1. 06 12月, 2006 3 次提交
  2. 30 9月, 2006 2 次提交
    • S
      [PATCH] pidspace: is_init() · f400e198
      Sukadev Bhattiprolu 提交于
      This is an updated version of Eric Biederman's is_init() patch.
      (http://lkml.org/lkml/2006/2/6/280).  It applies cleanly to 2.6.18-rc3 and
      replaces a few more instances of ->pid == 1 with is_init().
      
      Further, is_init() checks pid and thus removes dependency on Eric's other
      patches for now.
      
      Eric's original description:
      
      	There are a lot of places in the kernel where we test for init
      	because we give it special properties.  Most  significantly init
      	must not die.  This results in code all over the kernel test
      	->pid == 1.
      
      	Introduce is_init to capture this case.
      
      	With multiple pid spaces for all of the cases affected we are
      	looking for only the first process on the system, not some other
      	process that has pid == 1.
      Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
      Signed-off-by: NSukadev Bhattiprolu <sukadev@us.ibm.com>
      Cc: Dave Hansen <haveblue@us.ibm.com>
      Cc: Serge Hallyn <serue@us.ibm.com>
      Cc: Cedric Le Goater <clg@fr.ibm.com>
      Cc: <lxc-devel@lists.sourceforge.net>
      Acked-by: NPaul Mackerras <paulus@samba.org>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      f400e198
    • J
      [PATCH] make PROT_WRITE imply PROT_READ · df67b3da
      Jason Baron 提交于
      Make PROT_WRITE imply PROT_READ for a number of architectures which don't
      support write only in hardware.
      
      While looking at this, I noticed that some architectures which do not
      support write only mappings already take the exact same approach.  For
      example, in arch/alpha/mm/fault.c:
      
      "
              if (cause < 0) {
                      if (!(vma->vm_flags & VM_EXEC))
                              goto bad_area;
              } else if (!cause) {
                      /* Allow reads even for write-only mappings */
                      if (!(vma->vm_flags & (VM_READ | VM_WRITE)))
                              goto bad_area;
              } else {
                      if (!(vma->vm_flags & VM_WRITE))
                              goto bad_area;
              }
      "
      
      Thus, this patch brings other architectures which do not support write only
      mappings in-line and consistent with the rest.  I've verified the patch on
      ia64, x86_64 and x86.
      
      Additional discussion:
      
      Several architectures, including x86, can not support write-only mappings.
      The pte for x86 reserves a single bit for protection and its two states are
      read only or read/write.  Thus, write only is not supported in h/w.
      
      Currently, if i 'mmap' a page write-only, the first read attempt on that page
      creates a page fault and will SEGV.  That check is enforced in
      arch/blah/mm/fault.c.  However, if i first write that page it will fault in
      and the pte will be set to read/write.  Thus, any subsequent reads to the page
      will succeed.  It is this inconsistency in behavior that this patch is
      attempting to address.  Furthermore, if the page is swapped out, and then
      brought back the first read will also cause a SEGV.  Thus, any arbitrary read
      on a page can potentially result in a SEGV.
      
      According to the SuSv3 spec, "if the application requests only PROT_WRITE, the
      implementation may also allow read access." Also as mentioned, some
      archtectures, such as alpha, shown above already take the approach that i am
      suggesting.
      
      The counter-argument to this raised by Arjan, is that the kernel is enforcing
      the write only mapping the best it can given the h/w limitations.  This is
      true, however Alan Cox, and myself would argue that the inconsitency in
      behavior, that is applications can sometimes work/sometimes fails is highly
      undesireable.  If you read through the thread, i think people, came to an
      agreement on the last patch i posted, as nobody has objected to it...
      Signed-off-by: NJason Baron <jbaron@redhat.com>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Roman Zippel <zippel@linux-m68k.org>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Acked-by: NAndi Kleen <ak@muc.de>
      Acked-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
      Cc: Arjan van de Ven <arjan@linux.intel.com>
      Acked-by: NPaul Mundt <lethal@linux-sh.org>
      Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
      Cc: Ian Molton <spyro@f2s.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      df67b3da
  3. 27 9月, 2006 4 次提交
    • P
      sh: More cosmetic cleanups and trivial fixes. · 0f08f338
      Paul Mundt 提交于
      Nothing exciting here, just trivial fixes..
      Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      0f08f338
    • P
      sh: Fix split ptlock for user mappings in __do_page_fault(). · f647d33f
      Paul Mundt 提交于
      There was a bug that got introduced when the split ptlock changes
      went in where mm could be unintialized for user mappings, this
      fixes it up..
      Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      f647d33f
    • P
      sh: page table alloc cleanups and page fault optimizations. · 26ff6c11
      Paul Mundt 提交于
      Cleanup of page table allocators, using generic folded PMD and PUD
      helpers. TLB flushing operations are moved to a more sensible spot.
      
      The page fault handler is also optimized slightly, we no longer waste
      cycles on IRQ disabling for flushing of the page from the ITLB, since
      we're already under CLI protection by the initial exception handler.
      Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      26ff6c11
    • P
      sh: Add control register barriers. · 29847622
      Paul Mundt 提交于
      Currently when making changes to control registers, we
      typically need some time for changes to take effect (8
      nops, generally).  However, for sh4a we simply need to
      do an icbi..
      
      This is a simple patch for implementing a general purpose
      ctrl_barrier() which functions as a control register write
      barrier. There's some additional documentation in the patch
      itself, but it's pretty self explanatory.
      
      There were also some places where we were not doing the
      barrier, which didn't seem to have any adverse effects on
      legacy parts, but certainly did on sh4a. It's safer to have
      the barrier in place for legacy parts as well in these cases,
      though this does make flush_tlb_all() more expensive (by an
      order of 8 nops).  We can ifdef around the flush_tlb_all()
      case for now if it's clear that all legacy parts won't have
      a problem with this.
      Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
      29847622
  4. 30 10月, 2005 1 次提交
    • H
      [PATCH] mm: i386 sh sh64 ready for split ptlock · 60ec5585
      Hugh Dickins 提交于
      Use pte_offset_map_lock, instead of pte_offset_map (or inappropriate
      pte_offset_kernel) and mm-wide page_table_lock, in sundry arch places.
      
      The i386 vm86 mark_screen_rdonly: yes, there was and is an assumption that the
      screen fits inside the one page table, as indeed it does.
      
      The sh __do_page_fault: which handles both kernel faults (without lock) and
      user mm faults (locked - though it set_pte without locking before).
      
      The sh64 flush_cache_range and helpers: which wrongly thought callers held
      page_table_lock before (only its tlb_start_vma did, and no longer does so);
      moved the flush loop down, and adjusted the large versus small range decision
      to consider a range which spans page tables as large.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Acked-by: NPaul Mundt <lethal@linux-sh.org>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      60ec5585
  5. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      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!
      1da177e4