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}
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static unsigned paravirt_patch_jmp(void *insn_buff, const void *target,
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unsigned long addr, unsigned len)
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{
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struct branch *b = insn_buff;
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unsigned long delta = (unsigned long)target - (addr+5);
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if (len < 5) {
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#ifdef CONFIG_RETPOLINE
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WARN_ONCE(1, "Failing to patch indirect JMP in %ps\n", (void *)addr);
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#endif
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return len; /* call too long for patch site */
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}
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b->opcode = 0xe9; /* jmp */
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b->delta = delta;
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return 5;
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}
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#endif
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DEFINE_STATIC_KEY_TRUE(virt_spin_lock_key);
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void __init native_pv_lock_init(void)
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{
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if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
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static_branch_disable(&virt_spin_lock_key);
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}
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unsigned paravirt_patch_default(u8 type, void *insn_buff,
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unsigned long addr, unsigned len)
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{
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/*
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* Neat trick to map patch type back to the call within the
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* corresponding structure.
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*/
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void *opfunc = *((void **)&pv_ops + type);
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unsigned ret;
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if (opfunc == NULL)
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/* If there's no function, patch it with a ud2a (BUG) */
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ret = paravirt_patch_insns(insn_buff, len, ud2a, ud2a+sizeof(ud2a));
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else if (opfunc == _paravirt_nop)
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ret = 0;
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#ifdef CONFIG_PARAVIRT_XXL
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/* identity functions just return their single argument */
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else if (opfunc == _paravirt_ident_64)
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ret = paravirt_patch_ident_64(insn_buff, len);
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else if (type == PARAVIRT_PATCH(cpu.iret) ||
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type == PARAVIRT_PATCH(cpu.usergs_sysret64))
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/* If operation requires a jmp, then jmp */
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ret = paravirt_patch_jmp(insn_buff, opfunc, addr, len);
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#endif
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else
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/* Otherwise call the function. */
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ret = paravirt_patch_call(insn_buff, opfunc, addr, len);
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return ret;
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}
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unsigned paravirt_patch_insns(void *insn_buff, unsigned len,
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const char *start, const char *end)
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{
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unsigned insn_len = end - start;
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/* Alternative instruction is too large for the patch site and we cannot continue: */
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BUG_ON(insn_len > len || start == NULL);
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memcpy(insn_buff, start, insn_len);
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return insn_len;
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}
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struct static_key paravirt_steal_enabled;
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struct static_key paravirt_steal_rq_enabled;
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static u64 native_steal_clock(int cpu)
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{
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return 0;
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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_usergs_sysret64(void);
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static struct resource reserve_ioports = {
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.start = 0,
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.end = IO_SPACE_LIMIT,
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.name = "paravirt-ioport",
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.flags = IORESOURCE_IO | IORESOURCE_BUSY,
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};
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/*
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* Reserve the whole legacy IO space to prevent any legacy drivers
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* from wasting time probing for their hardware. This is a fairly
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* brute-force approach to disabling all non-virtual drivers.
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*
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* Note that this must be called very early to have any effect.
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*/
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int paravirt_disable_iospace(void)
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{
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return request_resource(&ioport_resource, &reserve_ioports);
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}
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static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
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static inline void enter_lazy(enum paravirt_lazy_mode mode)
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{
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BUG_ON(this_cpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
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this_cpu_write(paravirt_lazy_mode, mode);
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}
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static void leave_lazy(enum paravirt_lazy_mode mode)
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{
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BUG_ON(this_cpu_read(paravirt_lazy_mode) != mode);
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this_cpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
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}
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void paravirt_enter_lazy_mmu(void)
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{
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enter_lazy(PARAVIRT_LAZY_MMU);
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}
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void paravirt_leave_lazy_mmu(void)
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{
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leave_lazy(PARAVIRT_LAZY_MMU);
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}
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void paravirt_flush_lazy_mmu(void)
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{
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preempt_disable();
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if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
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arch_leave_lazy_mmu_mode();
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arch_enter_lazy_mmu_mode();
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}
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preempt_enable();
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}
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#ifdef CONFIG_PARAVIRT_XXL
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void paravirt_start_context_switch(struct task_struct *prev)
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{
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BUG_ON(preemptible());
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if (this_cpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
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arch_leave_lazy_mmu_mode();
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set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
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}
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enter_lazy(PARAVIRT_LAZY_CPU);
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}
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void paravirt_end_context_switch(struct task_struct *next)
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{
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BUG_ON(preemptible());
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leave_lazy(PARAVIRT_LAZY_CPU);
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if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
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arch_enter_lazy_mmu_mode();
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}
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#endif
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enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
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{
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if (in_interrupt())
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return PARAVIRT_LAZY_NONE;
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return this_cpu_read(paravirt_lazy_mode);
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}
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struct pv_info pv_info = {
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.name = "bare hardware",
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#ifdef CONFIG_PARAVIRT_XXL
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.extra_user_64bit_cs = __USER_CS,
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#endif
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};
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/* 64-bit pagetable entries */
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#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
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struct paravirt_patch_template pv_ops = {
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/* Init ops. */
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.init.patch = native_patch,
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/* Time ops. */
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.time.sched_clock = native_sched_clock,
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.time.steal_clock = native_steal_clock,
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/* Cpu ops. */
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.cpu.io_delay = native_io_delay,
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#ifdef CONFIG_PARAVIRT_XXL
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.cpu.cpuid = native_cpuid,
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.cpu.get_debugreg = native_get_debugreg,
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.cpu.set_debugreg = native_set_debugreg,
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.cpu.read_cr0 = native_read_cr0,
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.cpu.write_cr0 = native_write_cr0,
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.cpu.write_cr4 = native_write_cr4,
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.cpu.wbinvd = native_wbinvd,
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.cpu.read_msr = native_read_msr,
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.cpu.write_msr = native_write_msr,
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.cpu.read_msr_safe = native_read_msr_safe,
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.cpu.write_msr_safe = native_write_msr_safe,
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.cpu.read_pmc = native_read_pmc,
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.cpu.load_tr_desc = native_load_tr_desc,
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.cpu.set_ldt = native_set_ldt,
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.cpu.load_gdt = native_load_gdt,
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.cpu.load_idt = native_load_idt,
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.cpu.store_tr = native_store_tr,
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.cpu.load_tls = native_load_tls,
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.cpu.load_gs_index = native_load_gs_index,
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.cpu.write_ldt_entry = native_write_ldt_entry,
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.cpu.write_gdt_entry = native_write_gdt_entry,
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.cpu.write_idt_entry = native_write_idt_entry,
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.cpu.alloc_ldt = paravirt_nop,
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.cpu.free_ldt = paravirt_nop,
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.cpu.load_sp0 = native_load_sp0,
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.cpu.usergs_sysret64 = native_usergs_sysret64,
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.cpu.iret = native_iret,
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.cpu.swapgs = native_swapgs,
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#ifdef CONFIG_X86_IOPL_IOPERM
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.cpu.invalidate_io_bitmap = native_tss_invalidate_io_bitmap,
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.cpu.update_io_bitmap = native_tss_update_io_bitmap,
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#endif
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.cpu.start_context_switch = paravirt_nop,
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.cpu.end_context_switch = paravirt_nop,
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/* Irq ops. */
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.irq.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
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.irq.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
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.irq.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
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.irq.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
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.irq.safe_halt = native_safe_halt,
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.irq.halt = native_halt,
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#endif /* CONFIG_PARAVIRT_XXL */
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/* Mmu ops. */
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.mmu.flush_tlb_user = native_flush_tlb_local,
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.mmu.flush_tlb_kernel = native_flush_tlb_global,
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.mmu.flush_tlb_one_user = native_flush_tlb_one_user,
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.mmu.flush_tlb_others = native_flush_tlb_others,
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.mmu.tlb_remove_table =
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(void (*)(struct mmu_gather *, void *))tlb_remove_page,
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.mmu.exit_mmap = paravirt_nop,
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#ifdef CONFIG_PARAVIRT_XXL
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.mmu.read_cr2 = __PV_IS_CALLEE_SAVE(native_read_cr2),
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.mmu.write_cr2 = native_write_cr2,
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.mmu.read_cr3 = __native_read_cr3,
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.mmu.write_cr3 = native_write_cr3,
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.mmu.pgd_alloc = __paravirt_pgd_alloc,
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.mmu.pgd_free = paravirt_nop,
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.mmu.alloc_pte = paravirt_nop,
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.mmu.alloc_pmd = paravirt_nop,
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.mmu.alloc_pud = paravirt_nop,
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.mmu.alloc_p4d = paravirt_nop,
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.mmu.release_pte = paravirt_nop,
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.mmu.release_pmd = paravirt_nop,
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.mmu.release_pud = paravirt_nop,
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.mmu.release_p4d = paravirt_nop,
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.mmu.set_pte = native_set_pte,
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.mmu.set_pmd = native_set_pmd,
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.mmu.ptep_modify_prot_start = __ptep_modify_prot_start,
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.mmu.ptep_modify_prot_commit = __ptep_modify_prot_commit,
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.mmu.set_pud = native_set_pud,
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.mmu.pmd_val = PTE_IDENT,
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.mmu.make_pmd = PTE_IDENT,
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.mmu.pud_val = PTE_IDENT,
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.mmu.make_pud = PTE_IDENT,
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.mmu.set_p4d = native_set_p4d,
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#if CONFIG_PGTABLE_LEVELS >= 5
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.mmu.p4d_val = PTE_IDENT,
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.mmu.make_p4d = PTE_IDENT,
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.mmu.set_pgd = native_set_pgd,
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#endif /* CONFIG_PGTABLE_LEVELS >= 5 */
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.mmu.pte_val = PTE_IDENT,
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.mmu.pgd_val = PTE_IDENT,
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.mmu.make_pte = PTE_IDENT,
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.mmu.make_pgd = PTE_IDENT,
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.mmu.dup_mmap = paravirt_nop,
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.mmu.activate_mm = paravirt_nop,
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.mmu.lazy_mode = {
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.enter = paravirt_nop,
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.leave = paravirt_nop,
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.flush = paravirt_nop,
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},
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.mmu.set_fixmap = native_set_fixmap,
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#endif /* CONFIG_PARAVIRT_XXL */
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#if defined(CONFIG_PARAVIRT_SPINLOCKS)
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/* Lock ops. */
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#ifdef CONFIG_SMP
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.lock.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
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.lock.queued_spin_unlock =
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PV_CALLEE_SAVE(__native_queued_spin_unlock),
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.lock.wait = paravirt_nop,
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.lock.kick = paravirt_nop,
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.lock.vcpu_is_preempted =
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PV_CALLEE_SAVE(__native_vcpu_is_preempted),
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#endif /* SMP */
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#endif
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};
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#ifdef CONFIG_PARAVIRT_XXL
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/* At this point, native_get/set_debugreg has real function entries */
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NOKPROBE_SYMBOL(native_get_debugreg);
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NOKPROBE_SYMBOL(native_set_debugreg);
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NOKPROBE_SYMBOL(native_load_idt);
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#endif
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EXPORT_SYMBOL(pv_ops);
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EXPORT_SYMBOL_GPL(pv_info);
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