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![David Vrabel](/assets/img/avatar_default.png)
Allow the xen balloon driver to populate its list of extra pages from more than one region of memory. This will allow platforms to provide (for example) a region of low memory and a region of high memory. The maximum possible number of extra regions is 128 (== E820MAX) which is quite large so xen_extra_mem is placed in __initdata. This is safe as both xen_memory_setup() and balloon_init() are in __init. The balloon regions themselves are not altered (i.e., there is still only the one region). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
458 lines
12 KiB
C
458 lines
12 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 <linux/memblock.h>
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#include <linux/cpuidle.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/xen.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/memory.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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extern void xen_sysenter_target(void);
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extern void xen_syscall_target(void);
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extern void xen_syscall32_target(void);
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/* Amount of extra memory space we add to the e820 ranges */
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struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
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/* Number of pages released from the initial allocation. */
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unsigned long xen_released_pages;
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/*
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* The maximum amount of extra memory compared to the base size. The
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* main scaling factor is the size of struct page. At extreme ratios
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* of base:extra, all the base memory can be filled with page
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* structures for the extra memory, leaving no space for anything
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* else.
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*
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* 10x seems like a reasonable balance between scaling flexibility and
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* leaving a practically usable system.
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*/
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#define EXTRA_MEM_RATIO (10)
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static void __init xen_add_extra_mem(unsigned long pages)
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{
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unsigned long pfn;
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u64 size = (u64)pages * PAGE_SIZE;
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u64 extra_start = xen_extra_mem[0].start + xen_extra_mem[0].size;
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if (!pages)
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return;
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e820_add_region(extra_start, size, E820_RAM);
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sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
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xen_extra_mem[0].size += size;
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xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
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for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)
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__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
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}
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static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
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phys_addr_t end_addr)
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{
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struct xen_memory_reservation reservation = {
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.address_bits = 0,
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.extent_order = 0,
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.domid = DOMID_SELF
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};
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unsigned long start, end;
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unsigned long len = 0;
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unsigned long pfn;
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int ret;
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start = PFN_UP(start_addr);
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end = PFN_DOWN(end_addr);
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if (end <= start)
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return 0;
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for(pfn = start; pfn < end; pfn++) {
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unsigned long mfn = pfn_to_mfn(pfn);
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/* Make sure pfn exists to start with */
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if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
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continue;
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set_xen_guest_handle(reservation.extent_start, &mfn);
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reservation.nr_extents = 1;
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ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
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&reservation);
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WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
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if (ret == 1) {
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__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
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len++;
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}
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}
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printk(KERN_INFO "Freeing %lx-%lx pfn range: %lu pages freed\n",
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start, end, len);
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return len;
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}
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static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
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const struct e820map *e820)
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{
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phys_addr_t max_addr = PFN_PHYS(max_pfn);
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phys_addr_t last_end = ISA_END_ADDRESS;
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unsigned long released = 0;
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int i;
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/* Free any unused memory above the low 1Mbyte. */
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for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
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phys_addr_t end = e820->map[i].addr;
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end = min(max_addr, end);
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if (last_end < end)
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released += xen_release_chunk(last_end, end);
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last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
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}
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if (last_end < max_addr)
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released += xen_release_chunk(last_end, max_addr);
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printk(KERN_INFO "released %lu pages of unused memory\n", released);
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return released;
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}
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static unsigned long __init xen_set_identity(const struct e820entry *list,
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ssize_t map_size)
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{
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phys_addr_t last = xen_initial_domain() ? 0 : ISA_END_ADDRESS;
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phys_addr_t start_pci = last;
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const struct e820entry *entry;
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unsigned long identity = 0;
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int i;
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for (i = 0, entry = list; i < map_size; i++, entry++) {
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phys_addr_t start = entry->addr;
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phys_addr_t end = start + entry->size;
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if (start < last)
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start = last;
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if (end <= start)
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continue;
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/* Skip over the 1MB region. */
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if (last > end)
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continue;
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if ((entry->type == E820_RAM) || (entry->type == E820_UNUSABLE)) {
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if (start > start_pci)
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identity += set_phys_range_identity(
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PFN_UP(start_pci), PFN_DOWN(start));
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/* Without saving 'last' we would gooble RAM too
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* at the end of the loop. */
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last = end;
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start_pci = end;
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continue;
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}
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start_pci = min(start, start_pci);
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last = end;
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}
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if (last > start_pci)
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identity += set_phys_range_identity(
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PFN_UP(start_pci), PFN_DOWN(last));
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return identity;
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}
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static unsigned long __init xen_get_max_pages(void)
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{
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unsigned long max_pages = MAX_DOMAIN_PAGES;
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domid_t domid = DOMID_SELF;
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int ret;
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ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
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if (ret > 0)
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max_pages = ret;
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return min(max_pages, MAX_DOMAIN_PAGES);
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}
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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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static struct e820entry map[E820MAX] __initdata;
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static struct e820entry map_raw[E820MAX] __initdata;
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unsigned long max_pfn = xen_start_info->nr_pages;
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unsigned long long mem_end;
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int rc;
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struct xen_memory_map memmap;
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unsigned long extra_pages = 0;
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unsigned long extra_limit;
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unsigned long identity_pages = 0;
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int i;
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int op;
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max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
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mem_end = PFN_PHYS(max_pfn);
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memmap.nr_entries = E820MAX;
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set_xen_guest_handle(memmap.buffer, map);
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op = xen_initial_domain() ?
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XENMEM_machine_memory_map :
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XENMEM_memory_map;
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rc = HYPERVISOR_memory_op(op, &memmap);
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if (rc == -ENOSYS) {
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BUG_ON(xen_initial_domain());
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memmap.nr_entries = 1;
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map[0].addr = 0ULL;
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map[0].size = mem_end;
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/* 8MB slack (to balance backend allocations). */
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map[0].size += 8ULL << 20;
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map[0].type = E820_RAM;
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rc = 0;
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}
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BUG_ON(rc);
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memcpy(map_raw, map, sizeof(map));
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e820.nr_map = 0;
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xen_extra_mem[0].start = mem_end;
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for (i = 0; i < memmap.nr_entries; i++) {
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unsigned long long end;
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/* Guard against non-page aligned E820 entries. */
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if (map[i].type == E820_RAM)
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map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;
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end = map[i].addr + map[i].size;
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if (map[i].type == E820_RAM && end > mem_end) {
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/* RAM off the end - may be partially included */
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u64 delta = min(map[i].size, end - mem_end);
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map[i].size -= delta;
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end -= delta;
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extra_pages += PFN_DOWN(delta);
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/*
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* Set RAM below 4GB that is not for us to be unusable.
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* This prevents "System RAM" address space from being
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* used as potential resource for I/O address (happens
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* when 'allocate_resource' is called).
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*/
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if (delta &&
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(xen_initial_domain() && end < 0x100000000ULL))
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e820_add_region(end, delta, E820_UNUSABLE);
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}
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if (map[i].size > 0 && end > xen_extra_mem[0].start)
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xen_extra_mem[0].start = end;
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/* Add region if any remains */
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if (map[i].size > 0)
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e820_add_region(map[i].addr, map[i].size, map[i].type);
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}
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/* Align the balloon area so that max_low_pfn does not get set
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* to be at the _end_ of the PCI gap at the far end (fee01000).
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* Note that the start of balloon area gets set in the loop above
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* to be past the last E820 region. */
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if (xen_initial_domain() && (xen_extra_mem[0].start < (1ULL<<32)))
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xen_extra_mem[0].start = (1ULL<<32);
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/*
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* In domU, the ISA region is normal, usable memory, but we
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* reserve ISA memory anyway because too many things poke
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* about in there.
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*
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* In Dom0, the host E820 information can leave gaps in the
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* ISA range, which would cause us to release those pages. To
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* avoid this, we unconditionally reserve them here.
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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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memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
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__pa(xen_start_info->pt_base),
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"XEN START INFO");
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sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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extra_limit = xen_get_max_pages();
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if (max_pfn + extra_pages > extra_limit) {
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if (extra_limit > max_pfn)
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extra_pages = extra_limit - max_pfn;
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else
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extra_pages = 0;
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}
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xen_released_pages = xen_return_unused_memory(xen_start_info->nr_pages,
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&e820);
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extra_pages += xen_released_pages;
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/*
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* Clamp the amount of extra memory to a EXTRA_MEM_RATIO
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* factor the base size. On non-highmem systems, the base
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* size is the full initial memory allocation; on highmem it
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* is limited to the max size of lowmem, so that it doesn't
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* get completely filled.
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*
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* In principle there could be a problem in lowmem systems if
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* the initial memory is also very large with respect to
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* lowmem, but we won't try to deal with that here.
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*/
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extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
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max_pfn + extra_pages);
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if (extra_limit >= max_pfn)
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extra_pages = extra_limit - max_pfn;
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else
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extra_pages = 0;
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xen_add_extra_mem(extra_pages);
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/*
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* Set P2M for all non-RAM pages and E820 gaps to be identity
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* type PFNs. We supply it with the non-sanitized version
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* of the E820.
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*/
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identity_pages = xen_set_identity(map_raw, memmap.nr_entries);
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printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages);
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return "Xen";
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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 int __cpuinit 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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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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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 callback: %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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setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
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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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xen_panic_handler_init();
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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,
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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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#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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/* Set up idle, making sure it calls safe_halt() pvop */
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#ifdef CONFIG_X86_32
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boot_cpu_data.hlt_works_ok = 1;
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#endif
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disable_cpuidle();
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boot_option_idle_override = IDLE_HALT;
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fiddle_vdso();
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}
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