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| author | Andy Lutomirski <luto@kernel.org> | 2016-04-26 08:52:44 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-04-26 19:52:57 +0200 |
| commit | e16d8a6cbb499c5c8bfe9330d3351b649bded4af (patch) | |
| tree | 16f6883c63a4930e717bb4078dc385fb7a75bcd9 /arch | |
| parent | 707e59ba494372a90d245f18b0c78982caa88e48 (diff) | |
| download | linux-e16d8a6cbb499c5c8bfe9330d3351b649bded4af.tar.bz2 | |
Revert "x86/mm/32: Set NX in __supported_pte_mask before enabling paging"
This reverts commit 320d25b6a05f8b73c23fc21025d2906ecdd2d4fc.
This change was problematic for a couple of reasons:
1. It missed a some entry points (Xen things and 64-bit native).
2. The entry it changed can be executed more than once. This isn't
really a problem, but it conflated per-cpu state setup and global
state setup.
3. It broke 64-bit non-NX. 64-bit non-NX worked the other way around from
32-bit -- __supported_pte_mask had NX set initially and was *cleared*
in x86_configure_nx. With the patch applied, it never got cleared.
Reported-and-tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/59bd15f7f4b56b633a611b7f70876c6d2ad01a98.1461685884.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/head_32.S | 6 | ||||
| -rw-r--r-- | arch/x86/mm/setup_nx.c | 5 |
2 files changed, 3 insertions, 8 deletions
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 54cdbd2003fe..af1112980dd4 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -389,12 +389,6 @@ default_entry: /* Make changes effective */ wrmsr - /* - * And make sure that all the mappings we set up have NX set from - * the beginning. - */ - orl $(1 << (_PAGE_BIT_NX - 32)), pa(__supported_pte_mask + 4) - enable_paging: /* diff --git a/arch/x86/mm/setup_nx.c b/arch/x86/mm/setup_nx.c index 8bea84724a7d..f65a33f505b6 100644 --- a/arch/x86/mm/setup_nx.c +++ b/arch/x86/mm/setup_nx.c @@ -32,8 +32,9 @@ early_param("noexec", noexec_setup); void x86_configure_nx(void) { - /* If disable_nx is set, clear NX on all new mappings going forward. */ - if (disable_nx) + if (boot_cpu_has(X86_FEATURE_NX) && !disable_nx) + __supported_pte_mask |= _PAGE_NX; + else __supported_pte_mask &= ~_PAGE_NX; } |