20 Mar, 2006

10 commits

  • Another case where we have to force ourselves into global register
    level one. Also make sure the arguments passed to sun4v_do_mna() are
    correct.

    This area actually needs some more work, for example spill fixup is
    not necessarily going to do the right thing for this case.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • The C function is named sun4v_do_mna not sun4v_mna.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • Signed-off-by: David S. Miller

    David S. Miller
     
  • When saving and restoing trap state, do the window spill/fill
    handling inline so that we never trap deeper than 2 trap levels.
    This is important for chips like Niagara.

    The window fixup code is massively simplified, and many more
    improvements are now possible.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • This, as well as making the code cleaner, allows a simplification in
    the TSB miss handling path.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • If we are returning back to kernel mode, %g4 could be live
    (for example, in the case where we window spill in the etrap
    code). So do not change it's value if going back to kernel.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • Since we use %g5 itself as a temporary, it can get clobbered
    if we take an interrupt mid-stream and thus cause end up with
    the final %g5 value too early as a result of rtrap processing.

    Set %g5 at the very end, atomically, to avoid this problem.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • Some of the trap code was still assuming that alternate
    global %g6 was hard coded with current_thread_info().
    Let's just consistently flush at KERNBASE when we need
    a pipeline synchronization. That's locked into the TLB
    and will always work.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • UltraSPARC has special sets of global registers which are switched to
    for certain trap types. There is one set for MMU related traps, one
    set of Interrupt Vector processing, and another set (called the
    Alternate globals) for all other trap types.

    For what seems like forever we've hard coded the values in some of
    these trap registers. Some examples include:

    1) Interrupt Vector global %g6 holds current processors interrupt
    work struct where received interrupts are managed for IRQ handler
    dispatch.

    2) MMU global %g7 holds the base of the page tables of the currently
    active address space.

    3) Alternate global %g6 held the current_thread_info() value.

    Such hardcoding has resulted in some serious issues in many areas.
    There are some code sequences where having another register available
    would help clean up the implementation. Taking traps such as
    cross-calls from the OBP firmware requires some trick code sequences
    wherein we have to save away and restore all of the special sets of
    global registers when we enter/exit OBP.

    We were also using the IMMU TSB register on SMP to hold the per-cpu
    area base address, which doesn't work any longer now that we actually
    use the TSB facility of the cpu.

    The implementation is pretty straight forward. One tricky bit is
    getting the current processor ID as that is different on different cpu
    variants. We use a stub with a fancy calling convention which we
    patch at boot time. The calling convention is that the stub is
    branched to and the (PC - 4) to return to is in register %g1. The cpu
    number is left in %g6. This stub can be invoked by using the
    __GET_CPUID macro.

    We use an array of per-cpu trap state to store the current thread and
    physical address of the current address space's page tables. The
    TRAP_LOAD_THREAD_REG loads %g6 with the current thread from this
    table, it uses __GET_CPUID and also clobbers %g1.

    TRAP_LOAD_IRQ_WORK is used by the interrupt vector processing to load
    the current processor's IRQ software state into %g6. It also uses
    __GET_CPUID and clobbers %g1.

    Finally, TRAP_LOAD_PGD_PHYS loads the physical address base of the
    current address space's page tables into %g7, it clobbers %g1 and uses
    __GET_CPUID.

    Many refinements are possible, as well as some tuning, with this stuff
    in place.

    Signed-off-by: David S. Miller

    David S. Miller
     
  • We now use the TSB hardware assist features of the UltraSPARC
    MMUs.

    SMP is currently knowingly broken, we need to find another place
    to store the per-cpu base pointers. We hid them away in the TSB
    base register, and that obviously will not work any more :-)

    Another known broken case is non-8KB base page size.

    Also noticed that flush_tlb_all() is not referenced anywhere, only
    the internal __flush_tlb_all() (local cpu only) is used by the
    sparc64 port, so we can get rid of flush_tlb_all().

    The kernel gets it's own 8KB TSB (swapper_tsb) and each address space
    gets it's own private 8K TSB. Later we can add code to dynamically
    increase the size of per-process TSB as the RSS grows. An 8KB TSB is
    good enough for up to about a 4MB RSS, after which the TSB starts to
    incur many capacity and conflict misses.

    We even accumulate OBP translations into the kernel TSB.

    Another area for refinement is large page size support. We could use
    a secondary address space TSB to handle those.

    Signed-off-by: David S. Miller

    David S. Miller
     

05 Oct, 2005

1 commit


30 Aug, 2005

1 commit

  • Current uncorrectable error handling was poor enough
    that the processor could just loop taking the same
    trap over and over again. Fix things up so that we
    at least get a log message and perhaps even some register
    state.

    In the process, much consolidation became possible,
    particularly with the correctable error handler.

    Prefix assembler and C function names with "spitfire"
    to indicate that these are for Ultra-I/II/IIi/IIe only.

    More work is needed to make these routines robust and
    featureful to the level of the Ultra-III error handlers.

    Signed-off-by: David S. Miller

    David S. Miller
     

17 Apr, 2005

1 commit

  • 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!

    Linus Torvalds