Commit graph

23 commits

Author SHA1 Message Date
Ben Gras
565f13088f make vfs & filesystems use failable copying
Change the kernel to add features to vircopy and safecopies so that
transparent copy fixing won't happen to avoid deadlocks, and such copies
fail with EFAULT.

Transparently making copying work from filesystems (as normally done by
the kernel & VM when copying fails because of missing/readonly memory)
is problematic as it can happen that, for file-mapped ranges, that that
same filesystem that is blocked on the copy request is needed to satisfy
the memory range, leading to deadlock. Dito for VFS itself, if done with
a blocking call.

This change makes the copying done from a filesystem fail in such cases
with EFAULT by VFS adding the CPF_TRY flag to the grants. If a FS call
fails with EFAULT, VFS will then request the range to be made available
to VM after the FS is unblocked, allowing it to be used to satisfy the
range if need be in another VFS thread.

Similarly, for datacopies that VFS itself does, it uses the failable
vircopy variant and callers use a wrapper that talk to VM if necessary
to get the copy to work.

	. kernel: add CPF_TRY flag to safecopies
	. kernel: only request writable ranges to VM for the
	  target buffer when copying fails
	. do copying in VFS TRY-first
	. some fixes in VM to build SANITYCHECK mode
	. add regression test for the cases where
	  - a FS system call needs memory mapped in a process that the
	    FS itself must map.
	  - such a range covers more than one file-mapped region.
	. add 'try' mode to vircopy, physcopy
	. add flags field to copy kernel call messages
	. if CP_FLAG_TRY is set, do not transparently try
	  to fix memory ranges
	. for use by VFS when accessing user buffers to avoid
	  deadlock
	. remove some obsolete backwards compatability assignments
        . VFS: let thread scheduling work for VM requests too
          Allows VFS to make calls to VM while suspending and resuming
          the currently running thread. Does currently not work for the
          main thread.
        . VM: add fix memory range call for use by VFS

Change-Id: I295794269cea51a3163519a9cfe5901301d90b32
2014-07-28 17:05:14 +02:00
David van Moolenbroek
6b3f4dc157 Input infrastructure, INPUT server, PCKBD driver
This commit separates the low-level keyboard driver from TTY, putting
it in a separate driver (PCKBD). The commit also separates management
of raw input devices from TTY, and puts it in a separate server
(INPUT). All keyboard and mouse input from hardware is sent by drivers
to the INPUT server, which either sends it to a process that has
opened a raw input device, or otherwise forwards it to TTY for
standard processing.

Design by Dirk Vogt. Prototype by Uli Kastlunger.

Additional changes made to the prototype:

- the event communication is now based on USB HID codes; all input
  drivers have to use USB codes to describe events;
- all TTY keymaps have been converted to USB format, with the effect
  that a single keymap covers all keys; there is no (static) escaped
  keymap anymore;
- further keymap tweaks now allow remapping of literally all keys;
- input device renumbering and protocol rewrite;
- INPUT server rewrite, with added support for cancel and select;
- PCKBD reimplementation, including PC/AT-to-USB translation;
- support for manipulating keyboard LEDs has been added;
- keyboard and mouse multiplexer devices have been added to INPUT,
  primarily so that an X server need only open two devices;
- a new "libinputdriver" library abstracts away protocol details from
  input drivers, and should be used by all future input drivers;
- both INPUT and PCKBD can be restarted;
- TTY is now scheduled by KERNEL, so that it won't be punished for
  running a lot; without this, simply running "yes" on the console
  kills the system;
- the KIOCBELL IOCTL has been moved to /dev/console;
- support for the SCANCODES termios setting has been removed;
- obsolete keymap compression has been removed;
- the obsolete Olivetti M24 keymap has been removed.

Change-Id: I3a672fb8c4fd566734e4b46d3994b4b7fc96d578
2014-03-01 09:04:55 +01:00
David van Moolenbroek
78d707cd26 VM: support for shared call mask ACLs
The VM server now manages its call masks such that all user processes
share the same call mask. As a result, an update for the call mask of
any user process will apply to all user processes. This is similar to
the privilege infrastructure employed by the kernel, and may serve as
a template for similar fine-grained restrictions in other servers.

Concretely, this patch fixes the problem of "service edit init" not
applying the given VM call mask to user processes started from RC
scripts during system startup.

In addition, this patch makes RS set a proper VM call mask for each
recovery script it spawns.

Change-Id: I520a30d85a0d3f3502d2b158293a2258825358cf
2013-08-08 23:22:58 +02:00
Xiaoguang Sun
64f10ee644 Implement getrusage
Implement getrusage.
These fields of struct rusage are not supported and always set to zero at this time
long ru_nswap;           /* swaps */
long ru_inblock;         /* block input operations */
long ru_oublock;         /* block output operations */
long ru_msgsnd;          /* messages sent */
long ru_msgrcv;          /* messages received */
long ru_nvcsw;           /* voluntary context switches */
long ru_nivcsw;          /* involuntary context switches */

test75.c is the unit test for this new function

Change-Id: I3f1eb69de1fce90d087d76773b09021fc6106539
2013-07-01 23:00:47 +02:00
Ben Gras
49eb1f4806 vm: new secondary cache code
Primary purpose of change: to support the mmap implementation, VM must
know both (a) about some block metadata for FS cache blocks, i.e.
inode numbers and inode offsets where applicable; and (b) know about
*all* cache blocks, i.e.  also of the FS primary caches and not just
the blocks that spill into the secondary one. This changes the
interface and VM data structures.

This change is only for the interface (libminixfs) and VM data
structures; the filesystem code is unmodified, so although the
secondary cache will be used as normal, blocks will not be annotated
with inode information until the FS is modified to provide this
information. Until it is modified, mmap of files will fail gracefully
on such filesystems.

This is indicated to VFS/VM by returning ENOSYS for REQ_PEEK.

Change-Id: I1d2df6c485e6c5e89eb28d9055076cc02629594e
2013-04-24 10:18:16 +00:00
Ben Gras
adf2032bc0 vm: remove secondary cache code
This commit removes the secondary cache code implementation from
VM and its usage from libminixfs. It is to be replaced by a new
implementation.

Change-Id: I8fa3af06330e7604c7e0dd4cbe39d3ce353a05b1
2013-04-24 10:18:10 +00:00
Ben Gras
b1da7fafd0 vm: fix a null dereference on out-of-memory
. also make other out-of-memory conditions less fatal
	. add a test case for a user program using all the memory
	  it can
	. remove some diagnostic prints for situations that are normal
	  when running out of memory so running the test isn't noisy
2012-11-09 18:36:51 +01:00
Ben Gras
2cb560297c VM: remove unused dma memory support functions from vm
. unused calls / data structures
2012-09-18 13:17:47 +02:00
Ben Gras
50e2064049 No more intel/minix segments.
This commit removes all traces of Minix segments (the text/data/stack
memory map abstraction in the kernel) and significance of Intel segments
(hardware segments like CS, DS that add offsets to all addressing before
page table translation). This ultimately simplifies the memory layout
and addressing and makes the same layout possible on non-Intel
architectures.

There are only two types of addresses in the world now: virtual
and physical; even the kernel and processes have the same virtual
address space. Kernel and user processes can be distinguished at a
glance as processes won't use 0xF0000000 and above.

No static pre-allocated memory sizes exist any more.

Changes to booting:
        . The pre_init.c leaves the kernel and modules exactly as
          they were left by the bootloader in physical memory
        . The kernel starts running using physical addressing,
          loaded at a fixed location given in its linker script by the
          bootloader.  All code and data in this phase are linked to
          this fixed low location.
        . It makes a bootstrap pagetable to map itself to a
          fixed high location (also in linker script) and jumps to
          the high address. All code and data then use this high addressing.
        . All code/data symbols linked at the low addresses is prefixed by
          an objcopy step with __k_unpaged_*, so that that code cannot
          reference highly-linked symbols (which aren't valid yet) or vice
          versa (symbols that aren't valid any more).
        . The two addressing modes are separated in the linker script by
          collecting the unpaged_*.o objects and linking them with low
          addresses, and linking the rest high. Some objects are linked
          twice, once low and once high.
        . The bootstrap phase passes a lot of information (e.g. free memory
          list, physical location of the modules, etc.) using the kinfo
          struct.
        . After this bootstrap the low-linked part is freed.
        . The kernel maps in VM into the bootstrap page table so that VM can
          begin executing. Its first job is to make page tables for all other
          boot processes. So VM runs before RS, and RS gets a fully dynamic,
          VM-managed address space. VM gets its privilege info from RS as usual
          but that happens after RS starts running.
        . Both the kernel loading VM and VM organizing boot processes happen
	  using the libexec logic. This removes the last reason for VM to
	  still know much about exec() and vm/exec.c is gone.

Further Implementation:
        . All segments are based at 0 and have a 4 GB limit.
        . The kernel is mapped in at the top of the virtual address
          space so as not to constrain the user processes.
        . Processes do not use segments from the LDT at all; there are
          no segments in the LDT any more, so no LLDT is needed.
        . The Minix segments T/D/S are gone and so none of the
          user-space or in-kernel copy functions use them. The copy
          functions use a process endpoint of NONE to realize it's
          a physical address, virtual otherwise.
        . The umap call only makes sense to translate a virtual address
          to a physical address now.
        . Segments-related calls like newmap and alloc_segments are gone.
        . All segments-related translation in VM is gone (vir2map etc).
        . Initialization in VM is simpler as no moving around is necessary.
        . VM and all other boot processes can be linked wherever they wish
          and will be mapped in at the right location by the kernel and VM
          respectively.

Other changes:
        . The multiboot code is less special: it does not use mb_print
          for its diagnostics any more but uses printf() as normal, saving
          the output into the diagnostics buffer, only printing to the
          screen using the direct print functions if a panic() occurs.
        . The multiboot code uses the flexible 'free memory map list'
          style to receive the list of free memory if available.
        . The kernel determines the memory layout of the processes to
          a degree: it tells VM where the kernel starts and ends and
          where the kernel wants the top of the process to be. VM then
          uses this entire range, i.e. the stack is right at the top,
          and mmap()ped bits of memory are placed below that downwards,
          and the break grows upwards.

Other Consequences:
        . Every process gets its own page table as address spaces
          can't be separated any more by segments.
        . As all segments are 0-based, there is no distinction between
          virtual and linear addresses, nor between userspace and
          kernel addresses.
        . Less work is done when context switching, leading to a net
          performance increase. (8% faster on my machine for 'make servers'.)
	. The layout and configuration of the GDT makes sysenter and syscall
	  possible.
2012-07-15 22:30:15 +02:00
Ben Gras
040362e379 exec() cleanup, generalization, improvement
. make exec() callers (i.e. vfs and rs) determine the
	  memory layout by explicitly reserving regions using
	  mmap() calls on behalf of the exec()ing process,
	  i.e. handling all of the exec logic, thereby eliminating
	  all special exec() knowledge from VM.
	. the new procedure is: clear the exec()ing process
	  first, then call third-party mmap()s to reserve memory, then
	  copy the executable file section contents in, all using callbacks
	  tailored to the caller's way of starting an executable
	. i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM
	  as with rigid 2-section arguments
	. this naturally allows generalizing exec() by simply loading
	  all ELF sections
	. drop/merge of lots of duplicate exec() code into libexec
	. not copying the code sections to vfs and into the executable
	  again is a measurable performance improvement (about 3.3% faster
	  for 'make' in src/servers/)
2012-06-07 15:15:01 +02:00
Ben Gras
ee4016155e vm: add third-party mmap() mode and PROCCTL
these two functions will be used to support all exec() functionality
going into a single library shared by RS and VFS and exec() knowledge
leaving VM.

	. third-party mmap: allow certain processes (VFS, RS) to
	  do mmap() on behalf of another process
	. PROCCTL: used to free and clear a process' address space
2012-06-07 12:43:16 +02:00
Ben Gras
7336a67dfe retire PUBLIC, PRIVATE and FORWARD 2012-03-25 21:58:14 +02:00
Ben Gras
ddde360e3e vm - hash table for block cache 2010-10-15 09:10:14 +00:00
Ben Gras
a3f2df124c vm optimisation - maintain hint for new virtual region position. 2010-10-07 10:04:05 +00:00
Ben Gras
e2570d9b1b vm: optimisation: avl tree for virtual regions
- regions were preivous stored in a linked list, as 'normally'
    there are just 2 or 3 (text, data, stack), but that's slow
    if lots of regions are made with mmap()

  - measurable performance improvement with gcc and clang
2010-10-04 11:41:10 +00:00
Cristiano Giuffrida
06700d05d1 Give RS a page table. 2010-06-28 21:53:37 +00:00
Arun Thomas
b641afc78a VM: Remove legacy non-paging code paths 2010-06-05 14:39:40 +00:00
Ben Gras
f78d8e74fd secondary cache feature in vm.
A new call to vm lets processes yield a part of their memory to vm,
together with an id, getting newly allocated memory in return. vm is
allowed to forget about it if it runs out of memory. processes can ask
for it back using the same id. (These two operations are normally
combined in a single call.)

It can be used as a as-big-as-memory-will-allow block cache for
filesystems, which is how mfs now uses it.
2010-05-05 11:35:04 +00:00
Ben Gras
c78250332d let vm use physically fragmented memory for allocations.
map_copy_ph_block is replaced by map_clone_ph_block, which can
replace a single physical block by multiple physical blocks.

also,
 . merge map_mem.c with region.c, as they manipulate the same
   data structures
 . NOTRUNNABLE removed as sanity check
 . use direct functions for ALLOC_MEM and FREE_MEM again
 . add some checks to shared memory mapping code
 . fix for data structure integrity when using shared memory
 . fix sanity checks
2010-04-12 11:25:24 +00:00
Cristiano Giuffrida
cb176df60f New RS and new signal handling for system processes.
UPDATING INFO:
20100317:
        /usr/src/etc/system.conf updated to ignore default kernel calls: copy
        it (or merge it) to /etc/system.conf.
        The hello driver (/dev/hello) added to the distribution:
        # cd /usr/src/commands/scripts && make clean install
        # cd /dev && MAKEDEV hello

KERNEL CHANGES:
- Generic signal handling support. The kernel no longer assumes PM as a signal
manager for every process. The signal manager of a given process can now be
specified in its privilege slot. When a signal has to be delivered, the kernel
performs the lookup and forwards the signal to the appropriate signal manager.
PM is the default signal manager for user processes, RS is the default signal
manager for system processes. To enable ptrace()ing for system processes, it
is sufficient to change the default signal manager to PM. This will temporarily
disable crash recovery, though.
- sys_exit() is now split into sys_exit() (i.e. exit() for system processes,
which generates a self-termination signal), and sys_clear() (i.e. used by PM
to ask the kernel to clear a process slot when a process exits).
- Added a new kernel call (i.e. sys_update()) to swap two process slots and
implement live update.

PM CHANGES:
- Posix signal handling is no longer allowed for system processes. System
signals are split into two fixed categories: termination and non-termination
signals. When a non-termination signaled is processed, PM transforms the signal
into an IPC message and delivers the message to the system process. When a
termination signal is processed, PM terminates the process.
- PM no longer assumes itself as the signal manager for system processes. It now
makes sure that every system signal goes through the kernel before being
actually processes. The kernel will then dispatch the signal to the appropriate
signal manager which may or may not be PM.

SYSLIB CHANGES:
- Simplified SEF init and LU callbacks.
- Added additional predefined SEF callbacks to debug crash recovery and
live update.
- Fixed a temporary ack in the SEF init protocol. SEF init reply is now
completely synchronous.
- Added SEF signal event type to provide a uniform interface for system
processes to deal with signals. A sef_cb_signal_handler() callback is
available for system processes to handle every received signal. A
sef_cb_signal_manager() callback is used by signal managers to process
system signals on behalf of the kernel.
- Fixed a few bugs with memory mapping and DS.

VM CHANGES:
- Page faults and memory requests coming from the kernel are now implemented
using signals.
- Added a new VM call to swap two process slots and implement live update.
- The call is used by RS at update time and in turn invokes the kernel call
sys_update().

RS CHANGES:
- RS has been reworked with a better functional decomposition.
- Better kernel call masks. com.h now defines the set of very basic kernel calls
every system service is allowed to use. This makes system.conf simpler and
easier to maintain. In addition, this guarantees a higher level of isolation
for system libraries that use one or more kernel calls internally (e.g. printf).
- RS is the default signal manager for system processes. By default, RS
intercepts every signal delivered to every system process. This makes crash
recovery possible before bringing PM and friends in the loop.
- RS now supports fast rollback when something goes wrong while initializing
the new version during a live update.
- Live update is now implemented by keeping the two versions side-by-side and
swapping the process slots when the old version is ready to update.
- Crash recovery is now implemented by keeping the two versions side-by-side
and cleaning up the old version only when the recovery process is complete.

DS CHANGES:
- Fixed a bug when the process doing ds_publish() or ds_delete() is not known
by DS.
- Fixed the completely broken support for strings. String publishing is now
implemented in the system library and simply wraps publishing of memory ranges.
Ideally, we should adopt a similar approach for other data types as well.
- Test suite fixed.

DRIVER CHANGES:
- The hello driver has been added to the Minix distribution to demonstrate basic
live update and crash recovery functionalities.
- Other drivers have been adapted to conform the new SEF interface.
2010-03-17 01:15:29 +00:00
Ben Gras
32fbbd370c - pages that points to page directory values of all processes,
shared with the kernel, mapped into kernel address space; 
   kernel is notified of its location. kernel segment size is
   increased to make it fit.
 - map in kernel and other processes that don't have their
   own page table using single 4MB (global) mapping.
 - new sanity check facility: objects that are allocated with
   the slab allocator are, when running with sanity checking on,
   marked readonly until they are explicitly unlocked using the USE()
   macro.
 - another sanity check facility: collect all uses of memory and
   see if they don't overlap with (a) eachother and (b) free memory
 - own munmap() and munmap_text() functions.
 - exec() recovers from out-of-memory conditions properly now; this
   solves some weird exec() behaviour
 - chew off memory from the same side of the chunk as where we
   start scanning, solving some memory fragmentation issues
 - use avl trees for freelist and phys_ranges in regions
 - implement most useful part of munmap()
 - remap() stuff is GQ's for shared memory
2009-09-21 14:49:49 +00:00
Ben Gras
2dd02cc560 mark pages whose refcount were >1 and drop to 1 and are
read/write writable in the pagetable right away instead of waiting for
a pagefault. minor optimization.

some a sanity check of SLAB-allocated pointers.

vm gets its own _exit and __exit like PM, so the stock (library) panic works.
2009-04-22 12:39:29 +00:00
Ben Gras
c078ec0331 Basic VM and other minor improvements.
Not complete, probably not fully debugged or optimized.
2008-11-19 12:26:10 +00:00