[PATCH] sep initializing rework
[linux-2.6.git] / arch / i386 / kernel / sysenter.c
1 /*
2  * linux/arch/i386/kernel/sysenter.c
3  *
4  * (C) Copyright 2002 Linus Torvalds
5  *
6  * This file contains the needed initializations to support sysenter.
7  */
8
9 #include <linux/init.h>
10 #include <linux/smp.h>
11 #include <linux/thread_info.h>
12 #include <linux/sched.h>
13 #include <linux/gfp.h>
14 #include <linux/string.h>
15 #include <linux/elf.h>
16
17 #include <asm/cpufeature.h>
18 #include <asm/msr.h>
19 #include <asm/pgtable.h>
20 #include <asm/unistd.h>
21
22 extern asmlinkage void sysenter_entry(void);
23
24 void enable_sep_cpu(void)
25 {
26         int cpu = get_cpu();
27         struct tss_struct *tss = &per_cpu(init_tss, cpu);
28
29         if (!boot_cpu_has(X86_FEATURE_SEP)) {
30                 put_cpu();
31                 return;
32         }
33
34         tss->ss1 = __KERNEL_CS;
35         tss->esp1 = sizeof(struct tss_struct) + (unsigned long) tss;
36         wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
37         wrmsr(MSR_IA32_SYSENTER_ESP, tss->esp1, 0);
38         wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long) sysenter_entry, 0);
39         put_cpu();      
40 }
41
42 /*
43  * These symbols are defined by vsyscall.o to mark the bounds
44  * of the ELF DSO images included therein.
45  */
46 extern const char vsyscall_int80_start, vsyscall_int80_end;
47 extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
48
49 int __init sysenter_setup(void)
50 {
51         void *page = (void *)get_zeroed_page(GFP_ATOMIC);
52
53         __set_fixmap(FIX_VSYSCALL, __pa(page), PAGE_READONLY_EXEC);
54
55         if (!boot_cpu_has(X86_FEATURE_SEP)) {
56                 memcpy(page,
57                        &vsyscall_int80_start,
58                        &vsyscall_int80_end - &vsyscall_int80_start);
59                 return 0;
60         }
61
62         memcpy(page,
63                &vsyscall_sysenter_start,
64                &vsyscall_sysenter_end - &vsyscall_sysenter_start);
65
66         return 0;
67 }