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path: root/arch/sparc64/kernel/tsb.S
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2006-06-30Remove obsolete #include <linux/config.h>Jörn Engel
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-03-22[SPARC64]: Add a secondary TSB for hugepage mappings.David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Optimized TSB table initialization.David S. Miller
We only need to write an invalid tag every 16 bytes, so taking advantage of this can save many instructions compared to the simple memset() call we make now. A prefetching implementation is implemented for sun4u and a block-init store version if implemented for Niagara. The next trick is to be able to perform an init and a copy_tsb() in parallel when growing a TSB table. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Fix and re-enable dynamic TSB sizing.David S. Miller
This is good for up to %50 performance improvement of some test cases. The problem has been the race conditions, and hopefully I've plugged them all up here. 1) There was a serious race in switch_mm() wrt. lazy TLB switching to and from kernel threads. We could erroneously skip a tsb_context_switch() and thus use a stale TSB across a TSB grow event. There is a big comment now in that function describing exactly how it can happen. 2) All code paths that do something with the TSB need to be guarded with the mm->context.lock spinlock. This makes page table flushing paths properly synchronize with both TSB growing and TLB context changes. 3) TSB growing events are moved to the end of successful fault processing. Previously it was in update_mmu_cache() but that is deadlock prone. At the end of do_sparc64_fault() we hold no spinlocks that could deadlock the TSB grow sequence. We also have dropped the address space semaphore. While we're here, add prefetching to the copy_tsb() routine and put it in assembler into the tsb.S file. This piece of code is quite time critical. There are some small negative side effects to this code which can be improved upon. In particular we grab the mm->context.lock even for the tsb insert done by update_mmu_cache() now and that's a bit excessive. We can get rid of that locking, and the same lock taking in flush_tsb_user(), by disabling PSTATE_IE around the whole operation including the capturing of the tsb pointer and tsb_nentries value. That would work because anyone growing the TSB won't free up the old TSB until all cpus respond to the TSB change cross call. I'm not quite so confident in that optimization to put it in right now, but eventually we might be able to and the description is here for reference. This code seems very solid now. It passes several parallel GCC bootstrap builds, and our favorite "nut cruncher" stress test which is a full "make -j8192" build of a "make allmodconfig" kernel. That puts about 256 processes on each cpu's run queue, makes lots of process cpu migrations occur, causes lots of page table and TLB flushing activity, incurs many context version number changes, and it swaps the machine real far out to disk even though there is 16GB of ram on this test system. :-) Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Simplify TSB insert checks.David S. Miller
Don't try to avoid putting non-base page sized entries into the user TSB. It actually costs us more to check this than it helps. Eventually we'll have a multiple TSB scheme for user processes. Once a process starts using larger pages, we'll allocate and use such a TSB. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Fix _PAGE_EXEC handling.David S. Miller
First of all, use the known _PAGE_EXEC_{4U,4V} value instead of loading _PAGE_EXEC from memory. We either know which one to use by context, or we can code patch the test. Next, we need to check executability of a PTE in the generic TSB miss handler. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: More TLB/TSB handling fixes.David S. Miller
The SUN4V convention with non-shared TSBs is that the context bit of the TAG is clear. So we have to choose an "invalid" bit and initialize new TSBs appropriately. Otherwise a zero TAG looks "valid". Make sure, for the window fixup cases, that we use the right global registers and that we don't potentially trample on the live global registers in etrap/rtrap handling (%g2 and %g6) and that we put the missing virtual address properly in %g5. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Fix some SUN4V TLB handling bugs.David S. Miller
1) Add error return checking for TLB load hypervisor calls. 2) Don't fallthru to dtlb tsb miss handler from itlb tsb miss handler, oops. 3) On window fixups, propagate fault information to fixup handler correctly. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Do not write garbage into %pstate in tsb_context_switch().David S. Miller
For SUN4V, we were clobbering %o5 to do the hypervisor call. This clobbers the saved %pstate value and we end up writing garbage into that register as a result. Oops. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Deal with PTE layout differences in SUN4V.David S. Miller
Yes, you heard it right, they changed the PTE layout for SUN4V. Ho hum... This is the simple and inefficient way to support this. It'll get optimized, don't worry. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Simplify sun4v TLB handling using macros.David S. Miller
There was also a bug in sun4v_itlb_miss, it loaded the MMU Fault Status base into %g3 instead of %g2. This pointed out a fast path for TSB miss processing, since we have %g2 with the MMU Fault Status base, we can use that to quickly load up the PGD phys address. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Fix hypervisor call arg passing.David S. Miller
Function goes in %o5, args go in %o0 --> %o5. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Hypervisor TSB context switching.David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Implement sun4v TSB miss handlers.David S. Miller
When we register a TSB with the hypervisor, so that it or hardware can handle TLB misses and do the TSB walk for us, the hypervisor traps down to these trap when it incurs a TSB miss. Processing is simple, we load the missing virtual address and context, and do a full page table walk. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Rename gl_{1,2}insn_patch --> sun4v_{1,2}insn_patchDavid S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Initial sun4v TLB miss handling infrastructure.David S. Miller
Things are a little tricky because, unlike sun4u, we have to: 1) do a hypervisor trap to do the TLB load. 2) do the TSB lookup calculations by hand Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Sanitize %pstate writes for sun4v.David S. Miller
If we're just switching between different alternate global sets, nop it out on sun4v. Also, get rid of all of the alternate global save/restore in the OBP CIF trampoline code. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Refine register window trap handling.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 <davem@davemloft.net>
2006-03-20[SPARC64]: Add explicit register args to trap state loading macros.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 <davem@davemloft.net>
2006-03-20[SPARC64]: Access TSB with physical addresses when possible.David S. Miller
This way we don't need to lock the TSB into the TLB. The trick is that every TSB load/store is registered into a special instruction patch section. The default uses virtual addresses, and the patch instructions use physical address load/stores. We can't do this on all chips because only cheetah+ and later have the physical variant of the atomic quad load. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Fix too early reference to %g6David S. Miller
%g6 is not necessarily set to current_thread_info() at sparc64_realfault_common. So store the fault code and address after we invoke etrap and %g6 is properly set up. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Kill PROM locked TLB entry preservation code.David S. Miller
It is totally unnecessary complexity. After we take over the trap table, we handle all PROM tlb misses fully. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Use sparc64_highest_unlocked_tlb_ent in __tsb_context_switch()David S. Miller
Instead of ugly hard-coded value. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Preload TSB entries from update_mmu_cache().David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Add infrastructure for dynamic TSB sizing.David S. Miller
This also cleans up tsb_context_switch(). The assembler routine is now __tsb_context_switch() and the former is an inline function that picks out the bits from the mm_struct and passes it into the assembler code as arguments. setup_tsb_parms() computes the locked TLB entry to map the TSB. Later when we support using the physical address quad load instructions of Cheetah+ and later, we'll simply use the physical address for the TSB register value and set the map virtual and PTE both to zero. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: TSB refinements.David S. Miller
Move {init_new,destroy}_context() out of line. Do not put huge pages into the TSB, only base page size translations. There are some clever things we could do here, but for now let's be correct instead of fancy. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[SPARC64]: Elminate all usage of hard-coded trap globals.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 <davem@davemloft.net>
2006-03-20[SPARC64]: Move away from virtual page tables, part 1.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 <davem@davemloft.net>