70 lines
1.2 KiB
C
70 lines
1.2 KiB
C
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#include <linux/spinlock.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <asm/pgtable.h>
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int nx_enabled;
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#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
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static int disable_nx __cpuinitdata;
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/*
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* noexec = on|off
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*
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* Control non-executable mappings for processes.
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*
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* on Enable
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* off Disable
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*/
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static int __init noexec_setup(char *str)
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{
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if (!str)
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return -EINVAL;
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if (!strncmp(str, "on", 2)) {
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__supported_pte_mask |= _PAGE_NX;
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disable_nx = 0;
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} else if (!strncmp(str, "off", 3)) {
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disable_nx = 1;
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__supported_pte_mask &= ~_PAGE_NX;
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}
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return 0;
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}
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early_param("noexec", noexec_setup);
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#endif
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#ifdef CONFIG_X86_PAE
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void __init set_nx(void)
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{
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unsigned int v[4], l, h;
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if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
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cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
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if ((v[3] & (1 << 20)) && !disable_nx) {
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rdmsr(MSR_EFER, l, h);
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l |= EFER_NX;
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wrmsr(MSR_EFER, l, h);
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nx_enabled = 1;
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__supported_pte_mask |= _PAGE_NX;
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}
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}
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}
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#else
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void set_nx(void)
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{
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}
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#endif
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#ifdef CONFIG_X86_64
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void __cpuinit check_efer(void)
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{
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unsigned long efer;
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rdmsrl(MSR_EFER, efer);
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if (!(efer & EFER_NX) || disable_nx)
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__supported_pte_mask &= ~_PAGE_NX;
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}
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#endif
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