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![Jeremy Fitzhardinge](/assets/img/avatar_default.png)
AMD only supports "syscall" from 32-bit compat usermode. Intel and Centaur(?) only support "sysenter" from 32-bit compat usermode. Set the X86 feature bits accordingly, and set up the vdso in accordance with those bits. On the offchance we run on in a 64-bit environment which supports neither syscall nor sysenter from 32-bit mode, then fall back to the int $0x80 vdso. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
198 lines
4.7 KiB
C
198 lines
4.7 KiB
C
/*
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* Machine specific setup for xen
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*
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* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/pm.h>
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#include <asm/elf.h>
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#include <asm/vdso.h>
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#include <asm/e820.h>
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#include <asm/setup.h>
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#include <asm/acpi.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/hypercall.h>
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#include <xen/page.h>
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#include <xen/interface/callback.h>
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#include <xen/interface/physdev.h>
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#include <xen/features.h>
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#include "xen-ops.h"
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#include "vdso.h"
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/* These are code, but not functions. Defined in entry.S */
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extern const char xen_hypervisor_callback[];
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extern const char xen_failsafe_callback[];
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/**
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* machine_specific_memory_setup - Hook for machine specific memory setup.
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**/
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char * __init xen_memory_setup(void)
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{
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unsigned long max_pfn = xen_start_info->nr_pages;
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max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
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e820.nr_map = 0;
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e820_add_region(0, PFN_PHYS(max_pfn), E820_RAM);
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/*
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* Even though this is normal, usable memory under Xen, reserve
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* ISA memory anyway because too many things think they can poke
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* about in there.
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*/
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e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
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E820_RESERVED);
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/*
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* Reserve Xen bits:
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* - mfn_list
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* - xen_start_info
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* See comment above "struct start_info" in <xen/interface/xen.h>
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*/
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e820_add_region(__pa(xen_start_info->mfn_list),
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xen_start_info->pt_base - xen_start_info->mfn_list,
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E820_RESERVED);
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sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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return "Xen";
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}
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static void xen_idle(void)
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{
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local_irq_disable();
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if (need_resched())
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local_irq_enable();
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else {
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current_thread_info()->status &= ~TS_POLLING;
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smp_mb__after_clear_bit();
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safe_halt();
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current_thread_info()->status |= TS_POLLING;
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}
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}
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/*
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* Set the bit indicating "nosegneg" library variants should be used.
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* We only need to bother in pure 32-bit mode; compat 32-bit processes
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* can have un-truncated segments, so wrapping around is allowed.
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*/
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static void __init fiddle_vdso(void)
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{
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#ifdef CONFIG_X86_32
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u32 *mask;
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mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
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*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
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mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
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*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
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#endif
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}
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static __cpuinit int register_callback(unsigned type, const void *func)
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{
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struct callback_register callback = {
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.type = type,
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.address = XEN_CALLBACK(__KERNEL_CS, func),
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.flags = CALLBACKF_mask_events,
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};
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return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
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}
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void __cpuinit xen_enable_sysenter(void)
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{
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extern void xen_sysenter_target(void);
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int ret;
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unsigned sysenter_feature;
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#ifdef CONFIG_X86_32
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sysenter_feature = X86_FEATURE_SEP;
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#else
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sysenter_feature = X86_FEATURE_SYSENTER32;
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#endif
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if (!boot_cpu_has(sysenter_feature))
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return;
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ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
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if(ret != 0)
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setup_clear_cpu_cap(sysenter_feature);
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}
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void __cpuinit xen_enable_syscall(void)
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{
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#ifdef CONFIG_X86_64
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int ret;
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extern void xen_syscall_target(void);
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extern void xen_syscall32_target(void);
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ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
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if (ret != 0) {
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printk(KERN_ERR "Failed to set syscall: %d\n", ret);
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/* Pretty fatal; 64-bit userspace has no other
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mechanism for syscalls. */
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}
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if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
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ret = register_callback(CALLBACKTYPE_syscall32,
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xen_syscall32_target);
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if (ret != 0) {
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printk(KERN_INFO "Xen: 32-bit syscall not supported: disabling vdso\n");
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setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
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#ifdef CONFIG_COMPAT
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sysctl_vsyscall32 = 0;
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#endif
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}
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}
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#endif /* CONFIG_X86_64 */
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}
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void __init xen_arch_setup(void)
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{
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struct physdev_set_iopl set_iopl;
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int rc;
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HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
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HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
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if (!xen_feature(XENFEAT_auto_translated_physmap))
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HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_pae_extended_cr3);
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if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
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register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
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BUG();
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xen_enable_sysenter();
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xen_enable_syscall();
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set_iopl.iopl = 1;
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rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
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if (rc != 0)
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printk(KERN_INFO "physdev_op failed %d\n", rc);
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#ifdef CONFIG_ACPI
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if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
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printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
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disable_acpi();
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}
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#endif
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memcpy(boot_command_line, xen_start_info->cmd_line,
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MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
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COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
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pm_idle = xen_idle;
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paravirt_disable_iospace();
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fiddle_vdso();
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}
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