PageRenderTime 10ms CodeModel.GetById 5ms app.highlight 3ms RepoModel.GetById 1ms app.codeStats 0ms

/arch/i386/kernel/sysenter.c

https://bitbucket.org/evzijst/gittest
C | 65 lines | 42 code | 12 blank | 11 comment | 1 complexity | bc213c217721410d95fb153afc8f17fb MD5 | raw file
 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
22extern asmlinkage void sysenter_entry(void);
23
24void enable_sep_cpu(void *info)
25{
26	int cpu = get_cpu();
27	struct tss_struct *tss = &per_cpu(init_tss, cpu);
28
29	tss->ss1 = __KERNEL_CS;
30	tss->esp1 = sizeof(struct tss_struct) + (unsigned long) tss;
31	wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
32	wrmsr(MSR_IA32_SYSENTER_ESP, tss->esp1, 0);
33	wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long) sysenter_entry, 0);
34	put_cpu();	
35}
36
37/*
38 * These symbols are defined by vsyscall.o to mark the bounds
39 * of the ELF DSO images included therein.
40 */
41extern const char vsyscall_int80_start, vsyscall_int80_end;
42extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
43
44static int __init sysenter_setup(void)
45{
46	void *page = (void *)get_zeroed_page(GFP_ATOMIC);
47
48	__set_fixmap(FIX_VSYSCALL, __pa(page), PAGE_READONLY_EXEC);
49
50	if (!boot_cpu_has(X86_FEATURE_SEP)) {
51		memcpy(page,
52		       &vsyscall_int80_start,
53		       &vsyscall_int80_end - &vsyscall_int80_start);
54		return 0;
55	}
56
57	memcpy(page,
58	       &vsyscall_sysenter_start,
59	       &vsyscall_sysenter_end - &vsyscall_sysenter_start);
60
61	on_each_cpu(enable_sep_cpu, NULL, 1, 1);
62	return 0;
63}
64
65__initcall(sysenter_setup);