Commit graph

61 commits

Author SHA1 Message Date
Ben Gras
3771a0833d vm: merge i386 and arm pagetable code 2012-11-09 18:46:03 +01:00
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
196021cd82 drop safemap code 2012-10-30 13:55:42 +01:00
Ben Gras
aefc6db005 vm: fix potential null deref 2012-10-24 19:47:47 +02:00
Ben Gras
d343041caa VM: make mapping types explicit
Introduce explicit abstractions for different mapping types,
handling the instantiation, forking, pagefaults and freeing of
anonymous memory, direct physical mappings, shared memory and
physically contiguous anonymous memory as separate types, making
region.c more generic.

Also some other genericification like merging the 3 munmap cases
into one.

COW and SMAP safemap code is still implicit in region.c.
2012-10-12 14:52:01 +02:00
Ben Gras
fe6e291f59 vm, kernel, top: report memory usage of vm, kernel 2012-09-18 23:43:52 +02:00
Ben Gras
d526f1a0db some coverity fixes. 2012-09-18 15:11:51 +02:00
Ben Gras
ddf1981004 VM: restore >4k secondary cache functionality
. by storing length in the yielded blocks node again
2012-09-18 13:17:52 +02:00
Ben Gras
ed1af3c86c VM: full munmap
complete munmap implementation; single-page references made
a general munmap() implementation possible to write cleanly.

	. memory: let the MIOCRAMSIZE ioctl set the imgrd device
	  size (but only to 0)
	. let the ramdisk command set sizes to 0
	. use this command to set /dev/imgrd to 0 after mounting /usr
	  in /etc/rc, so the boot time ramdisk is freed (about 4MB
	  currently)
2012-09-18 13:17:52 +02:00
Ben Gras
16c3870b2e VM: abstract datastructures a bit
. a little less duplication in region.c
2012-09-18 13:17:51 +02:00
Ben Gras
19e6dad47b VM: only single page chunks
. only reference single pages in process data structures
   to simplify page faults, copy-on-write, etc.
 . this breaks the secondary cache for objects that are
   not one-page-sized; restored in a next commit
2012-09-18 13:17:49 +02:00
Ben Gras
6410f4b5db VM: some sanitycheck fixes
minor fixes to restore SANITYCHECKS
2012-09-18 13:17:45 +02:00
Arun Thomas
7ca1ce7968 VM: Add PTF_READ page table flag 2012-08-17 00:17:52 +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
769af57274 further libexec generalization
. new mode for sys_memset: include process so memset can be
	  done in physical or virtual address space.
	. add a mode to mmap() that lets a process allocate uninitialized
	  memory.
	. this allows an exec()er (RS, VFS, etc.) to request uninitialized
	  memory from VM and selectively clear the ranges that don't come
	  from a file, leaving no uninitialized memory left for the process
	  to see.
	. use callbacks for clearing the process, clearing memory in the
	  process, and copying into the process; so that the libexec code
	  can be used from rs, vfs, and in the future, kernel (to load vm)
	  and vm (to load boot-time processes)
2012-06-07 15:15:02 +02:00
Ben Gras
660e15b2d1 vm: break: allow brk() on any region
use the user-supplied point to lookup which region to perform brk() on,
and if it's a reasonable one, do it, no matter what vm's notion of the
heap region is.
2012-04-12 02:57:59 +02:00
Ben Gras
7336a67dfe retire PUBLIC, PRIVATE and FORWARD 2012-03-25 21:58:14 +02:00
Ben Gras
6a73e85ad1 retire _PROTOTYPE
. only good for obsolete K&R support
	. also remove a stray ansi.h and the proto cmd
2012-03-25 16:17:10 +02:00
Ben Gras
4668b84158 vm_remap_ro
- allows shared memory to be mapped in readonly

- ben@minix3.org & tom@minix3.org
2012-01-13 11:30:01 +00:00
Ben Gras
ef99a7a3dc vm: report cropped region sizes
. when reporting on regions, only report part of the
	  region (addr and length) that really has memory mapped
	  into it
	. to minimise core files
2011-11-26 15:12:17 +00:00
Ben Gras
85f6d866e6 rename mmap MAP_SHARED to MAP_IPC_SHARED
. MAP_SHARED was used to implement sysv shared memory
	. used to signal shareable memory region to VM
	. assumptions about this situation break when processes
	  use MAP_SHARED for its normal, standardised meaning
2011-07-15 18:10:50 +02:00
Erik van der Kouwe
0cb22acbda Fix VM -Wall warnings and enable -Werror 2011-06-01 11:30:58 +02:00
Ben Gras
5f1ab506c8 remove some debugging output from vm/region.c
- don't print verbose process map when legitimate errors occur
2011-03-16 11:57:35 +00:00
Ben Gras
ddde360e3e vm - hash table for block cache 2010-10-15 09:10:14 +00:00
Ben Gras
cb2e3a98a2 vm - fix for not placing region outside requested mmap addr 2010-10-15 09:09:29 +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
Tomas Hruby
6513d20744 SMP - Process is stopped when VM modifies the page tables
- RTS_VMINHIBIT flag is used to stop process while VM is fiddling with
  its pagetables

- more generic way of sending synchronous scheduling events among cpus

- do the x-cpu smp sched calls only if the target process is runnable.
  If it is not, it cannot be running and it cannot become runnable
  this CPU holds the BKL
2010-09-15 14:11:12 +00:00
David van Moolenbroek
3eb65448a6 VM: expose secondary cache size 2010-09-14 21:22:56 +00:00
Arun Thomas
de231a713e Move MIN() and MAX() macros to sys/params.h 2010-08-21 13:10:41 +00:00
Cristiano Giuffrida
40b4e71db2 COW for physically contiguous blocks in VM 2010-07-20 18:57:25 +00:00
Cristiano Giuffrida
1b7d95df29 Generalize interface of some VM functions 2010-07-20 02:08:28 +00:00
Ben Gras
b4bea1bfcb vm: fixes for clang warnings 2010-07-05 13:58:57 +00:00
Cristiano Giuffrida
9e4312453d Improve memory pinning. 2010-07-01 08:54:25 +00:00
Cristiano Giuffrida
06700d05d1 Give RS a page table. 2010-06-28 21:53:37 +00:00
Tomas Hruby
8214e5e284 Removed racy COW optimization
- enabling writing in COW once phys block is reference only once is racy if VM
  is preemptible. original memory location may get overwritten before COW copies
  the memory

- problem when DEBUG_RACE is on and a big problem for SMP
2010-06-18 12:46:18 +00:00
Arun Thomas
b641afc78a VM: Remove legacy non-paging code paths 2010-06-05 14:39:40 +00:00
Erik van der Kouwe
1f11a57141 Oops, last commit included more than was intended 2010-05-20 08:07:47 +00:00
Erik van der Kouwe
5f15ec05b2 More system processes, this was not enough for the release script to run on some configurations 2010-05-20 08:05:07 +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
1f1f8d2207 vm: don't force physical addresses to be nonzero. 2010-04-13 11:01:40 +00:00
Ben Gras
5f7c37bb84 vm: remove assert, map in of phys addr 0 is legit sometimes. 2010-04-13 10:39:46 +00:00
Ben Gras
27fc7ab1f3 vm: use assert() instead of vm_assert(); remove vm_assert(). 2010-04-12 12:37:28 +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
Ben Gras
ec30f25d0c VM: fix kernel mappings for children of non-paged parents. 2010-03-18 17:17:31 +00:00
Ben Gras
35a108b911 panic() cleanup.
this change
   - makes panic() variadic, doing full printf() formatting -
     no more NO_NUM, and no more separate printf() statements
     needed to print extra info (or something in hex) before panicing
   - unifies panic() - same panic() name and usage for everyone -
     vm, kernel and rest have different names/syntax currently
     in order to implement their own luxuries, but no longer
   - throws out the 1st argument, to make source less noisy.
     the panic() in syslib retrieves the server name from the kernel
     so it should be clear enough who is panicing; e.g.
         panic("sigaction failed: %d", errno);
     looks like:
         at_wini(73130): panic: sigaction failed: 0
         syslib:panic.c: stacktrace: 0x74dc 0x2025 0x100a
   - throws out report() - printf() is more convenient and powerful
   - harmonizes/fixes the use of panic() - there were a few places
     that used printf-style formatting (didn't work) and newlines
     (messes up the formatting) in panic()
   - throws out a few per-server panic() functions
   - cleans up a tie-in of tty with panic()

merging printf() and panic() statements to be done incrementally.
2010-03-05 15:05:11 +00:00
David van Moolenbroek
61bb82a44b VM information interface 2010-01-19 21:00:20 +00:00
Cristiano Giuffrida
c5b309ff07 Merge of Wu's GSOC 09 branch (src.20090525.r4372.wu)
Main changes:
- COW optimization for safecopy.
- safemap, a grant-based interface for sharing memory regions between processes.
- Integration with safemap and complete rework of DS, supporting new data types
  natively (labels, memory ranges, memory mapped ranges).
- For further information:
  http://wiki.minix3.org/en/SummerOfCode2009/MemoryGrants

Additional changes not included in the original Wu's branch:
- Fixed unhandled case in VM when using COW optimization for safecopy in case
  of a block that has already been shared as SMAP.
- Better interface and naming scheme for sys_saferevmap and ds_retrieve_map
  calls.
- Better input checking in syslib: check for page alignment when creating
  memory mapping grants.
- DS notifies subscribers when an entry is deleted.
- Documented the behavior of indirect grants in case of memory mapping.
- Test suite in /usr/src/test/safeperf|safecopy|safemap|ds/* reworked
  and extended.
- Minor fixes and general cleanup.
- TO-DO: Grant ids should be generated and managed the way endpoints are to make
sure grant slots are never misreused.
2010-01-14 15:24:16 +00:00
Ben Gras
8d800b3df7 Make VM fix up memory for kernel that crosses region boundaries
too.

Add a test to make this happen (triggers a vm panic before this commit).
2009-12-08 13:35:52 +00:00
Ben Gras
7a45f80bd5 threw out sanity checks before pagetable rewrites, triggering false
page table inconsistencies.

fix handle_memory logic. again.
2009-09-27 12:44:36 +00:00