arch/x86/xen/setup.c

   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 */
  29 extern const char xen_hypervisor_callback[];
  30 extern const char xen_failsafe_callback[];
  31 extern void xen_sysenter_target(void);
  32 extern void xen_syscall_target(void);
  33 extern void xen_syscall32_target(void);
  34
  35
  36 /**
  37  * machine_specific_memory_setup - Hook for machine specific memory setup.
  38  **/
  39
  40 char * __init xen_memory_setup(void)
  41 {
  42         unsigned long max_pfn = xen_start_info->nr_pages;
  43
  44         max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
  45
  46         e820.nr_map = 0;
  47
  48         e820_add_region(0, PFN_PHYS((u64)max_pfn), E820_RAM);
  49
  50         /*
  51          * Even though this is normal, usable memory under Xen, reserve
  52          * ISA memory anyway because too many things think they can poke
  53          * about in there.
  54          */
  55         e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
  56                         E820_RESERVED);
  57
  58         /*
  59          * Reserve Xen bits:
  60          *  - mfn_list
  61          *  - xen_start_info
  62          * See comment above "struct start_info" in <xen/interface/xen.h>
  63          */
  64         reserve_early(__pa(xen_start_info->mfn_list),
  65                       __pa(xen_start_info->pt_base),
  66                         "XEN START INFO");
  67
  68         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
  69
  70         return "Xen";
  71 }
  72
  73 static void xen_idle(void)
  74 {
  75         local_irq_disable();
  76
  77         if (need_resched())
  78                 local_irq_enable();
  79         else {
  80                 current_thread_info()->status &= ~TS_POLLING;
  81                 smp_mb__after_clear_bit();
  82                 safe_halt();
  83                 current_thread_info()->status |= TS_POLLING;
  84         }
  85 }
  86
  87 /*
  88  * Set the bit indicating "nosegneg" library variants should be used.
  89  * We only need to bother in pure 32-bit mode; compat 32-bit processes
  90  * can have un-truncated segments, so wrapping around is allowed.
  91  */
  92 static void __init fiddle_vdso(void)
  93 {
  94 #ifdef CONFIG_X86_32
  95         u32 *mask;
  96         mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
  97         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
  98         mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
  99         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 100 #endif
 101 }
 102
 103 static __cpuinit int register_callback(unsigned type, const void *func)
 104 {
 105         struct callback_register callback = {
 106                 .type = type,
 107                 .address = XEN_CALLBACK(__KERNEL_CS, func),
 108                 .flags = CALLBACKF_mask_events,
 109         };
 110
 111         return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
 112 }
 113
 114 void __cpuinit xen_enable_sysenter(void)
 115 {
 116         int ret;
 117         unsigned sysenter_feature;
 118
 119 #ifdef CONFIG_X86_32
 120         sysenter_feature = X86_FEATURE_SEP;
 121 #else
 122         sysenter_feature = X86_FEATURE_SYSENTER32;
 123 #endif
 124
 125         if (!boot_cpu_has(sysenter_feature))
 126                 return;
 127
 128         ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
 129         if(ret != 0)
 130                 setup_clear_cpu_cap(sysenter_feature);
 131 }
 132
 133 void __cpuinit xen_enable_syscall(void)
 134 {
 135 #ifdef CONFIG_X86_64
 136         int ret;
 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
 154 void __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,
 164                                      VMASST_TYPE_pae_extended_cr3);
 165
 166         if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
 167             register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
 168                 BUG();
 169
 170         xen_enable_sysenter();
 171         xen_enable_syscall();
 172
 173         set_iopl.iopl = 1;
 174         rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
 175         if (rc != 0)
 176                 printk(KERN_INFO "physdev_op failed %d\n", rc);
 177
 178 #ifdef CONFIG_ACPI
 179         if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 180                 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
 181                 disable_acpi();
 182         }
 183 #endif
 184
 185         memcpy(boot_command_line, xen_start_info->cmd_line,
 186                MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 187                COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 188
 189         pm_idle = xen_idle;
 190
 191         paravirt_disable_iospace();
 192
 193         fiddle_vdso();
 194 }