Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 }
195 
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