From 4763ed4d45522b876c97e1f7f4b659d211f75571 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 13 Nov 2009 15:28:16 -0800 Subject: 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 Cc: Tejun Heo Cc: Brian Gerst Cc: Yinghai Lu Cc: Pekka Enberg Cc: Vegard Nossum Cc: Jeremy Fitzhardinge Cc: Chris Wright LKML-Reference: <1258154897-6770-5-git-send-email-hpa@zytor.com> Acked-by: Kees Cook --- arch/x86/mm/init.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/mm/init.c') diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 73ffd5536f6..27ec2c23fd4 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -146,8 +146,8 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, use_gbpages = direct_gbpages; #endif - set_nx(); - if (nx_enabled) + /* XXX: replace this with Kees' improved messages */ + if (__supported_pte_mask & _PAGE_NX) printk(KERN_INFO "NX (Execute Disable) protection: active\n"); /* Enable PSE if available */ -- cgit From 4b0f3b81eb33ef18283aa71440cccfede1753ae0 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 13 Nov 2009 15:28:17 -0800 Subject: 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 Signed-off-by: H. Peter Anvin LKML-Reference: <1258154897-6770-6-git-send-email-hpa@zytor.com> --- arch/x86/mm/init.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'arch/x86/mm/init.c') diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 27ec2c23fd4..d406c523901 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -146,10 +146,6 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, use_gbpages = direct_gbpages; #endif - /* XXX: replace this with Kees' improved messages */ - if (__supported_pte_mask & _PAGE_NX) - printk(KERN_INFO "NX (Execute Disable) protection: active\n"); - /* Enable PSE if available */ if (cpu_has_pse) set_in_cr4(X86_CR4_PSE); -- cgit