)]}'
{
  "log": [
    {
      "commit": "2f569afd9ced9ebec9a6eb3dbf6f83429be0a7b4",
      "tree": "23a31763887d9505e62e9d7cc8ec2fa4b86bd380",
      "parents": [
        "13214adf738abc92b0a00c0763fd3be79eebaa7c"
      ],
      "author": {
        "name": "Martin Schwidefsky",
        "email": "schwidefsky@de.ibm.com",
        "time": "Fri Feb 08 04:22:04 2008 -0800"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@woody.linux-foundation.org",
        "time": "Fri Feb 08 09:22:42 2008 -0800"
      },
      "message": "CONFIG_HIGHPTE vs. sub-page page tables.\n\nBackground: I\u0027ve implemented 1K/2K page tables for s390.  These sub-page\npage tables are required to properly support the s390 virtualization\ninstruction with KVM.  The SIE instruction requires that the page tables\nhave 256 page table entries (pte) followed by 256 page status table entries\n(pgste).  The pgstes are only required if the process is using the SIE\ninstruction.  The pgstes are updated by the hardware and by the hypervisor\nfor a number of reasons, one of them is dirty and reference bit tracking.\nTo avoid wasting memory the standard pte table allocation should return\n1K/2K (31/64 bit) and 2K/4K if the process is using SIE.\n\nProblem: Page size on s390 is 4K, page table size is 1K or 2K.  That means\nthe s390 version for pte_alloc_one cannot return a pointer to a struct\npage.  Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one\ncannot return a pointer to a pte either, since that would require more than\n32 bit for the return value of pte_alloc_one (and the pte * would not be\naccessible since its not kmapped).\n\nSolution: The only solution I found to this dilemma is a new typedef: a\npgtable_t.  For s390 pgtable_t will be a (pte *) - to be introduced with a\nlater patch.  For everybody else it will be a (struct page *).  The\nadditional problem with the initialization of the ptl lock and the\nNR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and\na destructor pgtable_page_dtor.  The page table allocation and free\nfunctions need to call these two whenever a page table page is allocated or\nfreed.  pmd_populate will get a pgtable_t instead of a struct page pointer.\n To get the pgtable_t back from a pmd entry that has been installed with\npmd_populate a new function pmd_pgtable is added.  It replaces the pmd_page\ncall in free_pte_range and apply_to_pte_range.\n\nSigned-off-by: Martin Schwidefsky \u003cschwidefsky@de.ibm.com\u003e\nCc: \u003clinux-arch@vger.kernel.org\u003e\nSigned-off-by: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\n"
    },
    {
      "commit": "5e5419734c8719cbc01af959ad9c0844002c0df5",
      "tree": "a075dca3f719946689efa0245464855cbf2a20ce",
      "parents": [
        "9f8f2172537de7af0b0fbd33502d18d52b1339bc"
      ],
      "author": {
        "name": "Benjamin Herrenschmidt",
        "email": "benh@kernel.crashing.org",
        "time": "Mon Feb 04 22:29:14 2008 -0800"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@woody.linux-foundation.org",
        "time": "Tue Feb 05 09:44:18 2008 -0800"
      },
      "message": "add mm argument to pte/pmd/pud/pgd_free\n\n(with Martin Schwidefsky \u003cschwidefsky@de.ibm.com\u003e)\n\nThe pgd/pud/pmd/pte page table allocation functions get a mm_struct pointer as\nfirst argument.  The free functions do not get the mm_struct argument.  This\nis 1) asymmetrical and 2) to do mm related page table allocations the mm\nargument is needed on the free function as well.\n\n[kamalesh@linux.vnet.ibm.com: i386 fix]\n[akpm@linux-foundation.org: coding-syle fixes]\nSigned-off-by: Benjamin Herrenschmidt \u003cbenh@kernel.crashing.org\u003e\nSigned-off-by: Martin Schwidefsky \u003cschwidefsky@de.ibm.com\u003e\nCc: \u003clinux-arch@vger.kernel.org\u003e\nSigned-off-by: Kamalesh Babulal \u003ckamalesh@linux.vnet.ibm.com\u003e\nSigned-off-by: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\n"
    },
    {
      "commit": "fa28237cfcc5827553044cbd6ee52e33692b0faa",
      "tree": "2e34678548e5323eef7392a94a7415e1754cbd1e",
      "parents": [
        "0a0a5af30b9831e4f049610b5a2d9d5108ff027a"
      ],
      "author": {
        "name": "Paul Mackerras",
        "email": "paulus@samba.org",
        "time": "Thu Jan 24 08:35:13 2008 +1100"
      },
      "committer": {
        "name": "Paul Mackerras",
        "email": "paulus@samba.org",
        "time": "Thu Jan 24 10:06:01 2008 +1100"
      },
      "message": "[POWERPC] Provide a way to protect 4k subpages when using 64k pages\n\nUsing 64k pages on 64-bit PowerPC systems makes life difficult for\nemulators that are trying to emulate an ISA, such as x86, which use a\nsmaller page size, since the emulator can no longer use the MMU and\nthe normal system calls for controlling page protections.  Of course,\nthe emulator can emulate the MMU by checking and possibly remapping\nthe address for each memory access in software, but that is pretty\nslow.\n\nThis provides a facility for such programs to control the access\npermissions on individual 4k sub-pages of 64k pages.  The idea is\nthat the emulator supplies an array of protection masks to apply to a\nspecified range of virtual addresses.  These masks are applied at the\nlevel where hardware PTEs are inserted into the hardware page table\nbased on the Linux PTEs, so the Linux PTEs are not affected.  Note\nthat this new mechanism does not allow any access that would otherwise\nbe prohibited; it can only prohibit accesses that would otherwise be\nallowed.  This new facility is only available on 64-bit PowerPC and\nonly when the kernel is configured for 64k pages.\n\nThe masks are supplied using a new subpage_prot system call, which\ntakes a starting virtual address and length, and a pointer to an array\nof protection masks in memory.  The array has a 32-bit word per 64k\npage to be protected; each 32-bit word consists of 16 2-bit fields,\nfor which 0 allows any access (that is otherwise allowed), 1 prevents\nwrite accesses, and 2 or 3 prevent any access.\n\nImplicit in this is that the regions of the address space that are\nprotected are switched to use 4k hardware pages rather than 64k\nhardware pages (on machines with hardware 64k page support).  In fact\nthe whole process is switched to use 4k hardware pages when the\nsubpage_prot system call is used, but this could be improved in future\nto switch only the affected segments.\n\nThe subpage protection bits are stored in a 3 level tree akin to the\npage table tree.  The top level of this tree is stored in a structure\nthat is appended to the top level of the page table tree, i.e., the\npgd array.  Since it will often only be 32-bit addresses (below 4GB)\nthat are protected, the pointers to the first four bottom level pages\nare also stored in this structure (each bottom level page contains the\nprotection bits for 1GB of address space), so the protection bits for\naddresses below 4GB can be accessed with one fewer loads than those\nfor higher addresses.\n\nSigned-off-by: Paul Mackerras \u003cpaulus@samba.org\u003e\n"
    },
    {
      "commit": "a4c28ab7445f5ca60e56ffd90edb3e9fc1330b71",
      "tree": "d7ccd52c688f014c320a55c1b6fa512424b147f3",
      "parents": [
        "66b30922c8a2c880fe61080c5bf87ae6615b9f64"
      ],
      "author": {
        "name": "Akinobu Mita",
        "email": "mita@fixstars.com",
        "time": "Tue May 29 20:46:51 2007 +1000"
      },
      "committer": {
        "name": "Paul Mackerras",
        "email": "paulus@samba.org",
        "time": "Sat Jun 02 21:01:56 2007 +1000"
      },
      "message": "[POWERPC] Fix return from pte_alloc_one() in out-of-memory case\n\npte_alloc_one() is expected to return NULL if out of memory.\nBut it returns virt_to_page(NULL), which is not NULL.\nThis fixes it.\n\nCc: Paul Mackerras \u003cpaulus@samba.org\u003e\nSigned-off-by: Akinobu Mita \u003cmita@fixstars.com\u003e\nSigned-off-by: Paul Mackerras \u003cpaulus@samba.org\u003e\n"
    },
    {
      "commit": "517e22638c282bb07c52a11f928961ed4822196b",
      "tree": "7eab8eb1242ee18f75c325077f26bdcb86133512",
      "parents": [
        "f1fa74f4afe96b0e4ac2beaa61fa4f4667acdcbb"
      ],
      "author": {
        "name": "Hugh Dickins",
        "email": "hugh@veritas.com",
        "time": "Wed May 09 14:38:48 2007 +1000"
      },
      "committer": {
        "name": "Paul Mackerras",
        "email": "paulus@samba.org",
        "time": "Wed May 09 16:35:00 2007 +1000"
      },
      "message": "[POWERPC] Don\u0027t use SLAB/SLUB for PTE pages\n\nThe SLUB allocator relies on struct page fields first_page and slab,\noverwritten by ptl when SPLIT_PTLOCK: so the SLUB allocator cannot then\nbe used for the lowest level of pagetable pages.  This was obstructing\nSLUB on PowerPC, which uses kmem_caches for its pagetables.  So convert\nits pte level to use normal gfp pages (whereas pmd, pud and 64k-page pgd\nwant partpages, so continue to use kmem_caches for pmd, pud and pgd).\n\nSigned-off-by: Hugh Dickins \u003chugh@veritas.com\u003e\nSigned-off-by: Benjamin Herrenschmidt \u003cbenh@kernel.crashing.org\u003e\nSigned-off-by: Paul Mackerras \u003cpaulus@samba.org\u003e\n"
    },
    {
      "commit": "f88df14b1f15cdeffa060580a40c1ce3e13bb79e",
      "tree": "0619f32c2be79a85792537ad4410cc8d729f4f75",
      "parents": [
        "69d48b409cac747cc0707b05b769e38488a6ad35"
      ],
      "author": {
        "name": "David Gibson",
        "email": "david@gibson.dropbear.id.au",
        "time": "Mon Apr 30 16:30:56 2007 +1000"
      },
      "committer": {
        "name": "Paul Mackerras",
        "email": "paulus@samba.org",
        "time": "Wed May 02 20:04:30 2007 +1000"
      },
      "message": "[POWERPC] Remove arch/powerpc\u0027s dependence on asm-ppc/pg{alloc,table}.h\n\nCurrently, all 32-bit powerpc platforms use asm-ppc/pgtable.h and\nasm-ppc/pgalloc.h, even when otherwise compiled with ARCH\u003dpowerpc.\nThose asm-ppc files are a fairly nasty tangle of #ifdefs including a\nbunch of things which shouldn\u0027t be necessary any more in arch/powerpc.\n\nCleaning up that mess is going to take a while, but this patch is a\nfirst step.  It separates the asm-powerpc/pg{alloc,table}.h into 64\nbit and 32 bit versions in asm-powerpc, which the basic .h files in\nasm-powerpc select based on config.  We make a few tiny tweaks to the\ninnards of the files along the way, making the outermost ifdefs\n(double-inclusion protection and __KERNEL__) a little cleaner, and\n#including asm-generic/pgtable.h from the top-level\nasm-powerpc/pgtable.h (since both the old 32-bit and 64-bit versions\nended with such an #include).\n\nSigned-off-by: David Gibson \u003cdavid@gibson.dropbear.id.au\u003e\nSigned-off-by: Paul Mackerras \u003cpaulus@samba.org\u003e\n"
    }
  ]
}