when using an APIC. This simplifies the APIC code somewhat and also allows
us to be pedantically more compliant with ACPI which mandates no use of
mixed mode.
of the kernel address space already. Intel recommend this anyway, because
using a non-4GB limit adds an additional clock cycle to address generation.
We were able to install 4GB segments into the LDT, so any limits we imposed
on %cs and %ds were academic anyway. More importantly, this allows us to
make a page in the kernel readable to user applications, for holding things
like the signal trampoline and other fun things.
Move the user %cs/%ds segments from the LDT to the GDT. There was no good
reason for them to be there anyway. The old LDT entries are still there
but we can now relax the restriction that prevented users from emptying
the default LDT entries.
Putting user and kernel %cs and %ds together allows us to access the fast
sysenter/sysexit/syscall/sysret instructions. syscall/sysret in particular
require that the user/kernel segments be laid out this way. Reserve a slot
specifically for NDIS while here.
Create two user controllable slots in the GDT that are context switched
with the (kernel) thread. This allows user applications to set two
user privilige selectors to arbitary values. Create
i386_set_fsbase(void *base) and friends. (get/set, fs/gs). For i386,
%gs is used by tls and the thread libraries and this means that user
processes no longer have to have the cost of having a custom LDT, and
we will no longer to do a ldt switch when activating a kthread/ithread in
the usual case any more.
In other words, we can now set the base address for %fs and %gs to arbitary
addresses without the pain of messing with ldt segments.
of the __pcb_spare longs. Except that fields were changed and one of the
spare values was used and the __pcb_spare field was reduced from two to one
long. Now VM86 bios calls can trash the first 4 bytes of the next page
following the kernel stack/pcb. This Is Bad(TM). This bug has been
present in 5.2-release and onwards, and is still in RELENG_5.
Instead of tempting fate and trying to use "spare" fields, explicitly
reserve them.
critical_enter() and critical_exit() are now solely a mechanism for
deferring kernel preemptions. They no longer have any affect on
interrupts. This means that standalone critical sections are now very
cheap as they are simply unlocked integer increments and decrements for the
common case.
Spin mutexes now use a separate KPI implemented in MD code: spinlock_enter()
and spinlock_exit(). This KPI is responsible for providing whatever MD
guarantees are needed to ensure that a thread holding a spin lock won't
be preempted by any other code that will try to lock the same lock. For
now all archs continue to block interrupts in a "spinlock section" as they
did formerly in all critical sections. Note that I've also taken this
opportunity to push a few things into MD code rather than MI. For example,
critical_fork_exit() no longer exists. Instead, MD code ensures that new
threads have the correct state when they are created. Also, we no longer
try to fixup the idlethreads for APs in MI code. Instead, each arch sets
the initial curthread and adjusts the state of the idle thread it borrows
in order to perform the initial context switch.
This change is largely a big NOP, but the cleaner separation it provides
will allow for more efficient alternative locking schemes in other parts
of the kernel (bare critical sections rather than per-CPU spin mutexes
for per-CPU data for example).
Reviewed by: grehan, cognet, arch@, others
Tested on: i386, alpha, sparc64, powerpc, arm, possibly more
compiler features tests. This is ok, since machine/ieeefp.h is an internal
interface. But floatingpoint.h is a public interface and some ports use it,
so include sys/cdefs.h in the amd64 and i386 version of floatingpoint.h.
Note: some architectures don't provide recursive inclusion protection in
floatingpoint.h, namely alpha and ia64. Except for this part and now the
include of sys/cdefs.h, all those files are equal (from a compiler POV),
so they could be moved to only one version in src/include/.
Approved by: joerg
to mistakes from day 1, it has always had semantics inconsistent with
SVR4 and its successors. In particular, given argument M:
- On Solaris and FreeBSD/{alpha,sparc64}, it clobbers the old flags
and *sets* the new flag word to M. (NetBSD, too?)
- On FreeBSD/{amd64,i386}, it *clears* the flags that are specified in M
and leaves the remaining flags unchanged (modulo a small bug on amd64.)
- On FreeBSD/ia64, it is not implemented.
There is no way to fix fpsetsticky() to DTRT for both old FreeBSD apps
and apps ported from other operating systems, so the best approach
seems to be to kill the function and fix any apps that break. I
couldn't find any ports that use it, and any such ports would already
be broken on FreeBSD/ia64 and Linux anyway.
By the way, the routine has always been undocumented in FreeBSD,
except for an MLINK to a manpage that doesn't describe it. This
manpage has stated since 5.3-RELEASE that the functions it describes
are deprecated, so that must mean that functions that it is *supposed*
to describe but doesn't are even *more* deprecated. ;-)
Note that fpresetsticky() has been retained on FreeBSD/i386. As far
as I can tell, no other operating systems or ports of FreeBSD
implement it, so there's nothing for it to be inconsistent with.
PR: 75862
Suggested by: bde
sys/bus_dma.h instead of being copied in every single arch. This slightly
reorders a flag that was specific to AXP and thus changes the ABI there.
The interface still relies on bus_space definitions found in <machine/bus.h>
so it cannot be included on its own yet, but that will be fixed at a later
date. Add an MD <machine/bus_dma.h> for ever arch for consistency and to
allow for future MD augmentation of the API. sparc64 makes heavy use of
this right now due to its different bus_dma implemenation.
place.
This moves the dependency on GCC's and other compiler's features into
the central sys/cdefs.h file, while the individual source files can
then refer to #ifdef __COMPILER_FEATURE_FOO where they by now used to
refer to #if __GNUC__ > 3.1415 && __BARC__ <= 42.
By now, GCC and ICC (the Intel compiler) have been actively tested on
IA32 platforms by netchild. Extension to other compilers is supposed
to be possible, of course.
Submitted by: netchild
Reviewed by: various developers on arch@, some time ago
preliminary support for using the GCC-compatibility of ICC was committed
but couldn't be tested at that time due to problems with ICC itself. Since
ICC 8.1 it's possible to use its GCC-compatibility under FreeBSD and it
turned out that a typedef for __gnuc_va_list is required in that case.
Revert the part of rev. 1.8 which #ifdef'ed out __gnuc_va_list for ICC.
MFC after: 1 week
rather than forwarding interrupts from the clock devices around using IPIs:
- Add an IDT vector that pushes a clock frame and calls
lapic_handle_timer().
- Add functions to program the local APIC timer including setting the
divisor, and setting up the timer to either down a periodic countdown
or one-shot countdown.
- Add a lapic_setup_clock() function that the BSP calls from
cpu_init_clocks() to setup the local APIC timer if it is going to be
used. The setup uses a one-shot countdown to calibrate the timer. We
then program the timer on each CPU to fire at a frequency of hz * 3.
stathz is defined as freq / 23 (hz * 3 / 23), and profhz is defined as
freq / 2 (hz * 3 / 2). This gives the clocks relatively prime divisors
while keeping a low LCM for the frequency of the clock interrupts.
Thanks to Peter Jeremy for suggesting this approach.
- Remove the hardclock and statclock forwarding code including the two
associated IPIs. The bitmap IPI handler has now effectively degenerated
to just IPI_AST.
- When the local APIC timer is used we don't turn the RTC on at all, but
we still enable interrupts on the ISA timer 0 (i8254) for timecounting
purposes.
i386_{get,set}_ioperm() and make those APIs visible in the kernel namespace;
o use i386_{get,set}_ldt() and i386_{get,set}_ioperm() instead of sysarch()
in the linuxlator, which allows to kill another two stackgaps.
MFC after: 2 weeks
instead of burying that in the atpic(4) code as atpic(4) is not the only
user of elcr(4). Change the elcr(4) code to export a global elcr_found
variable that other code can check to see if a valid ELCR was found.
MFC after: 1 month
cuts to the chase and fills in a provided s/g list. This is meant to optimize
out the cost of the callback since the callback doesn't serve much purpose for
mbufs since mbuf loads will never be deferred. This is just for amd64 and
i386 at the moment, other arches will be coming shortly.
Currently this is only used to initiailize the TPR to 0 during initial
setup.
- Reallocate vectors for the local APIC timer, error, and thermal LVT
entries. The timer entry is allocated from the top of the I/O interrupt
range reducing the number of vectors available for hardware interrupts
to 191. Linux happens to use the same exact vector for its timer
interrupt as well. If the timer vector shared the same priority queue
as the IPI handlers, then the frequency that the timer vector will
eventually be firing at can interact badly with the IPIs resulting in
the queue filling and the dreaded IPI stuck panics, hence it being located
at the top of the previous priority queue instead.
- Fixup various minor nits in comments.
as this may cause deadlocks.
This should fix kern/72123.
Discussed with: jhb
Tested by: Nik Azim Azam, Andy Farkas, Flack Man, Aykut KARA
Izzet BESKARDES, Jens Binnewies, Karl Keusgen
Approved by: sam (mentor)
specified register, but a pointer to the in-memory representation of
that value. The reason for this is twofold:
1. Not all registers can be represented by a register_t. In particular
FP registers fall in that category. Passing the new register value
by reference instead of by value makes this point moot.
2. When we receive a G or P packet, both are for writing a register,
the packet will have the register value in target-byte order and
in the memory representation (modulo the fact that bytes are sent
as 2 printable hexadecimal numbers of course). We only need to
decode the packet to have a pointer to the register value.
This change fixes the bug of extracting the register value of the P
packet as a hexadecimal number instead of as a bit array. The quick
(and dirty) fix to bswap the register value in gdb_cpu_setreg() as
it has been added on i386 and amd64 can therefore be removed and has
in fact been that.
Tested on: alpha, amd64, i386, ia64, sparc64
of atomic_store_rel().
- Use the 80386 versions of atomic_load_acq() and atomic_store_rel() that
do not use serializing instructions on all UP kernels since a UP machine
does need to synchronize with other CPUs. This trims lots of cycles from
spin locks on UP kernels among other things.
Benchmarked by: rwatson
Expose some of the amd64-specific sysarch functions to allow alternative
implementations of the %fs/%gs code for TLS, threads, etc. USER_LDT does
not exist on the amd64 kernel, so we have to implement things other ways.
Restructure pmap_enter() to prevent the loss of a page modified (PG_M) bit
in a race between processors. (This restructuring assumes the newly atomic
pte_load_store() for correct operation.)
Reviewed by: tegge@
PR: i386/61852
pmap_copy(). This entails additional locking in pmap_copy() and the
addition of a "flags" parameter to the page table page allocator for
specifying whether it may sleep when memory is unavailable. (Already,
pmap_copy() checks the availability of memory, aborting if it is scarce.
In theory, another CPU could, however, allocate memory between
pmap_copy()'s check and the call to the page table page allocator,
causing the current thread to release its locks and sleep. This change
makes this scenario impossible.)
Reviewed by: tegge@
not sure yet about 5.x... MFC if needed.
Also fixes small problems with examining some registers and
some specific gdb transfer problems.
As the patch says:
This is not a pretty patch and only meant as a temporary
fix until a better solution is committed.
PR: i386/71715
Submitted by: Stephan Uphoff <ups@tree.com>
MFC after: 1 week
value was only enough for 8GB of RAM, the new value can do 16GB. This still
isn't optimal since it doesn't scale. Fixing this for amd64 looks to be
fairly easy, but for i386 will be quite difficult.
Reviewed by: peter
FULL_PREEMPTION is defined. Add a runtime warning to ULE if PREEMPTION is
enabled (code inspired by the PREEMPTION warning in kern_switch.c). This
is a possible MT5 candidate.
these two reasons:
1. On ia64 a function pointer does not hold the address of the first
instruction of a functions implementation. It holds the address
of a function descriptor. Hence the user(), btrap(), eintr() and
bintr() prototypes are wrong for getting the actual code address.
2. The logic forces interrupt, trap and exception entry points to
be layed-out contiguously. This can not be achieved on ia64 and is
generally just bad programming.
The MCOUNT_FROMPC_USER macro is used to set the frompc argument to
some kernel address which represents any frompc that falls outside
the kernel text range. The macro can expand to ~0U to bail out in
that case.
The MCOUNT_FROMPC_INTR macro is used to set the frompc argument to
some kernel address to represent a call to a trap or interrupt
handler. This to avoid that the trap or interrupt handler appear to
be called from everywhere in the call graph. The macro can expand
to ~0U to prevent adjusting frompc. Note that the argument is selfpc,
not frompc.
This commit defines the macros on all architectures equivalently to
the original code in sys/libkern/mcount.c. People can take it from
here...
Compile-tested on: alpha, amd64, i386, ia64 and sparc64
Boot-tested on: i386
