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Date: Tue, 08 Jan 2008 17:09:05 -0800 From: Jeremy Fitzhardinge <jeremy@...p.org> To: Ingo Molnar <mingo@...e.hu> CC: LKML <linux-kernel@...r.kernel.org>, Andi Kleen <ak@...e.de>, Glauber de Oliveira Costa <glommer@...il.com>, Jan Beulich <jbeulich@...ell.com> Subject: Re: [PATCH 00 of 10] x86: unify asm/pgtable.h Ingo Molnar wrote: > * Ingo Molnar <mingo@...e.hu> wrote: > > >> * Ingo Molnar <mingo@...e.hu> wrote: >> >> >>>>>>> #define __PAGE_KERNEL_EXEC \ >>>>>>> - (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL) >>>>>>> + (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED) >>>>>>> >>>>>>> >>>>> This shouldn't be necessary. The old 64-bit code defined everything >>>>> without _PAGE_GLOBAL, but then used a MAKE_GLOBAL() macro to OR it >>>>> in later. This seemed a bit roundabout to me, so I just put it in >>>>> from the outset. >>>>> >>> actually, this is wrong. >>> >>> a couple of places use __PAGE_* values, which you've now changed to >>> include the _PAGE_GLOBAL flag. >>> >> yep, fixing this resolves the crash. >> > > but then it crashes init: > > init[1]: segfault at ffffffffff600400 ip ffffffffff600400 sp > 7fff81bedda8 error5printk: 7740690 messages suppressed. > > because you changed __PAGE_KERNEL_VSYSCALL as well, from: > > #define __PAGE_KERNEL_VSYSCALL \ > (_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED) > > to: > > #define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RO | _PAGE_USER) > > but __PAGE_KERNEL_RO is an NX one, so the vsyscall cannot execute > instructions. > > so this wants to be: > > #define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER) > > this was the last bug and the resulting kernel boots fine. 3 nasty bugs > in one patch :-/ > > Ingo > > ----------------> > Subject: x86: move all asm/pgtable constants into one place, fix > From: Ingo Molnar <mingo@...e.hu> > > fix. > > Signed-off-by: Ingo Molnar <mingo@...e.hu> > --- > include/asm-x86/pgtable.h | 22 +++++++++++----------- > 1 file changed, 11 insertions(+), 11 deletions(-) > > Index: linux-x86.q/include/asm-x86/pgtable.h > =================================================================== > --- linux-x86.q.orig/include/asm-x86/pgtable.h > +++ linux-x86.q/include/asm-x86/pgtable.h > @@ -68,27 +68,27 @@ extern unsigned long long __PAGE_KERNEL, > #endif /* __ASSEMBLER__ */ > #else > #define __PAGE_KERNEL_EXEC \ > - (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL) > + (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED) > #define __PAGE_KERNEL (__PAGE_KERNEL_EXEC | _PAGE_NX) > #endif > > #define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW) > #define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW) > #define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT) > -#define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RO | _PAGE_USER) > +#define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER) > #define __PAGE_KERNEL_VSYSCALL_NOCACHE (__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT) > #define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE) > #define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE) > > -#define PAGE_KERNEL __pgprot(__PAGE_KERNEL) > -#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO) > -#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC) > -#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX) > -#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE) > -#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE) > -#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC) > -#define PAGE_KERNEL_VSYSCALL __pgprot(__PAGE_KERNEL_VSYSCALL) > -#define PAGE_KERNEL_VSYSCALL_NOCACHE __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE) > +#define PAGE_KERNEL __pgprot(__PAGE_KERNEL | _PAGE_GLOBAL) > +#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO | _PAGE_GLOBAL) > +#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC | _PAGE_GLOBAL) > +#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX | _PAGE_GLOBAL) > +#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE | _PAGE_GLOBAL) > +#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE | _PAGE_GLOBAL) > +#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC | _PAGE_GLOBAL) > +#define PAGE_KERNEL_VSYSCALL __pgprot(__PAGE_KERNEL_VSYSCALL | _PAGE_GLOBAL) > +#define PAGE_KERNEL_VSYSCALL_NOCACHE __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE | _PAGE_GLOBAL) > This isn't correct, because it will set _PAGE_GLOBAL on 32-bit unconditionally. It needs to be something like: diff -r a6d5e9e1a81d include/asm-x86/pgtable.h --- a/include/asm-x86/pgtable.h Tue Jan 08 13:59:42 2008 -0800 +++ b/include/asm-x86/pgtable.h Tue Jan 08 16:37:19 2008 -0800 @@ -68,7 +68,7 @@ extern unsigned long long __PAGE_KERNEL, #endif /* __ASSEMBLER__ */ #else #define __PAGE_KERNEL_EXEC \ - (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL) + (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED) #define __PAGE_KERNEL (__PAGE_KERNEL_EXEC | _PAGE_NX) #endif @@ -80,15 +80,17 @@ extern unsigned long long __PAGE_KERNEL, #define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE) #define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE) -#define PAGE_KERNEL __pgprot(__PAGE_KERNEL) -#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO) -#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC) -#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX) -#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE) -#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE) -#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC) -#define PAGE_KERNEL_VSYSCALL __pgprot(__PAGE_KERNEL_VSYSCALL) -#define PAGE_KERNEL_VSYSCALL_NOCACHE __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE) +#define GLOBAL_PGPROT(prot) __pgprot(prot | _PAGE_GLOBAL) + +#define PAGE_KERNEL GLOBAL_PGPROT(__PAGE_KERNEL) +#define PAGE_KERNEL_RO GLOBAL_PGPROT(__PAGE_KERNEL_RO) +#define PAGE_KERNEL_EXEC GLOBAL_PGPROT(__PAGE_KERNEL_EXEC) +#define PAGE_KERNEL_RX GLOBAL_PGPROT(__PAGE_KERNEL_RX) +#define PAGE_KERNEL_NOCACHE GLOBAL_PGPROT(__PAGE_KERNEL_NOCACHE) +#define PAGE_KERNEL_LARGE GLOBAL_PGPROT(__PAGE_KERNEL_LARGE) +#define PAGE_KERNEL_LARGE_EXEC GLOBAL_PGPROT(__PAGE_KERNEL_LARGE_EXEC) +#define PAGE_KERNEL_VSYSCALL GLOBAL_PGPROT(__PAGE_KERNEL_VSYSCALL) +#define PAGE_KERNEL_VSYSCALL_NOCACHE GLOBAL_PGPROT(__PAGE_KERNEL_VSYSCALL_NOCACHE) /* xwr */ #define __P000 PAGE_NONE -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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