Commit Graph

39 Commits

Author SHA1 Message Date
Konstantin Belousov
3e902b3d76 Make WRFSBASE and WRGSBASE instructions functional.
Right now, we enable the CR4.FSGSBASE bit on CPUs which support the
facility (Ivy and later), to allow usermode to read fs and gs bases
without syscalls. This bit also controls the write access to bases
from userspace, but WRFSBASE and WRGSBASE instructions currently
cannot be used, because return path from both exceptions or interrupts
overrides bases with the values from pcb.

Supporting the instructions is useful because this means that usermode
can implement green-threads completely in userspace without issuing
syscalls to change all of the machine context.

Support is implemented by saving the fs base and user gs base when
PCB_FULL_IRET flag is set. The flag is set on the context switch,
which potentially causes clobber of the bases due to activation of
another context, and when explicit modification of the user context by
a syscall or exception handler is performed. In particular, the patch
moves setting of the flag before syscalls change context.

The changes to doreti_exit and PUSH_FRAME to clear PCB_FULL_IRET on
entry from userspace can be considered a bug fixes on its own.

Reviewed by:	jhb (previous version)
Tested by:	pho (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks
Differential revision:	https://reviews.freebsd.org/D12023
2017-08-21 17:38:02 +00:00
Warner Losh
fbbd9655e5 Renumber copyright clause 4
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by:	Jan Schaumann <jschauma@stevens.edu>
Pull Request:	https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00
Scott Long
18e3d9f521 Extend earlier addition of stack frames to most of support.S. This makes
stack traces in KDB, HWPMC, and DTrace much more reliable and useful.

Reviewed by:	kan, kib
Obtained from:	Netflix, Inc.
MFC after:	5 days
2014-11-13 22:11:44 +00:00
Roger Pau Monné
1a9cdd373a xen: add PV/PVH kernel entry point
Add the PV/PVH entry point and the low level functions for PVH
early initialization.

Approved by: gibbs
Sponsored by: Citrix Systems R&D

amd64/amd64/genassym.c:
 - Add __FreeBSD_version define to assym.s so it can be used for the
   Xen notes.

amd64/amd64/locore.S:
 - Make bootstack global so it can be used from Xen kernel entry
   point.

amd64/amd64/xen-locore.S:
 - Add Xen notes to the kernel.
 - Add the Xen PV entry point, that is going to call hammer_time_xen.

amd64/include/asmacros.h:
 - Add ELFNOTE macros.

i386/xen/xen_machdep.c:
 - Define HYPERVISOR_start_info for the XEN i386 PV port, which is
   going to be used in some shared code between PV and PVH.

x86/xen/hvm.c:
 - Define HYPERVISOR_start_info for the PVH port.

x86/xen/pv.c:
 - Introduce hammer_time_xen which is going to perform early setup for
   Xen PVH:
    - Setup shared Xen variables start_info, shared_info and
      xen_store.
    - Set guest type.
    - Create initial page tables as FreeBSD expects to find them.
    - Call into native init function (hammer_time).

xen/xen-os.h:
 - Declare HYPERVISOR_start_info.

conf/files.amd64:
 - Add amd64/amd64/locore.S and x86/xen/pv.c to the list of files.
2014-03-11 10:07:01 +00:00
Konstantin Belousov
595473a587 Clear DF bit in eflags/rflags on the kernel entry. The i386 and amd64
ABI specifies the DF should be zero, and newer compilers do not clear
DF before using DF-sensitive instructions.

The DF clearing for signal handlers was done some time ago.

MFC after:	1 week
2010-06-23 20:44:07 +00:00
Konstantin Belousov
2c66cccab7 Save and restore segment registers on amd64 when entering and leaving
the kernel on amd64. Fill and read segment registers for mcontext and
signals. Handle traps caused by restoration of the
invalidated selectors.

Implement user-mode creation and manipulation of the process-specific
LDT descriptors for amd64, see sysarch(2).

Implement support for TSS i/o port access permission bitmap for amd64.

Context-switch LDT and TSS. Do not save and restore segment registers on
the context switch, that is handled by kernel enter/leave trampolines
now. Remove segment restore code from the signal trampolines for
freebsd/amd64, freebsd/ia32 and linux/i386 for the same reason.

Implement amd64-specific compat shims for sysarch.

Linuxolator (temporary ?) switched to use gsbase for thread_area pointer.

TODO:
Currently, gdb is not adapted to show segment registers from struct reg.
Also, no machine-depended ptrace command is added to set segment
registers for debugged process.

In collaboration with:	pho
Discussed with:	peter
Reviewed by:	jhb
Linuxolator tested by:	dchagin
2009-04-01 13:09:26 +00:00
Joseph Koshy
298889efcb Define an END() macro for use in i386 and amd64 assembly code, akin
to the one available on the ia64, sparc64, and sun4v architectures.

Approved by:	re (kensmith)
2007-08-22 04:26:07 +00:00
Bruce Evans
94450a83e8 Removed all traces of HIDENAME() in amd64 and i386 kernel code. Using
this used to be slightly cleaner than using ifdefs in a few places to
support both a.out and elf, but using it now just causes messes and
unportabilities.  It seems to be impossible to implement the elf
HIDENAME() portably in cpp (since token pasting of "." and <name> is
invalid).

*/prof_machdep.c:
- Removed all uses of CNAME().  CNAME() is easy enough to use in pure
  asm code, but using it in inline asm requires messy quoting.  The
  core pure asm code has been hacked on more and all uses of CNAME() in
  it have already gone away.  Just assume the elf convention here too.
- Removed now-uneeded include of <machine/asmacros.h>.
- Removed the workaround for a namespace conflict with this include.
2006-10-28 06:04:29 +00:00
Bruce Evans
447647908c Don't call mexitcount or provide a stub mexitcount to call when
profiling is configured but high resolution profiling is not configured.
Only functions in *.[Ss] called the stub, so efficiency was not
significantly affected.
2006-10-27 14:17:50 +00:00
Peter Wemm
8d0593f54e Merge/sync with i386: various cosmetic tweaks 2006-03-14 00:01:56 +00:00
John Baldwin
333b8de537 MFi386:
- Move PUSH_FRAME and POP_FRAME to asmacros.h and use PUSH_FRAME in
  atpic entry points.
- Move PCPU_* asm macros out of the middle of the asm profiling macros.
- Pass IRQ vector argument as an int rather than void * to reduce diffs
  with i386.
- EOI the lapic in C for the lapic timer handler.
- GC unused Xcpuast function.
- Split IPI_STOP handling code of ipi_nmi_handler() out into a
  cpustop_handler() function and call it from Xcpustop rather than
  duplicating all the logic in assembly.
- Fixup the list of symbols with interrupt frames in ddb traces.
  Xatpic_fastintr* have never existed on amd64, and the lapic timer
  handler and various IPI handlers were missing.
- Use trapframe instead of intrframe for interrupt entry points (on amd64
  the interrupt vector was already a separate argument, so the two frames
  were already identical) and GC intrframe.

Submitted by:	peter (3)
2005-12-08 18:33:30 +00:00
Warner Losh
29ae923f44 Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core
2004-04-05 21:29:41 +00:00
Peter Wemm
cda078658e Cosmetic and/or trivial sync up with i386.
Approved by:  re (rwatson)
2003-11-21 03:02:00 +00:00
Peter Wemm
0d2a298904 Initial landing of SMP support for FreeBSD/amd64.
- This is heavily derived from John Baldwin's apic/pci cleanup on i386.
- I have completely rewritten or drastically cleaned up some other parts.
  (in particular, bootstrap)
- This is still a WIP.  It seems that there are some highly bogus bioses
  on nVidia nForce3-150 boards.  I can't stress how broken these boards
  are.  I have a workaround in mind, but right now the Asus SK8N is broken.
  The Gigabyte K8NPro (nVidia based) is also mind-numbingly hosed.
- Most of my testing has been with SCHED_ULE.  SCHED_4BSD works.
- the apic and acpi components are 'standard'.
- If you have an nVidia nForce3-150 board, you are stuck with 'device
  atpic' in addition, because they somehow managed to forget to connect the
  8254 timer to the apic, even though its in the same silicon!  ARGH!
  This directly violates the ACPI spec.
2003-11-17 08:58:16 +00:00
Peter Wemm
afa8862328 Commit MD parts of a loosely functional AMD64 port. This is based on
a heavily stripped down FreeBSD/i386 (brutally stripped down actually) to
attempt to get a stable base to start from.  There is a lot missing still.
Worth noting:
- The kernel runs at 1GB in order to cheat with the pmap code.  pmap uses
  a variation of the PAE code in order to avoid having to worry about 4
  levels of page tables yet.
- It boots in 64 bit "long mode" with a tiny trampoline embedded in the
  i386 loader.  This simplifies locore.s greatly.
- There are still quite a few fragments of i386-specific code that have
  not been translated yet, and some that I cheated and wrote dumb C
  versions of (bcopy etc).
- It has both int 0x80 for syscalls (but using registers for argument
  passing, as is native on the amd64 ABI), and the 'syscall' instruction
  for syscalls.  int 0x80 preserves all registers, 'syscall' does not.
- I have tried to minimize looking at the NetBSD code, except in a couple
  of places (eg: to find which register they use to replace the trashed
  %rcx register in the syscall instruction).  As a result, there is not a
  lot of similarity.  I did look at NetBSD a few times while debugging to
  get some ideas about what I might have done wrong in my first attempt.
2003-05-01 01:05:25 +00:00
Alfred Perlstein
50225e2f48 Silence preprocessor warning, No need to use CONCAT with "," and "word". 2002-06-01 20:22:33 +00:00
John Baldwin
0bbc882680 Overhaul the per-CPU support a bit:
- The MI portions of struct globaldata have been consolidated into a MI
  struct pcpu.  The MD per-CPU data are specified via a macro defined in
  machine/pcpu.h.  A macro was chosen over a struct mdpcpu so that the
  interface would be cleaner (PCPU_GET(my_md_field) vs.
  PCPU_GET(md.md_my_md_field)).
- All references to globaldata are changed to pcpu instead.  In a UP kernel,
  this data was stored as global variables which is where the original name
  came from.  In an SMP world this data is per-CPU and ideally private to each
  CPU outside of the context of debuggers.  This also included combining
  machine/globaldata.h and machine/globals.h into machine/pcpu.h.
- The pointer to the thread using the FPU on i386 was renamed from
  npxthread to fpcurthread to be identical with other architectures.
- Make the show pcpu ddb command MI with a MD callout to display MD
  fields.
- The globaldata_register() function was renamed to pcpu_init() and now
  init's MI fields of a struct pcpu in addition to registering it with
  the internal array and list.
- A pcpu_destroy() function was added to remove a struct pcpu from the
  internal array and list.

Tested on:	alpha, i386
Reviewed by:	peter, jake
2001-12-11 23:33:44 +00:00
Peter Wemm
5107b058bc Always use the ELF naming after the demise of asnames.h. 2001-02-25 07:23:03 +00:00
Jake Burkholder
02318dac2c Remove the leading underscore from all symbols defined in x86 asm
and used in C or vice versa.  The elf compiler uses the same names
for both.  Remove asnames.h with great prejudice; it has served its
purpose.

Note that this does not affect the ability to generate an aout kernel
due to gcc's -mno-underscores option.

moral support from:	peter, jhb
2001-02-25 06:29:04 +00:00
Jake Burkholder
41ed17bfec Use %fs to access per-cpu variables in uni-processor kernels the same
as multi-processor kernels.  The old way made it difficult for kernel
modules to be portable between uni-processor and multi-processor
kernels.  It is no longer necessary to jump through hoops.

- always load %fs with the private segment on entry to the kernel
- change the type of the self referntial pointer from struct privatespace
  to struct globaldata
- make the globaldata symbol have value 0 in all cases, so the symbols
  in globals.s are always offsets, not aliases for fields in globaldata
- define the globaldata space used for uniprocessor kernels in C, rather
  than assembler
- change the assmebly language accessors to use %fs, add a macro
  PCPU_ADDR(member, reg), which loads the register reg with the address
  of the per-cpu variable member
2001-01-06 17:40:04 +00:00
Jake Burkholder
6d43764a10 Introduce a new potientially cleaner interface for accessing per-cpu
variables from i386 assembly language.  The syntax is PCPU(member)
where member is the capitalized name of the per-cpu variable, without
the gd_ prefix.  Example: movl %eax,PCPU(CURPROC).  The capitalization
is due to using the offsets generated by genassym rather than the symbols
provided by linking with globals.o.  asmacros.h is the wrong place for
this but it seemed as good a place as any for now.  The old implementation
in asnames.h has not been removed because it is still used to de-mangle
the symbols used by the C variables for the UP case.
2000-12-13 09:23:53 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Bruce Evans
ea2b3e3d1b Fixed profiling of elf kernels. Made high resolution profiling compile
for elf kernels (it is broken for all kernels due to lack of egcs support).

Renaming of many assembler labels is avoided by declaring by declaring
the labels that need to be visible to gprof as having type "function"
and depending on the elf version of gprof being zealous about discarding
the others.  A few type declarations are still missing, mainly for SMP.

PR:		9413
Submitted by:	Assar Westerlund <assar@sics.se> (initial parts)
1999-05-06 09:44:57 +00:00
John Polstra
9081eec1fb Make the necessary changes so that an ELF kernel can be built. I
have successfully built, booted, and run a number of different ELF
kernel configurations, including GENERIC.  LINT also builds and
links cleanly, though I have not tried to boot it.

The impact on developers is virtually nil, except for two things.
All linker sets that might possibly be present in the kernel must be
listed in "sys/i386/i386/setdefs.h".  And all C symbols that are
also referenced from assembly language code must be listed in
"sys/i386/include/asnames.h".  It so happens that failure to do
these things will have no impact on the a.out kernel.  But it will
break the build of the ELF kernel.

The ELF bootloader works, but it is not ready to commit quite yet.
1997-04-22 06:55:47 +00:00
Bruce Evans
13a44161a2 Moved userland assembler macros from <machine/asmacros.h> to
<machine/asm.h>.
1997-03-09 13:57:33 +00:00
Peter Wemm
6875d25465 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
Bruce Evans
f79ef55e7a Replaced START_ENTRY by _START_ENTRY. -current hasn't got my cleanup
of DEFS.h which renamed it.
1997-02-17 07:21:28 +00:00
Bruce Evans
dab159e3d6 Select between the generic math functions and the i387-specific ones
at runtime.

etc/make.conf:
Nuked HAVE_FPU option.

lib/msun/Makefile:
Always build the i387 objects.  Copy the i387 source files at build
time so that the i387 objects have different names.  This is simpler
than renaming the files in the cvs repository or repeating half of
bsd.lib.mk to add explicit rules.

lib/msun/src/*.c:
Renamed all functions that have an i387-specific version by adding
`__generic_' to their names.

lib/msun/src/get_hw_float.c:
New file for getting machdep.hw_float from the kernel.

sys/i386/include/asmacros.h:
Abuse the ENTRY() macro to generate jump vectors and associated code.
This works much like PIC PLT dynamic initialization.  The PIC case is
messy.  The old i387 entry points are renamed.  Renaming is easier
here because the names are given by macro expansions.
1997-02-16 18:26:31 +00:00
Bruce Evans
47cac30b9a Align text to 16-byte boundaries if profiling is enabled. This will
allow a fourfold reduction in the size of the profiling buffers.  This
goes with rev.1.91 of Makefile.i386 which does the same thing for C
functions.
1997-02-13 08:31:53 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
Bruce Evans
435929a84b Added macros CROSSJUMP(), CROSSJUMP_LABEL() and GPROF_RET. These will
be used to fix some benign(?) bugs in GUPROF profiling.

Fixed stale comments and long lines.
1996-10-16 18:13:25 +00:00
Peter Wemm
ee323f62ad Jump some hoops to have the *.s code being able to be run through both an
ansi and traditional cpp.

The nesting rules of macros are different, which required some changes.
Use __CONCAT(x,y) instead of /**/.
Redo some comments to use /* */ rather than "# comment" because the ansi
  cpp cares about those, and also cares about quote matching.
1996-05-31 01:08:08 +00:00
Bruce Evans
048cd610ad Finished removing NOP macros. 1996-03-31 04:17:25 +00:00
Bruce Evans
912e603778 Implemented non-statistical kernel profiling. This is based on
looking at a high resolution clock for each of the following events:
function call, function return, interrupt entry, interrupt exit,
and interesting branches.  The differences between the times of
these events are added at appropriate places in a ordinary histogram
(as if very fast statistical profiling sampled the pc at those
places) so that ordinary gprof can be used to analyze the times.

gmon.h:
Histogram counters need to be 4 bytes for microsecond resolutions.
They will need to be larger for the 586 clock.
The comments were vax-centric and wrong even on vaxes.  Does anyone
disagree?

gprof4.c:
The standard gprof should support counters of all integral sizes
and the size of the counter should be in the gmon header.  This
hack will do until then.  (Use gprof4 -u to examine the results
of non-statistical profiling.)

config/*:
Non-statistical profiling is configured with `config -pp'.
`config -p' still gives ordinary profiling.

kgmon/*:
Non-statistical profiling is enabled with `kgmon -B'.  `kgmon -b'
still enables ordinary profiling (and distables non-statistical
profiling) if non-statistical profiling is configured.
1995-12-29 15:30:05 +00:00
Bruce Evans
ab9678ac9d Get all the definitions from DEFS.h and not directly from asmacros.h
if KERNEL is not defined.  lib/msun/i387/*.S include asmacros.h to
get the definitions of ENTRY(), etc.  This is bogus since asmacros.h
is only supposed to give definitions suitable for the kernel.  The
current definitions for the kernel almost worked but are missing
the ".type" declarations.  This caused the linker to print warnings
about doubtful relocations for almost anything linked to libm[sun].

Uniformize name and use of idempotence identifier.
1994-09-08 12:25:18 +00:00
Jordan K. Hubbard
6605d9f3db 1. Make this idempotent.
2. Hack.

	Hack is to define RCSID() to null macro so that new msun stuff
	will compile.  This does NOT belong here, and I DON'T want it to
	stay, I just need to put this here for now to enable msun and we need
	to talk about what our RCSID story is supposed to be.  We talked about
	supporting RCSID() one day, and everyone seemed to like the idea
	reasonably well of making it a macro you could just no-op this way,
	but we never did anything.  Now I see that JTCs code has it and I'm
	loath to remove it or do anything until we've discussed it some more.

	Well, so how about it?  What's our story vis-a-vis RCSID() going to
	be?

Submitted by:	jkh
1994-08-19 11:20:11 +00:00
David Greenman
3c4dd3568f Added $Id$ 1994-08-02 07:55:43 +00:00
David Greenman
d230622648 New interrupt code from Bruce Evans. In additional to Bruce's attached
list of changes, I've made the following additional changes:

1) i386/include/ipl.h renamed to spl.h as the name conflicts with the
   file of the same name in i386/isa/ipl.h.
2) changed all use of *mask (i.e. netmask, biomask, ttymask, etc) to
   *_imask (net_imask, etc).
3) changed vestige of splnet use in if_is to splimp.
4) got rid of "impmask" completely (Bruce had gotten rid of netmask),
   and are now using net_imask instead.
5) dozens of minor cruft to glue in Bruce's changes.

   These require changes I made to config(8) as well, and thus it must
be rebuilt.

-DG

from Bruce Evans:

sio:
	o No diff is supplied.  Remove the define of setsofttty().  I hope
	  that is enough.

*.s:
	o i386/isa/debug.h no longer exists.  The event counters became too
	  much trouble to maintain.  All function call entry and exception
	  entry counters can be recovered by using profiling kernel (the new
	  profiling supports all entry points; however, it is too slow to
	  leave enabled all the time; it also).  Only BDBTRAP() from debug.h
	  is now used.  That is moved to exception.s.  It might be worth
	  preserving SHOW_BITS() and calling it from _mcount() (if enabled).
	o T_ASTFLT is now only set just before calling trap().
	o All exception handlers set SWI_AST_MASK in cpl as soon as possible
	  after entry and arrange for _doreti to restore it atomically with
	  exiting.  It is not possible to set it atomically with entering
	  the kernel, so it must be checked against the user mode bits in
	  the trap frame before committing to using it.  There is no place
	  to store the old value of cpl for syscalls or traps, so there are
	  some complications restoring it.

Profiling stuff (mostly in *.s):
	o Changes to kern/subr_mcount.c, gcc and gprof are not supplied yet.
	o All interesting labels `foo' are renamed `_foo' and all
	  uninteresting labels `_bar' are renamed `bar'.  A small change
	  to gprof allows ignoring labels not starting with underscores.
	o MCOUNT_LABEL() is to provide names for counters for times spent
	  in exception handlers.
	o FAKE_MCOUNT() is a version of MCOUNT() suitable for exception
	  handlers.  Its arg is the pc where the exception occurred.  The
	  new mcount() pretends that this was a call from that pc to a
	  suitable MCOUNT_LABEL().
	o MEXITCOUNT is to turn off any timer started by MCOUNT().

/usr/src/sys/i386/i386/exception.s:
	o The non-BDB BPTTRAP() macros were doing a sti even when interrupts
	  were disabled when the trap occurred.  The sti (fixed) sti is
	  actually a no-op unless you have my changes to machdep.c that make
	  the debugger trap gates interrupt gates, but fixing that would
	  make the ifdefs messier.  ddb seems to be unharmed by both
	  interrupts always disabled and always enabled (I had the branch in
	  the fix back to front for some time :-().
	o There is no known pushal bug.
	o tf_err can be left as garbage for syscalls.

/usr/src/sys/i386/i386/locore.s:
	o Fix and update BDE_DEBUGGER support.
	o ENTRY(btext) before initialization was dangerous.
	o Warm boot shot was longer than intended.

/usr/src/sys/i386/i386/machdep.c:
	o DON'T APPLY ALL OF THIS DIFF.  It's what I'm using, but may require
	  other changes.
	  Use the following:
		o Remove aston() and setsoftclock().
	  Maybe use the following:
		o No netisr.h.
		o Spelling fix.
		o Delay to read the Rebooting message.
		o Fix for vm system unmapping a reduced area of memory
		  after bounds_check_with_label() reduces the size of
		  a physical i/o for a partition boundary.  A similar
		  fix is required in kern_physio.c.
		o Correct use of __CONCAT.  It never worked here for non-
		  ANSI cpp's.  Is it time to drop support for non-ANSI?
		o gdt_segs init.  0xffffffffUL is bogus because ssd_limit
		  is not 32 bits.  The replacement may have the same
		  value :-), but is more natural.
		o physmem was one page too low.  Confusing variable names.
	  Don't use the following:
		o Better numbers of buffers.  Each 8K page requires up to
		  16 buffer headers.  On my system, this results in 5576
		  buffers containing [up to] 2854912 bytes of memory.
		  The usual allocation of about 384 buffers only holds
		  192K of disk if you use it on an fs with a block size
		  of 512.
		o gdt changes for bdb.
		o *TGT -> *IDT changes for bdb.
		o #ifdefed changes for bdb.

/usr/src/sys/i386/i386/microtime.s:
	o Use the correct asm macros.  I think asm.h was copied from Mach
	  just for microtime and isn't used now.  It certainly doesn't
	  belong in <sys>.  Various macros are also duplicated in
	  sys/i386/boot.h and libc/i386/*.h.
	o Don't switch to and from the IRR; it is guaranteed to be selected
	  (default after ICU init and explicitly selected in isa.c too, and
	  never changed until the old microtime clobbered it).

/usr/src/sys/i386/i386/support.s:
	o Non-essential changes (none related to spls or profiling).
	o Removed slow loads of %gs again.  The LDT support may require
	  not relying on %gs, but loading it is not the way to fix it!
	  Some places (copyin ...) forgot to load it.  Loading it clobbers
	  the user %gs.  trap() still loads it after certain types of
	  faults so that fuword() etc can rely on it without loading it
	  explicitly.  Exception handlers don't restore it.  If we want
	  to preserve the user %gs, then the fastest method is to not
	  touch it except for context switches.  Comparing with
	  VM_MAXUSER_ADDRESS and branching takes only 2 or 4 cycles on
	  a 486, while loading %gs takes 9 cycles and using it takes
	  another.
	o Fixed a signed branch to unsigned.

/usr/src/sys/i386/i386/swtch.s:
	o Move spl0() outside of idle loop.
	o Remove cli/sti from idle loop.  sw1 does a cli, and in the
	  unlikely event of an interrupt occurring and whichqs becoming
	  zero, sw1 will just jump back to _idle.
	o There's no spl0() function in asm any more, so use splz().
	o swtch() doesn't need to be superaligned, at least with the
	  new mcounting.
	o Fixed a signed branch to unsigned.
	o Removed astoff().

/usr/src/sys/i386/i386/trap.c:
	o The decentralized extern decls were inconsistent, of course.
	o Fixed typo MATH_EMULTATE in comments. */
	o Removed unused variables.
	o Old netmask is now impmask; print it instead.  Perhaps we
	  should print some of the new masks.
	o BTW, trap() should not print anything for normal debugger
	  traps.

/usr/src/sys/i386/include/asmacros.h:
	o DON'T APPLY ALL OF THIS DIFF.  Just use some of the null macros
	  as necessary.

/usr/src/sys/i386/include/cpu.h:
	o CLKF_BASEPRI() changes since cpl == SWI_AST_MASK is now normal
	  while the kernel is running.
	o Don't use var++ to set boolean variables.  It fails after a mere
	  4G times :-) and is slower than storing a constant on [3-4]86s.

/usr/src/sys/i386/include/cpufunc.h:
	o DON'T APPLY ALL OF THIS DIFF.  You need mainly the include of
	  <machine/ipl.h>.  Unfortunately, <machine/ipl.h> is needed by
	  almost everything for the inlines.

/usr/src/sys/i386/include/ipl.h:
	o New file.  Defines spl inlines and SWI macros and declares most
	  variables related to hard and soft interrupt masks.

/usr/src/sys/i386/isa/icu.h:
	o Moved definitions to <machine/ipl.h>

/usr/src/sys/i386/isa/icu.s:
	o Software interrupts (SWIs) and delayed hardware interrupts (HWIs)
	  are now handled uniformally, and dispatching them from splx() is
	  more like dispatching them from _doreti.  The dispatcher is
	  essentially *(handler[ffs(ipending & ~cpl)]().
	o More care (not quite enough) is taken to avoid unbounded nesting
	  of interrupts.
	o The interface to softclock() is changed so that a trap frame is
	  not required.
	o Fast interrupt handlers are now handled more uniformally.
	  Configuration is still too early (new handlers would require
	  bits in <machine/ipl.h> and functions to vector.s).
	o splnnn() and splx() are no longer here; they are inline functions
	  (could be macros for other compilers).  splz() is the nontrivial
	  part of the old splx().

/usr/src/sys/i386/isa/ipl.h
	o New file.  Supposed to have only bus-dependent stuff.  Perhaps
	  the h/w masks should be declared here.

/usr/src/sys/i386/isa/isa.c:
	o DON'T APPLY ALL OF THIS DIFF.  You need only things involving
	  *mask and *MASK and comments about them.  netmask is now a pure
	  software mask.  It works like the softclock mask.

/usr/src/sys/i386/isa/vector.s:
	o Reorganize AUTO_EOI* macros.
	o Option FAST_INTR_HANDLER_USERS_ES for people who don't trust
	  fastintr handlers.
	o fastintr handlers need to metamorphose into ordinary interrupt
	  handlers if their SWI bit has become set.  Previously, sio had
	  unintended latency for handling output completions and input
	  of SLIP framing characters because this was not done.

/usr/src/sys/net/netisr.h:
	o The machine-dependent stuff is now imported from <machine/ipl.h>.

/usr/src/sys/sys/systm.h
	o DON'T APPLY ALL OF THIS DIFF.  You need mainly the different
	  splx() prototype.  The spl*() prototypes are duplicated as
	  inlines in <machine/ipl.h> but they need to be duplicated here
	  in case there are no inlines.  I sent systm.h and cpufunc.h
	  to Garrett.  We agree that spl0 should be replaced by splnone
	  and not the other way around like I've done.

/usr/src/sys/kern/kern_clock.c
	o splsoftclock() now lowers cpl so the direct call to softclock()
	  works as intended.
	o softclock() interface changed to avoid passing the whole frame
	  (some machines may need another change for profile_tick()).
	o profiling renamed _profiling to avoid ANSI namespace pollution.
	  (I had to improve the mcount() interface and may as well fix it.)
	  The GUPROF variant doesn't actually reference profiling here,
	  but the 'U' in GUPROF should mean to select the microtimer
	  mcount() and not change the interface.
1994-04-02 07:00:53 +00:00
David Greenman
0967373e1c First steps in rewriting locore.s, and making info useful
when the machine panics.

i386/i386/locore.s:
1) got rid of most .set directives that were being used like
	#define's, and replaced them with appropriate #define's in
	the appropriate header files (accessed via genassym).
2) added comments to header inclusions and global definitions,
	and global variables
3) replaced some hardcoded constants with cpp defines (such as
	PDESIZE and others)
4) aligned all comments to the same column to make them easier to
	read
5) moved macro definitions for ENTRY, ALIGN, NOP, etc. to
	/sys/i386/include/asmacros.h
6) added #ifdef BDE_DEBUGGER around all of Bruce's debugger code
7) added new global '_KERNend' to store last location+1 of kernel
8) cleaned up zeroing of bss so that only bss is zeroed
9) fix zeroing of page tables so that it really does zero them all
	- not just if they follow the bss.
10) rewrote page table initialization code so that 1) works correctly
	and 2) write protects the kernel text by default
11) properly initialize the kernel page directory, upages, p0stack PT,
	and page tables. The previous scheme was more than a bit
	screwy.
12) change allocation of virtual area of IO hole so that it is
	fixed at KERNBASE + 0xa0000. The previous scheme put it
	right after the kernel page tables and then later expected
	it to be at KERNBASE +0xa0000
13) change multiple bogus settings of user read/write of various
	areas of kernel VM - including the IO hole; we should never
	be accessing the IO hole in user mode through the kernel
	page tables
14) split kernel support routines such as bcopy, bzero, copyin,
	copyout, etc. into a seperate file 'support.s'
15) split swtch and related routines into a seperate 'swtch.s'
16) split routines related to traps, syscalls, and interrupts
	into a seperate file 'exception.s'
17) remove some unused global variables from locore that got
	inserted by Garrett when he pulled them out of some .h
	files.

i386/isa/icu.s:
1) clean up global variable declarations
2) move in declaration of astpending and netisr

i386/i386/pmap.c:
1) fix calculation of virtual_avail. It previously was calculated
	to be right in the middle of the kernel page tables - not
	a good place to start allocating kernel VM.
2) properly allocate kernel page dir/tables etc out of kernel map
	- previously only took out 2 pages.

i386/i386/machdep.c:
1) modify boot() to print a warning that the system will reboot in
	PANIC_REBOOT_WAIT_TIME amount of seconds, and let the user
	abort with a key on the console. The machine will wait for
	ever if a key is typed before the reboot. The default is
	15 seconds, but can be set to 0 to mean don't wait at all,
	-1 to mean wait forever, or any positive value to wait for
	that many seconds.
2) print "Rebooting..." just before doing it.

kern/subr_prf.c:
1) remove PANICWAIT as it is deprecated by the change to machdep.c

i386/i386/trap.c:
1) add table of trap type strings and use it to print a real trap/
	panic message rather than just a number. Lot's of work to
	be done here, but this is the first step. Symbolic traceback
	is in the TODO.

i386/i386/Makefile.i386:
1) add support in to build support.s, exception.s and swtch.s

...and various changes to various header files to make all of the
	above happen.
1993-11-13 02:25:21 +00:00