Commit graph

21 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
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
0a70e23d1d is - no more getlocktimings. 2011-02-04 13:34:43 +00:00
David van Moolenbroek
56d485c1d6 Various small IS, TTY, isofs fixes
IS:
- do not use p_getfrom_e for a process that is sending
- register with TTY only function keys that are used
- various header and formatting fixes
- proper shutdown code

TTY:
- restore proper Ctrl+F1 dump contents

isofs:
- don't even try to call sys_exit()
2009-11-02 23:04:52 +00:00
David van Moolenbroek
f89388c241 Kernel, servers: remove unused proto.h definitions 2009-10-31 14:11:50 +00:00
Ben Gras
08d291da53 no more scheduling queue dumps (kernel will print this over serial);
initial vm stats retrieve support
2009-09-21 14:47:24 +00:00
Ben Gras
c628f24bc2 moved stacktrace to sysctl, as vmctl is very privileged so can't
be used outside VM. IS code cleanup. added stacktrace feature to IS.
2009-01-27 12:54:33 +00:00
Jorrit Herder
021e3234d8 Jorrit's ... "progress?" 2006-03-10 16:10:05 +00:00
Jorrit Herder
288860f6e6 New dumps for RS and DS server. 2005-10-20 20:28:54 +00:00
Ben Gras
abd0b53e0a PM: added possibility to copy hole list from alloc.c to outside, for
misc.c to copy it away by getsysinfo
IS: prints out hole list + stats such as largest contiguous chunk
2005-10-13 12:48:43 +00:00
Jorrit Herder
5a9dec8bd2 New signal handling behaviour at PM (services can be killed).
New Shift-F6 dump for RS server at IS.
New getnpid, getnproc, getpproc library calls at PM.
New reincarnation server (basic functionality is there now).
2005-10-12 15:07:38 +00:00
Ben Gras
6a44098b96 Added Shift+F5 debug dump - show debug dumps. 2005-09-22 12:21:26 +00:00
Jorrit Herder
a238c1ba48 Cleanup with gcc. 2005-08-25 12:04:36 +00:00
Jorrit Herder
872687ddfc Scheduling updates to the kernel. Sched() function now is single point for
policy. Actual policy not yet implemented.

PM calculates nice values for processes in boot image.

IS debug dumps improved (Shift+F1-F4).
2005-08-22 15:14:11 +00:00
Jorrit Herder
f44725b777 Created new devctl system call to FS. Moved dmap.h header to include/minix/.
Various updates to support dynamically starting servers and suppress output.
2005-08-02 15:29:17 +00:00
Jorrit Herder
808202ee30 Removed printing functionality from IS server.
This functionality is now provided by the LOG driver.
2005-07-21 18:31:27 +00:00
Jorrit Herder
570eac1f53 Renamed system library functionality.
Updated debug dumps of IS server.
2005-07-14 15:16:12 +00:00
Jorrit Herder
37a1e3f8e3 Removed mem chunks dump. (No longer available from kernel.) 2005-06-17 09:13:32 +00:00
Jorrit Herder
c2cd510adf Removed debug dumps from the PM and FS servers. The dumps are now done by the
IS servers, which obtains a copy of the data through the getsysinfo() system
call. CTRL-F1 now is a special TTY key to shows function key mappings.
2005-06-07 14:43:35 +00:00
Jorrit Herder
6d23f072f3 Cleaned up src/lib/utils library. Renamed server_ functions to more logical
names. All system processes can now either use panic() or report() from
libutils, or redefine their own function. Assertions are done via the standard
<assert.h> functionality.
2005-06-01 14:31:00 +00:00
Ben Gras
9865aeaa79 Initial revision 2005-04-21 14:53:53 +00:00