direct-io.hg

view linux-2.6-xen-sparse/arch/x86_64/ia32/syscall32-xen.c @ 11690:38f9bd7a4ce6

[NET] Make MAX_SKBUFF_ORDER page-size independent.
Original patch from Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Keir Fraser <keir@xensource.com>
author kfraser@localhost.localdomain
date Tue Oct 03 11:39:22 2006 +0100 (2006-10-03)
parents 436c4c83a200
children
line source
1 /* Copyright 2002,2003 Andi Kleen, SuSE Labs */
3 /* vsyscall handling for 32bit processes. Map a stub page into it
4 on demand because 32bit cannot reach the kernel's fixmaps */
6 #include <linux/mm.h>
7 #include <linux/string.h>
8 #include <linux/kernel.h>
9 #include <linux/gfp.h>
10 #include <linux/init.h>
11 #include <linux/stringify.h>
12 #include <linux/security.h>
13 #include <asm/proto.h>
14 #include <asm/tlbflush.h>
15 #include <asm/ia32_unistd.h>
17 #ifdef USE_INT80
18 extern unsigned char syscall32_int80[], syscall32_int80_end[];
19 #endif
20 extern unsigned char syscall32_syscall[], syscall32_syscall_end[];
21 extern unsigned char syscall32_sysenter[], syscall32_sysenter_end[];
22 extern int sysctl_vsyscall32;
24 char *syscall32_page;
25 #ifndef USE_INT80
26 static int use_sysenter = -1;
27 #endif
29 static struct page *
30 syscall32_nopage(struct vm_area_struct *vma, unsigned long adr, int *type)
31 {
32 struct page *p = virt_to_page(adr - vma->vm_start + syscall32_page);
33 get_page(p);
34 return p;
35 }
37 /* Prevent VMA merging */
38 static void syscall32_vma_close(struct vm_area_struct *vma)
39 {
40 }
42 static struct vm_operations_struct syscall32_vm_ops = {
43 .close = syscall32_vma_close,
44 .nopage = syscall32_nopage,
45 };
47 struct linux_binprm;
49 /* Setup a VMA at program startup for the vsyscall page */
50 int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
51 {
52 int npages = (VSYSCALL32_END - VSYSCALL32_BASE) >> PAGE_SHIFT;
53 struct vm_area_struct *vma;
54 struct mm_struct *mm = current->mm;
55 int ret;
57 vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
58 if (!vma)
59 return -ENOMEM;
61 memset(vma, 0, sizeof(struct vm_area_struct));
62 /* Could randomize here */
63 vma->vm_start = VSYSCALL32_BASE;
64 vma->vm_end = VSYSCALL32_END;
65 /* MAYWRITE to allow gdb to COW and set breakpoints */
66 vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
67 vma->vm_flags |= mm->def_flags;
68 vma->vm_page_prot = protection_map[vma->vm_flags & 7];
69 vma->vm_ops = &syscall32_vm_ops;
70 vma->vm_mm = mm;
72 down_write(&mm->mmap_sem);
73 if ((ret = insert_vm_struct(mm, vma))) {
74 up_write(&mm->mmap_sem);
75 kmem_cache_free(vm_area_cachep, vma);
76 return ret;
77 }
78 mm->total_vm += npages;
79 up_write(&mm->mmap_sem);
80 return 0;
81 }
83 static int __init init_syscall32(void)
84 {
85 syscall32_page = (void *)get_zeroed_page(GFP_KERNEL);
86 if (!syscall32_page)
87 panic("Cannot allocate syscall32 page");
89 #ifdef USE_INT80
90 /*
91 * At this point we use int 0x80.
92 */
93 memcpy(syscall32_page, syscall32_int80,
94 syscall32_int80_end - syscall32_int80);
95 #else
96 if (use_sysenter > 0) {
97 memcpy(syscall32_page, syscall32_sysenter,
98 syscall32_sysenter_end - syscall32_sysenter);
99 } else {
100 memcpy(syscall32_page, syscall32_syscall,
101 syscall32_syscall_end - syscall32_syscall);
102 }
103 #endif
104 return 0;
105 }
107 /*
108 * This must be done early in case we have an initrd containing 32-bit
109 * binaries (e.g., hotplug). This could be pushed upstream to arch/x86_64.
110 */
111 core_initcall(init_syscall32);
113 /* May not be __init: called during resume */
114 void syscall32_cpu_init(void)
115 {
116 #ifndef USE_INT80
117 if (use_sysenter < 0)
118 use_sysenter = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL);
120 /* Load these always in case some future AMD CPU supports
121 SYSENTER from compat mode too. */
122 checking_wrmsrl(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
123 checking_wrmsrl(MSR_IA32_SYSENTER_ESP, 0ULL);
124 checking_wrmsrl(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
126 wrmsrl(MSR_CSTAR, ia32_cstar_target);
127 #endif
128 }