linux/arch/x86/xen/setup.c
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   1/*
   2 * Machine specific setup for xen
   3 *
   4 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
   5 */
   6
   7#include <linux/module.h>
   8#include <linux/sched.h>
   9#include <linux/mm.h>
  10#include <linux/pm.h>
  11
  12#include <asm/elf.h>
  13#include <asm/vdso.h>
  14#include <asm/e820.h>
  15#include <asm/setup.h>
  16#include <asm/acpi.h>
  17#include <asm/xen/hypervisor.h>
  18#include <asm/xen/hypercall.h>
  19
  20#include <xen/page.h>
  21#include <xen/interface/callback.h>
  22#include <xen/interface/physdev.h>
  23#include <xen/features.h>
  24
  25#include "xen-ops.h"
  26#include "vdso.h"
  27
  28/* These are code, but not functions.  Defined in entry.S */
  29extern const char xen_hypervisor_callback[];
  30extern const char xen_failsafe_callback[];
  31
  32
  33/**
  34 * machine_specific_memory_setup - Hook for machine specific memory setup.
  35 **/
  36
  37char * __init xen_memory_setup(void)
  38{
  39        unsigned long max_pfn = xen_start_info->nr_pages;
  40
  41        max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
  42
  43        e820.nr_map = 0;
  44
  45        e820_add_region(0, PFN_PHYS((u64)max_pfn), E820_RAM);
  46
  47        /*
  48         * Even though this is normal, usable memory under Xen, reserve
  49         * ISA memory anyway because too many things think they can poke
  50         * about in there.
  51         */
  52        e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
  53                        E820_RESERVED);
  54
  55        /*
  56         * Reserve Xen bits:
  57         *  - mfn_list
  58         *  - xen_start_info
  59         * See comment above "struct start_info" in <xen/interface/xen.h>
  60         */
  61        e820_add_region(__pa(xen_start_info->mfn_list),
  62                        xen_start_info->pt_base - xen_start_info->mfn_list,
  63                        E820_RESERVED);
  64
  65        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
  66
  67        return "Xen";
  68}
  69
  70static void xen_idle(void)
  71{
  72        local_irq_disable();
  73
  74        if (need_resched())
  75                local_irq_enable();
  76        else {
  77                current_thread_info()->status &= ~TS_POLLING;
  78                smp_mb__after_clear_bit();
  79                safe_halt();
  80                current_thread_info()->status |= TS_POLLING;
  81        }
  82}
  83
  84/*
  85 * Set the bit indicating "nosegneg" library variants should be used.
  86 * We only need to bother in pure 32-bit mode; compat 32-bit processes
  87 * can have un-truncated segments, so wrapping around is allowed.
  88 */
  89static void __init fiddle_vdso(void)
  90{
  91#ifdef CONFIG_X86_32
  92        u32 *mask;
  93        mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
  94        *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
  95        mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
  96        *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
  97#endif
  98}
  99
 100static __cpuinit int register_callback(unsigned type, const void *func)
 101{
 102        struct callback_register callback = {
 103                .type = type,
 104                .address = XEN_CALLBACK(__KERNEL_CS, func),
 105                .flags = CALLBACKF_mask_events,
 106        };
 107
 108        return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
 109}
 110
 111void __cpuinit xen_enable_sysenter(void)
 112{
 113        extern void xen_sysenter_target(void);
 114        int ret;
 115        unsigned sysenter_feature;
 116
 117#ifdef CONFIG_X86_32
 118        sysenter_feature = X86_FEATURE_SEP;
 119#else
 120        sysenter_feature = X86_FEATURE_SYSENTER32;
 121#endif
 122
 123        if (!boot_cpu_has(sysenter_feature))
 124                return;
 125
 126        ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
 127        if(ret != 0)
 128                setup_clear_cpu_cap(sysenter_feature);
 129}
 130
 131void __cpuinit xen_enable_syscall(void)
 132{
 133#ifdef CONFIG_X86_64
 134        int ret;
 135        extern void xen_syscall_target(void);
 136        extern void xen_syscall32_target(void);
 137
 138        ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
 139        if (ret != 0) {
 140                printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
 141                /* Pretty fatal; 64-bit userspace has no other
 142                   mechanism for syscalls. */
 143        }
 144
 145        if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
 146                ret = register_callback(CALLBACKTYPE_syscall32,
 147                                        xen_syscall32_target);
 148                if (ret != 0)
 149                        setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
 150        }
 151#endif /* CONFIG_X86_64 */
 152}
 153
 154void __init xen_arch_setup(void)
 155{
 156        struct physdev_set_iopl set_iopl;
 157        int rc;
 158
 159        HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
 160        HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
 161
 162        if (!xen_feature(XENFEAT_auto_translated_physmap))
 163                HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_pae_extended_cr3);
 164
 165        if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
 166            register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
 167                BUG();
 168
 169        xen_enable_sysenter();
 170        xen_enable_syscall();
 171
 172        set_iopl.iopl = 1;
 173        rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
 174        if (rc != 0)
 175                printk(KERN_INFO "physdev_op failed %d\n", rc);
 176
 177#ifdef CONFIG_ACPI
 178        if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 179                printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
 180                disable_acpi();
 181        }
 182#endif
 183
 184        memcpy(boot_command_line, xen_start_info->cmd_line,
 185               MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 186               COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 187
 188        pm_idle = xen_idle;
 189
 190        paravirt_disable_iospace();
 191
 192        fiddle_vdso();
 193}
 194