16 Oct
2015
16 Oct
'15
1:55 a.m.
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, <sginsberg(a)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.…
==============================================================================
--- 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…
==============================================================================
--- 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?…
==============================================================================
--- 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…
==============================================================================
--- 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;