- 02 May, 2007 40 commits
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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:
Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by:
Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de>
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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:
Zachary Amsden <zach@vmware.com> 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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Jeremy Fitzhardinge authored
Add hooks to allow a paravirt implementation to track the lifetime of an mm. Paravirtualization requires three hooks, but only two are needed in common code. They are: arch_dup_mmap, which is called when a new mmap is created at fork arch_exit_mmap, which is called when the last process reference to an mm is dropped, which typically happens on exit and exec. The third hook is activate_mm, which is called from the arch-specific activate_mm() macro/function, and so doesn't need stub versions for other architectures. It's called when an mm is first used. Signed-off-by:
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Jeremy Fitzhardinge authored
Normally when running in PAE mode, the 4th PMD maps the kernel address space, which can be shared among all processes (since they all need the same kernel mappings). Xen, however, does not allow guests to have the kernel pmd shared between page tables, so parameterize pgtable.c to allow both modes of operation. There are several side-effects of this. One is that vmalloc will update the kernel address space mappings, and those updates need to be propagated into all processes if the kernel mappings are not intrinsically shared. In the non-PAE case, this is done by maintaining a pgd_list of all processes; this list is used when all process pagetables must be updated. pgd_list is threaded via otherwise unused entries in the page structure for the pgd, which means that the pgd must be page-sized for this to work. Normally the PAE pgd is only 4x64 byte entries large, but Xen requires the PAE pgd to page aligned anyway, so this patch forces the pgd to be page aligned+sized when the kernel pmd is unshared, to accomodate both these requirements. Also, since there may be several distinct kernel pmds (if the user/kernel split is below 3G), there's no point in allocating them from a slab cache; they're just allocated with get_free_page and initialized appropriately. (Of course the could be cached if there is just a single kernel pmd - which is the default with a 3G user/kernel split - but it doesn't seem worthwhile to add yet another case into this code). [ Many thanks to wli for review comments. ] Signed-off-by:
William Lee Irwin III <wli@holomorphy.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Jeremy Fitzhardinge authored
Allocate a fixmap slot for use by a paravirt_ops implementation. This is intended for early-boot bootstrap mappings. Once the zones and allocator have been set up, it would be better to use get_vm_area() to allocate some virtual space. Xen uses this to map the hypervisor's shared info page, which doesn't have a pseudo-physical page number, and therefore can't be mapped ordinarily. It is needed early because it contains the vcpu state, including the interrupt mask. Signed-off-by:
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Jeremy Fitzhardinge authored
This patch introduces paravirt_ops hooks to control how the kernel's initial pagetable is set up. In the case of a native boot, the very early bootstrap code creates a simple non-PAE pagetable to map the kernel and physical memory. When the VM subsystem is initialized, it creates a proper pagetable which respects the PAE mode, large pages, etc. When booting under a hypervisor, there are many possibilities for what paging environment the hypervisor establishes for the guest kernel, so the constructon of the kernel's pagetable depends on the hypervisor. In the case of Xen, the hypervisor boots the kernel with a fully constructed pagetable, which is already using PAE if necessary. Also, Xen requires particular care when constructing pagetables to make sure all pagetables are always mapped read-only. In order to make this easier, kernel's initial pagetable construction has been changed to only allocate and initialize a pagetable page if there's no page already present in the pagetable. This allows the Xen paravirt backend to make a copy of the hypervisor-provided pagetable, allowing the kernel to establish any more mappings it needs while keeping the existing ones. A slightly subtle point which is worth highlighting here is that Xen requires all kernel mappings to share the same pte_t pages between all pagetables, so that updating a kernel page's mapping in one pagetable is reflected in all other pagetables. This makes it possible to allocate a page and attach it to a pagetable without having to explicitly enumerate that page's mapping in all pagetables. And: +From: "Eric W. Biederman" <ebiederm@xmission.com> If we don't set the leaf page table entries it is quite possible that will inherit and incorrect page table entry from the initial boot page table setup in head.S. So we need to redo the effort here, so we pick up PSE, PGE and the like. Hypervisors like Xen require that their page tables be read-only, which is slightly incompatible with our low identity mappings, however I discussed this with Jeremy he has modified the Xen early set_pte function to avoid problems in this area. Signed-off-by:
Eric W. Biederman <ebiederm@xmission.com> Signed-off-by:
William Irwin <bill.irwin@oracle.com> Cc: Ingo Molnar <mingo@elte.hu>
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Jeremy Fitzhardinge authored
Add a set of accessors to pack, unpack and modify page table entries (at all levels). This allows a paravirt implementation to control the contents of pgd/pmd/pte entries. For example, Xen uses this to convert the (pseudo-)physical address into a machine address when populating a pagetable entry, and converting back to pphys address when an entry is read. Signed-off-by:
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Jeremy Fitzhardinge authored
Add a _paravirt_nop function for use as a stub for no-op operations, and paravirt_nop #defined void * version to make using it easier (since all its uses are as a void *). This is useful to allow the patcher to automatically identify noop operations so it can simply nop out the callsite. Signed-off-by:
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Jeremy Fitzhardinge authored
Remove CONFIG_DEBUG_PARAVIRT. When inlining code, this option attempts to trash registers in the patch-site's "clobber" field, on the grounds that this should find bugs with incorrect clobbers. Unfortunately, the clobber field really means "registers modified by this patch site", which includes return values. Because of this, this option has outlived its usefulness, so remove it. Signed-off-by:
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Jeremy Fitzhardinge authored
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Rusty Russell authored
On Thu, 2007-03-29 at 13:16 +0200, Andi Kleen wrote: > Please clean it up properly with two structs. Not sure about this, now I've done it. Running it here. If you like it, I can do x86-64 as well. == lguest defines its own TSS struct because the "struct tss_struct" contains linux-specific additions. Andi asked me to split the struct in processor.h. Unfortunately it makes usage a little awkward. Signed-off-by:
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James Puthukattukaran authored
I have a 4 socket AMD Operton system. The 2.6.18 kernel I have crashes when there is no memory in node0. AK: changed call to _nopanic Cc: Andi Kleen <ak@suse.de> Signed-off-by:
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Glauber de Oliveira Costa authored
Setting the DEBUG_SIG flag breaks compilation due to a wrong struct access. Aditionally, it raises two warnings. This is one patch to fix them all. Signed-off-by:
Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by:
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Jeremy Fitzhardinge authored
Add "noreplace-smp" to disable SMP instruction replacement. Signed-off-by:
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Jeremy Fitzhardinge authored
The .smp_altinstructions section and its corresponding symbols are completely unused, so remove them. Also, remove stray #ifdef __KENREL__ in asm-i386/alternative.h Signed-off-by:
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H. Peter Anvin authored
This patch is based on Rusty's recent cleanup of the EFLAGS-related macros; it extends the same kind of cleanup to control registers and MSRs. It also unifies these between i386 and x86-64; at least with regards to MSRs, the two had definitely gotten out of sync. Signed-off-by:
H. Peter Anvin <hpa@zytor.com> Signed-off-by:
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Jeremy Fitzhardinge authored
Let's allow page-alignment in general for per-cpu data (wanted by Xen, and Ingo suggested KVM as well). Because larger alignments can use more room, we increase the max per-cpu memory to 64k rather than 32k: it's getting a little tight. Signed-off-by:
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Andi Kleen authored
As a bug workaround bank 0 on K7s is normally disabled, but no need to do that on other AMD CPUs. Cc: davej@redhat.com Signed-off-by: -
Jeremy Fitzhardinge authored
Update documentation for i386 smp_call_function* functions. As reported by Randy Dunlap <rdunlap@xenotime.net> [ I've posted this before but it seems to have been lost along the way. ] Signed-off-by:
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Jan Engelhardt authored
(I hope Andi is the right one to Cc, otherwise please add, thanks!) Use menuconfigs instead of menus, so the whole menu can be disabled at once instead of going through all options. Signed-off-by:
Jan Engelhardt <jengelh@gmx.de> Signed-off-by:
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Andi Kleen authored
It doesn't put the CPU into deeper sleep states, so it's better to use the standard idle loop to save power. But allow to reenable it anyways for benchmarking. I also removed the obsolete idle=halt on i386 Cc: andreas.herrmann@amd.com Signed-off-by: -
Jeremy Fitzhardinge authored
Most of asm-x86_64/bugs.h is code which should be in a C file, so put it there. Signed-off-by:
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Jeremy Fitzhardinge authored
Now that relocation of the VDSO for COMPAT_VDSO users is done at runtime rather than compile time, it is possible to enable/disable compat mode at runtime. This patch allows you to enable COMPAT_VDSO mode with "vdso=2" on the kernel command line, or via sysctl. (Switching on a running system shouldn't be done lightly; any process which was relying on the compat VDSO will be upset if it goes away.) The COMPAT_VDSO config option still exists, but if enabled it just makes vdso_enabled default to VDSO_COMPAT. +From: Hugh Dickins <hugh@veritas.com> Fix oops from i386-make-compat_vdso-runtime-selectable.patch. Even mingetty at system startup finds it easy to trigger an oops while reading /proc/PID/maps: though it has a good hold on the mm itself, that cannot stop exit_mm() from resetting tsk->mm to NULL. (It is usually show_map()'s call to get_gate_vma() which oopses, and I expect we could change that to check priv->tail_vma instead; but no matter, even m_start()'s call just after get_task_mm() is racy.) Signed-off-by:
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Jeremy Fitzhardinge authored
Some versions of libc can't deal with a VDSO which doesn't have its ELF headers matching its mapped address. COMPAT_VDSO maps the VDSO at a specific system-wide fixed address. Previously this was all done at build time, on the grounds that the fixed VDSO address is always at the top of the address space. However, a hypervisor may reserve some of that address space, pushing the fixmap address down. This patch does the adjustment dynamically at runtime, depending on the runtime location of the VDSO fixmap. [ Patch has been through several hands: Jan Beulich wrote the orignal version; Zach reworked it, and Jeremy converted it to relocate phdrs as well as sections. ] Signed-off-by:
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Jeremy Fitzhardinge authored
identify_cpu() is used to identify both the boot CPU and secondary CPUs, but it performs some actions which only apply to the boot CPU. Those functions are therefore really __init functions, but because they're called by identify_cpu(), they must be marked __cpuinit. This patch splits identify_cpu() into identify_boot_cpu() and identify_secondary_cpu(), and calls the appropriate init functions from each. Also, identify_boot_cpu() and all the functions it dominates are marked __init. Signed-off-by:
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