- 31 Oct, 2014 40 commits
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Andy Shevchenko authored
commit b41583e7 upstream. In case of 8 bit mode and DMA usage we end up with every second byte written as 0. We have to respect bits_per_word settings what this patch actually does. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Bryan O'Donoghue authored
commit ee1b5b16 upstream. Quark x1000 advertises PGE via the standard CPUID method PGE bits exist in Quark X1000's PTEs. In order to flush an individual PTE it is necessary to reload CR3 irrespective of the PTE.PGE bit. See Quark Core_DevMan_001.pdf section 6.4.11 This bug was fixed in Galileo kernels, unfixed vanilla kernels are expected to crash and burn on this platform. Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/1411514784-14885-1-git-send-email-pure.logic@nexus-software.ieSigned-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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David Matlack authored
commit 2ea75be3 upstream. vcpu ioctls can hang the calling thread if issued while a vcpu is running. However, invalid ioctls can happen when userspace tries to probe the kind of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case, we know the ioctl is going to be rejected as invalid anyway and we can fail before trying to take the vcpu mutex. This patch does not change functionality, it just makes invalid ioctls fail faster. Signed-off-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Christian Borntraeger authored
commit f346026e upstream. We must not fallthrough if the conditions for external call are not met. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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David Matlack authored
commit ee3d1570 upstream. vcpu exits and memslot mutations can run concurrently as long as the vcpu does not aquire the slots mutex. Thus it is theoretically possible for memslots to change underneath a vcpu that is handling an exit. If we increment the memslot generation number again after synchronize_srcu_expedited(), vcpus can safely cache memslot generation without maintaining a single rcu_dereference through an entire vm exit. And much of the x86/kvm code does not maintain a single rcu_dereference of the current memslots during each exit. We can prevent the following case: vcpu (CPU 0) | thread (CPU 1) --------------------------------------------+-------------------------- 1 vm exit | 2 srcu_read_unlock(&kvm->srcu) | 3 decide to cache something based on | old memslots | 4 | change memslots | (increments generation) 5 | synchronize_srcu(&kvm->srcu); 6 retrieve generation # from new memslots | 7 tag cache with new memslot generation | 8 srcu_read_unlock(&kvm->srcu) | ... | <action based on cache occurs even | though the caching decision was based | on the old memslots> | ... | <action *continues* to occur until next | memslot generation change, which may | be never> | | By incrementing the generation after synchronizing with kvm->srcu readers, we ensure that the generation retrieved in (6) will become invalid soon after (8). Keeping the existing increment is not strictly necessary, but we do keep it and just move it for consistency from update_memslots to install_new_memslots. It invalidates old cached MMIOs immediately, instead of having to wait for the end of synchronize_srcu_expedited, which makes the code more clearly correct in case CPU 1 is preempted right after synchronize_srcu() returns. To avoid halving the generation space in SPTEs, always presume that the low bit of the generation is zero when reconstructing a generation number out of an SPTE. This effectively disables MMIO caching in SPTEs during the call to synchronize_srcu_expedited. Using the low bit this way is somewhat like a seqcount---where the protected thing is a cache, and instead of retrying we can simply punt if we observe the low bit to be 1. Signed-off-by: David Matlack <dmatlack@google.com> Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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David Matlack authored
commit 56f17dd3 upstream. The following events can lead to an incorrect KVM_EXIT_MMIO bubbling up to userspace: (1) Guest accesses gpa X without a memory slot. The gfn is cached in struct kvm_vcpu_arch (mmio_gfn). On Intel EPT-enabled hosts, KVM sets the SPTE write-execute-noread so that future accesses cause EPT_MISCONFIGs. (2) Host userspace creates a memory slot via KVM_SET_USER_MEMORY_REGION covering the page just accessed. (3) Guest attempts to read or write to gpa X again. On Intel, this generates an EPT_MISCONFIG. The memory slot generation number that was incremented in (2) would normally take care of this but we fast path mmio faults through quickly_check_mmio_pf(), which only checks the per-vcpu mmio cache. Since we hit the cache, KVM passes a KVM_EXIT_MMIO up to userspace. This patch fixes the issue by using the memslot generation number to validate the mmio cache. Signed-off-by: David Matlack <dmatlack@google.com> [xiaoguangrong: adjust the code to make it simpler for stable-tree fix.] Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: David Matlack <dmatlack@google.com> Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Tested-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Josef Ahmad authored
commit bb048713 upstream. This patch adds the PCI id for Intel Quark ILB. It will be used for GPIO and Multifunction device driver. Signed-off-by: Josef Ahmad <josef.ahmad@intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Bryan O'Donoghue authored
commit a68df706 upstream. This patch is to enable the USB gadget device for Intel Quark X1000 Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@intel.com> Signed-off-by: Bing Niu <bing.niu@intel.com> Signed-off-by: Alvin (Weike) Chen <alvin.chen@intel.com> Signed-off-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Sage Weil authored
commit 42383020 upstream. We check whether transid is already committed via last_trans_committed and then search through trans_list for pending transactions. If last_trans_committed is updated by btrfs_commit_transaction after we check it (there is no locking), we will fail to find the committed transaction and return EINVAL to the caller. This has been observed occasionally by ceph-osd (which uses this ioctl heavily). Fix by rechecking whether the provided transid <= last_trans_committed after the search fails, and if so return 0. Signed-off-by: Sage Weil <sage@redhat.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Josef Bacik authored
commit bbe90514 upstream. Marc Merlin sent me a broken fs image months ago where it would blow up in the upper->checked BUG_ON() in build_backref_tree. This is because we had a scenario like this block a -- level 4 (not shared) | block b -- level 3 (reloc block, shared) | block c -- level 2 (not shared) | block d -- level 1 (shared) | block e -- level 0 (shared) We go to build a backref tree for block e, we notice block d is shared and add it to the list of blocks to lookup it's backrefs for. Now when we loop around we will check edges for the block, so we will see we looked up block c last time. So we lookup block d and then see that the block that points to it is block c and we can just skip that edge since we've already been up this path. The problem is because we clear need_check when we see block d (as it is shared) we never add block b as needing to be checked. And because block c is in our path already we bail out before we walk up to block b and add it to the backref check list. To fix this we need to reset need_check if we trip over a block that doesn't need to be checked. This will make sure that any subsequent blocks in the path as we're walking up afterwards are added to the list to be processed. With this patch I can now mount Marc's fs image and it'll complete the balance without panicing. Thanks, Reported-by: Marc MERLIN <marc@merlins.org> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Josef Bacik authored
commit 75bfb9af upstream. When balance panics it tends to panic in the BUG_ON(!upper->checked); test, because it means it couldn't build the backref tree properly. This is annoying to users and frankly a recoverable error, nothing in this function is actually fatal since it is just an in-memory building of the backrefs for a given bytenr. So go through and change all the BUG_ON()'s to ASSERT()'s, and fix the BUG_ON(!upper->checked) thing to just return an error. This patch also fixes the error handling so it tears down the work we've done properly. This code was horribly broken since we always just panic'ed instead of actually erroring out, so it needed to be completely re-worked. With this patch my broken image no longer panics when I mount it. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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Josef Bacik authored
commit 1d52c78a upstream. When doing log replay we may have to update inodes, which traditionally goes through our delayed inode stuff. This will try to move space over from the trans handle, but we don't reserve space in our trans handle on replay since we don't know how much we will need, so instead we try to flush. But because we have a trans handle open we won't flush anything, so if we are out of reserve space we will simply return ENOSPC. Since we know that if an operation made it into the log then we definitely had space before the box bought the farm then we don't need to worry about doing this space reservation. Use the fs_info->log_root_recovering flag to skip the delayed inode stuff and update the item directly. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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David Sterba authored
commit 2fad4e83 upstream. The transaction thread may want to do more work, namely it pokes the cleaner ktread that will start processing uncleaned subvols. This can be triggered by user via the 'btrfs fi sync' command, otherwise there was a delay up to 30 seconds before the cleaner started to clean old snapshots. Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
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David S. Miller authored
[ Upstream commit d195b71b ] swapper_low_pmd_dir and swapper_pud_dir are actually completely useless and unnecessary. We just need swapper_pg_dir[]. Naturally the other page table chunks will be allocated on an as-needed basis. Since the kernel actually accesses these tables in the PAGE_OFFSET view, there is not even a TLB locality advantage of placing them in the kernel image. Use the hard coded vmlinux.ld.S slot for swapper_pg_dir which is naturally page aligned. Increase MAX_BANKS to 1024 in order to handle heavily fragmented virtual guests. Even with this MAX_BANKS increase, the kernel is 20K+ smaller. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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bob picco authored
[ Upstream commit ee6a9333 ] This patch attempts to do a few things. The highlights are: 1) enable SPARSE_IRQ unconditionally, 2) kills off !SPARSE_IRQ code 3) allocates ivector_table at boot time and 4) default to cookie only VIRQ mechanism for supported firmware. The first firmware with cookie only support for me appears on T5. You can optionally force the HV firmware to not cookie only mode which is the sysino support. The sysino is a deprecated HV mechanism according to the most recent SPARC Virtual Machine Specification. HV_GRP_INTR is what controls the cookie/sysino firmware versioning. The history of this interface is: 1) Major version 1.0 only supported sysino based interrupt interfaces. 2) Major version 2.0 added cookie based VIRQs, however due to the fact that OSs were using the VIRQs without negoatiating major version 2.0 (Linux and Solaris are both guilty), the VIRQs calls were allowed even with major version 1.0 To complicate things even further, the VIRQ interfaces were only actually hooked up in the hypervisor for LDC interrupt sources. VIRQ calls on other device types would result in HV_EINVAL errors. So effectively, major version 2.0 is unusable. 3) Major version 3.0 was created to signal use of VIRQs and the fact that the hypervisor has these calls hooked up for all interrupt sources, not just those for LDC devices. A new boot option is provided should cookie only HV support have issues. hvirq - this is the version for HV_GRP_INTR. This is related to HV API versioning. The code attempts major=3 first by default. The option can be used to override this default. I've tested with SPARSE_IRQ on T5-8, M7-4 and T4-X and Jalap?no. Signed-off-by: Bob Picco <bob.picco@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
[ Upstream commit bb4e6e85 ] In order to accomodate embedded per-cpu allocation with large numbers of cpus and numa nodes, we have to use as much virtual address space as possible for the vmalloc region. Otherwise we can get things like: PERCPU: max_distance=0x380001c10000 too large for vmalloc space 0xff00000000 So, once we select a value for PAGE_OFFSET, derive the size of the vmalloc region based upon that. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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David S. Miller authored
commit 7c0fa0f2 upstream. Make sure, at compile time, that the kernel can properly support whatever MAX_PHYS_ADDRESS_BITS is defined to. On M7 chips, use a max_phys_bits value of 49. Based upon a patch by Bob Picco. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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David S. Miller authored
[ Upstream commit c06240c7 ] For sparse memory configurations, the vmemmap array behaves terribly and it takes up an inordinate amount of space in the BSS section of the kernel image unconditionally. Just build huge PMDs and look them up just like we do for TLB misses in the vmalloc area. Kernel BSS shrinks by about 2MB. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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David S. Miller authored
[ Upstream commit 0dd5b7b0 ] If max_phys_bits needs to be > 43 (f.e. for T4 chips), things like DEBUG_PAGEALLOC stop working because the 3-level page tables only can cover up to 43 bits. Another problem is that when we increased MAX_PHYS_ADDRESS_BITS up to 47, several statically allocated tables became enormous. Compounding this is that we will need to support up to 49 bits of physical addressing for M7 chips. The two tables in question are sparc64_valid_addr_bitmap and kpte_linear_bitmap. The first holds a bitmap, with 1 bit for each 4MB chunk of physical memory, indicating whether that chunk actually exists in the machine and is valid. The second table is a set of 2-bit values which tell how large of a mapping (4MB, 256MB, 2GB, 16GB, respectively) we can use at each 256MB chunk of ram in the system. These tables are huge and take up an enormous amount of the BSS section of the sparc64 kernel image. Specifically, the sparc64_valid_addr_bitmap is 4MB, and the kpte_linear_bitmap is 128K. So let's solve the space wastage and the DEBUG_PAGEALLOC problem at the same time, by using the kernel page tables (as designed) to manage this information. We have to keep using large mappings when DEBUG_PAGEALLOC is disabled, and we do this by encoding huge PMDs and PUDs. On a T4-2 with 256GB of ram the kernel page table takes up 16K with DEBUG_PAGEALLOC disabled and 256MB with it enabled. Furthermore, this memory is dynamically allocated at run time rather than coded statically into the kernel image. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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David S. Miller authored
[ Upstream commit 8c82dc0e ] As currently coded the KTSB accesses in the kernel only support up to 47 bits of physical addressing. Adjust the instruction and patching sequence in order to support arbitrary 64 bits addresses. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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David S. Miller authored
[ Upstream commit 4397bed0 ] Now that we use 4-level page tables, we can provide up to 53-bits of virtual address space to the user. Adjust the VA hole based upon the capabilities of the cpu type probed. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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David S. Miller authored
[ Upstream commit ac55c768 ] This has become necessary with chips that support more than 43-bits of physical addressing. Based almost entirely upon a patch by Bob Picco. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
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bob picco authored
commit 05aa1651 upstream. The T5 (niagara5) has different PCR related HV fast trap values and a new HV API Group. This patch utilizes these and shares when possible with niagara4. We use the same sparc_pmu niagara4_pmu. Should there be new effort to obtain the MCU perf statistics then this would have to be changed. Cc: sparclinux@vger.kernel.org Signed-off-by: Bob Picco <bob.picco@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Allen Pais authored
commit 40831625 upstream. Signed-off-by: Allen Pais <allen.pais@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Allen Pais authored
commit 9bd3ee33 upstream. Add M6 and M7 chip type in cpumap.c to correctly build CPU distribution map that spans all online CPUs. Signed-off-by: Allen Pais <allen.pais@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Allen Pais authored
commit cadbb580 upstream. The following patch adds support for correctly recognising M6 and M7 cpu type. Signed-off-by: Allen Pais <allen.pais@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
commit 9d0713ed upstream. We changed PAGE_OFFSET to be a variable rather than a constant, but this reference here in the hibernate assembler got missed. Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
[ Upstream commit 26cf4325 ] Instead of returning false we should at least check the most basic things, otherwise page table corruptions will be very difficult to debug. PMD and PTE tables are of size PAGE_SIZE, so none of the sub-PAGE_SIZE bits should be set. We also complement this with a check that the physical address the pud/pmd points to is valid memory. PowerPC was used as a guide while implementating this. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David S. Miller authored
[ Upstream commit 0eef331a ] Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David S. Miller authored
[ Upstream commit ee73887e ] In commit b2d43834 ("sparc64: Make PAGE_OFFSET variable."), the MAX_PHYS_ADDRESS_BITS value was increased (to 47). This constant reference to '41UL' was missed. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David S. Miller authored
[ Upstream commit eaf85da8 ] Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David S. Miller authored
[ Upstream commit c2e4e676 ] When _PAGE_SPECIAL and _PAGE_PMD_HUGE were added to the mask, the comment was not updated. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David S. Miller authored
[ Upstream commit 04df419d ] The large PMD path needs to check _PAGE_VALID not _PAGE_PRESENT, to decide if it needs to bail and return 0. pmd_large() should therefore just check _PAGE_PMD_HUGE. Calls to gup_huge_pmd() are guarded with a check of pmd_large(), so we just need to add a valid bit check. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David S. Miller authored
[ Upstream commit 51e5ef1b ] On sparc64 "present" and "valid" are seperate PTE bits, this allows us to naturally distinguish between the user explicitly asking for PROT_NONE with mprotect() and other situations. However we weren't handling this properly in the huge PMD paths. First of all, the page table walker in the TSB miss path only checks for _PAGE_PMD_HUGE. So the generic pmdp_invalidate() would clear _PAGE_PRESENT but the TLB miss paths would still load it into the TLB as a valid huge PMD. Fix this by clearing the valid bit in pmdp_invalidate(), and also checking the valid bit in USER_PGTABLE_CHECK_PMD_HUGE using "brgez" since _PAGE_VALID is bit 63 in both the sun4u and sun4v pte layouts. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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David S. Miller authored
[ Upstream commit 5b1e94fa ] This code was mistakenly using the exec bit from the PMD in all cases, even when the PMD isn't a huge PMD. If it's not a huge PMD, test the exec bit in the individual ptes down in tlb_batch_pmd_scan(). Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Dave Kleikamp authored
This reverts commit 145e1c00. This commit broke the behavior of __copy_from_user_inatomic when it is only partially successful. Instead of returning the number of bytes not copied, it now returns 1. This translates to the wrong value being returned by iov_iter_copy_from_user_atomic. xfstests generic/246 and LTP writev01 both fail on btrfs and nfs because of this. Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: sparclinux@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
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oftedal authored
commit 557fc587 upstream. The SIMBA APB Bridges lacks the 'ranges' of-property describing the PCI I/O and memory areas located beneath the bridge. Faking this information has been performed by reading range registers in the APB bridge, and calculating the corresponding areas. In commit 01f94c4a ("Fix sabre pci controllers with new probing scheme.") a bug was introduced into this calculation, causing the PCI memory areas to be calculated incorrectly: The shift size was set to be identical for I/O and MEM ranges, which is incorrect. This patch set the shift size of the MEM range back to the value used before 01f94c4a. Signed-off-by: Kjetil Oftedal <oftedal@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
commit a7b9403f upstream. Now that we have 64-bits for PMDs we can stop using special encodings for the huge PMD values, and just put real PTEs in there. We allocate a _PAGE_PMD_HUGE bit to distinguish between plain PMDs and huge ones. It is the same for both 4U and 4V PTE layouts. We also use _PAGE_SPECIAL to indicate the splitting state, since a huge PMD cannot also be special. All of the PMD --> PTE translation code disappears, and most of the huge PMD bit modifications and tests just degenerate into the PTE operations. In particular USER_PGTABLE_CHECK_PMD_HUGE becomes trivial. As a side effect, normal PMDs don't shift the physical address around. This also speeds up the page table walks in the TLB miss paths since they don't have to do the shifts any more. Another non-trivial aspect is that pte_modify() has to be changed to preserve the _PAGE_PMD_HUGE bits as well as the page size field of the pte. Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
commit 2b77933c upstream. To make the page tables compact, we were using 32-bit PGDs and PMDs. We only had to support <= 43 bits of physical addresses so this was quite feasible. In order to support larger physical addresses we have to move to 64-bit PGDs and PMDs. Most of the changes are straight-forward: 1) {pgd,pmd}_t --> unsigned long 2) Anything that tries to use plain "unsigned int" types with pgd/pmd values needs to be adjusted. In particular things like "0U" become "0UL". 3) {PGDIR,PMD}_BITS decrease by one. 4) In the assembler page table walkers, use "ldxa" instead of "lduwa" and adjust the low bit masks to clear out the low 3 bits instead of just the low 2 bits during pgd/pmd address formation. Also, use PTRS_PER_PGD and PTRS_PER_PMD in the sizing of the swapper_{pg_dir,low_pmd_dir} arrays. This patch does not try to take advantage of having 64-bits in the PMDs to simplify the hugepage code, that will come in a subsequent change. Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
commit 37b3a8ff upstream. The impetus for this is that we would like to move to 64-bit PMDs and PGDs, but that would result in only supporting a 42-bit address space with the current page table layout. It'd be nice to support at least 43-bits. The reason we'd end up with only 42-bits after making PMDs and PGDs 64-bit is that we only use half-page sized PTE tables in order to make PMDs line up to 4MB, the hardware huge page size we use. So what we do here is we make huge pages 8MB, and fabricate them using 4MB hw TLB entries. Facilitate this by providing a "REAL_HPAGE_SHIFT" which is used in places that really need to operate on hardware 4MB pages. Use full pages (512 entries) for PTE tables, and adjust PMD_SHIFT, PGD_SHIFT, and the build time CPP test as needed. Use a CPP test to make sure REAL_HPAGE_SHIFT and the _PAGE_SZHUGE_* we use match up. This makes the pgtable cache completely unused, so remove the code managing it and the state used in mm_context_t. Now we have less spinlocks taken in the page table allocation path. The technique we use to fabricate the 8MB pages is to transfer bit 22 from the missing virtual address into the PTEs physical address field. That takes care of the transparent huge pages case. For hugetlb, we fill things in at the PTE level and that code already puts the sub huge page physical bits into the PTEs, based upon the offset, so there is nothing special we need to do. It all just works out. So, a small amount of complexity in the THP case, but this code is about to get much simpler when we move the 64-bit PMDs as we can move away from the fancy 32-bit huge PMD encoding and just put a real PTE value in there. With bug fixes and help from Bob Picco. Signed-off-by: David S. Miller <davem@davemloft.net>
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