- 04 2月, 2008 3 次提交
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由 Jeremy Fitzhardinge 提交于
Remove bogus reference to "Pentium-II erratum A13" and point to the actual canonical source of information about what requirements x86 processors have for PAE pagetable updates. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
Rather than unconditionally reloading cr3, only do so if the pud we're updating is within the active pgd. This eliminates TLB flushes most of the time. The performance-critical uses of pud_clear are during execve and exit, but in those cases cr3 is referring to some other pagetable. The only other use of pud_clear is during a large (1Gbyte+) munmap, and those are sufficiently rare that a couple of cr3 reloads won't hurt. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
Revert "defer cr3 reload when doing pud_clear()" since I'm going to replace it. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 30 1月, 2008 9 次提交
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由 Jeremy Fitzhardinge 提交于
PAE mode requires that we reload cr3 in order to guarantee that changes to the pgd will be noticed by the processor. This means that in principle pud_clear needs to reload cr3 every time. However, because reloading cr3 implies a tlb flush, we want to avoid it where possible. pud_clear() is only used in a couple of places: - in free_pmd_range(), when pulling down a range of process address space, and - huge_pmd_unshare() In both cases, the calling code will do a a tlb flush anyway, so there's no need to do it within pud_clear(). In free_pmd_range(), the pud_clear is immediately followed by pmd_free_tlb(); we can hook that to make the mmu_gather do an unconditional full flush to make sure cr3 gets reloaded. In huge_pmd_unshare, it is followed by flush_tlb_range, which always results in a full cr3-reload tlb flush. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: William Irwin <wli@holomorphy.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
In x86 PAE mode, stop treating pmds as a special case. Previously they were always allocated and freed with the pgd. The modifies the code to be the same as 64-bit mode, where they are allocated on demand. This is a step on the way to unifying 32/64-bit pagetable allocation as much as possible. There is a complicating wart, however. When you install a new reference to a pmd in the pgd, the processor isn't guaranteed to see it unless you reload cr3. Since reloading cr3 also has the side-effect of flushing the tlb, this is an expense that we want to avoid whereever possible. This patch simply avoids reloading cr3 unless the update is to the current pagetable. Later patches will optimise this further. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: William Irwin <wli@holomorphy.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Andi Kleen 提交于
- Rename it to pte_exec() from pte_exec_kernel(). There is nothing kernel specific in there. - Move it into the common file because _PAGE_NX is 0 on !PAE and then pte_exec() will be always evaluate to true. Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
Convert macros into inline functions, for better type-checking. This patch required a little bit of fiddling with headers in order to make __(pte|pmd)_free_tlb inline rather than macros. asm-generic/tlb.h includes asm/pgalloc.h, though it doesn't directly use any pgalloc definitions. I removed this include to avoid an include cycle, but it may cause secondary compile failures by things depending on the indirect inclusion; arch/x86/mm/hugetlbpage.c was one such place; there may be others. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
Put all the defines for mapping pagetable operations to their native versions (for the non-paravirt case) into one place. Make the corresponding changes to paravirt.h. The tricky part here is that when a pagetable entry can't be updated atomically (ie, 32-bit PAE), we need special handlers for pte_clear, set_pte_atomic and set_pte_present. However, the other two modes don't need special handling for these, and can use a common set_pte(_at) path. [ mingo@elte.hu: fixes ] Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
Make various pte accessors common. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
Make sure pte_t, whatever its definition, has a pte element with type pteval_t. This allows common code to access it without needing to be specifically parameterised on what pagetable mode we're compiling for. For 32-bit, this means that pte_t becomes a union with "pte" and "{ pte_low, pte_high }" (PAE) or just "pte_low" (non-PAE). Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
Make users of supported_pte_mask common. This has the side-effect of introducing the variable for 32-bit non-PAE, but I think its a pretty small cost to simplify the code. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jeremy Fitzhardinge 提交于
In 32-bit PAE, mask NX from pte_pfn, since it isn't part of the PFN. This code is due for unification anyway, but this fixes a latent bug. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 11 10月, 2007 1 次提交
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由 Thomas Gleixner 提交于
Move the headers to include/asm-x86 and fixup the header install make rules Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 17 7月, 2007 1 次提交
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由 Jan Beulich 提交于
Kill pte_rdprotect(), pte_exprotect(), pte_mkread(), pte_mkexec(), pte_read(), pte_exec(), and pte_user() except where arch-specific code is making use of them. Signed-off-by: NJan Beulich <jbeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 03 5月, 2007 4 次提交
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由 Zachary Amsden 提交于
Add comment and condense code to make use of native_local_ptep_get_and_clear function. Also, it turns out the 2-level and 3-level paging definitions were identical, so move the common definition into pgtable.h Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NAndi Kleen <ak@suse.de>
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由 Zachary Amsden 提交于
In situations where page table updates need only be made locally, and there is no cross-processor A/D bit races involved, we need not use the heavyweight xchg instruction to atomically fetch and clear page table entries. Instead, we can just read and clear them directly. This introduces a neat optimization for non-SMP kernels; drop the atomic xchg operations from page table updates. Thanks to Michel Lespinasse for noting this potential optimization. Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NAndi Kleen <ak@suse.de>
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由 Jeremy Fitzhardinge 提交于
Normally when running in PAE mode, the 4th PMD maps the kernel address space, which can be shared among all processes (since they all need the same kernel mappings). Xen, however, does not allow guests to have the kernel pmd shared between page tables, so parameterize pgtable.c to allow both modes of operation. There are several side-effects of this. One is that vmalloc will update the kernel address space mappings, and those updates need to be propagated into all processes if the kernel mappings are not intrinsically shared. In the non-PAE case, this is done by maintaining a pgd_list of all processes; this list is used when all process pagetables must be updated. pgd_list is threaded via otherwise unused entries in the page structure for the pgd, which means that the pgd must be page-sized for this to work. Normally the PAE pgd is only 4x64 byte entries large, but Xen requires the PAE pgd to page aligned anyway, so this patch forces the pgd to be page aligned+sized when the kernel pmd is unshared, to accomodate both these requirements. Also, since there may be several distinct kernel pmds (if the user/kernel split is below 3G), there's no point in allocating them from a slab cache; they're just allocated with get_free_page and initialized appropriately. (Of course the could be cached if there is just a single kernel pmd - which is the default with a 3G user/kernel split - but it doesn't seem worthwhile to add yet another case into this code). [ Many thanks to wli for review comments. ] Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NWilliam Lee Irwin III <wli@holomorphy.com> Signed-off-by: NAndi Kleen <ak@suse.de> Cc: Zachary Amsden <zach@vmware.com> Cc: Christoph Lameter <clameter@sgi.com> Acked-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
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由 Jeremy Fitzhardinge 提交于
Add a set of accessors to pack, unpack and modify page table entries (at all levels). This allows a paravirt implementation to control the contents of pgd/pmd/pte entries. For example, Xen uses this to convert the (pseudo-)physical address into a machine address when populating a pagetable entry, and converting back to pphys address when an entry is read. Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: NAndi Kleen <ak@suse.de> Acked-by: NIngo Molnar <mingo@elte.hu>
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- 07 12月, 2006 3 次提交
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由 Zachary Amsden 提交于
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: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndi 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: NAndrew Morton <akpm@osdl.org>
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由 Zachary Amsden 提交于
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: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndi 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: NAndrew Morton <akpm@osdl.org>
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由 Rusty Russell 提交于
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: NZachary Amsden <zach@vmware.com> Signed-off-by: NChris Wright <chrisw@sous-sol.org> Signed-off-by: NAndi Kleen <ak@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: NAndrew Morton <akpm@osdl.org>
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- 01 10月, 2006 2 次提交
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由 Zachary Amsden 提交于
Now that ptep_establish has a definition in PAE i386 3-level paging code, the only paging model which is insane enough to have multi-word hardware PTEs which are not efficient to set atomically, we can remove the ghost of set_pte_atomic from other architectures which falesly duplicated it, and remove all knowledge of it from the generic pgtable code. set_pte_atomic is now a private pte operator which is specific to i386 Signed-off-by: NZachary 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: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zachary Amsden 提交于
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: NZachary 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: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 26 9月, 2006 2 次提交
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由 Rusty Russell 提交于
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: NZachary Amsden <zach@vmware.com> Signed-off-by: NRusty Russell <rusty@rustcorp.com.au> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Dave McCracken 提交于
One of the changes necessary for shared page tables is to standardize the pxx_page macros. pte_page and pmd_page have always returned the struct page associated with their entry, while pte_page_kernel and pmd_page_kernel have returned the kernel virtual address. pud_page and pgd_page, on the other hand, return the kernel virtual address. Shared page tables needs pud_page and pgd_page to return the actual page structures. There are very few actual users of these functions, so it is simple to standardize their usage. Since this is basic cleanup, I am submitting these changes as a standalone patch. Per Hugh Dickins' comments about it, I am also changing the pxx_page_kernel macros to pxx_page_vaddr to clarify their meaning. Signed-off-by: NDave McCracken <dmccr@us.ibm.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 28 4月, 2006 1 次提交
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由 Zachary Amsden 提交于
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: NZachary Amsden <zach@vmware.com> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 23 3月, 2006 1 次提交
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由 Jan Beulich 提交于
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: NJan Beulich <jbeulich@novell.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 31 10月, 2005 1 次提交
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Join together some common functions (pmd_page{,_kernel}) over 2level and 3level pages. Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: NHugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 05 9月, 2005 1 次提交
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由 Zachary Amsden 提交于
Also, setting PDPEs in PAE mode does not require atomic operations, since the PDPEs are cached by the processor, and only reloaded on an explicit or implicit reload of CR3. Since the four PDPEs must always be present in an active root, and the kernel PDPE is never updated, we are safe even from SMIs and interrupts / NMIs using task gates (which reload CR3). Actually, much of this is moot, since the user PDPEs are never updated either, and the only usage of task gates is by the doublefault handler. It appears the only place PGDs get updated in PAE mode is in init_low_mappings() / zap_low_mapping() for initial page table creation and recovery from ACPI sleep state, and these sites are safe by inspection. Getting rid of the cmpxchg8b saves code space and 720 cycles in pgd_alloc on P4. Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 17 4月, 2005 1 次提交
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由 Linus Torvalds 提交于
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!
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