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