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-rw-r--r--arch/i386/kernel/sysenter.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c
new file mode 100644
index 000000000000..960d8bd137d0
--- /dev/null
+++ b/arch/i386/kernel/sysenter.c
@@ -0,0 +1,65 @@
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);