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kernel_samsung_sm7125/arch/x86/mm/setup_nx.c

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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 <jeremy.fitzhardinge@citrix.com>
15 years ago
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <asm/pgtable.h>
x86, mm: Clean up and simplify NX enablement The 32- and 64-bit code used very different mechanisms for enabling NX, but even the 32-bit code was enabling NX in head_32.S if it is available. Furthermore, we had a bewildering collection of tests for the available of NX. This patch: a) merges the 32-bit set_nx() and the 64-bit check_efer() function into a single x86_configure_nx() function. EFER control is left to the head code. b) eliminates the nx_enabled variable entirely. Things that need to test for NX enablement can verify __supported_pte_mask directly, and cpu_has_nx gives the supported status of NX. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Tejun Heo <tj@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegardno@ifi.uio.no> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Chris Wright <chrisw@sous-sol.org> LKML-Reference: <1258154897-6770-5-git-send-email-hpa@zytor.com> Acked-by: Kees Cook <kees.cook@canonical.com>
15 years ago
#include <asm/proto.h>
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 <jeremy.fitzhardinge@citrix.com>
15 years ago
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)) {
disable_nx = 0;
} else if (!strncmp(str, "off", 3)) {
disable_nx = 1;
}
x86, mm: Clean up and simplify NX enablement The 32- and 64-bit code used very different mechanisms for enabling NX, but even the 32-bit code was enabling NX in head_32.S if it is available. Furthermore, we had a bewildering collection of tests for the available of NX. This patch: a) merges the 32-bit set_nx() and the 64-bit check_efer() function into a single x86_configure_nx() function. EFER control is left to the head code. b) eliminates the nx_enabled variable entirely. Things that need to test for NX enablement can verify __supported_pte_mask directly, and cpu_has_nx gives the supported status of NX. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Tejun Heo <tj@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegardno@ifi.uio.no> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Chris Wright <chrisw@sous-sol.org> LKML-Reference: <1258154897-6770-5-git-send-email-hpa@zytor.com> Acked-by: Kees Cook <kees.cook@canonical.com>
15 years ago
x86_configure_nx();
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 <jeremy.fitzhardinge@citrix.com>
15 years ago
return 0;
}
early_param("noexec", noexec_setup);
x86, mm: Clean up and simplify NX enablement The 32- and 64-bit code used very different mechanisms for enabling NX, but even the 32-bit code was enabling NX in head_32.S if it is available. Furthermore, we had a bewildering collection of tests for the available of NX. This patch: a) merges the 32-bit set_nx() and the 64-bit check_efer() function into a single x86_configure_nx() function. EFER control is left to the head code. b) eliminates the nx_enabled variable entirely. Things that need to test for NX enablement can verify __supported_pte_mask directly, and cpu_has_nx gives the supported status of NX. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Tejun Heo <tj@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegardno@ifi.uio.no> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Chris Wright <chrisw@sous-sol.org> LKML-Reference: <1258154897-6770-5-git-send-email-hpa@zytor.com> Acked-by: Kees Cook <kees.cook@canonical.com>
15 years ago
void __cpuinit x86_configure_nx(void)
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 <jeremy.fitzhardinge@citrix.com>
15 years ago
{
x86, mm: Clean up and simplify NX enablement The 32- and 64-bit code used very different mechanisms for enabling NX, but even the 32-bit code was enabling NX in head_32.S if it is available. Furthermore, we had a bewildering collection of tests for the available of NX. This patch: a) merges the 32-bit set_nx() and the 64-bit check_efer() function into a single x86_configure_nx() function. EFER control is left to the head code. b) eliminates the nx_enabled variable entirely. Things that need to test for NX enablement can verify __supported_pte_mask directly, and cpu_has_nx gives the supported status of NX. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Tejun Heo <tj@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Vegard Nossum <vegardno@ifi.uio.no> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Chris Wright <chrisw@sous-sol.org> LKML-Reference: <1258154897-6770-5-git-send-email-hpa@zytor.com> Acked-by: Kees Cook <kees.cook@canonical.com>
15 years ago
if (cpu_has_nx && !disable_nx)
__supported_pte_mask |= _PAGE_NX;
else
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 <jeremy.fitzhardinge@citrix.com>
15 years ago
__supported_pte_mask &= ~_PAGE_NX;
}
x86, mm: Report state of NX protections during boot It is possible for x86_64 systems to lack the NX bit either due to the hardware lacking support or the BIOS having turned off the CPU capability, so NX status should be reported. Additionally, anyone booting NX-capable CPUs in 32bit mode without PAE will lack NX functionality, so this change provides feedback for that case as well. Signed-off-by: Kees Cook <kees.cook@canonical.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> LKML-Reference: <1258154897-6770-6-git-send-email-hpa@zytor.com>
15 years ago
void __init x86_report_nx(void)
{
if (!cpu_has_nx) {
printk(KERN_NOTICE "Notice: NX (Execute Disable) protection "
"missing in CPU or disabled in BIOS!\n");
} else {
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
if (disable_nx) {
printk(KERN_INFO "NX (Execute Disable) protection: "
"disabled by kernel command line option\n");
} else {
printk(KERN_INFO "NX (Execute Disable) protection: "
"active\n");
}
#else
/* 32bit non-PAE kernel, NX cannot be used */
printk(KERN_NOTICE "Notice: NX (Execute Disable) protection "
"cannot be enabled: non-PAE kernel!\n");
#endif
}
}