Commit graph

780 commits

Author SHA1 Message Date
Tomas Hruby
98c93e76d7 Zero no more hardwired as BSP apic id
- the BSP apic id is written in the io apic redirection entries to
  deliver the interrupts to BSP
2010-10-21 17:07:07 +00:00
Tomas Hruby
a1eefc013e single shot timer interrupts fix
- accidentaly this wasn't part of the SMP merge and the implementation
  remained uncomplete with the timer keeping ticking periodically

- APIC timer is set for a signel shot and restarted everytime it
  expires. This way we can keep the AP's trully idle

- the timer is restarted a little later before leaving to userspace

- LAPIC_TIMER_ICR is written before LAPIC_LVTTR so the newest value is
  used
2010-10-21 17:07:01 +00:00
Tomas Hruby
ebbc730fc3 spurious and error interrupt apic handlers
- fixed spurious and error interrupt handlers

- not to hog the system the warning isn't reported every time, just
  once every 100 times, similarly for the spurious PIC interrupts
2010-10-19 17:07:21 +00:00
Tomas Hruby
f42b90806a BSP apic id
- BSP apic id used uninitialized causes problems
2010-10-19 17:07:19 +00:00
Tomas Hruby
e6b1a30a26 panic in dummy apic handlers
- as panic can do the same as printf now, let's rather panic when a
  dummy apic interrupt vector handler is hit
2010-10-19 17:07:17 +00:00
Tomas Hruby
2419ab589d Fixed BKL statistics 2010-10-19 17:07:11 +00:00
Tomas Hruby
8145b458d6 A klib.S include fix
- by Antoine Leca
2010-10-15 22:21:01 +00:00
Ben Gras
c521f2a138 kernel: fix idle time accounting. 2010-10-04 19:12:55 +00:00
Tomas Hruby
1786291e32 Watchdog and kernel profiling for AMD
- a different set of MSRs and performance counters is used on AMD

- when initializing NMI watchdog the test for Intel architecture
  performance counters feature only applies to Intel now

- NMI is enabled if the CPU belongs to a family which has the
  performance counters that we use
2010-09-23 14:42:30 +00:00
Tomas Hruby
8eece1c00c CPU type detection
- sometimes the system needs to know precisely on what type of cpu is
  running. The cpu type id detected during arch specific
  initialization and kept in the machine structure for later use.

- as a side-effect the information is exported to userland
2010-09-23 14:42:19 +00:00
Tomas Hruby
ef92583c3a Busy idle loop when profiling
- the Intel architecture cycle counter (performance counter) does not
  count when the CPU is idle therefore we use busy loop instead of
  halting the cpu when there is nothing to schedule

- the downside is that handling interrupts may be accounted as idle
  time if a sample is taken before we get out of the nested trap and
  pick a new process
2010-09-23 10:49:52 +00:00
Tomas Hruby
d2b56f60da sprofile exports kernel sample entries
- in case of kernel hit while proc_ptr is IDLE, account for idle time
  instead of taking kernel sample
2010-09-23 10:49:50 +00:00
Tomas Hruby
87c576584d Internal 64M buffer for profiling
- when profiling is compiled in kernel includes a 64M buffer for
  sample

- 64M is the default used by profile tool as its buffer

- when using nmi profiling it is not possible to always copy sample
  stright to userland as the nmi may (and does) happen in bad moments

- reduces sampling overhead as samples are copied out only when
  profiling stops
2010-09-23 10:49:48 +00:00
Tomas Hruby
e63b85a50b NMI sampling
- if profile --nmi kernel uses NMI watchdog based sampling based on
  Intel architecture performance counters

- using NMI makes kernel profiling possible

- watchdog kernel lockup detection is disabled while sampling as we
  may get unpredictable interrupts in kernel and thus possibly many
  false positives

- if watchdog is not enabled at boot time, profiling enables it and
  turns it of again when done
2010-09-23 10:49:45 +00:00
Tomas Hruby
db12229ce3 New profile protocol
- when kernel profiles a process for the first time it saves an entry
  describing the process [endpoint|name]

- every profile sample is only [endpoint|pc]

- profile utility creates a table of endpoint <-> name relations and
  translates endpoints of samples into names and writing out the
  results to comply with the processing tools

- "task" endpoints like KERNEL are negative thus we must cast it to
  unsigned when hashing
2010-09-23 10:49:39 +00:00
Tomas Hruby
123a968be3 32bit process flags
- we are running out of space in 16bit flags
2010-09-23 10:49:36 +00:00
Ben Gras
82d576c9ca enable_fpu_exception() - only write cr0 if bit isn't already on.
(NMI profiling results indicate this both is relatively expensive and
happens a lot unnecessarily if the fpu is in use.)
2010-09-22 14:31:06 +00:00
Tomas Hruby
2d1c8849d8 Remove unnecessary TLB flushes
- this should be only for SMP
2010-09-22 08:01:36 +00:00
Tomas Hruby
08bf4dec4f Fixed comments in watchdog 2010-09-19 23:23:44 +00:00
Tomas Hruby
e9ecba9fc7 fix - forgotten debug print 2010-09-19 15:54:31 +00:00
Tomas Hruby
a665ae3de1 Userspace scheduling - exporting stats
- contributed by Bjorn Swift

- adds process accounting, for example counting the number of messages
  sent, how often the process was preemted and how much time it spent
  in the run queue. These statistics, along with the current cpu load,
  are sent back to the user-space scheduler in the Out Of Quantum
  message.

- the user-space scheduler may choose to make use of these statistics
  when making scheduling decisions. For isntance the cpu load becomes
  especially useful when scheduling on multiple cores.
2010-09-19 15:52:12 +00:00
Tomas Hruby
13bda81ee0 Fixed FPU for single cpu 2010-09-16 09:51:45 +00:00
Tomas Hruby
72cc01ff48 apic_timer_x
- set the apic_timer_x factor variable to slowdown apic timer in
  virtual machines
2010-09-16 07:18:47 +00:00
Tomas Hruby
4ee139b0be SMP - all process have pagetables
- all processes have private pagetables if CONFIG_SMP is set

- this make possible to safely schedule PM, RS, VFS anywhere
2010-09-15 14:11:30 +00:00
Tomas Hruby
5b8b623765 SMP - lazy FPU
- when a process is migrated to a different CPU it may have an active
  FPU context in the processor registers. We must save it and migrate
  it together with the process.
2010-09-15 14:11:25 +00:00
Tomas Hruby
1f89845bb2 SMP - can boot even if some cpus fail to boot
- EBADCPU is returned is scheduler tries to run a process on a CPU
  that either does not exist or isn't booted

- this change was originally meant to deal with stupid cpuid
  instruction which provides totally useless information about
  hyper-threading and MPS which does not deal with ht at all. ACPI
  provides correct information. If ht is turned off it looks like some
  CPUs failed to boot.  Nevertheless this patch may be handy for
  testing/benchmarking in the future.
2010-09-15 14:11:21 +00:00
Tomas Hruby
421f324baa SMP - Make sure that VM does not change pt of a process while kernel copies 2010-09-15 14:11:19 +00:00
Tomas Hruby
e4283176ae SMP - Force TLB flush before scheduling a process
- this makes sure that each process always run with updated TLB

- this is the simplest way how to achieve the consistency. As it means
  significant performace degradation when not require, this is nto the
  final solution and will be refined
2010-09-15 14:11:17 +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
Tomas Hruby
906a81a1c7 SMP - runctl() can stop across cpus
- if stopping a process that runs on a different CPU we tell the
  remote cpu to do that
2010-09-15 14:11:09 +00:00
Tomas Hruby
e2701da5a9 SMP - Single shot local timer
- APIC timer always reprogrammed if expired

- timer tick never happens when in kernel => never immediate return
  from userspace to kernel because of a buffered interrupt

- renamed argument to lapic_set_timer_one_shot()

- removed arch_ prefix from timer functions
2010-09-15 14:11:06 +00:00
Tomas Hruby
e87d29171f SMP - Compiles for both single and multi processor again
- this patch adds various fixes as some of the previous patches break
  compilations without CONFIG_SMP being set
2010-09-15 14:11:03 +00:00
Tomas Hruby
454589debd SMP - Print cpu of the process
- adds '4' to print processes assigned to each cpu without printing
  the process it is blocked on (a lightweight '1')
2010-09-15 14:11:01 +00:00
Tomas Hruby
0ac9b6d4cf SMP - trully idle APs
- any cpu can use smp_schedule() to tell another cpu to reschedule

- if an AP is idle, it turns off timer as there is nothing to
  preempt, no need to wakeup just to go back to sleep again

- if a cpu makes a process runnable on an idle cpu, it must wake it up
  to reschedule
2010-09-15 14:10:57 +00:00
Tomas Hruby
387e1835d1 SMP - BSP halts APs before shutting down 2010-09-15 14:10:54 +00:00
Tomas Hruby
311f145bc7 SMP - Balancing run queues for SMP
- it preempts running processes though :( this is not the final
  solution
2010-09-15 14:10:51 +00:00
Tomas Hruby
06b6e5624a SMP - Changed prototype of sys_schedule()
- sys_schedule can change only selected values, -1 means that the
  current value should be kept unchanged. For instance we mostly want
  to change the scheduling quantum and priority but we want to keep
  the process at the current cpu

- RS can hand off its processes to scheduler

- service can read the destination cpu from system.conf

- RS can pass the information farther
2010-09-15 14:10:42 +00:00
Tomas Hruby
c554aef0e1 SMP - BKL statistics
- pressing 'B' on the serial cnsole prints statistics for BKL per cpu.

- 'b' resets the counters

- it presents number of cycles each CPU spends in kernel, how many
  cycyles it spends spinning while waiting for the BKL

- it shows optimistic estimation in how many cases we get the lock
  immediately without spinning. As the test is not atomic the lock may
  be already held by some other cpu before we actually try to acquire
  it.
2010-09-15 14:10:37 +00:00
Tomas Hruby
93b9873a56 SMP - Free PDE slots are split among CPU
- cross-address space copies use these slots to map user memory for
  kernel. This avoid any collisions between CPUs

- well, we only have a single CPU running at a time, this is just to
  be safe for the future
2010-09-15 14:10:36 +00:00
Tomas Hruby
1e273f640e SMP - Scheduler can assign process to a cpu
- machine information contains the number of cpus and the bsp id

- a dummy SMP scheduler which keeps all system processes on BSP and
  all other process on APs. The scheduler remembers how many processes
  are assigned to each CPU and always picks the one with the least
  processes for a new process.
2010-09-15 14:10:33 +00:00
Tomas Hruby
9e12630d75 SMP - APs are fully enabled
- apic_send_ipi() to send inter-processor interrupts (IPIs)

- APIC IPI schedule and halt handlers to signal x-cpu that a cpu shold
  reschedule or halt

- various little changes to let APs run

- no processes are scheduled at the APs and therefore they are idle
  except being interrupted by a timer time to time
2010-09-15 14:10:30 +00:00
Tomas Hruby
d37b7ebc0b SMP - CPU local cycles accounting
- tsc_ctr_switch is made cpu local

- although an x86 specific variable it must be declared globaly as the
  cpulocal implementation does not allow otherwise
2010-09-15 14:10:27 +00:00
Tomas Hruby
67f039540c SMP - proc_ptr and bill_ptr initialization
- they should point somewhere
2010-09-15 14:10:24 +00:00
Tomas Hruby
865e21b884 SMP - CPU local idle stub
- each CPU has its own pseudo idle process and its structure

- idle cycles accounting is agregated when exporting to userspace
2010-09-15 14:10:21 +00:00
Tomas Hruby
fac5fbfdbf SMP - CPU local run queues
- each CPU has its own runqueues

- processes on BSP are put on the runqueues later after a switch to
  the final stack when cpuid works to avoid special cases

- enqueue() and dequeue() use the run queues of the cpu the process is
  assigned to

- pick_proc() uses the local run queues

- printing of per-CPU run queues ('2') on serial console
2010-09-15 14:10:18 +00:00
Tomas Hruby
ad73a4f50c SMP - CPU and CPU mask for processes
- each process has associated information about the cpu it is currently
  scheduled on and the mask of cpus it is allowed to use.
2010-09-15 14:10:16 +00:00
Tomas Hruby
9b6d66c787 SMP - BSP waits until the APs finish their booting
- APs configure local timers

- while configuring local APIC timer the CPUs fiddle with the interrupt
  handlers. As the interrupt table is shared the BSP must not run
2010-09-15 14:10:12 +00:00
Tomas Hruby
b7aed08e65 SMP - Only a single APIC timer handler
- bsp_timer_int_handler() and ap_timer_int_handler() unified into
  timer_int_handler()

- global realtime updated only on BSP
2010-09-15 14:10:09 +00:00
Tomas Hruby
85cca7096f SMP - The slave CPUs turn paging on
- APs wait until BSP turns paging on, it is not possible to safely
  execute any code on APs until we can turn paging on as well as it
  must be done synchronously everywhere

- APs turn paging on but do not continue and wait
2010-09-15 14:10:07 +00:00
Tomas Hruby
6aa26565e6 SMP - Big kernel lock (BKL)
- to isolate execution inside kernel we use a big kernel lock
  implemented as a spinlock

- the lock is acquired asap after entering kernel mode and released as
  late as possible. Only one CPU as a time can execute the core kernel
  code

- measurement son real hw show that the overhead of this lock is close
  to 0% of kernel time for the currnet system

- the overhead of this lock may be as high as 45% of kernel time in
  virtual machines depending on the ratio between physical CPUs
  available and emulated CPUs. The performance degradation is
  significant
2010-09-15 14:10:03 +00:00
Tomas Hruby
a42ab504a0 SMP - Kernel is loaded above 1M by default
- the 16-bit trampoline must be within the first megabyte of physical
  memory thus the smp trampoline is copied explicitly below 1M
2010-09-15 14:10:00 +00:00
Tomas Hruby
62c666566e SMP - We boot APs
- kernel detects CPUs by searching ACPI tables for local apic nodes

- each CPU has its own TSS that points to its own stack. All cpus boot
  on the same boot stack (in sequence) but switch to its private stack
  as soon as they can.

- final booting code in main() placed in bsp_finish_booting() which is
  executed only after the BSP switches to its final stack

- apic functions to send startup interrupts

- assembler functions to handle CPU features not needed for single cpu
  mode like memory barries, HT detection etc.

- new files kernel/smp.[ch], kernel/arch/i386/arch_smp.c and
  kernel/arch/i386/include/arch_smp.h

- 16-bit trampoline code for the APs. It is executed by each AP after
  receiving startup IPIs it brings up the CPUs to 32bit mode and let
  them spin in an infinite loop so they don't do any damage.

- implementation of kernel spinlock

- CONFIG_SMP and CONFIG_MAX_CPUS set by the build system
2010-09-15 14:09:52 +00:00
Tomas Hruby
13a0d5fa5e SMP - Cpu local variables
- most global variables carry information which is specific to the
  local CPU and each CPU must have its own copy

- cpu local variable must be declared in cpulocal.h between
  DECLARE_CPULOCAL_START and DECLARE_CPULOCAL_END markers using
  DECLARE_CPULOCAL macro

- to access the cpu local data the provided macros must be used

	get_cpu_var(cpu, name)
	get_cpu_var_ptr(cpu, name)

	get_cpulocal_var(name)
	get_cpulocal_var_ptr(name)

- using this macros makes future changes in the implementation
  possible

- switching to ELF will make the declaration of cpu local data much
  simpler, e.g.

  CPULOCAL int blah;

  anywhere in the kernel source code
2010-09-15 14:09:46 +00:00
Tomas Hruby
2a2a19e542 proc_init()
- code that initializes proc.c structures removed from main() and placed in
  proc_init() function
2010-09-15 14:09:43 +00:00
Tomas Hruby
ce4fd0c0fb Enable paging - some more code reshuffling 2010-09-15 14:09:41 +00:00
Tomas Hruby
6c3b981cd6 arch proto.h renamed to arch_proto.h
- the file moved to the arch include dir
2010-09-15 14:09:36 +00:00
Ben Gras
2065c9982b include - minor compile fixes (including <ansi.h> in files that use it)
workaround for kernel/debug.h that causes <ansi.h> to be included in mpx.S
indirectly.
2010-09-15 08:47:10 +00:00
Ben Gras
eaa37fd21c make, lib changes to make gcc/clang format libraries in /usr/lib instead of /usr/gnu/lib. 2010-09-13 16:37:02 +00:00
Tomas Hruby
e6ebac015d APIC mode uses IO APICs
- kernel turns on IO APICs if no_apic is _not_ set or is equal 0

- pci driver must use the acpi driver to setup IRQ routing otherwise
  the system cannot work correctly except systems like KVM that use
  only legacy (E)ISA IRQs 0-15
2010-09-07 07:18:11 +00:00
Tomas Hruby
2440ffae49 Kernel exports DSDP and apic_enabled in machine structure
- kernel exports DSDP (the root pointer where ACPI parsing starts) and
  apic_enabled in the machine structure.

- ACPI driver uses DSDP to locate ACPI in memory. acpi_enabled tell
  PCI driver to query ACPI for IRQ routing information.
2010-09-02 15:43:56 +00:00
Tomas Hruby
344e9221ec Kernel supports up to 64 IRQs
- enough for 2 io apics (usually with 24 pins)
2010-09-02 15:43:54 +00:00
Tomas Hruby
45badf4c05 ACPI in kernel
- the ability for kernel to use ACPI tables to detect IO APICs. It is
  the bare minimum the kernel needs to know about ACPI tables.

- it will be used to find out about processors as the MPS tables are
  deprecated by ACPI and not all vendorsprovide them.
2010-09-02 15:43:51 +00:00
Ben Gras
b3c3a1cb1e gcc compiles - add -fno-builtin so that gcc optimisations don't break things.
- kernel compile was broken with gcc as putchar() was added by gcc in
    stacktrace.c
  - add -fno-builtin everywhere to avoid such problems in the future
  - -fno-builtin in kernel now redundant
2010-08-31 16:42:44 +00:00
Erik van der Kouwe
1f2054c89c Shutdown changes for multiboot: CTRL-ALT-DEL resets, panic halts 2010-08-30 19:01:58 +00:00
Erik van der Kouwe
50ca7f7f8f Zero out to three stack dwords to fix boot errors 2010-08-24 12:51:11 +00:00
Arun Thomas
de231a713e Move MIN() and MAX() macros to sys/params.h 2010-08-21 13:10:41 +00:00
Erik van der Kouwe
b9f5e50421 Provide boot image process main functions with a full parameter list, so that bad things don't heppen when using getenv 2010-08-20 11:07:16 +00:00
Arun Thomas
9a21d1a2fd Macros for symbols used in both ASM and C
-The macros take care of prepending the leading underscore when
 necessary.
2010-08-17 16:44:07 +00:00
Tomas Hruby
f7ef192c02 Fixed warning noreturn function returns in arch_system.c 2010-08-06 12:48:26 +00:00
Tomas Hruby
58654acf08 both ack and gcc can compile klib16.S 2010-08-06 12:46:44 +00:00
Tomas Hruby
ac9a7f47bd Missing prototype in pre_init.c
- gcc does not like it
2010-08-06 12:26:26 +00:00
Erik van der Kouwe
25397ef756 Deal all shutdown cases with multiboot as either reset or poweroff depending on their type (contributed by Feiran 'Fam' Zheng) 2010-08-02 14:41:45 +00:00
Erik van der Kouwe
ebec792700 Display fallback message in case poweroff fails (contributed by Feiran 'Fam' Zheng) 2010-08-02 14:40:26 +00:00
Ben Gras
b9cea27497 kernel: deadlock test with endpoints instead of slot numbers, slightly cleaner 2010-07-28 14:14:06 +00:00
Erik van der Kouwe
df0ba02a38 Multiboot support (contributed by Feiran "Fam" Zheng);
keep in mind that GRUB needs to be patched to read MFS for now;
use /boot/image_latest to boot the last compiled image in GRUB
2010-07-23 14:24:34 +00:00
Erik van der Kouwe
f389ad2655 Move sensitive instructions from libc into kernel 2010-07-23 07:12:47 +00:00
Ben Gras
fe343bb002 Make kernel ipc log scripts work for separate ${.OBJDIR}.
contributed by Antoine Leca.
2010-07-22 22:04:37 +00:00
Cristiano Giuffrida
03bb1e5750 Don't panic so easily on unexpected pagefault. 2010-07-20 23:51:34 +00:00
Cristiano Giuffrida
0d984b36ef Get rid of static spare pages after VM startup. 2010-07-20 21:59:27 +00:00
Ben Gras
7f343ed574 kernel: clear MF_CONTEXT_SET on kernel exit. 2010-07-20 17:13:44 +00:00
Ben Gras
c0074d3aa9 kernel: fix case of EAX getting clobbered after sigreturn. 2010-07-20 17:10:09 +00:00
Ben Gras
e0701109ca kernel: make loading kernel in 2nd chunk of memory (at 1MB) the default.
(indicated by flags hardcoded in kernel that the boot monitor
interprets.)
2010-07-19 16:33:49 +00:00
Ben Gras
b05c989298 kernel - prettier output for ipc errors, call names instead of trap numbers 2010-07-16 15:36:29 +00:00
Cristiano Giuffrida
20101b3bab Remove patch leftovers. 2010-07-13 22:40:14 +00:00
Cristiano Giuffrida
f8a8ea0a79 Dynamic configuration in system.conf for boot system services. 2010-07-13 21:11:44 +00:00
Cristiano Giuffrida
8cedace2f5 Scheduling parameters out of the kernel. 2010-07-13 15:30:17 +00:00
Ben Gras
12e9303297 kernel: compile with -mi386 under gcc/clang to not generate SSE code in-kernel. 2010-07-12 10:11:50 +00:00
Cristiano Giuffrida
8427d774b6 RS live update support. 2010-07-09 18:29:04 +00:00
Cristiano Giuffrida
1f8dbed029 RS crash recovery support. 2010-07-06 22:05:21 +00:00
Ben Gras
e920c1e1df kernel: fix main prototype 2010-07-06 12:14:59 +00:00
Ben Gras
f6f814cb02 include, kernel: minor fixes to make compiling and linking work with clang.
(fixing warnings)
2010-07-06 11:59:19 +00:00
Kees van Reeuwijk
0cfdb11450 Repair errors and warnings flagged by llvm. 2010-07-06 11:29:23 +00:00
Ben Gras
42399159da kernel: these asserts from r7657 are not reasonable
will fire if copy needs more than one try, which is legit.
2010-07-05 17:45:16 +00:00
Ben Gras
545054c608 kernel: use MF_KCALL_RESUME instead of RTS_VMREQUEST for memcopy retry.
solves tracker item 499, submitted by Roman Ignatov.
2010-07-04 23:09:24 +00:00
Tomas Hruby
97eb470bee Fix 2010-07-01 12:31:53 +00:00
Tomas Hruby
7920d48156 FPU cleanup
- last reference to MF_USED_FPU removed

- proc_used_fpu() used to test for MF_FPU_INITIALIZED
2010-07-01 12:23:25 +00:00
Erik van der Kouwe
23284ee7bd User-space scheduling for system processes 2010-07-01 08:32:33 +00:00
Cristiano Giuffrida
180358ffb4 Give RS a page table. 2010-06-28 22:07:49 +00:00
Cristiano Giuffrida
06700d05d1 Give RS a page table. 2010-06-28 21:53:37 +00:00
Ben Gras
8379b08845 library function to retrieve kernel proc table and sanity check it 2010-06-28 11:05:15 +00:00
Tomas Hruby
67fa273d00 MF_REPLY_PEND should be removed when sendrec finishes 2010-06-28 08:32:49 +00:00
Kees van Reeuwijk
5eb6f6e922 Fixed a type declaration inconsistency. 2010-06-26 21:13:36 +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
Erik van der Kouwe
fe07e7c984 Optional IPC logging 2010-06-24 13:31:40 +00:00
Ben Gras
b3a0a2d86f kernel: don't initialize catch_pagefaults at the extern declaration. 2010-06-24 12:23:23 +00:00
Tomas Hruby
76708e9bf4 mini_receive() clean up
- for better readability xpp is substitued by sender

- makes sure that the dequeued sender has p_q_link == NULL and that
  this condition holds when enqueuing the sender again. This is a
  sanity check to make sure that the new sender is not enqueued
  already

- Before this change the dequeued sender's p_q_link may not be NULL
  and it was only set to NULL when enqueued again
2010-06-23 10:36:19 +00:00
Tomas Hruby
6bc21b6992 Cycle counters zeroed after fork for the child 2010-06-18 14:01:34 +00:00
Tomas Hruby
360de619c0 No linear addresses in message delivery
- removes p_delivermsg_lin item from the process structure and code
  related to it

- as the send part, the receive does not need to use the
  PHYS_COPY_CATCH() and umap_local() couple.  

- The address space of the target process is installed before
  delivermsg() is called.

- unlike the linear address, the virtual address does not change when
  paging is turned on nor after fork().
2010-06-11 08:16:10 +00:00
Ben Gras
a6e357da22 kernel: fix assert condition after a caught in-kernel pagefault 2010-06-09 10:59:57 +00:00
Kees van Reeuwijk
826b9590f2 More endpoint_t correctness.
More const correctness.
Other code cleanup.
2010-06-08 14:09:18 +00:00
Arun Thomas
4c10a31440 Remove legacy MM, FS, and FS_PROC_NR macros 2010-06-08 13:58:01 +00:00
Erik van der Kouwe
7bd7946346 Remove redundant macro cproc_addr 2010-06-08 13:38:44 +00:00
Erik van der Kouwe
78186ee5f5 Add endpoint checks in scheduling kernel calls 2010-06-08 12:04:21 +00:00
Ben Gras
a09a8d4f3e kernel: fix for vm_init that triggered assert(ptproc == newptproc)
- zero cr3 in vm_init() to avoid switch_address_space() not doing anything.

 - add vm_stop() to disable paging on shutdown.
2010-06-07 22:21:45 +00:00
Tomas Hruby
cbc9586c13 Lazy FPU
- FPU context is stored only if conflict between 2 FPU users or while
  exporting context of a process to userspace while it is the active
  user of FPU

- FPU has its owner (fpu_owner) which points to the process whose
  state is currently loaded in FPU

- the FPU exception is only turned on when scheduling a process which
  is not the owner of FPU

- FPU state is restored for the process that generated the FPU
  exception. This process runs immediately without letting scheduler
  to pick a new process to resolve the FPU conflict asap, to minimize
  the FPU thrashing and FPU exception hadler execution

- faster all non-FPU-exception kernel entries as FPU state is not
  checked nor saved

- removed MF_USED_FPU flag, only MF_FPU_INITIALIZED remains to signal
  that a process has used FPU in the past
2010-06-07 07:43:17 +00:00
Cristiano Giuffrida
a53514d4a9 Fix range checking in safecopy. 2010-06-04 18:05:38 +00:00
Tomas Hruby
f28acecb78 Removed a buggy assert unintentionally commted in r7044 2010-06-04 10:54:43 +00:00
Ben Gras
2f892aca91 kernel fpu context switching: fix race condition
There seems to have been a broken assumption in the fpu context
restoring code.  It restores the context of the running process, without
guarantee that the current process is the one that will be scheduled.
This caused fpu saving for a different process to be triggered without
fpu hardware being enabled, causing an fpu exception in the kernel. This
practically only shows up with DEBUG_RACE on. Fix my thruby+me.

The fix
 . is to only set the fpu-in-use-by-this-process flag in the
   exception handler, and then take care of fpu restoring when
   actually returning to userspace

And the patch
 . translates fpu saving and restoring to c in arch_system.c,
   getting rid of a juicy chunk of assembly
 . makes osfxsr_feature private to arch_system.c
 . removes most of the arch dependent code from do_sigsend
2010-06-03 11:32:22 +00:00
Kees van Reeuwijk
36e12d5bd8 Use endpoint_t for the destination of mini_send and _syscall, and the
source of mini_receive.

Also some small cleanup.
2010-06-02 21:51:32 +00:00
Kees van Reeuwijk
ed0b81c25c Removed some unused variables and functions. 2010-06-02 19:41:38 +00:00
Tomas Hruby
463be393c2 Gracefull crash if FPU exception in kernel 2010-06-02 13:59:55 +00:00
Tomas Hruby
7bfa47476c Fixed stack trace if panic in stop_context() 2010-06-02 08:53:49 +00:00
Arun Thomas
8579c59b3f Minor makefile changes for GCC 2010-06-01 09:41:31 +00:00
Tomas Hruby
40f440b8cd KCall methods do not depend on m_source and m_type fields
- substituted the use of the m_source message field by
  caller->p_endpoint in kernel calls. It is the same information, just
  passed more intuitively.
  
- the last dependency on m_type field is removed.
  
- do_unused() is substituted by a check for NULL.

- this pretty much removes the depency of kernel calls on the general
  message format. In the future this may be used to pass the kcall
  arguments in a different structure or registers (x86-64, ARM?) The
  kcall number may be passed in a register already.
2010-06-01 08:54:31 +00:00
Tomas Hruby
ebbd319ac0 do_safecopy split
- removes dependency of do_safecopy() on the m_type field of the kcall
  messages.

- instead of do_safecopy() figuring out what action is requested, the
  correct safecopy method is called right away.
2010-06-01 08:51:37 +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
Tomas Hruby
24764ff47a Fixed ms-based scheduling for legacy timer 2010-05-26 08:20:29 +00:00
David van Moolenbroek
51ff10d7c0 reset alarm timer on PRIVCTL 2010-05-26 07:10:28 +00:00
Tomas Hruby
451a6890d6 scheduling - time quantum in miliseconds
- Currently the cpu time quantum is timer-ticks based. Thus the
  remaining quantum is decreased only if the processes is interrupted
  by a timer tick. As processes block a lot this typically does not
  happen for normal user processes. Also the quantum depends on the
  frequency of the timer.

- This change makes the quantum miliseconds based. Internally the
  miliseconds are translated into cpu cycles. Everytime userspace
  execution is interrupted by kernel the cycles just consumed by the
  current process are deducted from the remaining quantum.

- It makes the quantum system timer frequency independent.

- The boot processes quantum is loosely derived from the tick-based
  quantas and 60Hz timer and subject to future change

- the 64bit arithmetics is a little ugly, will be changes once we have
  compiler support for 64bit integers (soon)
2010-05-25 08:06:14 +00:00
Kees van Reeuwijk
ac14a989b3 Fixed some inconsistent strict typing declarations.
Better strict typing.
2010-05-25 07:23:24 +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
Arun Thomas
b0159ad168 Buildsystem changes for GCC
-Makefile updates
-Update mkdep
-Build fixes/warning cleanups for some programs
-Restore leading underscores on global syms in kernel asm files
-Increase ramdisk size
2010-05-19 13:24:15 +00:00
Ben Gras
6d0e53c2ca use oxpcie only if enabled to avoid baud bottleneck of uart. 2010-05-19 10:18:46 +00:00
Ben Gras
9ba760e603 kernel: oxpcie serial card support.
ask to map in oxpcie i/o memory and support serial i/o for it in the
kernel. set oxpcie=<address> in boot monitor (retrieve address using
pci_debug=1 output). (no sanity checking is done on the address
currently.) disabled by default.

The change also contains some other minor cleanup (a new serial.h to set
register info common to UART and the OXPCIe card, in-kernel memory
mapping a little more structured and env_get() to get sysenv variables
without knowing about the params_buffer).
2010-05-19 10:00:02 +00:00
Tomas Hruby
dcc81d73e8 boot image - no need for entry point
- removes the initial_pc from struct boot_image. It is always set
  to 0 and RS uses a.out headers.
2010-05-18 13:51:46 +00:00
Tomas Hruby
b09bcf6779 Scheduling server (by Bjorn Swift)
In this second phase, scheduling is moved from PM to its own
scheduler (see r6557 for phase one). In the next phase we hope to a)
include useful information in the "out of quantum" message and b)
create some simple scheduling policy that makes use of that
information.

When the system starts up, PM will iterate over its process table and
ask SCHED to take over scheduling unprivileged processes. This is
done by sending a SCHEDULING_START message to SCHED. This message
includes the processes endpoint, the parent's endpoint and its nice
level. The scheduler adds this process to its schedproc table, issues
a schedctl, and returns its own endpoint to PM - as the endpoint of
the effective scheduler. When a process terminates, a SCHEDULING_STOP
message is sent to the scheduler.

The reason for this effective endpoint is for future compatibility.
Some day, we may have a scheduler that, instead of scheduling the
process itself, forwards the SCHEDULING_START message on to another
scheduler.

PM has information on who schedules whom. As such, scheduling
messages from user-land are sent through PM. An example is when
processes change their priority, using nice(). In that case, a
getsetpriority message is sent to PM, which then sends a
SCHEDULING_SET_NICE to the process's effective scheduler.

When a process is forked through PM, it inherits its parent's
scheduler, but is spawned with an empty quantum. As before, a request
to fork a process flows through VM before returning to PM, which then
wakes up the child process. This flow has been modified slightly so
that PM notifies the scheduler of the new process, before waking up
the child process. If the scheduler fails to take over scheduling,
the child process is torn down and the fork fails with an erroneous
value.

Process priority is entirely decided upon using nice levels. PM
stores a copy of each process's nice level and when a child is
forked, its parent's nice level is sent in the SCHEDULING_START
message. How this level is mapped to a priority queue is up to the
scheduler. It should be noted that the nice level is used to
determine the max_priority and the parent could have been in a lower
priority when it was spawned. To prevent a CPU intensive process from
hawking the CPU by continuously forking children that get scheduled
in the max_priority, the scheduler should determine in which queue
the parent is currently scheduled, and schedule the child in that
same queue.

Other fixes: The USER_Q in kernel/proc.h was incorrectly defined as
NR_SCHED_QUEUES/2. That results in a "off by one" error when
converting priority->nice->priority for nice=0. This also had the
side effect that if someone were to set the MAX_USER_Q to something
else than 0, then USER_Q would be off.
2010-05-18 13:39:04 +00:00
Tomas Hruby
b90c2d7026 rename of mode/context switching functions
- this patch only renames schedcheck() to switch_to_user(),
  cycles_accounting_stop() to context_stop() and restart() to
  +restore_user_context()

- the motivation is that since the introduction of schedcheck() it has
  been abused for many things. It deserves a better name.  It should
  express the fact that from the moment we call the function we are in
  the process of switching to user.

- cycles_accounting_stop() was originally a single purpose function.
  As this function is called at were convenient places it is used in
  for other things too, e.g. (un)locking the kernel. Thus it deserves
  a better name too.

- using the old name, restart() does not call schedcheck(), however
  calls to restart are replaced by calls to schedcheck()
  [switch_to_user] and it calls restart() [restore_user_context]
2010-05-18 13:00:39 +00:00
Ben Gras
bfc9c5c3a8 kernel: small ammendment to pagefault-in-kernel panic 2010-05-12 08:56:11 +00:00
Ben Gras
c5c25e7abc kernel/vm: change pde table info from single buffer to explicit per-process.
makes code in kernel more readable, and allows better sanity checking on
using the pde info.
2010-05-12 08:31:05 +00:00
Ben Gras
7c5e1d1b29 kernel - don't print info about scheduled process if pagefault happened in kernel. 2010-05-11 15:14:10 +00:00
Erik van der Kouwe
b7bf2733d6 Intermediate boot verbosity level EXTRA (2), MAX moved to 3 2010-05-10 18:07:59 +00:00
Tomas Hruby
6e25ad8b0a Use of all NIL_* defines converted to NULL 2010-05-10 13:26:00 +00:00
Ben Gras
a1636b85b7 kernel: new DEBUG_RACE option. try to provoke race conditions between processes.
it does this by 
  - making all processes interruptible by running out of quantum
  - giving all processes a single tick of quantum
  - picking a random runnable process instead of in order, and
    from a single pool of runnable processes (no priorities)

This together with very high HZ values currently provokes some race conditions
seen earlier only when running with SMP.
2010-05-08 18:00:03 +00:00
Ben Gras
72335b7642 kernel: print spurious interrupt message with increasing interval. 2010-05-08 17:21:37 +00:00
Tomas Hruby
4f962b4798 A small mini_receive() cleanup
- this patch substitutes *xpp for sender to increase readability of
  mini_receive().

- makes sure that the dequeued sender has p_q_link == NULL and that
  this condition holds when enqueuing the sender again. 

- it is a sanity check to make sure that the new sender is not
  enqueued already. Before this change the dequeued sender's p_q_link
  may not be NULL and it was only set to NULL when enqueued again.
2010-05-07 11:22:49 +00:00
Ben Gras
b8eddf00d8 kernel: don't try to lookup ANY in debug output. 2010-05-06 22:39:11 +00:00
Ben Gras
0194fe55dc kernel: increase some per-process privilege limits. 2010-05-06 22:21:08 +00:00
Tomas Hruby
ec56479675 deadlock() - more info
- deadlock() is more verbose in case of a detected deadlock. First, it
  lists all processses in the deadlock group. Then it prints the proc
  extra info, not only  stack trace and register dump
2010-05-03 17:38:54 +00:00
Tomas Hruby
57a88ce708 debugging - printing processes on serial
- this patch moves the former printslot() from arch_system.c to
  debug.c and reimplements it slightly. The output is not changed,
  however, the process information is printed in a separate function
  print_proc() in debug.c as such a function is also handy in other
  situations and should be publicly available when debugging.
2010-05-03 17:37:18 +00:00
Ben Gras
4e837dcfb3 kernel: more diagnostics for privctl ENOMEM conditions. 2010-04-29 08:50:52 +00:00
Ben Gras
50335291ae kernel: fpu_init: only enable OSXMMEXCPT in CR4 on at least SSE1 machines.
Found and debugged by totalinux at yandex.ru and Evgeniy Ivanov, thanks!
2010-04-28 13:51:02 +00:00
Ben Gras
c37401f23f kernel: fpu init to separate function; also move fpu init down
moving the fpu code causes exceptions raised by it to be trapped
neatly instead of causing a triple fault, before the IDT is initialized.
2010-04-28 13:25:29 +00:00
Erik van der Kouwe
84d404aba3 Fix types in debug register functions 2010-04-28 08:35:05 +00:00
Tomas Hruby
b528d52ea8 pagefault() is private 2010-04-27 20:30:33 +00:00
Erik van der Kouwe
4bddc57477 Remove debug printfs in breakpoints.c, they should never have been there 2010-04-27 12:25:04 +00:00
Tomas Hruby
f51eea4b32 Changed pagefault delivery to VM
this patch changes the way pagefaults are delivered to VM. It adopts
the same model as the out-of-quantum messages sent by kernel to a
scheduler.

- everytime a userspace pagefault occurs, kernel creates a message
  which is sent to VM on behalf of the faulting process

- the process is blocked on delivery to VM in the standard IPC code
  instead of waiting in a spacial in-kernel queue (stack) and is not
  runnable until VM tell kernel that the pagefault is resolved and is
  free to clear the RTS_PAGEFAULT flag.

- VM does not need call kernel and poll the pagefault information
  which saves many (1/2?) calls and kernel calls that return "no more
  data"

- VM notification by kernel does not need to use signals

- each entry in proc table is by 12 bytes smaller (~3k save)
2010-04-26 23:21:26 +00:00
Ben Gras
86e8eff905 remove intr_disabled() as interrupts are always disabled in the kernel now. 2010-04-26 15:32:42 +00:00
Cristiano Giuffrida
0f353411d7 Set IPC status code only for RECEIVE 2010-04-26 14:43:59 +00:00
Kees van Reeuwijk
d106968d77 Remove useless symbol declarations from headers, make symbols local where possible, add some explicit initialization to global variables. 2010-04-22 07:49:40 +00:00
Kees van Reeuwijk
86a23c1fbd Remove U16_t and most other similar types. Rewrite functions to ansi-style
declaration if necessary.
2010-04-21 11:05:22 +00:00
Kees van Reeuwijk
b412fb7ad5 Code cleanup: remove unused #include, variables and code, 2010-04-15 18:49:36 +00:00
Erik van der Kouwe
8b459cfbb3 Provide information on lethal signals (stacktrace and signo) 2010-04-14 09:06:34 +00:00
Kees van Reeuwijk
fa3adedf63 Remove some duplicate declarations in headers.
Explicitly declare some functions as returning void.
2010-04-13 15:22:38 +00:00
Kees van Reeuwijk
bc314bda91 Remove the types Dev_t, _mnx_Gui, _mnx_Uid, and similar.
Use ANSI-style function declarations where necessary.
2010-04-13 10:58:41 +00:00
Tomas Hruby
9b599bac1d Quantum in fork
- This patch removes the time slice split between parent and child in
  fork.

- The time slice of the parent remains unchanged and the child does
  not have any.

- If the process has a scheduler, the scheduler must assign the
  quantum and priority of the new process and let it run.

- If the child does not inherit a scheduler, it is scheduled by the
  dummy default kernel policy. (servers, drivers, etc.)

- In theory, the scheduler can change the quantum even of the parent
  process and implement any policy for splitting the quantum as
  neither the parent nor the child are runnable.  Sending the
  out-of_quantum message on behalf of the processes may look like the
  right solution, however, the scheduler would probably handle the
  message before the whole fork protocol is finished. This way the
  scheduler has absolute control when the process should become
  runnable.
2010-04-10 15:27:38 +00:00
Tomas Hruby
512058ca98 This tiny cleanup makes the naming a variables in createpde() more clear. 2010-04-10 15:22:41 +00:00
Tomas Hruby
9fdb773cdb A simpler test whether to use kernel's default scheduling
- this is a small addition to the userspace scheduling.
  proc_kernel_scheduler() tests whether to use the default scheduling
  policy in kernel. It is true if the process' scheduler is NULL _or_
  self. Currently none of the tests was complete.
2010-04-10 15:19:25 +00:00
Tomas Hruby
485a037563 do_schedule() cleanup
- it is not neccessary to test whether the scheduler is a system
  process as the process already head permissions to make this call.

- it is better to test whether the scheduler has permission to make
  changes to this process before testing whether the values are valid.
2010-04-10 15:17:09 +00:00
Cristiano Giuffrida
48c6bb79f4 Driver refactory for live update and crash recovery.
SYSLIB CHANGES:
- DS calls to publish / retrieve labels consider endpoints instead of u32_t.

VFS CHANGES:
- mapdriver() only adds an entry in the dmap table in VFS.
- dev_up() is only executed upon reception of a driver up event.

INET CHANGES:
- INET no longer searches for existing drivers instances at startup.
- A newtwork driver is (re)initialized upon reception of a driver up event.
- Networking startup is now race-free by design. No need to waste 5 seconds
at startup any more.

DRIVER CHANGES:
- Every driver publishes driver up events when starting for the first time or
in case of restart when recovery actions must be taken in the upper layers.
- Driver up events are published by drivers through DS. 
- For regular drivers, VFS is normally the only subscriber, but not necessarily.
For instance, when the filter driver is in use, it must subscribe to driver
up events to initiate recovery.
- For network drivers, inet is the only subscriber for now.
- Every VFS driver is statically linked with libdriver, every network driver
is statically linked with libnetdriver.

DRIVER LIBRARIES CHANGES:
- Libdriver is extended to provide generic receive() and ds_publish() interfaces
for VFS drivers.
- driver_receive() is a wrapper for sef_receive() also used in driver_task()
to discard spurious messages that were meant to be delivered to a previous
version of the driver.
- driver_receive_mq() is the same as driver_receive() but integrates support
for queued messages.
- driver_announce() publishes a driver up event for VFS drivers and marks
the driver as initialized and expecting a DEV_OPEN message.
- Libnetdriver is introduced to provide similar receive() and ds_publish()
interfaces for network drivers (netdriver_announce() and netdriver_receive()).
- Network drivers all support live update with no state transfer now.

KERNEL CHANGES:
- Added kernel call statectl for state management. Used by driver_announce() to
unblock eventual callers sendrecing to the driver.
2010-04-08 13:41:35 +00:00
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
b464da5d73 do_nice.c
- this file is not used and should have been remove in r6557
2010-04-06 13:44:03 +00:00
Tomas Hruby
987b87e2ad Small fixes
- do_sync_ipc() is private

- fixed typo in a comment
2010-04-06 11:29:31 +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
Tomas Hruby
b0d37b81c4 RTS_SYS_LOCK and do_runctl()
- No need for RTS_SYS_LOCK as there are no tasks anymore.
2010-04-06 11:18:04 +00:00
Tomas Hruby
cdd6743e88 do_vtimer()
- removed comment which is not true anymore as we don't have any
  tasks. No need to take any special measures.
2010-04-06 11:16:14 +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
Cristiano Giuffrida
d8b42a755d Move kernel signal SIGKNDELAY to system signal SIGSNDELAY and fix broken ptrace. 2010-03-31 08:55:12 +00:00
Kees van Reeuwijk
4865e3f4f9 More use of endpoint_t. Other code cleanup. 2010-03-30 14:07:15 +00:00
Tomas Hruby
63e2d73d1b Fixed brackets in bitmap macros 2010-03-30 08:34:33 +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
5b52c5aa02 A reliable way for userspace to check if a msg is from kernel
- IPC_FLG_MSG_FROM_KERNEL status flag is returned to userspace if the
  receive was satisfied by s message which was sent by the kernel on
  behalf of a process. This perfectly reliale information.

- MF_SENDING_FROM_KERNEL flag added to processes to be able to set
  IPC_FLG_MSG_FROM_KERNEL when finishing receive if the receiver
  wasn't ready to receive immediately.

- PM is changed to use this information to confirm that the scheduling
  messages are indeed from the kernel and not faked by a process.

  PM uses sef_receive_status()

- get_work() is removed from PM to make the changes simpler
2010-03-29 11:25:01 +00:00
Tomas Hruby
2521cc6bdf Slightly faster IPC
- there are cycles wasted in the IPC call due to a fairly compliacted
  way of copying messages from userland to kernel. Sometimes this
  complicated way (generic though) is used even for copying within the
  kernel address space, sometimes it is used for copying in case _no_
  copying is necessary. The goal of this patch is to improve this a
  little bit.

- the places where a copy is from user to kernel use the
  copy_msg_from_user() kernel-kernel copies are turned into
  assignments and BuildNotifyMessage uses the delivery buffers to
  avoid copying.

- copy_msg_from_user() was introduced when removing the system task
  and is about 2/3 faster then using the current mechanism
  (phys_copy). It also avoids the PHYS_COPY_CATCH macro. Assignment is
  also faster and no copy is the fastest ;-) so perhaps there will be
  some hardly noticable performance gain besides the clean up.
2010-03-29 11:16:37 +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
Tomas Hruby
a3ffc0f7ad Removed NIL_SYS_PROC and NIL_PROC
- NIL_PROC replaced by simple NULLs
2010-03-28 09:54:32 +00:00
Kees van Reeuwijk
98493805fd Lots of const correctness. 2010-03-27 14:31:00 +00:00
Cristiano Giuffrida
9192dbecc9 Preserve the order of IPC messages between two parties.
Currently a sequence of messages between a sender A and a receiver B of the
form: A.asynsend(M1, B); A.send(M2, B) may result in the receiver receiving
M1 first and then M2 or viceversa. This patch makes sure that the original
order M1, M2 is always preserved.

Note that the order of a hypotetical sequence A.asynsend(M1, B);
A.asynsend(M2, B) is already guaranteed by the implementation of
asynsend by design. Other senda-based wrappers can define their own
semantics.
2010-03-27 00:09:22 +00:00
Tomas Hruby
8e5a82fd49 Comment in proc.h
- This comment is not correct as the pproc_addr array does not exist.
2010-03-26 13:19:04 +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
Cristiano Giuffrida
bde2109b7c IPC status code for receive().
IPC changes:
- receive() is changed to take an additional parameter, which is a pointer to
a status code.
- The status code is filled in by the kernel to provide additional information
to the caller. For now, the kernel only fills in the IPC call used by the
sender.

Syslib changes:
- sef_receive() has been split into sef_receive() (with the original semantics)
and sef_receive_status() which exposes the status code to userland.
- Ideally, every sys process should gradually switch to sef_receive_status()
and use is_ipc_notify() as a dependable way to check for notify.
- SEF has been modified to use is_ipc_notify() and demonstrate how to use the
new status code.
2010-03-23 00:09:11 +00:00
Cristiano Giuffrida
45db6482e8 Prioritized NOTIFY messages for reliable asynchonrous delivery of system events. 2010-03-22 23:44:55 +00:00
Kees van Reeuwijk
c33102ea6b Miscellaneous code cleanup. 2010-03-22 20:43:06 +00:00
Ben Gras
4b2310a7ee only print 1 every 1000 spurious interrupts (per interrupt). 2010-03-22 13:55:51 +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