Commit graph

23 commits

Author SHA1 Message Date
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
Thomas Veerman
f09c2e014f Use MACHINE_ARCH instead of ARCH 2012-06-18 10:53:35 +00:00
Thomas Veerman
f93afa00e9 Remove MINIXSRCDIR and use NETBSDSRCDIR
NETBSDSRCDIR is used all over the place anyway, and this reduces
our diff with NetBSD a little.
2012-06-18 10:53:35 +00:00
Arun Thomas
ff56906879 Remove obsolete INSTALLFLAGS from makefiles 2012-02-16 23:26:38 +01:00
Arun Thomas
93ae43f577 boot: Add multiboot support
Not yet fully spec-compliant; work in progress
2011-06-24 17:21:51 +02:00
Erik van der Kouwe
c2da8cb535 Globally enable -Wall warnings for GCC 2011-06-08 19:21:03 +00:00
Erik van der Kouwe
0cb22acbda Fix VM -Wall warnings and enable -Werror 2011-06-01 11:30:58 +02:00
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
Ben Gras
6e47e2996f sep ${.OBJDIR} fixes by Antoine Leica. 2010-06-27 23:47:23 +00:00
Arun Thomas
c0c8d25799 Rename mkfiles from minix.*.mk to bsd.*.mk
Makes things easier for pkgsrc
2010-06-25 18:29:09 +00:00
Arun Thomas
007104d60e GCC build fixes/updates
-Set stack sizes for boot image processes
-Increase RS stack size
-Reduce ramdisk size
-HARDWARE task should use kernel stack
-Minor asm tweaks for leading underscores
2010-05-26 18:45:55 +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
Arun Thomas
4ed3a0cf3a Convert kernel over to bsdmake 2010-04-01 22:22:33 +00:00
Arun Thomas
436d6012a3 Convert drivers/ and servers/ over to bsdmake
-Move libdriver to lib/
-Install all boot image services on filesystem to aid restartability
2010-03-22 21:25:22 +00:00
Arun Thomas
1f9ce647cf Move archtypes.h, fpu.h, and stackframe.h
Move archtypes.h to include/ dir, since several servers require it. Move
fpu.h and stackframe.h to arch-specific header directory. Make source
files and makefiles aware of the new header locations.
2010-03-09 09:41:14 +00:00
Arun Thomas
b706112487 Incorporate bsdmake into buildsystem and reorganize libs 2010-02-16 14:41:33 +00:00
Ben Gras
35b471ad94 removal of unused vm<->vfs code. 2010-02-03 13:35:17 +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
4c11d7e6f5 - simplify findhole() for use for 1 page only
- do WMF_FREE
 - added WMF_VERIFY to check page table contents
 - randomize address space usage in vm self
2009-09-23 13:33:01 +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
ade4c03b73 Don't build arch objs more than once. 2009-05-11 19:05:45 +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