- 02 May, 2007 40 commits
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Fernando Luis VazquezCao authored
The functionality provided by the new safe_apic_wait_icr_idle is being open-coded all over "kernel/smpboot.c". Use safe_apic_wait_icr_idle instead to consolidate code and ease maintenance. Signed-off-by:
Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Signed-off-by:
Andi Kleen <ak@suse.de>
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Fernando Luis VazquezCao authored
The functionality provided by the new safe_apic_wait_icr_idle is being open-coded all over "kernel/smpboot.c". Use safe_apic_wait_icr_idle instead to consolidate code and ease maintenance. Signed-off-by:
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Fernando Luis VazquezCao authored
apic_wait_icr_idle looks like this: static __inline__ void apic_wait_icr_idle(void) { while (apic_read(APIC_ICR) & APIC_ICR_BUSY) cpu_relax(); } The busy loop in this function would not be problematic if the corresponding status bit in the ICR were always updated, but that does not seem to be the case under certain crash scenarios. Kdump uses an IPI to stop the other CPUs in the event of a crash, but when any of the other CPUs are locked-up inside the NMI handler the CPU that sends the IPI will end up looping forever in the ICR check, effectively hard-locking the whole system. Quoting from Intel's "MultiProcessor Specification" (Version 1.4), B-3: "A local APIC unit indicates successful dispatch of an IPI by resetting the Delivery Status bit in the Interrupt Command Register (ICR). The operating system polls the delivery status bit after sending an INIT or STARTUP IPI until the command has been dispatched. A period of 20 microseconds should be sufficient for IPI dispatch to complete under normal operating conditions. If the IPI is not successfully dispatched, the operating system can abort the command. Alternatively, the operating system can retry the IPI by writing the lower 32-bit double word of the ICR. This “time-out” mechanism can be implemented through an external interrupt, if interrupts are enabled on the processor, or through execution of an instruction or time-stamp counter spin loop." Intel's documentation suggests the implementation of a time-out mechanism, which, by the way, is already being open-coded in some parts of the kernel that tinker with ICR. Create a apic_wait_icr_idle replacement that implements the time-out mechanism and that can be used to solve the aforementioned problem. AK: moved both functions out of line AK: Added improved loop from Keith Owens Signed-off-by: -
Fernando Luis VazquezCao authored
apic_wait_icr_idle looks like this: static __inline__ void apic_wait_icr_idle(void) { while (apic_read(APIC_ICR) & APIC_ICR_BUSY) cpu_relax(); } The busy loop in this function would not be problematic if the corresponding status bit in the ICR were always updated, but that does not seem to be the case under certain crash scenarios. Kdump uses an IPI to stop the other CPUs in the event of a crash, but when any of the other CPUs are locked-up inside the NMI handler the CPU that sends the IPI will end up looping forever in the ICR check, effectively hard-locking the whole system. Quoting from Intel's "MultiProcessor Specification" (Version 1.4), B-3: "A local APIC unit indicates successful dispatch of an IPI by resetting the Delivery Status bit in the Interrupt Command Register (ICR). The operating system polls the delivery status bit after sending an INIT or STARTUP IPI until the command has been dispatched. A period of 20 microseconds should be sufficient for IPI dispatch to complete under normal operating conditions. If the IPI is not successfully dispatched, the operating system can abort the command. Alternatively, the operating system can retry the IPI by writing the lower 32-bit double word of the ICR. This “time-out” mechanism can be implemented through an external interrupt, if interrupts are enabled on the processor, or through execution of an instruction or time-stamp counter spin loop." Intel's documentation suggests the implementation of a time-out mechanism, which, by the way, is already being open-coded in some parts of the kernel that tinker with ICR. Create a apic_wait_icr_idle replacement that implements the time-out mechanism and that can be used to solve the aforementioned problem. AK: moved both functions out of line AK: added improved loop from Keith Owens Signed-off-by: -
Bernhard Kaindl authored
If our copy of the MTRRs of the BSP has RdMem or WrMem set, and we are running on an AMD64/K8 system, the boot CPU must have had MtrrFixDramEn and MtrrFixDramModEn set (otherwise our RDMSR would have copied these bits cleared), so we set them on this CPU as well. This allows us to keep the AMD64/K8 RdMem and WrMem bits in sync across the CPUs of SMP systems in order to fullfill the duty of system software to "initialize and maintain MTRR consistency across all processors." as written in the AMD and Intel manuals. If an WRMSR instruction fails because MtrrFixDramModEn is not set, I expect that also the Intel-style MTRR bits are not updated. AK: minor cleanup, moved MSR defines around Signed-off-by:
Bernhard Kaindl <bk@suse.de> Signed-off-by:
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Bernhard Kaindl authored
Note: This patch didn'nt need an update since it's initial post. Some BIOSes may modify fixed-range MTRRs in SMM, e.g. when they transition the system into ACPI mode, which is entered thru an SMI, triggered by Linux in acpi_enable(). SMIs which cause that Linux is interrupted and BIOS code is executed (which may change e.g. fixed-range MTRRs) in SMM may be raised by an embedded system controller which is often found in notebooks also at other occasions. If we would not update our copy of the fixed-range MTRRs before suspending to RAM or to disk, restore_processor_state() would set the fixed-range MTRRs of the BSP using old backup values which may be outdated and this could cause the system to fail later during resume. This patch ensures that our copy of the fixed-range MTRRs is updated when saving the boot processor state on suspend to disk and suspend to RAM. In combination with other patches this allows to fix s2ram and s2disk on the Acer Ferrari 1000 notebook and at least s2disk on the Acer Ferrari 5000 notebook. Signed-off-by:
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Bernhard Kaindl authored
Applied fix by Andew Morton: http://lkml.org/lkml/2007/4/8/88 - Fix `make headers_check'. AMD and Intel x86 CPU manuals state that it is the responsibility of system software to initialize and maintain MTRR consistency across all processors in Multi-Processing Environments. Quote from page 188 of the AMD64 System Programming manual (Volume 2): 7.6.5 MTRRs in Multi-Processing Environments "In multi-processing environments, the MTRRs located in all processors must characterize memory in the same way. Generally, this means that identical values are written to the MTRRs used by the processors." (short omission here) "Failure to do so may result in coherency violations or loss of atomicity. Processor implementations do not check the MTRR settings in other processors to ensure consistency. It is the responsibility of system software to initialize and maintain MTRR consistency across all processors." Current Linux MTRR code already implements the above in the case that the BIOS does not properly initialize MTRRs on the secondary processors, but the case where the fixed-range MTRRs of the boot processor are changed after Linux started to boot, before the initialsation of a secondary processor, is not handled yet. In this case, secondary processors are currently initialized by Linux with MTRRs which the boot processor had very early, when mtrr_bp_init() did run, but not with the MTRRs which the boot processor uses at the time when that secondary processors is actually booted, causing differing MTRR contents on the secondary processors. Such situation happens on Acer Ferrari 1000 and 5000 notebooks where the BIOS enables and sets AMD-specific IORR bits in the fixed-range MTRRs of the boot processor when it transitions the system into ACPI mode. The SMI handler of the BIOS does this in SMM, entered while Linux ACPI code runs acpi_enable(). Other occasions where the SMI handler of the BIOS may change bits in the MTRRs could occur as well. To initialize newly booted secodary processors with the fixed-range MTRRs which the boot processor uses at that time, this patch saves the fixed-range MTRRs of the boot processor before new secondary processors are started. When the secondary processors run their Linux initialisation code, their fixed-range MTRRs will be updated with the saved fixed-range MTRRs. If CONFIG_MTRR is not set, we define mtrr_save_state as an empty statement because there is nothing to do. Possible TODOs: *) CPU-hotplugging outside of SMP suspend/resume is not yet tested with this patch. *) If, even in this case, an AP never runs i386/do_boot_cpu or x86_64/cpu_up, then the calls to mtrr_save_state() could be replaced by calls to mtrr_save_fixed_ranges(NULL) and mtrr_save_state() would not be needed. That would need either verification of the CPU-hotplug code or at least a test on a >2 CPU machine. *) The MTRRs of other running processors are not yet checked at this time but it might be interesting to syncronize the MTTRs of all processors before booting. That would be an incremental patch, but of rather low priority since there is no machine known so far which would require this. AK: moved prototypes on x86-64 around to fix warnings Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
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Bernhard Kaindl authored
In this current implementation which is used in other patches, mtrr_save_fixed_ranges() accepts a dummy void pointer because in the current implementation of one of these patches, this function may be called from smp_call_function_single() which requires that this function takes a void pointer argument. This function calls get_fixed_ranges(), passing mtrr_state.fixed_ranges which is the element of the static struct which stores our current backup of the fixed-range MTRR values which all CPUs shall be using. Because mtrr_save_fixed_ranges calls get_fixed_ranges after kernel initialisation time, __init needs to be removed from the declaration of get_fixed_ranges(). If CONFIG_MTRR is not set, we define mtrr_save_fixed_ranges as an empty statement because there is nothing to do. AK: Moved prototypes for x86-64 around to fix warnings Signed-off-by:
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Andi Kleen authored
Signed-off-by: -
Jeremy Fitzhardinge authored
Three cleanups: 1: ELF notes are never mapped, so there's no need to have any access flags in their phdr. 2: When generating them from asm, tell the assembler to use a SHT_NOTE section type. There doesn't seem to be a way to do this from C. 3: Use ANSI rather than traditional cpp behaviour to stringify the macro argument. Signed-off-by:
Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by:
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Andi Kleen authored
Otherwise non GPL modules cannot even do basic operations like disabling interrupts anymore, which would be excessive. Longer term should split the single structure up into internal and external symbols and not export the internal ones at all. Signed-off-by: -
Jeremy Fitzhardinge authored
The other symbols used to delineate the alt-instructions sections have the form __foo/__foo_end. Rename parainstructions to match. Signed-off-by:
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Zachary Amsden authored
Convert VMI timer to use clock events, making it properly able to use the NO_HZ infrastructure. On UP systems, with no local APIC, we just continue to route these events through the PIT. On systems with a local APIC, or SMP, we provide a single source interrupt chip which creates the local timer IRQ. It actually gets delivered by the APIC hardware, but we don't want to use the same local APIC clocksource processing, so we create our own handler here. Signed-off-by:
Zachary Amsden <zach@vmware.com> Signed-off-by:
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Zachary Amsden authored
Implement vmi_kmap_atomic_pte in terms of the backend set_linear_mapping operation. The conversion is rather straighforward; call kmap_atomic and then inform the hypervisor of the page mapping. The _flush_tlb damage is due to macros being pulled in from highmem.h. Signed-off-by:
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Zachary Amsden authored
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Zachary Amsden authored
No, just no. You do not use goto to skip a code block. You do not return an obvious variable from a singly-inlined function and give the function a return value. You don't put unexplained comments about kmalloc in code which doesn't do dynamic allocation. And you don't leave stray warnings around for no good reason. Also, when possible, it is better to use block scoped variables because gcc can sometime generate better code. Signed-off-by:
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Jeremy Fitzhardinge authored
Add "noreplace-paravirt" to disable paravirt_ops patching. Signed-off-by:
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Zachary Amsden authored
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Jeremy Fitzhardinge authored
Remove spurious comments, headers and keywords from x86-64 bugs.[ch]. Use identify_boot_cpu() AK: merged with other patch Signed-off-by:
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Jeremy Fitzhardinge authored
head.S creates the very initial pagetable for the kernel. This just maps enough space for the kernel itself, and an allocation bitmap. The amount of mapped memory is rounded up to 4Mbytes, and so this typically ends up mapping 8Mbytes of memory. When booting, pagetable_init() needs to create mappings for all lowmem, and the pagetables for these mappings are allocated from the free pages around the kernel in low memory. If the number of pagetable pages + kernel size exceeds head.S's initial mapping, it will end up faulting on an unmapped page. This will only happen with specific combinations of kernel size and memory size. This patch makes sure that head.S also maps enough space to fit the kernel pagetables as well as the kernel itself. It ends up using an additional two pages of unreclaimable memory. Signed-off-by:
"H. Peter Anvin" <hpa@zytor.com> Cc: Andi Kleen <ak@suse.de> Cc: Zachary Amsden <zach@vmware.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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Jeremy Fitzhardinge authored
Fixes two problems with the GDT when compiling for uniprocessor: - There's no percpu segment, so trying to load its selector into %fs fails. Use a null selector instead. - The real gdt needs to be loaded at some point. Do it in cpu_init(). Signed-off-by:
Chris Wright <chrisw@sous-sol.org> Signed-off-by:
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Jeremy Fitzhardinge authored
Define per_cpu_offset in asm-i386/percpu.h when SMP defined, like asm-generic/percpu.h does for UP. Signed-off-by:
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Jeremy Fitzhardinge authored
This patch does a few small cleanups: - use PER_CPU_NAME to generate the names of per-cpu variables - use lea to add the per_cpu offset in PER_CPU(), because it doesn't affect condition flags - add PER_CPU_VAR which allows direct access to pre-cpu variables with the %fs: prefix on SMP. Signed-off-by:
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Jeremy Fitzhardinge authored
Currently x86 (similar to x84-64) has a special per-cpu structure called "i386_pda" which can be easily and efficiently referenced via the %fs register. An ELF section is more flexible than a structure, allowing any piece of code to use this area. Indeed, such a section already exists: the per-cpu area. So this patch: (1) Removes the PDA and uses per-cpu variables for each current member. (2) Replaces the __KERNEL_PDA segment with __KERNEL_PERCPU. (3) Creates a per-cpu mirror of __per_cpu_offset called this_cpu_off, which can be used to calculate addresses for this CPU's variables. (4) Simplifies startup, because %fs doesn't need to be loaded with a special segment at early boot; it can be deferred until the first percpu area is allocated (or never for UP). The result is less code and one less x86-specific concept. Signed-off-by:Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
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Jeremy Fitzhardinge authored
Xen wants a dedicated page for the GDT. I believe VMI likes it too. lguest, KVM and native don't care. Simple transformation to page-aligned "struct gdt_page". Signed-off-by:
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Jeremy Fitzhardinge authored
inflate_dynamic() has piggy stack usage too, so heap allocate it too. I'm not sure it actually gets used, but it shows up large in "make checkstack". Signed-off-by:
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Jeremy Fitzhardinge authored
inflate_fixed and huft_build together use around 2.7k of stack. When using 4k stacks, I saw stack overflows from interrupts arriving while unpacking the root initrd: do_IRQ: stack overflow: 384 [<c0106b64>] show_trace_log_lvl+0x1a/0x30 [<c01075e6>] show_trace+0x12/0x14 [<c010763f>] dump_stack+0x16/0x18 [<c0107ca4>] do_IRQ+0x6d/0xd9 [<c010202b>] xen_evtchn_do_upcall+0x6e/0xa2 [<c0106781>] xen_hypervisor_callback+0x25/0x2c [<c010116c>] xen_restore_fl+0x27/0x29 [<c0330f63>] _spin_unlock_irqrestore+0x4a/0x50 [<c0117aab>] change_page_attr+0x577/0x584 [<c0117b45>] kernel_map_pages+0x8d/0xb4 [<c016a314>] cache_alloc_refill+0x53f/0x632 [<c016a6c2>] __kmalloc+0xc1/0x10d [<c0463d34>] malloc+0x10/0x12 [<c04641c1>] huft_build+0x2a7/0x5fa [<c04645a5>] inflate_fixed+0x91/0x136 [<c04657e2>] unpack_to_rootfs+0x5f2/0x8c1 [<c0465acf>] populate_rootfs+0x1e/0xe4 (This was under Xen, but there's no reason it couldn't happen on bare hardware.) This patch mallocs the local variables, thereby reducing the stack usage to sane levels. Also, up the heap size for the kernel decompressor to deal with the extra allocation. Signed-off-by:
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Jeremy Fitzhardinge authored
In shadow mode hypervisors, ptep_get_and_clear achieves the desired purpose of keeping the shadows in sync by issuing a native_get_and_clear, followed by a call to pte_update, which indicates the PTE has been modified. Direct mode hypervisors (Xen) have no need for this anyway, and will trap the update using writable pagetables. This means no hypervisor makes use of ptep_get_and_clear; there is no reason to have it in the paravirt-ops structure. Change confusing terminology about raw vs. native functions into consistent use of native_pte_xxx for operations which do not invoke paravirt-ops. Signed-off-by:
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Jeremy Fitzhardinge authored
Replace all the open-coded macros for generating calls with a pair of more general macros (__PVOP_CALL/VCALL), and redefine all the PVOP_V?CALL[0-4] in terms of them. [ Andrew, Andi: this should slot in immediately after "Document asm-i386/paravirt.h" (paravirt_ops-document-asm-i386-paravirth.patch) ] Signed-off-by:
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Jeremy Fitzhardinge authored
Remove #defines, add enum for PARAVIRT_LAZY_FLUSH. Signed-off-by:
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Jeremy Fitzhardinge authored
kunmap_atomic should flush any pending lazy mmu updates, mainly to be consistent with kmap_atomic, and to preserve its normal behaviour. Signed-off-by:
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Jeremy Fitzhardinge authored
Xen and VMI both have special requirements when mapping a highmem pte page into the kernel address space. These can be dealt with by adding a new kmap_atomic_pte() function for mapping highptes, and hooking it into the paravirt_ops infrastructure. Xen specifically wants to map the pte page RO, so this patch exposes a helper function, kmap_atomic_prot, which maps the page with the specified page protections. This also adds a kmap_flush_unused() function to clear out the cached kmap mappings. Xen needs this to clear out any potential stray RW mappings of pages which will become part of a pagetable. [ Zach - vmi.c will need some attention after this patch. It wasn't immediately obvious to me what needs to be done. ] Signed-off-by:
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Jeremy Fitzhardinge authored
Back out the map_pt_hook to clear the way for kmap_atomic_pte. Signed-off-by:
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Jeremy Fitzhardinge authored
This patch adds a pv_op for flush_tlb_others. Linux running on native hardware uses cross-CPU IPIs to flush the TLB on any CPU which may have a particular mm's pagetable entries cached in its TLB. This is inefficient in a paravirtualized environment, since the hypervisor knows which real CPUs actually contain cached mappings, which may be a small subset of a guest's VCPUs. Signed-off-by:
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Jeremy Fitzhardinge authored
Implement the actual patching machinery. paravirt_patch_default() contains the logic to automatically patch a callsite based on a few simple rules: - if the paravirt_op function is paravirt_nop, then patch nops - if the paravirt_op function is a jmp target, then jmp to it - if the paravirt_op function is callable and doesn't clobber too much for the callsite, call it directly paravirt_patch_default is suitable as a default implementation of paravirt_ops.patch, will remove most of the expensive indirect calls in favour of either a direct call or a pile of nops. Backends may implement their own patcher, however. There are several helper functions to help with this: paravirt_patch_nop nop out a callsite paravirt_patch_ignore leave the callsite as-is paravirt_patch_call patch a call if the caller and callee have compatible clobbers paravirt_patch_jmp patch in a jmp paravirt_patch_insns patch some literal instructions over the callsite, if they fit This patch also implements more direct patches for the native case, so that when running on native hardware many common operations are implemented inline. Signed-off-by:Ingo Molnar <mingo@elte.hu>
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Jeremy Fitzhardinge authored
Clean things up, and broadly document: - the paravirt_ops functions themselves - the patching mechanism Signed-off-by:
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Jeremy Fitzhardinge authored
Wrap a set of interesting paravirt_ops calls in a wrapper which makes the callsites available for patching. Unfortunately this is pretty ugly because there's no way to get gcc to generate a function call, but also wrap just the callsite itself with the necessary labels. This patch supports functions with 0-4 arguments, and either void or returning a value. 64-bit arguments must be split into a pair of 32-bit arguments (lower word first). Small structures are returned in registers. Signed-off-by:
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Jeremy Fitzhardinge authored
Fix a few clobbers to include the return register. The clobbers set is the set of all registers modified (or may be modified) by the code snippet, regardless of whether it was deliberate or accidental. Also, make sure that callsites which are used in contexts which don't allow clobbers actually save and restore all clobberable registers. Signed-off-by:
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Jeremy Fitzhardinge authored
Use patch type identifiers derived from the offset of the operation in the paravirt_ops structure. This avoids having to maintain a separate enum for patch site types. Also, since the identifier is derived from the offset into paravirt_ops, the offset can be derived from the identifier. This is used to remove replicated information in the various callsite macros, which has been a source of bugs in the past. This patch also drops the fused save_fl+cli operation, which doesn't really add much and makes things more complex - specifically because it breaks the 1:1 relationship between identifiers and offsets. If this operation turns out to be particularly beneficial, then the right answer is to define a new entrypoint for it. Signed-off-by:
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Jeremy Fitzhardinge authored
Rename struct paravirt_patch to paravirt_patch_site, so that it clearly refers to a callsite, and not the patch which may be applied to that callsite. Signed-off-by:
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