Commit graph

124 commits

Author SHA1 Message Date
Tomas Hruby
25f2145956 Fixed a panic message
- exceptions cannot occur in kernel tasks as we don't have kernel
  tasks anymore
2010-04-07 12:50:43 +00:00
Kees van Reeuwijk
94a81c840a Removed unused variables, added const where possible. 2010-04-07 11:25:51 +00:00
Tomas Hruby
a774cc832f do_ipc() rearrangements
this patch does not add or change any functionality of do_ipc(), it
only makes things a little cleaner (hopefully).

Until now do_ipc() was responsible for handling all ipc calls. The
catch is that SENDA is fairly different which results in some ugly
code like this typecasting and variables naming which does not make
much sense for SENDA and makes the code hard to read.

result = mini_senda(caller_ptr, (asynmsg_t *)m_ptr, (size_t)src_dst_e);

As it is called directly from assembly, the new do_ipc() takes as
input values of 3 registers in reg_t variables (it used to be 4,
however, bit_map wasn't used so I removed it), does the checks common
to all ipc calls and call the appropriate handler either for
do_sync_ipc() (all except SENDA) or mini_senda() (for SENDA) while
typecasting the reg_t values correctly. As a result, handling SENDA
differences in do_sync_ipc() is no more needed. Also the code that
uses msg_size variable is improved a little bit.

arch_do_syscall() is simplified too.
2010-04-06 11:24:26 +00:00
Arun Thomas
4ed3a0cf3a Convert kernel over to bsdmake 2010-04-01 22:22:33 +00:00
Kees van Reeuwijk
0a04f49d2b Fixed some incorrect uses of printf-like functions. 2010-04-01 14:30:36 +00:00
Kees van Reeuwijk
fc7dced1fa Fix printfs with too few or too many parms, remove unused vars, fix incorrect flag tests, other code cleanup. 2010-04-01 13:25:05 +00:00
Kees van Reeuwijk
4865e3f4f9 More use of endpoint_t. Other code cleanup. 2010-03-30 14:07:15 +00:00
Ben Gras
f2b87f5fb7 don't print SYSTEM stacktrace on exceptions as it's not scheduled any more. 2010-03-29 15:32:19 +00:00
Tomas Hruby
62203ec287 NOREC_ENTER and NOREC_RETURN checks removed
- the reasons for these checks no longer exist

- these check are problematic on SMP
2010-03-29 11:43:10 +00:00
Tomas Hruby
b4cf88a04f Userspace scheduling
- cotributed by Bjorn Swift

- In this first phase, scheduling is moved from the kernel to the PM
  server. The next steps are to a) moving scheduling to its own server
  and b) include useful information in the "out of quantum" message,
  so that the scheduler can make use of this information.

- The kernel process table now keeps record of who is responsible for
  scheduling each process (p_scheduler). When this pointer is NULL,
  the process will be scheduled by the kernel. If such a process runs
  out of quantum, the kernel will simply renew its quantum an requeue
  it.

- When PM loads, it will take over scheduling of all running
  processes, except system processes, using sys_schedctl().
  Essentially, this only results in taking over init. As children
  inherit a scheduler from their parent, user space programs forked by
  init will inherit PM (for now) as their scheduler.

 - Once a process has been assigned a scheduler, and runs out of
   quantum, its RTS_NO_QUANTUM flag will be set and the process
   dequeued. The kernel will send a message to the scheduler, on the
   process' behalf, informing the scheduler that it has run out of
   quantum. The scheduler can take what ever action it pleases, based
   on its policy, and then reschedule the process using the
   sys_schedule() system call.

- Balance queues does not work as before. While the old in-kernel
  function used to renew the quantum of processes in the highest
  priority run queue, the user-space implementation only acts on
  processes that have been bumped down to a lower priority queue.
  This approach reacts slower to changes than the old one, but saves
  us sending a sys_schedule message for each process every time we
  balance the queues. Currently, when processes are moved up a
  priority queue, their quantum is also renewed, but this can be
  fiddled with.

- do_nice has been removed from kernel. PM answers to get- and
  setpriority calls, updates it's own nice variable as well as the
  max_run_queue. This will be refactored once scheduling is moved to a
  separate server. We will probably have PM update it's local nice
  value and then send a message to whoever is scheduling the process.

- changes to fix an issue in do_fork() where processes could run out
  of quantum but bypassing the code path that handles it correctly.
  The future plan is to remove the policy from do_fork() and implement
  it in userspace too.
2010-03-29 11:07:20 +00:00
Kees van Reeuwijk
98493805fd Lots of const correctness. 2010-03-27 14:31:00 +00:00
Tomas Hruby
1dd6f5573a Direction flag
- ack assumes that the direction flag in eflags is clear when
  assigning two structures. It is implemented by a call to a built-in
  function which is like memcpy but needs the flag to be clear
  otherwise rubish is copied. This patch fixes the kernel entries.
2010-03-26 12:29:52 +00:00
Tomas Hruby
8451a86f0a Interrupts hadling while idle
- When the cpu halts, the interrupts are enable so the cpu may be
  woken up. When the interrupt handler returns but another interrupt
  is available it is also serviced immediately. This is not a problem
  per-se. It only slightly breaks time accounting as idle accounted is
  for the kernel time in the interrupt handler.
  
  
-  As the big kernel lock is lock/unlocked in the smp branch in the
   time acounting functions as they are called exactly at the places
   we need to take the lock) this leads to a deadlock.

- we make sure that once the interrupt handler returns from the nested
  trap, the interrupts are disabled. This means that only one
  interrupt is serviced after idle is interrupted.

- this requires the loop in apic timer calibration to keep reenabling
  the interrupts. I admit it is a little bit hackish (one line),
  however, this code is a stupid corner case at the boot time.
  Hopefully it does not matter too much.
2010-03-23 13:35:01 +00:00
Kees van Reeuwijk
c33102ea6b Miscellaneous code cleanup. 2010-03-22 20:43:06 +00:00
Tomas Hruby
12ef495cac atomicity fix when enabling paging
- before enabling paging VM asks kernel to resize its segments. This
  may cause kernel to segfault if APIC is used and an interrupt
  happens between this and paging enabled. As these are 2 separate
  vmctl calls it is not atomic. This patch fixes this problem. VM does
  not ask kernel to resize the segments in a separate call anymore.
  The new segments limit is part of the "enable paging" call. It
  generalizes this call in such a way that more information can be
  passed as need be or the information may be completely different if
  another architecture requires this.
2010-03-22 07:42:52 +00:00
Tomas Hruby
a5094f7d7f Kernel dumps its registers when exception
- if an exception occurs in kernel and this exception is not handled
  in an sane way and the kernel crashes, it also dumps what was loaded
  in the general purpose registers exactly at the time of the
  exception to help to debug the problem
2010-03-20 14:59:18 +00:00
Erik van der Kouwe
b42c66ed10 this patch adds access to the debug breakpoints to
the kernel. They are not used atm, but having them in trunk allows them
to be easily used when needed. To set a breakpoint that triggers when
the variable foo is written to (the most common use case), one calls:

breakpoint_set(vir2phys((vir_bytes) &foo), 0,
  BREAKPOINT_FLAG_MODE_GLOBAL |
  BREAKPOINT_FLAG_RW_WRITE |
  BREAKPOINT_FLAG_LEN_4);

It can later be disabled using:

breakpoint_set(vir2phys((vir_bytes) &foo), 0,
  BREAKPOINT_FLAG_MODE_OFF);

There are some limitations:

- There are at most four breakpoints (hardware limit); the index of the
  breakpoint (0-3) is specified as the second parameter of
  breakpoint_set.

- The breakpoint exception in the kernel is not handled and causes a
  panic; it would be reasonably easy to change this by inspecing DR6,
  printing a message, disabling the breakpoint and continuing. However,
  in my experience even just a panic can be very useful.

- Breakpoints can be set only in the part of the address space that is
  in every page table. It is useful for the kernel, but to use this for
  user processes would require saving and restoring the debug registers
  as part of the context switch. Although the CPU provides support for
  local breakpoints (I implemened this as BREAKPOINT_FLAG_LOCAL) they
  only work if task switching is used.
2010-03-19 19:15:20 +00:00
Erik van der Kouwe
19ff96081c Specify missing return type 2010-03-19 19:07:00 +00:00
Tomas Hruby
a0602c06a3 Fixed kernel stack comment 2010-03-18 16:18:22 +00:00
Ben Gras
f250bfaa13 change messy CREATEPDE macro to clean little function.
forget about the dirtypde bitmap and WIPEPDE/DONEPDE macros too.

check if mapping happens to already be in place, and if so, don't
reload cr3 (on the account of that mapping, that is).

don't reload cr3 unconditionally.
2010-03-18 13:35:41 +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
0937d6c367 re-establish kernel assert()s.
use the regular <assert.h> assert() instead of vmassert() in
kernel. throw out some #if 0 code. fix a few assert() conditions.
enable by default.
2010-03-10 13:00:05 +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
2a8fabf4ad Include directory reorg and makefile updates.
-Convert the include directory over to using bsdmake
 syntax
-Update/add mkfiles
-Modify install(1) so that it can create symlinks
-Update makefiles to use new install(1) options
-Rename /usr/include/ibm to /usr/include/i386
-Create /usr/include/machine symlink to arch header files
-Move vm_i386.h to its new home in the /usr/include/i386
-Update source files to #include the header files at their
 new homes.
-Add new gnu-includes target for building GCC headers
2010-03-08 11:04:59 +00:00
Tomas Hruby
ecf1a36d48 Fix for FPU broken by r6131
- cycles accounting must be called earlier, firstly not to clobber the %ebx
  register, secondly to be correctly called in both branches.
2010-03-05 22:23:03 +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
Ben Gras
e6cb76a2e2 no more kprintf - kernel uses libsys printf now, only kputc is special
to the kernel.
2010-03-03 15:45:01 +00:00
Ben Gras
18924ea563 New P_BLOCKEDON for kernel - a macro that encodes the "who is this
process waiting for" logic, which is duplicated a few times in the
kernel. (For a new feature for top.)

Introducing it and throwing out ESRCDIED and EDSTDIED (replaced by
EDEADSRCDST - so we don't have to care which part of the blocking is
failing in system.c) simplifies some code in the kernel and callers that
check for E{DEADSRCDST,ESRCDIED,EDSTDIED}, but don't care about the
difference, a fair bit, and more significantly doesn't duplicate the
'blocked-on' logic.
2010-03-03 15:32:26 +00:00
Arun Thomas
cbd276e4ce Convert library asm files to GAS syntax 2010-03-03 14:27:30 +00:00
Kees van Reeuwijk
bf7397b64e More correctly use cp_grant_id_t.
More correctly use vir_bytes.
More correctly use endpoint_t.
2010-03-02 23:12:13 +00:00
Kees van Reeuwijk
1ba0936619 Fix some uses of uninitialized variables. 2010-02-19 10:41:02 +00:00
Kees van Reeuwijk
97c169b93a Remove some unused #include.
Remove some unused variables and computations on them.
2010-02-17 20:24:42 +00:00
Arun Thomas
b706112487 Incorporate bsdmake into buildsystem and reorganize libs 2010-02-16 14:41:33 +00:00
David van Moolenbroek
e306663455 fix the somehow newly introduced warnings 2010-02-14 18:39:47 +00:00
Kees van Reeuwijk
df60646f98 Undo the use of #include <...> because it caused some errors. 2010-02-12 14:43:18 +00:00
Tomas Hruby
1b56fdb33c Time accounting based on TSC
- as thre are still KERNEL and IDLE entries, time accounting for
  kernel and idle time works the same as for any other process

- everytime we stop accounting for the currently running process,
  kernel or idle, we read the TSC counter and increment the p_cycles
  entry.

- the process cycles inherently include some of the kernel cycles as
  we can stop accounting for the process only after we save its
  context and we start accounting just before we restore its context

- this assumes that the system does not scale the CPU frequency which
  will be true for ... long time ;-)
2010-02-10 15:36:54 +00:00
Tomas Hruby
c6fec6866f No locking in kernel code
- No locking in RTS_(UN)SET macros

- No lock_notify()

- Removed unused lock_send()

- No lock/unlock macros anymore
2010-02-09 15:26:58 +00:00
Tomas Hruby
391fd926ff TASK_PRIVILEGE and level0() removed
- there are no tasks running, we don't need TASK_PRIVILEGE priviledge anymore

- as there is no ring 1 anymore, there is no need for level0() to call sensitive
  code from ring 1 in ring 0

- 286 related macros removed as clean up
2010-02-09 15:23:31 +00:00
Tomas Hruby
728f0f0c49 Removal of the system task
* Userspace change to use the new kernel calls

	- _taskcall(SYSTASK...) changed to _kernel_call(...)

	- int 32 reused for the kernel calls

	- _do_kernel_call() to make the trap to kernel

	- kernel_call() to make the actuall kernel call from C using
	  _do_kernel_call()

	- unlike ipc call the kernel call always succeeds as kernel is
	  always available, however, kernel may return an error

* Kernel side implementation of kernel calls

	- the SYSTEm task does not run, only the proc table entry is
	  preserved

	- every data_copy(SYSTEM is no data_copy(KERNEL

	- "locking" is an empty operation now as everything runs in
	  kernel

	- sys_task() is replaced by kernel_call() which copies the
	  message into kernel, dispatches the call to its handler and
	  finishes by either copying the results back to userspace (if
	  need be) or by suspending the process because of VM

	- suspended processes are later made runnable once the memory
	  issue is resolved, picked up by the scheduler and only at
	  this time the call is resumed (in fact restarted) which does
	  not need to copy the message from userspace as the message
	  is already saved in the process structure.

	- no ned for the vmrestart queue, the scheduler will restart
	  the system calls

	- no special case in do_vmctl(), all requests remove the
	  RTS_VMREQUEST flag
2010-02-09 15:20:09 +00:00
Tomas Hruby
5e57818431 copy_msg_from_user() and copy_msg_to_user()
- copies a mesage from/to userspace without need of translating
  addresses

- the assumption is that the address space is installed, i.e. ldt and
  cr3 are loaded correctly

- if a pagefault or a general protection occurs while copying from
  userland to kernel (or vice versa) and error is returned which gives
  the caller a chance to respond in a proper way

- error happens _only_ because of a wrong user pointer if the function
  is used correctly

- if the prerequisites of the function do no hold, the function will
  most likely fail as the user address becomes random
2010-02-09 15:15:45 +00:00
Tomas Hruby
ad9ba944d1 Early address space switch
- switch_address_space() implements a switch of the user address space
  for the destination process

- this makes memory of this process easily accessible, e.g. a pointer
  valid in the userspace can be used with a little complexity to
  access the process's memory

- the switch does not happed only just before we return to userspace,
  however, it happens right after we know which process we are going
  to schedule. This happens before we start processing the misc flags
  of this process so its memory is available

- if the process becomes not runnable while processing the mics flags
  we pick a new process and we switch the address space again which
  introduces possibly a little bit more overhead, however, it is
  hopefully hidden by reducing the overheads when we actually access
  the memory
2010-02-09 15:13:52 +00:00
Tomas Hruby
b14a86ca5c Sys calls are called ipc calls now
- the syscalls are pretty much just ipc calls, however, sendrec() is
  used to implement system task (sys) calls

- sendrec() won't be used anymore for this, therefore ipc calls will
  become pure ipc calls
2010-02-09 15:13:07 +00:00
Tomas Hruby
cca24d06d8 This patch removes the global variables who_p and who_e from the
kernel (sys task).  The main reason is that these would have to become
cpu local variables on SMP.  Once the system task is not a task but a
genuine part of the kernel there is even less reason to have these
extra variables as proc_ptr will already contain all neccessary
information. In addition converting who_e to the process pointer and
back again all the time will be avoided.

Although proc_ptr will contain all important information, accessing it
as a cpu local variable will be fairly expensive, hence the value
would be assigned to some on stack local variable. Therefore it is
better to add the 'caller' argument to the syscall handlers to pass
the value on stack anyway. It also clearly denotes on who's behalf is
the syscall being executed.

This patch also ANSIfies the syscall function headers.

Last but not least, it also fixes a potential bug in virtual_copy_f()
in case the check is disabled. So far the function in case of a
failure could possible reuse an old who_p in case this function had
not been called from the system task.

virtual_copy_f() takes the caller as a parameter too. In case the
checking is disabled, the caller must be NULL and non NULL if it is
enabled as we must be able to suspend the caller.
2010-02-03 09:04:48 +00:00
Kees van Reeuwijk
477b616fe8 Fixed a number of complaints about missing return statements.
Some cases were fixed by declaring the function void, others were fixed
by adding a return <value> statement, thereby avoiding potentially
incorrect behavior (usually in error handling).
Some enum correctness in boot.c.
2010-01-28 13:17:07 +00:00
Kees van Reeuwijk
c8a11b5453 Fixed some type inconsistencies in the kernel. 2010-01-26 12:26:06 +00:00
Kees van Reeuwijk
b67f788eea Removed a number of useless #includes 2010-01-26 10:59:01 +00:00
Kees van Reeuwijk
a701e290f7 Removed unused symbols.
Made some functions PRIVATE, including ones that aren't used anywhere.
2010-01-25 18:13:48 +00:00
Kees van Reeuwijk
a7cee5bec4 Removed unused symbols.
Minor cleanups.
2010-01-22 22:01:08 +00:00
Kees van Reeuwijk
f30c82b430 Restored idt_reload() prototype. 2010-01-21 11:40:22 +00:00
Kees van Reeuwijk
d6383bef47 Removed some unused tests. 2010-01-20 17:55:14 +00:00