121 lines
2.5 KiB
C
121 lines
2.5 KiB
C
/*
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* (C) Copyright 2002 Linus Torvalds
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* Portions based on the vdso-randomization code from exec-shield:
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* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
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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/kernel.h>
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#include <linux/mm_types.h>
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#include <asm/cpufeature.h>
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#include <asm/processor.h>
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#include <asm/vdso.h>
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#ifdef CONFIG_COMPAT_VDSO
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#define VDSO_DEFAULT 0
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#else
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#define VDSO_DEFAULT 1
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#endif
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/*
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* Should the kernel map a VDSO page into processes and pass its
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* address down to glibc upon exec()?
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*/
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unsigned int __read_mostly vdso32_enabled = VDSO_DEFAULT;
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static int __init vdso32_setup(char *s)
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{
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vdso32_enabled = simple_strtoul(s, NULL, 0);
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if (vdso32_enabled > 1)
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pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n");
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return 1;
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}
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/*
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* For consistency, the argument vdso32=[012] affects the 32-bit vDSO
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* behavior on both 64-bit and 32-bit kernels.
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* On 32-bit kernels, vdso=[012] means the same thing.
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*/
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__setup("vdso32=", vdso32_setup);
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#ifdef CONFIG_X86_32
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__setup_param("vdso=", vdso_setup, vdso32_setup, 0);
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#endif
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#ifdef CONFIG_X86_64
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#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SYSENTER32))
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#define vdso32_syscall() (boot_cpu_has(X86_FEATURE_SYSCALL32))
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#else /* CONFIG_X86_32 */
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#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SEP))
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#define vdso32_syscall() (0)
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#endif /* CONFIG_X86_64 */
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#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
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const struct vdso_image *selected_vdso32;
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#endif
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int __init sysenter_setup(void)
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{
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#ifdef CONFIG_COMPAT
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if (vdso32_syscall())
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selected_vdso32 = &vdso_image_32_syscall;
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else
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#endif
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if (vdso32_sysenter())
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selected_vdso32 = &vdso_image_32_sysenter;
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else
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selected_vdso32 = &vdso_image_32_int80;
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init_vdso_image(selected_vdso32);
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return 0;
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}
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#ifdef CONFIG_X86_64
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subsys_initcall(sysenter_setup);
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#ifdef CONFIG_SYSCTL
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/* Register vsyscall32 into the ABI table */
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#include <linux/sysctl.h>
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static struct ctl_table abi_table2[] = {
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{
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.procname = "vsyscall32",
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.data = &vdso32_enabled,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec
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},
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{}
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};
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static struct ctl_table abi_root_table2[] = {
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{
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.procname = "abi",
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.mode = 0555,
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.child = abi_table2
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},
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{}
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};
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static __init int ia32_binfmt_init(void)
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{
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register_sysctl_table(abi_root_table2);
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return 0;
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}
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__initcall(ia32_binfmt_init);
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#endif /* CONFIG_SYSCTL */
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#endif /* CONFIG_X86_64 */
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