68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
/*
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* linux/arch/i386/kernel/sysenter.c
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*
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* (C) Copyright 2002 Linus Torvalds
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*
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* This file contains the needed initializations to support sysenter.
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*/
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#include <linux/init.h>
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#include <linux/smp.h>
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#include <linux/thread_info.h>
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#include <linux/sched.h>
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#include <linux/gfp.h>
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#include <linux/string.h>
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#include <linux/elf.h>
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#include <asm/cpufeature.h>
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#include <asm/msr.h>
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#include <asm/pgtable.h>
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#include <asm/unistd.h>
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extern asmlinkage void sysenter_entry(void);
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void enable_sep_cpu(void)
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{
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int cpu = get_cpu();
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struct tss_struct *tss = &per_cpu(init_tss, cpu);
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if (!boot_cpu_has(X86_FEATURE_SEP)) {
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put_cpu();
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return;
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}
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tss->ss1 = __KERNEL_CS;
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tss->esp1 = sizeof(struct tss_struct) + (unsigned long) tss;
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wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
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wrmsr(MSR_IA32_SYSENTER_ESP, tss->esp1, 0);
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wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long) sysenter_entry, 0);
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put_cpu();
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}
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/*
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* These symbols are defined by vsyscall.o to mark the bounds
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* of the ELF DSO images included therein.
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*/
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extern const char vsyscall_int80_start, vsyscall_int80_end;
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extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
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int __init sysenter_setup(void)
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{
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void *page = (void *)get_zeroed_page(GFP_ATOMIC);
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__set_fixmap(FIX_VSYSCALL, __pa(page), PAGE_READONLY_EXEC);
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if (!boot_cpu_has(X86_FEATURE_SEP)) {
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memcpy(page,
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&vsyscall_int80_start,
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&vsyscall_int80_end - &vsyscall_int80_start);
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return 0;
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}
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memcpy(page,
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&vsyscall_sysenter_start,
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&vsyscall_sysenter_end - &vsyscall_sysenter_start);
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return 0;
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}
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