From c44c9ec0f38b939b3200436e3aa95c1aa83c41c7 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Mon, 21 Sep 2009 13:40:42 -0700 Subject: [PATCH] x86: split NX setup into separate file to limit unstack-protected code 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 --- arch/x86/include/asm/pgtable_types.h | 1 + arch/x86/mm/Makefile | 4 +- arch/x86/mm/init.c | 63 ------------------------- arch/x86/mm/setup_nx.c | 69 ++++++++++++++++++++++++++++ 4 files changed, 72 insertions(+), 65 deletions(-) create mode 100644 arch/x86/mm/setup_nx.c diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 54cb697f490..e9918d99f83 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -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 diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index dd313d035de..06630d26e56 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -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 diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 0607119cef9..73ffd5536f6 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -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) { diff --git a/arch/x86/mm/setup_nx.c b/arch/x86/mm/setup_nx.c new file mode 100644 index 00000000000..513d8ed5d2e --- /dev/null +++ b/arch/x86/mm/setup_nx.c @@ -0,0 +1,69 @@ +#include +#include +#include + +#include + +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 + -- 2.43.2