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57 Commits

Author SHA1 Message Date
chs 43973be0c5 introduce a new UVM fault type, VM_FAULT_WIREMAX. this is different
from VM_FAULT_WIRE in that when the pages being wired are faulted in,
the simulated fault is at the maximum protection allowed for the mapping
instead of the current protection.  use this in uvm_map_pageable{,_all}()
to fix the problem where writing via ptrace() to shared libraries that
are also mapped with wired mappings in another process causes a
diagnostic panic when the wired mapping is removed.

this is a really obscure problem so it deserves some more explanation.
ptrace() writing to another process ends up down in uvm_map_extract(),
which for MAP_PRIVATE mappings (such as shared libraries) will cause
the amap to be copied or created.  then the amap is made shared
(ie. the AMAP_SHARED flag is set) between the kernel and the ptrace()d
process so that the kernel can modify pages in the amap and have the
ptrace()d process see the changes.  then when the page being modified
is actually faulted on, the object pages (from the shared library vnode)
is copied to a new anon page and inserted into the shared amap.
to make all the processes sharing the amap actually see the new anon
page instead of the vnode page that was there before, we need to
invalidate all the pmap-level mappings of the vnode page in the pmaps
of the processes sharing the amap, but we don't have a good way of
doing this.  the amap doesn't keep track of the vm_maps which map it.
so all we can do at this point is to remove all the mappings of the
page with pmap_page_protect(), but this has the unfortunate side-effect
of removing wired mappings as well.  removing wired mappings with
pmap_page_protect() is a legitimate operation, it can happen when a file
with a wired mapping is truncated.  so the pmap has no way of knowing
whether a request to remove a wired mapping is normal or when it's due to
this weird situation.  so the pmap has to remove the weird mapping.
the process being ptrace()d goes away and life continues.  then,
much later when we go to unwire or remove the wired vm_map mapping,
we discover that the pmap mapping has been removed when it should
still be there, and we panic.

so where did we go wrong?  the problem is that we don't have any way
to update just the pmap mappings that need to be updated in this
scenario.  we could invent a mechanism to do this, but that is much
more complicated than this change and it doesn't seem like the right
way to go in the long run either.

the real underlying problem here is that wired pmap mappings just
aren't a good concept.  one of the original properties of the pmap
design was supposed to be that all the information in the pmap could
be thrown away at any time and the VM system could regenerate it all
through fault processing, but wired pmap mappings don't allow that.
a better design for UVM would not require wired pmap mappings,
and Chuck C. and I are talking about this, but it won't be done
anytime soon, so this change will do for now.

this change has the effect of causing MAP_PRIVATE mappings to be
copied to anonymous memory when they are mlock()d, so that uvm_fault()
doesn't need to copy these pages later when called from ptrace(), thus
avoiding the call to pmap_page_protect() and the panic that results
from this when the mlock()d region is unlocked or freed.  note that
this change doesn't help the case where the wired mapping is MAP_SHARED.

discussed at great length with Chuck Cranor.
fixes PRs 10363, 12554, 12604, 13041, 13487, 14580 and 14853.
2001-12-31 22:34:39 +00:00
thorpej 06920aef28 Move the code that walks the process's VM map during a coredump
into uvm_coredump_walkmap(), and use callbacks into the coredump
routine to do something with each section.
2001-12-10 01:52:26 +00:00
lukem b616d1ca1d add RCSIDs, and in some cases, slightly cleanup #include order 2001-11-10 07:36:59 +00:00
chs d8cbdbb0da in uvm_exit(), don't bother to unwire the uarea before we free it,
the pages will be freed anyway.
2001-11-06 05:34:42 +00:00
chs a467bddfdc bump the rusage counter for "swaps" when we swap out a process.
addresses PR 6170.
2001-09-23 07:10:08 +00:00
chs 64c6d1d2dc a whole bunch of changes to improve performance and robustness under load:
- remove special treatment of pager_map mappings in pmaps.  this is
   required now, since I've removed the globals that expose the address range.
   pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
   no longer any need to special-case it.
 - eliminate struct uvm_vnode by moving its fields into struct vnode.
 - rewrite the pageout path.  the pager is now responsible for handling the
   high-level requests instead of only getting control after a bunch of work
   has already been done on its behalf.  this will allow us to UBCify LFS,
   which needs tighter control over its pages than other filesystems do.
   writing a page to disk no longer requires making it read-only, which
   allows us to write wired pages without causing all kinds of havoc.
 - use a new PG_PAGEOUT flag to indicate that a page should be freed
   on behalf of the pagedaemon when it's unlocked.  this flag is very similar
   to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
   pageout fails due to eg. an indirect-block buffer being locked.
   this allows us to remove the "version" field from struct vm_page,
   and together with shrinking "loan_count" from 32 bits to 16,
   struct vm_page is now 4 bytes smaller.
 - no longer use PG_RELEASED for swap-backed pages.  if the page is busy
   because it's being paged out, we can't release the swap slot to be
   reallocated until that write is complete, but unlike with vnodes we
   don't keep a count of in-progress writes so there's no good way to
   know when the write is done.  instead, when we need to free a busy
   swap-backed page, just sleep until we can get it busy ourselves.
 - implement a fast-path for extending writes which allows us to avoid
   zeroing new pages.  this substantially reduces cpu usage.
 - encapsulate the data used by the genfs code in a struct genfs_node,
   which must be the first element of the filesystem-specific vnode data
   for filesystems which use genfs_{get,put}pages().
 - eliminate many of the UVM pagerops, since they aren't needed anymore
   now that the pager "put" operation is a higher-level operation.
 - enhance the genfs code to allow NFS to use the genfs_{get,put}pages
   instead of a modified copy.
 - clean up struct vnode by removing all the fields that used to be used by
   the vfs_cluster.c code (which we don't use anymore with UBC).
 - remove kmem_object and mb_object since they were useless.
   instead of allocating pages to these objects, we now just allocate
   pages with no object.  such pages are mapped in the kernel until they
   are freed, so we can use the mapping to find the page to free it.
   this allows us to remove splvm() protection in several places.

The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.
2001-09-15 20:36:31 +00:00
chris 0e7661f023 Update pmap_update to now take the updated pmap as an argument.
This will allow improvements to the pmaps so that they can more easily defer expensive operations, eg tlb/cache flush, til the last possible moment.

Currently this is a no-op on most platforms, so they should see no difference.

Reviewed by Jason.
2001-09-10 21:19:08 +00:00
chs 821ec03ed9 replace vm_map{,_entry}_t with struct vm_map{,_entry} *. 2001-06-02 18:09:08 +00:00
lukem d84d2c6c85 add missing #include "opt_kgdb.h" 2001-05-30 15:24:23 +00:00
chs 3845302904 remove trailing whitespace. 2001-05-25 04:06:11 +00:00
thorpej 1c3a62e066 Sprinkle pmap_update() calls after calls to:
- pmap_enter()
- pmap_remove()
- pmap_protect()
- pmap_kenter_pa()
- pmap_kremove()
as described in pmap(9).

These calls are relatively conservative.  It may be possible to
optimize these a little more.
2001-04-24 04:30:50 +00:00
thorpej 0115ec662c The pmap_update() call at the end of uvm_swapout_threads() is
completely useless.  Nuke it.
2001-04-21 17:38:24 +00:00
chs ac3bc537bd eliminate the KERN_* error codes in favor of the traditional E* codes.
the mapping is:

KERN_SUCCESS			0
KERN_INVALID_ADDRESS		EFAULT
KERN_PROTECTION_FAILURE		EACCES
KERN_NO_SPACE			ENOMEM
KERN_INVALID_ARGUMENT		EINVAL
KERN_FAILURE			various, mostly turn into KASSERTs
KERN_RESOURCE_SHORTAGE		ENOMEM
KERN_NOT_RECEIVER		<unused>
KERN_NO_ACCESS			<unused>
KERN_PAGES_LOCKED		<unused>
2001-03-15 06:10:32 +00:00
eeh ec22628573 Move maxdmap and maxsmap where they belong and make them big enough. 2001-02-06 19:54:43 +00:00
chs 2ed28d2c7a lots of cleanup:
use queue.h macros and KASSERT().
address amap offsets in pages instead of bytes.
make amap_ref() and amap_unref() take an amap, offset and length
  instead of a vm_map_entry_t.
improve whitespace and comments.
2000-11-25 06:27:59 +00:00
thorpej 76589fafd4 - uvmspace_share(): If p2 has a vmspace already, make sure to deactivate
it and free it as appropriate.  Activate p2's new address space once
  it references p1's.
- uvm_fork(): Make sure the child's vmspace is NULL before calling
  uvmspace_share() (the child doens't have one already in this case).

These changes do not change the behavior for the current use of
uvmspace_share() (vfork(2)), but make it possible for an already
running process (such as a kernel thread) to properly attach to
another process's address space.
2000-10-11 17:27:58 +00:00
enami 9308eaef21 splstatclock is insufficient to protect run queues. Acquire scheduler
lock instead.
2000-09-23 00:43:10 +00:00
thorpej 9bd3060650 Remove a totally unnecessary splhigh/spl0 pair. 2000-08-21 02:29:32 +00:00
sommerfeld a7449460ec add comment warning about possible unlock/sleep race 2000-08-12 17:46:25 +00:00
mrg dea44a9ec4 remove include of <vm/vm.h> 2000-06-27 17:29:17 +00:00
mrg 2f159a1bac remove/move more mach vm header files:
<vm/pglist.h> -> <uvm/uvm_pglist.h>
	<vm/vm_inherit.h> -> <uvm/uvm_inherit.h>
	<vm/vm_kern.h> -> into <uvm/uvm_extern.h>
	<vm/vm_object.h> -> nothing
	<vm/vm_pager.h> -> into <uvm/uvm_pager.h>

also includes a bunch of <vm/vm_page.h> include removals (due to redudancy
with <vm/vm.h>), and a scattering of other similar headers.
2000-06-26 14:20:25 +00:00
simonb 58d0ed9dd2 Set p->p_addr to NULL after it gets freed. 2000-06-18 05:20:27 +00:00
thorpej b0afc900f5 Change UVM_UNLOCK_AND_WAIT() to use ltsleep() (it is now atomic, as
advertised).  Garbage-collect uvm_sleep().
2000-06-08 05:52:34 +00:00
thorpej e03e9e8086 Rather than starting init and creating kthreads by forking and then
doing a cpu_set_kpc(), just pass the entry point and argument all
the way down the fork path starting with fork1().  In order to
avoid special-casing the normal fork in every cpu_fork(), MI code
passes down child_return() and the child process pointer explicitly.

This fixes a race condition on multiprocessor systems; a CPU could
grab the newly created processes (which has been placed on a run queue)
before cpu_set_kpc() would be performed.
2000-05-28 05:48:59 +00:00
thorpej 8964c35eca Introduce a new process state distinct from SRUN called SONPROC
which indicates that the process is actually running on a
processor.  Test against SONPROC as appropriate rather than
combinations of SRUN and curproc.  Update all context switch code
to properly set SONPROC when the process becomes the current
process on the CPU.
2000-05-26 00:36:42 +00:00
augustss 641df97d12 Remove more register declarations. 2000-03-30 12:31:50 +00:00
kleink 6e5b64c8a0 Merge parts of chs-ubc2 into the trunk:
Add a new type voff_t (defined as a synonym for off_t) to describe offsets
into uvm objects, and update the appropriate interfaces to use it, the
most visible effect being the ability to mmap() file offsets beyond
the range of a vaddr_t.

Originally by Chuck Silvers; blame me for problems caused by merging this
into non-UBC.
2000-03-26 20:54:45 +00:00
thorpej 1da427a80a Change the pmap_enter() API slightly; pmap_enter() now returns an error
value (KERN_SUCCESS or KERN_RESOURCE_SHORTAGE) indicating if it succeeded
or failed.  Change the `wired' and `access_type' arguments to a single
`flags' argument, which includes the access type, and flags:

	PMAP_WIRED	the old `wired' boolean
	PMAP_CANFAIL	pmap_enter() is allowed to fail

If PMAP_CANFAIL is not specified, the pmap should behave as it always
has in the face of a drastic resource shortage: fall over dead.

Change the fault handler to deal with failure (which indicates resource
shortage) by unlocking everything, waiting for the pagedaemon to free
more memory, then retrying the fault.
1999-11-13 00:24:38 +00:00
thorpej ea8fb3e04a Turn the proclist lock into a read/write spinlock. Update proclist locking
calls to reflect this.  Also, block statclock rather than softclock during
in the proclist locking functions, to address a problem reported on
current-users by Sean Doran.
1999-07-25 06:30:33 +00:00
thorpej 3f176180d5 Garbage collect thread_sleep()/thread_wakeup() left over from the old
Mach VM code.  Also nuke iprintf(), which was no longer used anywhere.

Add proclist locking where appropriate.
1999-07-22 22:58:38 +00:00
thorpej 3ebbe095e0 Change the pmap_extract() interface to:
boolean_t pmap_extract(pmap_t, vaddr_t, paddr_t *);
This makes it possible for the pmap to map physical address 0.
1999-07-08 18:05:21 +00:00
thorpej 12347b2657 Make uvm_vslock() return the error code from uvm_fault_wire(). All places
which use uvm_vslock() should now test the return value.  If it's not
KERN_SUCCESS, wiring the pages failed, so the operation which is using
uvm_vslock() should error out.

XXX We currently just EFAULT a failed uvm_vslock().  We may want to do
more about translating error codes in the future.
1999-06-17 15:47:22 +00:00
thorpej 1f97ad987f In uvm_useracc(), make sure we have a read lock on the map before
calling uvm_map_checkprot().
1999-06-17 05:57:33 +00:00
thorpej f274deb90a The i386 and pc532 pmaps are officially fixed. 1999-06-17 00:24:10 +00:00
thorpej 8d8badbd8f Make uvm_fault_unwire() take a vm_map_t, rather than a pmap_t, for
consistency.  Use this opportunity for checking for intrsafe map use
in this routine (which is illegal).
1999-05-28 20:49:51 +00:00
thorpej b2e9c635ec Pass an access_type to uvm_vslock(). 1999-05-26 01:05:24 +00:00
thorpej 9d0ea0969e - uvm_fork()/uvm_swapin(): pass VM_PROT_READ|VM_PROT_WRITE access_type
to uvm_fault_wire(), to guarantee that the kernel stacks will not
  cause even a mod/ref emulation fault.
- uvm_vslock(): pass VM_PROT_NONE until this function is updated.
1999-05-26 00:33:52 +00:00
thorpej c10a926030 Allow the caller to specify a stack for the child process. If NULL,
the child inherits the stack pointer from the parent (traditional
behavior).  Like the signal stack, the stack area is secified as
a low address and a size; machine-dependent code accounts for stack
direction.

This is required for clone(2).
1999-05-13 21:58:32 +00:00
thorpej 2835fc6e46 Pull signal actions out of struct user, make them a separate proc
substructure, and allow them to be shared.

Required for clone(2).
1999-04-30 21:23:49 +00:00
mycroft 31a2536cd0 Add a new `access type' argument to pmap_enter(). This indicates what type of
memory access a mapping was caused by.  This is passed through from uvm_fault()
and udv_fault(), and in most other cases is 0.
The pmap module may use this to preset R/M information.  On MMUs which require
R/M emulation, the implementation may preset the bits and avoid taking another
fault.  On MMUs which keep R/M information in hardware, the implementation may
preset its cached bits to speed up the next call to pmap_is_modified() or
pmap_is_referenced().
1999-03-26 21:58:39 +00:00
mrg a0139bc39d remove now >1 year old pre-release message. 1999-03-25 18:48:49 +00:00
chs e2d0bfbb09 remove a debugging printf. 1999-03-15 07:55:19 +00:00
tron c71ccab136 Defopt SYSVMSG, SYSVSEM and SYSVSHM. 1998-10-19 22:21:19 +00:00
thorpej 28904fca48 Implement uvm_exit(), which frees VM resources when a process finishes
exiting.
1998-09-08 23:44:21 +00:00
eeh a2dd74ed79 Merge paddr_t changes into the main branch. 1998-08-13 02:10:37 +00:00
perry 2c8717021d bzero->memset, bcopy->memcpy, bcmp->memcmp 1998-08-09 22:36:37 +00:00
kleink afeaa5bb57 Use size_t to pass the length of the memory region to operate on to chgkprot(),
kernacc(), useracc(), vslock() and vsunlock(); (unsigned) ints are not
adequate on all platforms.
1998-05-09 15:04:39 +00:00
kleink d9066c40e9 Make uvm_vsunlock() actually use the proc * passed to it; per discussion
with Jason Thorpe.
1998-05-08 17:41:41 +00:00
thorpej 73863dd3c9 Pass vslock() and vsunlock() a proc *, rather than implicitly operating
on curproc.
1998-04-30 06:28:57 +00:00
thorpej fe97b1da8e Oops, fix a typo. 1998-04-09 00:24:05 +00:00