This is wrong, wrong, wrong. 1) The feature needs to be enabled on all processors, not just one. There's a reason for that loop.
2) ValidKernelPte/Pde being marked global will make ALL kernel pages global. This is probably not what you want. Best regards, Alex Ionescu On Wed, Oct 14, 2015 at 12:33 PM, <sginsb...@svn.reactos.org> wrote: > Author: sginsberg > Date: Wed Oct 14 19:33:35 2015 > New Revision: 69528 > > URL: http://svn.reactos.org/svn/reactos?rev=69528&view=rev > Log: > [NTOS] > Add super-complicated handling of global pages to KeFlushCurrentTb (pretty > much the same code which has been in HalpFlushTLB for the past ~6 years). > This should be all that is required to make this feature work (everything > else being in place already), and *seems* to work fine but is disabled > under a switch until tested thoroughly. > > Global pages, an important optimization that allows for not flushing the > whole x86 TLB every time CR3 is changed (typically on context switch to a > new process, or during process attach/detach), relies on us doing extra > work whenever we do alter a global page. This is likely where any bugs will > have to be flushed out! > > Fixup Ki386EnableGlobalPage while we are at it -- disable/restore > interrupts properly, and verify PGE-bit isn't set (nothing should have > touched it before this routine, which is responsible for initializing it, > so we shouldn't have to disable it). Fix, but disable, the CPU-sync spin as > well as there should be no particular reason to do this for PGE-enabling > during initialization (no other processor will be messing with PTEs at this > stage, as compared to a call to KeFlushEntireTb). > > Everyone, repeat after me: Global pages are awesome! > > Modified: > trunk/reactos/ntoskrnl/include/ntoskrnl.h > trunk/reactos/ntoskrnl/ke/i386/cpu.c > trunk/reactos/ntoskrnl/ke/i386/patpge.c > trunk/reactos/ntoskrnl/mm/ARM3/i386/init.c > > Modified: trunk/reactos/ntoskrnl/include/ntoskrnl.h > URL: > http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/include/ntoskrnl.h?rev=69528&r1=69527&r2=69528&view=diff > > ============================================================================== > --- trunk/reactos/ntoskrnl/include/ntoskrnl.h [iso-8859-1] (original) > +++ trunk/reactos/ntoskrnl/include/ntoskrnl.h [iso-8859-1] Wed Oct 14 > 19:33:35 2015 > @@ -98,6 +98,14 @@ > #define ASSERT NT_ASSERT > #endif > > + > +// > +// Switch for enabling global page support > +// > + > +//#define _GLOBAL_PAGES_ARE_AWESOME_ > + > + > /* Internal Headers */ > #include "internal/ntoskrnl.h" > #include "config.h" > > Modified: trunk/reactos/ntoskrnl/ke/i386/cpu.c > URL: > http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/i386/cpu.c?rev=69528&r1=69527&r2=69528&view=diff > > ============================================================================== > --- trunk/reactos/ntoskrnl/ke/i386/cpu.c [iso-8859-1] (original) > +++ trunk/reactos/ntoskrnl/ke/i386/cpu.c [iso-8859-1] Wed Oct 14 > 19:33:35 2015 > @@ -878,8 +878,37 @@ > NTAPI > KeFlushCurrentTb(VOID) > { > + > +#if !defined(_GLOBAL_PAGES_ARE_AWESOME_) > + > /* Flush the TLB by resetting CR3 */ > __writecr3(__readcr3()); > + > +#else > + > + /* Check if global pages are enabled */ > + if (KeFeatureBits & KF_GLOBAL_PAGE) > + { > + ULONG Cr4; > + > + /* Disable PGE */ > + Cr4 = __readcr4() & ~CR4_PGE; > + __writecr4(Cr4); > + > + /* Flush everything */ > + __writecr3(__readcr3()); > + > + /* Re-enable PGE */ > + __writecr4(Cr4 | CR4_PGE); > + } > + else > + { > + /* No global pages, resetting CR3 is enough */ > + __writecr3(__readcr3()); > + } > + > +#endif > + > } > > VOID > > Modified: trunk/reactos/ntoskrnl/ke/i386/patpge.c > URL: > http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/i386/patpge.c?rev=69528&r1=69527&r2=69528&view=diff > > ============================================================================== > --- trunk/reactos/ntoskrnl/ke/i386/patpge.c [iso-8859-1] (original) > +++ trunk/reactos/ntoskrnl/ke/i386/patpge.c [iso-8859-1] Wed Oct 14 > 19:33:35 2015 > @@ -17,40 +17,41 @@ > > /* FUNCTIONS > *****************************************************************/ > > +INIT_SECTION > ULONG_PTR > NTAPI > -INIT_FUNCTION > Ki386EnableGlobalPage(IN ULONG_PTR Context) > { > - PLONG Count = (PLONG)Context; > - ULONG Cr4, Cr3; > + //PLONG Count; > +#if defined(_GLOBAL_PAGES_ARE_AWESOME_) > + ULONG Cr4; > +#endif > + BOOLEAN Enable; > > /* Disable interrupts */ > - _disable(); > - > - /* Decrease CPU Count and loop until it's reached 0 */ > - do {InterlockedDecrement(Count);} while (!*Count); > - > - /* Now check if this is the Boot CPU */ > - if (!KeGetPcr()->Number) > - { > - /* It is.FIXME: Patch KeFlushCurrentTb */ > - } > - > - /* Now get CR4 and make sure PGE is masked out */ > + Enable = KeDisableInterrupts(); > + > + /* Spin until other processors are ready */ > + //Count = (PLONG)Context; > + //InterlockedDecrement(Count); > + //while (*Count) YieldProcessor(); > + > +#if defined(_GLOBAL_PAGES_ARE_AWESOME_) > + > + /* Get CR4 and ensure global pages are disabled */ > Cr4 = __readcr4(); > - __writecr4(Cr4 & ~CR4_PGE); > - > - /* Flush the TLB */ > - Cr3 = __readcr3(); > - __writecr3(Cr3); > + ASSERT(!(Cr4 & CR4_PGE)); > + > + /* Reset CR3 to flush the TLB */ > + __writecr3(__readcr3()); > > /* Now enable PGE */ > - DPRINT("Global page support detected but not yet taken advantage > of\n"); > - //__writecr4(Cr4 | CR4_PGE); > - > - /* Restore interrupts */ > - _enable(); > + __writecr4(Cr4 | CR4_PGE); > + > +#endif > + > + /* Restore interrupts and return */ > + KeRestoreInterrupts(Enable); > return 0; > } > > > Modified: trunk/reactos/ntoskrnl/mm/ARM3/i386/init.c > URL: > http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/i386/init.c?rev=69528&r1=69527&r2=69528&view=diff > > ============================================================================== > --- trunk/reactos/ntoskrnl/mm/ARM3/i386/init.c [iso-8859-1] (original) > +++ trunk/reactos/ntoskrnl/mm/ARM3/i386/init.c [iso-8859-1] Wed Oct 14 > 19:33:35 2015 > @@ -249,15 +249,18 @@ > PMMPFN Pfn1; > ULONG Flags; > > +#if defined(_GLOBAL_PAGES_ARE_AWESOME_) > + > /* Check for global bit */ > -#if 0 > if (KeFeatureBits & KF_GLOBAL_PAGE) > { > /* Set it on the template PTE and PDE */ > ValidKernelPte.u.Hard.Global = TRUE; > ValidKernelPde.u.Hard.Global = TRUE; > } > + > #endif > + > /* Now templates are ready */ > TempPte = ValidKernelPte; > TempPde = ValidKernelPde; > > >
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