Commit bdccc4ed authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'stable/for-linus-3.20-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen features and fixes from David Vrabel:

 - Reworked handling for foreign (grant mapped) pages to simplify the
   code, enable a number of additional use cases and fix a number of
   long-standing bugs.

 - Prefer the TSC over the Xen PV clock when dom0 (and the TSC is
   stable).

 - Assorted other cleanup and minor bug fixes.

* tag 'stable/for-linus-3.20-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (25 commits)
  xen/manage: Fix USB interaction issues when resuming
  xenbus: Add proper handling of XS_ERROR from Xenbus for transactions.
  xen/gntdev: provide find_special_page VMA operation
  xen/gntdev: mark userspace PTEs as special on x86 PV guests
  xen-blkback: safely unmap grants in case they are still in use
  xen/gntdev: safely unmap grants in case they are still in use
  xen/gntdev: convert priv->lock to a mutex
  xen/grant-table: add a mechanism to safely unmap pages that are in use
  xen-netback: use foreign page information from the pages themselves
  xen: mark grant mapped pages as foreign
  xen/grant-table: add helpers for allocating pages
  x86/xen: require ballooned pages for grant maps
  xen: remove scratch frames for ballooned pages and m2p override
  xen/grant-table: pre-populate kernel unmap ops for xen_gnttab_unmap_refs()
  mm: add 'foreign' alias for the 'pinned' page flag
  mm: provide a find_special_page vma operation
  x86/xen: cleanup arch/x86/xen/mmu.c
  x86/xen: add some __init annotations in arch/x86/xen/mmu.c
  x86/xen: add some __init and static annotations in arch/x86/xen/setup.c
  x86/xen: use correct types for addresses in arch/x86/xen/setup.c
  ...
parents 98368ab4 72978b2f
......@@ -92,7 +92,7 @@ extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
struct page **pages, unsigned int count);
extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct gnttab_unmap_grant_ref *kunmap_ops,
struct page **pages, unsigned int count);
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
......
......@@ -29,10 +29,10 @@
struct start_info _xen_start_info;
struct start_info *xen_start_info = &_xen_start_info;
EXPORT_SYMBOL_GPL(xen_start_info);
EXPORT_SYMBOL(xen_start_info);
enum xen_domain_type xen_domain_type = XEN_NATIVE;
EXPORT_SYMBOL_GPL(xen_domain_type);
EXPORT_SYMBOL(xen_domain_type);
struct shared_info xen_dummy_shared_info;
struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
......
......@@ -149,7 +149,7 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
struct dma_map_ops *xen_dma_ops;
EXPORT_SYMBOL_GPL(xen_dma_ops);
EXPORT_SYMBOL(xen_dma_ops);
static struct dma_map_ops xen_swiotlb_dma_ops = {
.mapping_error = xen_swiotlb_dma_mapping_error,
......
......@@ -102,7 +102,7 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct gnttab_unmap_grant_ref *kunmap_ops,
struct page **pages, unsigned int count)
{
int i;
......
......@@ -55,9 +55,8 @@ extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count);
extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct gnttab_unmap_grant_ref *kunmap_ops,
struct page **pages, unsigned int count);
extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
/*
* Helper functions to write or read unsigned long values to/from
......@@ -154,21 +153,12 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
return mfn;
pfn = mfn_to_pfn_no_overrides(mfn);
if (__pfn_to_mfn(pfn) != mfn) {
/*
* If this appears to be a foreign mfn (because the pfn
* doesn't map back to the mfn), then check the local override
* table to see if there's a better pfn to use.
*
* m2p_find_override_pfn returns ~0 if it doesn't find anything.
*/
pfn = m2p_find_override_pfn(mfn, ~0);
}
if (__pfn_to_mfn(pfn) != mfn)
pfn = ~0;
/*
* pfn is ~0 if there are no entries in the m2p for mfn or if the
* entry doesn't map back to the mfn and m2p_override doesn't have a
* valid entry for it.
* pfn is ~0 if there are no entries in the m2p for mfn or the
* entry doesn't map back to the mfn.
*/
if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn))
pfn = mfn;
......
......@@ -1489,7 +1489,7 @@ static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
native_set_pte(ptep, pte);
}
static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
{
struct mmuext_op op;
op.cmd = cmd;
......@@ -1657,7 +1657,7 @@ void __init xen_reserve_top(void)
* Like __va(), but returns address in the kernel mapping (which is
* all we have until the physical memory mapping has been set up.
*/
static void *__ka(phys_addr_t paddr)
static void * __init __ka(phys_addr_t paddr)
{
#ifdef CONFIG_X86_64
return (void *)(paddr + __START_KERNEL_map);
......@@ -1667,7 +1667,7 @@ static void *__ka(phys_addr_t paddr)
}
/* Convert a machine address to physical address */
static unsigned long m2p(phys_addr_t maddr)
static unsigned long __init m2p(phys_addr_t maddr)
{
phys_addr_t paddr;
......@@ -1678,13 +1678,14 @@ static unsigned long m2p(phys_addr_t maddr)
}
/* Convert a machine address to kernel virtual */
static void *m2v(phys_addr_t maddr)
static void * __init m2v(phys_addr_t maddr)
{
return __ka(m2p(maddr));
}
/* Set the page permissions on an identity-mapped pages */
static void set_page_prot_flags(void *addr, pgprot_t prot, unsigned long flags)
static void __init set_page_prot_flags(void *addr, pgprot_t prot,
unsigned long flags)
{
unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
pte_t pte = pfn_pte(pfn, prot);
......@@ -1696,7 +1697,7 @@ static void set_page_prot_flags(void *addr, pgprot_t prot, unsigned long flags)
if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
BUG();
}
static void set_page_prot(void *addr, pgprot_t prot)
static void __init set_page_prot(void *addr, pgprot_t prot)
{
return set_page_prot_flags(addr, prot, UVMF_NONE);
}
......@@ -1733,10 +1734,8 @@ static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
pte_t pte;
#ifdef CONFIG_X86_32
if (pfn > max_pfn_mapped)
max_pfn_mapped = pfn;
#endif
if (!pte_none(pte_page[pteidx]))
continue;
......@@ -1769,7 +1768,7 @@ void __init xen_setup_machphys_mapping(void)
}
#ifdef CONFIG_X86_64
static void convert_pfn_mfn(void *v)
static void __init convert_pfn_mfn(void *v)
{
pte_t *pte = v;
int i;
......
......@@ -84,8 +84,6 @@
#define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE)
static void __init m2p_override_init(void);
unsigned long *xen_p2m_addr __read_mostly;
EXPORT_SYMBOL_GPL(xen_p2m_addr);
unsigned long xen_p2m_size __read_mostly;
......@@ -402,8 +400,6 @@ void __init xen_vmalloc_p2m_tree(void)
xen_p2m_size = xen_max_p2m_pfn;
xen_inv_extra_mem();
m2p_override_init();
}
unsigned long get_phys_to_machine(unsigned long pfn)
......@@ -652,100 +648,21 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
return true;
}
#define M2P_OVERRIDE_HASH_SHIFT 10
#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
static struct list_head *m2p_overrides;
static DEFINE_SPINLOCK(m2p_override_lock);
static void __init m2p_override_init(void)
{
unsigned i;
m2p_overrides = alloc_bootmem_align(
sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH,
sizeof(unsigned long));
for (i = 0; i < M2P_OVERRIDE_HASH; i++)
INIT_LIST_HEAD(&m2p_overrides[i]);
}
static unsigned long mfn_hash(unsigned long mfn)
{
return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT);
}
/* Add an MFN override for a particular page */
static int m2p_add_override(unsigned long mfn, struct page *page,
struct gnttab_map_grant_ref *kmap_op)
{
unsigned long flags;
unsigned long pfn;
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
pfn = page_to_pfn(page);
if (!PageHighMem(page)) {
address = (unsigned long)__va(pfn << PAGE_SHIFT);
ptep = lookup_address(address, &level);
if (WARN(ptep == NULL || level != PG_LEVEL_4K,
"m2p_add_override: pfn %lx not mapped", pfn))
return -EINVAL;
}
if (kmap_op != NULL) {
if (!PageHighMem(page)) {
struct multicall_space mcs =
xen_mc_entry(sizeof(*kmap_op));
MULTI_grant_table_op(mcs.mc,
GNTTABOP_map_grant_ref, kmap_op, 1);
xen_mc_issue(PARAVIRT_LAZY_MMU);
}
}
spin_lock_irqsave(&m2p_override_lock, flags);
list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]);
spin_unlock_irqrestore(&m2p_override_lock, flags);
/* p2m(m2p(mfn)) == mfn: the mfn is already present somewhere in
* this domain. Set the FOREIGN_FRAME_BIT in the p2m for the other
* pfn so that the following mfn_to_pfn(mfn) calls will return the
* pfn from the m2p_override (the backend pfn) instead.
* We need to do this because the pages shared by the frontend
* (xen-blkfront) can be already locked (lock_page, called by
* do_read_cache_page); when the userspace backend tries to use them
* with direct_IO, mfn_to_pfn returns the pfn of the frontend, so
* do_blockdev_direct_IO is going to try to lock the same pages
* again resulting in a deadlock.
* As a side effect get_user_pages_fast might not be safe on the
* frontend pages while they are being shared with the backend,
* because mfn_to_pfn (that ends up being called by GUPF) will
* return the backend pfn rather than the frontend pfn. */
pfn = mfn_to_pfn_no_overrides(mfn);
if (__pfn_to_mfn(pfn) == mfn)
set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));
return 0;
}
int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count)
{
int i, ret = 0;
bool lazy = false;
pte_t *pte;
if (xen_feature(XENFEAT_auto_translated_physmap))
return 0;
if (kmap_ops &&
!in_interrupt() &&
paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
arch_enter_lazy_mmu_mode();
lazy = true;
if (kmap_ops) {
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
kmap_ops, count);
if (ret)
goto out;
}
for (i = 0; i < count; i++) {
......@@ -764,170 +681,28 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
}
pfn = page_to_pfn(pages[i]);
WARN_ON(PagePrivate(pages[i]));
SetPagePrivate(pages[i]);
set_page_private(pages[i], mfn);
pages[i]->index = pfn_to_mfn(pfn);
WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
ret = -ENOMEM;
goto out;
}
if (kmap_ops) {
ret = m2p_add_override(mfn, pages[i], &kmap_ops[i]);
if (ret)
goto out;
}
}
out:
if (lazy)
arch_leave_lazy_mmu_mode();
return ret;
}
EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
static struct page *m2p_find_override(unsigned long mfn)
{
unsigned long flags;
struct list_head *bucket;
struct page *p, *ret;
if (unlikely(!m2p_overrides))
return NULL;
ret = NULL;
bucket = &m2p_overrides[mfn_hash(mfn)];
spin_lock_irqsave(&m2p_override_lock, flags);
list_for_each_entry(p, bucket, lru) {
if (page_private(p) == mfn) {
ret = p;
break;
}
}
spin_unlock_irqrestore(&m2p_override_lock, flags);
return ret;
}
static int m2p_remove_override(struct page *page,
struct gnttab_map_grant_ref *kmap_op,
unsigned long mfn)
{
unsigned long flags;
unsigned long pfn;
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
pfn = page_to_pfn(page);
if (!PageHighMem(page)) {
address = (unsigned long)__va(pfn << PAGE_SHIFT);
ptep = lookup_address(address, &level);
if (WARN(ptep == NULL || level != PG_LEVEL_4K,
"m2p_remove_override: pfn %lx not mapped", pfn))
return -EINVAL;
}
spin_lock_irqsave(&m2p_override_lock, flags);
list_del(&page->lru);
spin_unlock_irqrestore(&m2p_override_lock, flags);
if (kmap_op != NULL) {
if (!PageHighMem(page)) {
struct multicall_space mcs;
struct gnttab_unmap_and_replace *unmap_op;
struct page *scratch_page = get_balloon_scratch_page();
unsigned long scratch_page_address = (unsigned long)
__va(page_to_pfn(scratch_page) << PAGE_SHIFT);
/*
* It might be that we queued all the m2p grant table
* hypercalls in a multicall, then m2p_remove_override
* get called before the multicall has actually been
* issued. In this case handle is going to -1 because
* it hasn't been modified yet.
*/
if (kmap_op->handle == -1)
xen_mc_flush();
/*
* Now if kmap_op->handle is negative it means that the
* hypercall actually returned an error.
*/
if (kmap_op->handle == GNTST_general_error) {
pr_warn("m2p_remove_override: pfn %lx mfn %lx, failed to modify kernel mappings",
pfn, mfn);
put_balloon_scratch_page();
return -1;
}
xen_mc_batch();
mcs = __xen_mc_entry(
sizeof(struct gnttab_unmap_and_replace));
unmap_op = mcs.args;
unmap_op->host_addr = kmap_op->host_addr;
unmap_op->new_addr = scratch_page_address;
unmap_op->handle = kmap_op->handle;
MULTI_grant_table_op(mcs.mc,
GNTTABOP_unmap_and_replace, unmap_op, 1);
mcs = __xen_mc_entry(0);
MULTI_update_va_mapping(mcs.mc, scratch_page_address,
pfn_pte(page_to_pfn(scratch_page),
PAGE_KERNEL_RO), 0);
xen_mc_issue(PARAVIRT_LAZY_MMU);
kmap_op->host_addr = 0;
put_balloon_scratch_page();
}
}
/* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present
* somewhere in this domain, even before being added to the
* m2p_override (see comment above in m2p_add_override).
* If there are no other entries in the m2p_override corresponding
* to this mfn, then remove the FOREIGN_FRAME_BIT from the p2m for
* the original pfn (the one shared by the frontend): the backend
* cannot do any IO on this page anymore because it has been
* unshared. Removing the FOREIGN_FRAME_BIT from the p2m entry of
* the original pfn causes mfn_to_pfn(mfn) to return the frontend
* pfn again. */
mfn &= ~FOREIGN_FRAME_BIT;
pfn = mfn_to_pfn_no_overrides(mfn);
if (__pfn_to_mfn(pfn) == FOREIGN_FRAME(mfn) &&
m2p_find_override(mfn) == NULL)
set_phys_to_machine(pfn, mfn);
return 0;
}
int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct gnttab_unmap_grant_ref *kunmap_ops,
struct page **pages, unsigned int count)
{
int i, ret = 0;
bool lazy = false;
if (xen_feature(XENFEAT_auto_translated_physmap))
return 0;
if (kmap_ops &&
!in_interrupt() &&
paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
arch_enter_lazy_mmu_mode();
lazy = true;
}
for (i = 0; i < count; i++) {
unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
unsigned long pfn = page_to_pfn(pages[i]);
......@@ -937,36 +712,16 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
goto out;
}
set_page_private(pages[i], INVALID_P2M_ENTRY);
WARN_ON(!PagePrivate(pages[i]));
ClearPagePrivate(pages[i]);
set_phys_to_machine(pfn, pages[i]->index);
if (kmap_ops)
ret = m2p_remove_override(pages[i], &kmap_ops[i], mfn);
if (ret)
goto out;
set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
}
if (kunmap_ops)
ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
kunmap_ops, count);
out:
if (lazy)
arch_leave_lazy_mmu_mode();
return ret;
}
EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn)
{
struct page *p = m2p_find_override(mfn);
unsigned long ret = pfn;
if (p)
ret = page_to_pfn(p);
return ret;
}
EXPORT_SYMBOL_GPL(m2p_find_override_pfn);
#ifdef CONFIG_XEN_DEBUG_FS
#include <linux/debugfs.h>
#include "debugfs.h"
......
......@@ -32,16 +32,6 @@
#include "p2m.h"
#include "mmu.h"
/* These are code, but not functions. Defined in entry.S */
extern const char xen_hypervisor_callback[];
extern const char xen_failsafe_callback[];
#ifdef CONFIG_X86_64
extern asmlinkage void nmi(void);
#endif
extern void xen_sysenter_target(void);
extern void xen_syscall_target(void);
extern void xen_syscall32_target(void);
/* Amount of extra memory space we add to the e820 ranges */
struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
......@@ -74,7 +64,7 @@ static unsigned long xen_remap_mfn __initdata = INVALID_P2M_ENTRY;
*/
#define EXTRA_MEM_RATIO (10)
static void __init xen_add_extra_mem(u64 start, u64 size)
static void __init xen_add_extra_mem(phys_addr_t start, phys_addr_t size)
{
int i;
......@@ -97,10 +87,10 @@ static void __init xen_add_extra_mem(u64 start, u64 size)
memblock_reserve(start, size);
}
static void __init xen_del_extra_mem(u64 start, u64 size)
static void __init xen_del_extra_mem(phys_addr_t start, phys_addr_t size)
{
int i;
u64 start_r, size_r;
phys_addr_t start_r, size_r;
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
start_r = xen_extra_mem[i].start;
......@@ -267,7 +257,7 @@ static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
static void __init xen_update_mem_tables(unsigned long pfn, unsigned long mfn)
{
struct mmu_update update = {
.ptr = ((unsigned long long)mfn << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE,
.ptr = ((uint64_t)mfn << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE,
.val = pfn
};
......@@ -545,20 +535,21 @@ static unsigned long __init xen_get_max_pages(void)
return min(max_pages, MAX_DOMAIN_PAGES);
}
static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
static void __init xen_align_and_add_e820_region(phys_addr_t start,
phys_addr_t size, int type)
{
u64 end = start + size;
phys_addr_t end = start + size;
/* Align RAM regions to page boundaries. */
if (type == E820_RAM) {
start = PAGE_ALIGN(start);
end &= ~((u64)PAGE_SIZE - 1);
end &= ~((phys_addr_t)PAGE_SIZE - 1);
}
e820_add_region(start, end - start, type);
}
void xen_ignore_unusable(struct e820entry *list, size_t map_size)
static void __init xen_ignore_unusable(struct e820entry *list, size_t map_size)
{
struct e820entry *entry;
unsigned int i;
......@@ -577,7 +568,7 @@ char * __init xen_memory_setup(void)
static struct e820entry map[E820MAX] __initdata;
unsigned long max_pfn = xen_start_info->nr_pages;
unsigned long long mem_end;
phys_addr_t mem_end;
int rc;
struct xen_memory_map memmap;
unsigned long max_pages;
......@@ -652,16 +643,16 @@ char * __init xen_memory_setup(void)
extra_pages);
i = 0;
while (i < memmap.nr_entries) {
u64 addr = map[i].addr;
u64 size = map[i].size;
phys_addr_t addr = map[i].addr;
phys_addr_t size = map[i].size;
u32 type = map[i].type;
if (type == E820_RAM) {
if (addr < mem_end) {
size = min(size, mem_end - addr);
} else if (extra_pages) {
size = min(size, (u64)extra_pages * PAGE_SIZE);
extra_pages -= size / PAGE_SIZE;
size = min(size, PFN_PHYS(extra_pages));
extra_pages -= PFN_DOWN(size);
xen_add_extra_mem(addr, size);
xen_max_p2m_pfn = PFN_DOWN(addr + size);
} else
......
......@@ -507,7 +507,7 @@ static int xen_cpu_disable(void)
static void xen_cpu_die(unsigned int cpu)
{
while (xen_pv_domain() && HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL)) {
current->state = TASK_UNINTERRUPTIBLE;
__set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(HZ/10);
}
......
......@@ -479,6 +479,10 @@ static void __init xen_time_init(void)
int cpu = smp_processor_id();
struct timespec tp;
/* As Dom0 is never moved, no penalty on using TSC there */
if (xen_initial_domain())
xen_clocksource.rating = 275;
clocksource_register_hz(&xen_clocksource, NSEC_PER_SEC);
if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) {
......
......@@ -10,6 +10,12 @@
extern const char xen_hypervisor_callback[];
extern const char xen_failsafe_callback[];
void xen_sysenter_target(void);
#ifdef CONFIG_X86_64
void xen_syscall_target(void);
void xen_syscall32_target(void);
#endif
extern void *xen_initial_gdt;
struct trap_info;
......