It is never used. I left it there from pre-KSE days as I didn't know
if I'd need it or not but now I know I don't.. It's functionality
is in TDI_IWAIT in the thread.
in specific situations. The owner thread must be blocked, and the
borrower can not proceed back to user space with the borrowed KSE.
The borrower will return the KSE on the next context switch where
teh owner wants it back. This removes a lot of possible
race conditions and deadlocks. It is consceivable that the
borrower should inherit the priority of the owner too.
that's another discussion and would be simple to do.
Also, as part of this, the "preallocatd spare thread" is attached to the
thread doing a syscall rather than the KSE. This removes the need to lock
the scheduler when we want to access it, as it's now "at hand".
DDB now shows a lot mor info for threaded proceses though it may need
some optimisation to squeeze it all back into 80 chars again.
(possible JKH project)
Upcalls are now "bound" threads, but "KSE Lending" now means that
other completing syscalls can be completed using that KSE before the upcall
finally makes it back to the UTS. (getting threads OUT OF THE KERNEL is
one of the highest priorities in the KSE system.) The upcall when it happens
will present all the completed syscalls to the KSE for selection.
name instead. (e.g., SLOCK instead of SMTX, TD_ON_LOCK() instead of
TD_ON_MUTEX()) Eventually a turnstile abstraction will be added that
will be shared with mutexes and other types of locks. SLOCK/TDI_LOCK will
be used internally by the turnstile code and will not be specific to
mutexes. Making the change now ensures that turnstiles can be dropped
in at a later date without affecting the ABI of userland applications.
MD function is just a wrapper around db_stack_trace_cmd() that prints out
a backtrace of curthread. Currently, this function is only implemented
on i386 and alpha (and the alpha version isn't quite tested yet, will do
that in a bit). Other changes:
- For i386, fix a bug in the raw frame address case. The eip we extract
from the passed in frame address does not match the frame we received.
Thus, instead of printing a bogus frame with the wrong eip, go ahead
and advance frame down to the same frame as the eip we are using.
- For alpha, attempt to add a way of doing a raw trace for alpha. Instead
of passing a frame address in 'addr', pass in a pointer to a structure
containing PC and KSP and use those to start the backtrace. The alpha
db_print_backtrace() uses asm to read in the current PC and KSP values
into such a request.
Tested on: i386
Requested by: many
X_db_search_symbol(). Otherwise we don't see important symbols in
non-verbosely written assembler code.
NetBSD already has this. The kld version already has a stronger form
of it without really trying -- linker_ddb_search_symbol() doesn't
support ddb's symbol search strategy parameter, so the kld
X_db_search_symbol() doesn't pass the parameter to linker_ddb...() and
linker_ddb...() doesn't make distinctions based on the symbol type.
db_elf.c now works better than db_kld.c when it works (which is essentially
when there are no modules except the kernel). It works after booting
with -d. db_kld.c doesn't work until lots of SYSINIT()s have run.
symbol table sections. Reconstruct the necessary section headers from
(ksym_start, ksym_end). This was much easier than converting to use
module metadata, and just works for static symbols, unlike db_kld when
there is no module metadata. Initialize (ksym_start, ksym_end) from
bootinfo on i386's only.
The boot loader should load section headers for all sections that it
loads, and apparently did this for at least the symbol table sections
when this file last worked under FreeBSD (on alphas only) and always
did this under NetBSD (where this file was obtained from). At least
on i386's, boot2 discards the section headers (except for converting
them to (bootinfo.bi_symtab, bootinfo.bi_esymtab), and as far as I can
tell, loader(8) discards them apart from converting them to the bootinfo
values and module metadata.
and renaming ALIGNED_POINTER() to _ALIGNED_POINTER() plus the following
hacks for i386's:
- define _ALIGNED_POINTER() if it is not already defined. Most non-i386
arches define it <machine/param.h> define it in <machine/param.h>,
although none actually used it in the kernel.
- define ksym_start and ksym_end. Most non-i386 arches still define and
initialize these in machdep.c although they didn't used them. Here is
a better place to define them but not to initialize them.
Don't attempt to follow null pointers for zombie processes in db_ps().
Style fix: use explicit an comparison with NULL for all null pointer
checks in db_ps() instead of for half of them.
db_interface.c:
Fixed ddb's handling of traps from with ddb on i386's only.
This was mostly fixed in rev.1.27 (by longjmp()'ing back to the top
level) but was completly broken in rev.1.48 (by not unwinding the new
state (mainly db_active) either before or after the longjmp(). This
mostly never worked for other arches, since rev.1.27 has not been ported
and lower level longjmp()'s only handle traps for memory accesses. All
cases should be handled at a lower level to provided better control and
simplify unwinding of state.
Implementation details: don't pretend to maintain db_active in a nested
way -- ddb cannot be reentered in a nested way. Use db_active instead
of the db_global_jmpbuf_valid flag and longjmp()'s return value for things
related to reentering ddb. [re]entering is still not atomic enough.
The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)
Reviewed by: Almost everyone who counts
(at various times, peter, jhb, matt, alfred, mini, bernd,
and a cast of thousands)
NOTE: this is still Beta code, and contains lots of debugging stuff.
expect slight instability in signals..
the indirection operator ('*') and address examination ('x/a') on
big-endian platoforms for which the above is not true, as well as on
little-endian platforms if the cut-off bits are not 0.
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.
Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
respects locks. Before SMPng, one was able to call psignal()
using the "call" command, but this is no longer possible because it
does not respect locks by itself. This is very useful when one has
gotten their machine into a state where it is impossible to spawn
ps/kill or su to root.
In this case, respecting locks essentially means trying to aquire the
proc lock before calling psignal(). We can't block in the debugger,
so if trylock fails, the operation fails. This also means that we
can't use pfind(), since that will attempt to lock the process for us.
Reviewed by: jhb
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
'dwatch'. The new commands install hardware watchpoints if supported
by the architecture and if there are enough registers to cover the
desired memory area.
No objection by: audit@, hackers@
MFC after: 2 weeks
Replace the a.out emulation of 'struct linker_set' with something
a little more flexible. <sys/linker_set.h> now provides macros for
accessing elements and completely hides the implementation.
The linker_set.h macros have been on the back burner in various
forms since 1998 and has ideas and code from Mike Smith (SET_FOREACH()),
John Polstra (ELF clue) and myself (cleaned up API and the conversion
of the rest of the kernel to use it).
The macros declare a strongly typed set. They return elements with the
type that you declare the set with, rather than a generic void *.
For ELF, we use the magic ld symbols (__start_<setname> and
__stop_<setname>). Thanks to Richard Henderson <rth@redhat.com> for the
trick about how to force ld to provide them for kld's.
For a.out, we use the old linker_set struct.
NOTE: the item lists are no longer null terminated. This is why
the code impact is high in certain areas.
The runtime linker has a new method to find the linker set
boundaries depending on which backend format is in use.
linker sets are still module/kld unfriendly and should never be used
for anything that may be modular one day.
Reviewed by: eivind
real uid, saved uid, real gid, and saved gid to ucred, as well as the
pcred->pc_uidinfo, which was associated with the real uid, only rename
it to cr_ruidinfo so as not to conflict with cr_uidinfo, which
corresponds to the effective uid.
o Remove p_cred from struct proc; add p_ucred to struct proc, replacing
original macro that pointed.
p->p_ucred to p->p_cred->pc_ucred.
o Universally update code so that it makes use of ucred instead of pcred,
p->p_ucred instead of p->p_pcred, cr_ruidinfo instead of p_uidinfo,
cr_{r,sv}{u,g}id instead of p_*, etc.
o Remove pcred0 and its initialization from init_main.c; initialize
cr_ruidinfo there.
o Restruction many credential modification chunks to always crdup while
we figure out locking and optimizations; generally speaking, this
means moving to a structure like this:
newcred = crdup(oldcred);
...
p->p_ucred = newcred;
crfree(oldcred);
It's not race-free, but better than nothing. There are also races
in sys_process.c, all inter-process authorization, fork, exec, and
exit.
o Remove sigio->sio_ruid since sigio->sio_ucred now contains the ruid;
remove comments indicating that the old arrangement was a problem.
o Restructure exec1() a little to use newcred/oldcred arrangement, and
use improved uid management primitives.
o Clean up exit1() so as to do less work in credential cleanup due to
pcred removal.
o Clean up fork1() so as to do less work in credential cleanup and
allocation.
o Clean up ktrcanset() to take into account changes, and move to using
suser_xxx() instead of performing a direct uid==0 comparision.
o Improve commenting in various kern_prot.c credential modification
calls to better document current behavior. In a couple of places,
current behavior is a little questionable and we need to check
POSIX.1 to make sure it's "right". More commenting work still
remains to be done.
o Update credential management calls, such as crfree(), to take into
account new ruidinfo reference.
o Modify or add the following uid and gid helper routines:
change_euid()
change_egid()
change_ruid()
change_rgid()
change_svuid()
change_svgid()
In each case, the call now acts on a credential not a process, and as
such no longer requires more complicated process locking/etc. They
now assume the caller will do any necessary allocation of an
exclusive credential reference. Each is commented to document its
reference requirements.
o CANSIGIO() is simplified to require only credentials, not processes
and pcreds.
o Remove lots of (p_pcred==NULL) checks.
o Add an XXX to authorization code in nfs_lock.c, since it's
questionable, and needs to be considered carefully.
o Simplify posix4 authorization code to require only credentials, not
processes and pcreds. Note that this authorization, as well as
CANSIGIO(), needs to be updated to use the p_cansignal() and
p_cansched() centralized authorization routines, as they currently
do not take into account some desirable restrictions that are handled
by the centralized routines, as well as being inconsistent with other
similar authorization instances.
o Update libkvm to take these changes into account.
Obtained from: TrustedBSD Project
Reviewed by: green, bde, jhb, freebsd-arch, freebsd-audit
other "system" header files.
Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.
Sort sys/*.h includes where possible in affected files.
OK'ed by: bde (with reservations)
with 'options DDB'). Setting this to `ddb' or `gdb' breaks into the
kernel debugger in the corresponding mode. This mechanism has proven
very useful at Whistle for setting breakpoints, etc., while doing
remote serial line kernel debugging.
Obtained from: Whistle source tree
