- 20 3月, 2006 2 次提交
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由 David S. Miller 提交于
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: NDavid S. Miller <davem@davemloft.net>
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由 David S. Miller 提交于
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: NDavid S. Miller <davem@davemloft.net>
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- 27 2月, 2006 1 次提交
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由 David S. Miller 提交于
The change to kernel/sched.c's init code to use for_each_cpu() requires that the cpu_possible_map be setup much earlier. Set it up via setup_arch(), constrained to NR_CPUS, and later constrain it to max_cpus in smp_prepare_cpus(). This fixes SMP booting on sparc64. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 13 1月, 2006 1 次提交
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 12 11月, 2005 1 次提交
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由 David S. Miller 提交于
Noticed by Tom 'spot' Callaway. Even on uniprocessor we always reported the number of physical cpus in the system via /proc/cpuinfo. But when this got changed to use num_possible_cpus() it always reads as "1" on uniprocessor. This change was unintentional. So scan the firmware device tree and count the number of cpu nodes, and report that, as we always did. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 09 11月, 2005 2 次提交
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由 Nick Piggin 提交于
Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce confusion, and make their semantics rigid. Improves efficiency of resched_task and some cpu_idle routines. * In resched_task: - TIF_NEED_RESCHED is only cleared with the task's runqueue lock held, and as we hold it during resched_task, then there is no need for an atomic test and set there. The only other time this should be set is when the task's quantum expires, in the timer interrupt - this is protected against because the rq lock is irq-safe. - If TIF_NEED_RESCHED is set, then we don't need to do anything. It won't get unset until the task get's schedule()d off. - If we are running on the same CPU as the task we resched, then set TIF_NEED_RESCHED and no further action is required. - If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set after TIF_NEED_RESCHED has been set, then we need to send an IPI. Using these rules, we are able to remove the test and set operation in resched_task, and make clear the previously vague semantics of POLLING_NRFLAG. * In idle routines: - Enter cpu_idle with preempt disabled. When the need_resched() condition becomes true, explicitly call schedule(). This makes things a bit clearer (IMO), but haven't updated all architectures yet. - Many do a test and clear of TIF_NEED_RESCHED for some reason. According to the resched_task rules, this isn't needed (and actually breaks the assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock held). So remove that. Generally one less locked memory op when switching to the idle thread. - Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner most polling idle loops. The above resched_task semantics allow it to be set until before the last time need_resched() is checked before going into a halt requiring interrupt wakeup. Many idle routines simply never enter such a halt, and so POLLING_NRFLAG can be always left set, completely eliminating resched IPIs when rescheduling the idle task. POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs. Signed-off-by: NNick Piggin <npiggin@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Con Kolivas <kernel@kolivas.org> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Nick Piggin 提交于
Run idle threads with preempt disabled. Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()). How did it ever work before? Might fix the CPU hotplugging hang which Nigel Cunningham noted. We think the bug hits if the idle thread is preempted after checking need_resched() and before going to sleep, then the CPU offlined. After calling stop_machine_run, the CPU eventually returns from preemption and into the idle thread and goes to sleep. The CPU will continue executing previous idle and have no chance to call play_dead. By disabling preemption until we are ready to explicitly schedule, this bug is fixed and the idle threads generally become more robust. From: alexs <ashepard@u.washington.edu> PPC build fix From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> MIPS build fix Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NYoichi Yuasa <yuasa@hh.iij4u.or.jp> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 08 11月, 2005 2 次提交
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由 David S. Miller 提交于
It isn't needed any longer, as noted by Hugh Dickins. We still need the flush routines, due to the one remaining call site in hugetlb_prefault_arch_hook(). That can be eliminated at some later point, however. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Hugh Dickins 提交于
sparc64 is unique among architectures in taking the page_table_lock in its context switch (well, cris does too, but erroneously, and it's not yet SMP anyway). This seems to be a private affair between switch_mm and activate_mm, using page_table_lock as a per-mm lock, without any relation to its uses elsewhere. That's fine, but comment it as such; and unlock sooner in switch_mm, more like in activate_mm (preemption is disabled here). There is a block of "if (0)"ed code in smp_flush_tlb_pending which would have liked to rely on the page_table_lock, in switch_mm and elsewhere; but its comment explains how dup_mmap's flush_tlb_mm defeated it. And though that could have been changed at any time over the past few years, now the chance vanishes as we push the page_table_lock downwards, and perhaps split it per page table page. Just delete that block of code. Which leaves the mysterious spin_unlock_wait(&oldmm->page_table_lock) in kernel/fork.c copy_mm. Textual analysis (supported by Nick Piggin) suggests that the comment was written by DaveM, and that it relates to the defeated approach in the sparc64 smp_flush_tlb_pending. Just delete this block too. Signed-off-by: NHugh Dickins <hugh@veritas.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 15 10月, 2005 1 次提交
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由 David S. Miller 提交于
Doing a "SUNW,stop-self" firmware call on the other cpus is not the correct thing to do when dropping into the firmware for a halt, reboot, or power-off. For now, just do nothing to quiet the other cpus, as the system should be quiescent enough. Later we may decide to implement smp_send_stop() like the other SMP platforms do. Based upon a report from Christopher Zimmermann. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 26 9月, 2005 1 次提交
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由 David S. Miller 提交于
At boot time, determine the D-cache, I-cache and E-cache size and line-size. Use them in cache flushes when appropriate. This change was motivated by discovering that the D-cache on UltraSparc-IIIi and later are 64K not 32K, and the flushes done by the Cheetah error handlers were assuming a 32K size. There are still some pieces of code that are hard coding things and will need to be fixed up at some point. While we're here, fix the D-cache and I-cache parity error handlers to run with interrupts disabled, and when the trap occurs at trap level > 1 log the event via a counter displayed in /proc/cpuinfo. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 30 8月, 2005 1 次提交
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由 David S. Miller 提交于
It appears that a memory barrier soon after a mispredicted branch, not just in the delay slot, can cause the hang condition of this cpu errata. So move them out-of-line, and explicitly put them into a "branch always, predict taken" delay slot which should fully kill this problem. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 25 7月, 2005 1 次提交
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由 David S. Miller 提交于
These two bits were accesses non-atomically from assembler code. So, in order to eliminate any potential races resulting from that, move these pieces of state into two bytes elsewhere in struct thread_info. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 13 7月, 2005 1 次提交
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由 Andrew Morton 提交于
arch/sparc64/kernel/smp.c:48: error: parse error before "__attribute__" arch/sparc64/kernel/smp.c:49: error: parse error before "__attribute__" Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 11 7月, 2005 1 次提交
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由 David S. Miller 提交于
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 24 5月, 2005 1 次提交
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由 David S. Miller 提交于
Older UltraSPARC-III chips have a P-Cache bug that makes us disable it by default at boot time. However, this does hurt performance substantially, particularly with memcpy(), and the bug is _incredibly_ obscure. I have never seen it triggered in practice, ever. So provide a "-P" boot option that forces the P-Cache on. It taints the kernel, so if it does trigger and cause some data corruption or OOPS, we will find out in the logs that this option was on when it happened. Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 17 4月, 2005 1 次提交
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由 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!
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