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path: root/include/asm-i386/pgtable-2level.h
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2006-12-07[PATCH] paravirt: fix missing pte updateZachary Amsden
The function ptep_get_and_clear uses an atomic instruction sequence to get and clear an active pte. Rather than add such an atomic operator to all virtual machine implementations in paravirt-ops, it is easier to support the raw atomic sequence and use either a trapping writable pagetable approach, or a post-update notification. For the post update notification, we require the pte_update function to be called after the access. Combine the 2-level and 3-level paging operators into one common function which does the post-update notification, and rename the actual atomic sequences to raw_ptep_xxx operators. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@muc.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org>
2006-12-07[PATCH] paravirt: Preparatory mmu header movementZachary Amsden
Move header includes for the nopud / nopmd types to the location of the actual pte / pgd type definitions. This allows generic 4-level page type code to be written before the split 2/3 level page table headers are included. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@muc.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org>
2006-12-07[PATCH] paravirt: Add MMU virtualization to paravirt_opsRusty Russell
Add the three bare TLB accessor functions to paravirt-ops. Most amusingly, flush_tlb is redefined on SMP, so I can't call the paravirt op flush_tlb. Instead, I chose to indicate the actual flush type, kernel (global) vs. user (non-global). Global in this sense means using the global bit in the page table entry, which makes TLB entries persistent across CR3 reloads, not global as in the SMP sense of invoking remote shootdowns, so the term is confusingly overloaded. AK: folded in fix from Zach for PAE compilation Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@osdl.org>
2006-10-01[PATCH] paravirt: optimize ptep establish for paeZachary Amsden
The ptep_establish macro is only used on user-level PTEs, for P->P mapping changes. Since these always happen under protection of the pagetable lock, the strong synchronization of a 64-bit cmpxchg is not needed, in fact, not even a lock prefix needs to be used. We can simply instead clear the P-bit, followed by a normal set. The write ordering is still important to avoid the possibility of the TLB snooping a partially written PTE and getting a bad mapping installed. Signed-off-by: Zachary Amsden <zach@vmware.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26[PATCH] x86: trivial move of __HAVE macros in i386 pagetable headersRusty Russell
Move the __HAVE_ARCH_PTEP defines to accompany the function definitions. Anything else is just a complete nightmare to track through the 2/3-level paging code, and this caused duplicate definitions to be needed (pte_same), which could have easily been taken care of with the asm-generic pgtable functions. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-27[PATCH] x86/PAE: Fix pte_clear for the >4GB RAM caseZachary Amsden
Proposed fix for ptep_get_and_clear_full PAE bug. Pte_clear had the same bug, so use the same fix for both. Turns out pmd_clear had it as well, but pgds are not affected. The problem is rather intricate. Page table entries in PAE mode are 64-bits wide, but the only atomic 8-byte write operation available in 32-bit mode is cmpxchg8b, which is expensive (at least on P4), and thus avoided. But it can happen that the processor may prefetch entries into the TLB in the middle of an operation which clears a page table entry. So one must always clear the P-bit in the low word of the page table entry first when clearing it. Since the sequence *ptep = __pte(0) leaves the order of the write dependent on the compiler, it must be coded explicitly as a clear of the low word followed by a clear of the high word. Further, there must be a write memory barrier here to enforce proper ordering by the compiler (and, in the future, by the processor as well). On > 4GB memory machines, the implementation of pte_clear for PAE was clearly deficient, as it could leave virtual mappings of physical memory above 4GB aliased to memory below 4GB in the TLB. The implementation of ptep_get_and_clear_full has a similar bug, although not nearly as likely to occur, since the mappings being cleared are in the process of being destroyed, and should never be dereferenced again. But, as luck would have it, it is possible to trigger bugs even without ever dereferencing these bogus TLB mappings, even if the clear is followed fairly soon after with a TLB flush or invalidation. The problem is that memory above 4GB may now be aliased into the first 4GB of memory, and in fact, may hit a region of memory with non-memory semantics. These regions include AGP and PCI space. As such, these memory regions are not cached by the processor. This introduces the bug. The processor can speculate memory operations, including memory writes, as long as they are committed with the proper ordering. Speculating a memory write to a linear address that has a bogus TLB mapping is possible. Normally, the speculation is harmless. But for cached memory, it does leave the falsely speculated cacheline unmodified, but in a dirty state. This cache line will be eventually written back. If this cacheline happens to intersect a region of memory that is not protected by the cache coherency protocol, it can corrupt data in I/O memory, which is generally a very bad thing to do, and can cause total system failure or just plain undefined behavior. These bugs are extremely unlikely, but the severity is of such magnitude, and the fix so simple that I think fixing them immediately is justified. Also, they are nearly impossible to debug. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23[PATCH] i386: actively synchronize vmalloc area when registering certain ↵Jan Beulich
callbacks Registering a callback handler through register_die_notifier() is obviously primarily intended for use by modules. However, the way these currently get called it is basically impossible for them to actually be used by modules, as there is, on non-PAE configurationes, a good chance (the larger the module, the better) for the system to crash as a result. This is because the callback gets invoked (a) in the page fault path before the top level page table propagation gets carried out (hence a fault to propagate the top level page table entry/entries mapping to module's code/data would nest infinitly) and (b) in the NMI path, where nested faults must absolutely not happen, since otherwise the IRET from the nested fault re-enables NMIs, potentially resulting in nested NMI occurences. Besides the modular aspect, similar problems would even arise for in- kernel consumers of the API if they touched ioremap()ed or vmalloc()ed memory inside their handlers. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] i386: little pgtable.h consolidation vs 2/3levelPaolo 'Blaisorblade' Giarrusso
Join together some common functions (pmd_page{,_kernel}) over 2level and 3level pages. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!