xen64: disable 32-bit syscall/sysenter if not supported.
[linux-3.10.git] / 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
32
33 /**
34  * machine_specific_memory_setup - Hook for machine specific memory setup.
35  **/
36
37 char * __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(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
70 static 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  */
87 static void __init fiddle_vdso(void)
88 {
89 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
90         extern const char vdso32_default_start;
91         u32 *mask = VDSO32_SYMBOL(&vdso32_default_start, NOTE_MASK);
92         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
93 #endif
94 }
95
96 static __cpuinit int register_callback(unsigned type, const void *func)
97 {
98         struct callback_register callback = {
99                 .type = type,
100                 .address = XEN_CALLBACK(__KERNEL_CS, func),
101                 .flags = CALLBACKF_mask_events,
102         };
103
104         return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
105 }
106
107 void __cpuinit xen_enable_sysenter(void)
108 {
109         extern void xen_sysenter_target(void);
110         int ret;
111         unsigned sysenter_feature;
112
113 #ifdef CONFIG_X86_32
114         sysenter_feature = X86_FEATURE_SEP;
115 #else
116         sysenter_feature = X86_FEATURE_SYSENTER32;
117 #endif
118
119         if (!boot_cpu_has(sysenter_feature))
120                 return;
121
122         ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
123         if(ret != 0)
124                 setup_clear_cpu_cap(sysenter_feature);
125 }
126
127 void __cpuinit xen_enable_syscall(void)
128 {
129 #ifdef CONFIG_X86_64
130         int ret;
131         extern void xen_syscall_target(void);
132         extern void xen_syscall32_target(void);
133
134         ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
135         if (ret != 0) {
136                 printk(KERN_ERR "Failed to set syscall: %d\n", ret);
137                 /* Pretty fatal; 64-bit userspace has no other
138                    mechanism for syscalls. */
139         }
140
141         if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
142                 ret = register_callback(CALLBACKTYPE_syscall32,
143                                         xen_syscall32_target);
144                 if (ret != 0) {
145                         printk(KERN_INFO "Xen: 32-bit syscall not supported: disabling vdso\n");
146                         setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
147                         sysctl_vsyscall32 = 0;
148                 }
149         }
150 #endif /* CONFIG_X86_64 */
151 }
152
153 void __init xen_arch_setup(void)
154 {
155         struct physdev_set_iopl set_iopl;
156         int rc;
157
158         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
159         HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
160
161         if (!xen_feature(XENFEAT_auto_translated_physmap))
162                 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_pae_extended_cr3);
163
164         if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
165             register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
166                 BUG();
167
168         xen_enable_sysenter();
169         xen_enable_syscall();
170
171         set_iopl.iopl = 1;
172         rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
173         if (rc != 0)
174                 printk(KERN_INFO "physdev_op failed %d\n", rc);
175
176 #ifdef CONFIG_ACPI
177         if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
178                 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
179                 disable_acpi();
180         }
181 #endif
182
183         memcpy(boot_command_line, xen_start_info->cmd_line,
184                MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
185                COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
186
187         pm_idle = xen_idle;
188
189         paravirt_disable_iospace();
190
191         fiddle_vdso();
192 }