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x86: split NX setup into separate file to limit unstack-protected code

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Move the NX setup into a separate file so that it can be compiled
without stack-protection while leaving the rest of the mm/init code
protected.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
This commit is contained in:
Jeremy Fitzhardinge 2009-09-21 13:40:42 -07:00
parent b75fe4e5b8
commit c44c9ec0f3
4 changed files with 72 additions and 65 deletions
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1
arch/x86/include/asm/pgtable_types.h
View File

@ -277,6 +277,7 @@ static inline pteval_t pte_flags(pte_t pte)
typedef struct page *pgtable_t;
extern pteval_t __supported_pte_mask;
extern void set_nx(void);
extern int nx_enabled;
#define pgprot_writecombine pgprot_writecombine

4
arch/x86/mm/Makefile
View File

@ -1,10 +1,10 @@
obj-y := init.o init_$(BITS).o fault.o ioremap.o extable.o pageattr.o mmap.o \
pat.o pgtable.o physaddr.o gup.o
pat.o pgtable.o physaddr.o gup.o setup_nx.o
# Make sure __phys_addr has no stackprotector
nostackp := $(call cc-option, -fno-stack-protector)
CFLAGS_physaddr.o := $(nostackp)
CFLAGS_init.o := $(nostackp)
CFLAGS_setup_nx.o := $(nostackp)
obj-$(CONFIG_SMP) += tlb.o

63
arch/x86/mm/init.c
View File

@ -28,69 +28,6 @@ int direct_gbpages
#endif
;
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
static 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
static inline 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
static void __init find_early_table_space(unsigned long end, int use_pse,
int use_gbpages)
{

69
arch/x86/mm/setup_nx.c Normal file
View File

@ -0,0 +1,69 @@
#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