2 * linux/arch/i386/kernel/sysenter.c
4 * (C) Copyright 2002 Linus Torvalds
6 * This file contains the needed initializations to support sysenter.
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>
17 #include <asm/cpufeature.h>
19 #include <asm/pgtable.h>
20 #include <asm/unistd.h>
22 extern asmlinkage void sysenter_entry(void);
24 void enable_sep_cpu(void)
27 struct tss_struct *tss = &per_cpu(init_tss, cpu);
29 if (!boot_cpu_has(X86_FEATURE_SEP)) {
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);
43 * These symbols are defined by vsyscall.o to mark the bounds
44 * of the ELF DSO images included therein.
46 extern const char vsyscall_int80_start, vsyscall_int80_end;
47 extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
49 int __init sysenter_setup(void)
51 void *page = (void *)get_zeroed_page(GFP_ATOMIC);
53 __set_fixmap(FIX_VSYSCALL, __pa(page), PAGE_READONLY_EXEC);
55 if (!boot_cpu_has(X86_FEATURE_SEP)) {
57 &vsyscall_int80_start,
58 &vsyscall_int80_end - &vsyscall_int80_start);
63 &vsyscall_sysenter_start,
64 &vsyscall_sysenter_end - &vsyscall_sysenter_start);