FreeBSD/alpha. The most significant item is to change the command
argument to ioctl functions from int to u_long. This change brings us
inline with various other BSD versions. Driver writers may like to
use (__FreeBSD_version == 300003) to detect this change.
The prototype FreeBSD/alpha machdep will follow in a couple of days
time.
probe and intialisation. This will ultimately remove the grubby (but
functional) hack that copies a real-mode function into low memory
early in locore.s.
a test of the irq number, and made failure of this test non-fatal.
Removed related unused complications for the APIC_IO case. Removed the
no-test3 flag.
Deverbosified the failure messages for the other tests. Removed the
per-port verbose flag - just use the general verbose flag.
Clean up (or if antipodic: down) some of the msgbuf stuff.
Use an inline function rather than a macro for timecounter delta.
Maintain process "on-cpu" time as 64 bits of microseconds to avoid
needless second rollover overhead.
Avoid calling microuptime the second time in mi_switch() if we do
not pass through _idle in cpu_switch()
This should reduce our context-switch overhead a bit, in particular
on pre-P5 and SMP systems.
WARNING: Programs which muck about with struct proc in userland
will have to be fixed.
Reviewed, but found imperfect by: bde
unexpectedly do not complete writes even with sync I/O requests.
This should help the behavior of mmaped files when using
softupdates (and perhaps in other circumstances also.)
Althought the comments say the datasheet doesn't list the device ID
registers on the M2/MX, they seem to be there and quite alive.
(It's interesting to note that the M2/MX calls itself a 686 class cpu but
is missing a heck of a lot of features, including VME, PGE, PSE, etc)
available. The per-cpu variable ss_tpr has been replaced by ss_eflags.
This reduced the number of interrupts sent to the wrong CPU, due to
the cpu having the global lock being inside a critical region.
Remove some unneeded manipulation of tpr register in mplock.s.
Adjust code in mplock.s to be aware of variables on the stack being
destroyed by MPgetlock if GRAB_LOPRIO is defined.
update of cpu usage as shown by top when one process is cpu bound
(no system calls) while the system is otherwise idle (except for top).
Don't attempt to switch to the BSP in boot(). If the system was idle when
an interrupt caused a panic, this won't work. Instead, switch to the BSP
in cpu_reset.
Remove some spurious forward_statclock/forward_hardclock warnings.
Windows 95 after rebooting FreeBSD without power off. In PC-98
system, reboot mode is set via I/O port 0x37 in cpu_reset(), and
accessing of this port is the reason of the problem. To avnoid the
fault, current status of reboot mode should be checked before
accessing the I/O port.
that local APIC should be disabled in UP system. However, some of old
BIOS does not disable local APIC, and virtual wire mode through local
APIC may cause int 15.
This is a result of discussions on the mailing lists. Kudos to those who
have found the issue and created work-arounds. I have chosen Tor's fix
for now, before we can all work the issue more completely.
Submitted by: Tor Egge
possibly non-open devices, and we don't want to restrict dumping
to swap devices anwyay. It is especially invalid to call d_ioctl()
in non-process context for panics. d_psize() can be called on
non-open devices, at least on non-SLICED ones that support d_dump(),
and setdumpdev() has depended on this for a long time although it
is probably wrong, but even d_psize() can't be called in non-process
context - that's why dumpsys() depends on previously computed values
although these values may be stale. The historical restriction to
devices with dkpart(dev) == SWAP_PART should go away.
Linux emulation. This make Allegro Common Lisp 4.3 work under
FreeBSD!
Submitted by: Fred Gilham <gilham@csl.sri.com>
Commented on by: bde, dg, msmith, tg
Hoping he got everything right: eivind
This code will be turned on with the TWO options
DEVFS and SLICE. (see LINT)
Two labels PRE_DEVFS_SLICE and POST_DEVFS_SLICE will deliniate these changes.
/dev will be automatically mounted by init (thanks phk)
on bootup. See /sys/dev/slice/slice.4 for more info.
All code should act the same without these options enabled.
Mike Smith, Poul Henning Kamp, Soeren, and a few dozen others
This code does not support the following:
bad144 handling.
Persistance. (My head is still hurting from the last time we discussed this)
ATAPI flopies are not handled by the SLICE code yet.
When this code is running, all major numbers are arbitrary and COULD
be dynamically assigned. (this is not done, for POLA only)
Minor numbers for disk slices ARE arbitray and dynamically assigned.
ints. Remove some no longer needed casts. Initialize the per-cpu
global data area using the structs rather than knowing too much about
layout, alignment, etc.
* Figure out UTC relative to boottime. Four new functions provide
time relative to boottime.
* move "runtime" into struct proc. This helps fix the calcru()
problem in SMP.
* kill mono_time.
* add timespec{add|sub|cmp} macros to time.h. (XXX: These may change!)
* nanosleep, select & poll takes long sleeps one day at a time
Reviewed by: bde
Tested by: ache and others
- Attempt to handle PCI devices where the interrupt is
an ISA/EISA interrupt according to the mp table.
- Attempt to handle multiple IO APIC pins connected to
the same PCI or ISA/EISA interrupt source. Print a
warning if this happens, since performance is suboptimal.
This workaround is only used for PCI devices.
With these two workarounds, the -SMP kernel is capable of running on
my Asus P/I-P65UP5 motherboard when version 1.4 of the MP table is disabled.
"time" wasn't a atomic variable, so splfoo() protection were needed
around any access to it, unless you just wanted the seconds part.
Most uses of time.tv_sec now uses the new variable time_second instead.
gettime() changed to getmicrotime(0.
Remove a couple of unneeded splfoo() protections, the new getmicrotime()
is atomic, (until Bruce sets a breakpoint in it).
A couple of places needed random data, so use read_random() instead
of mucking about with time which isn't random.
Add a new nfs_curusec() function.
Mark a couple of bogosities involving the now disappeard time variable.
Update ffs_update() to avoid the weird "== &time" checks, by fixing the
one remaining call that passwd &time as args.
Change profiling in ncr.c to use ticks instead of time. Resolution is
the same.
Add new function "tvtohz()" to avoid the bogus "splfoo(), add time, call
hzto() which subtracts time" sequences.
Reviewed by: bde
_KPOSIX_PRIORITY_SCHEDULING options to work. Changes:
Change all "posix4" to "p1003_1b". Misnamed files are left
as "posix4" until I'm told if I can simply delete them and add
new ones;
Add _POSIX_PRIORITY_SCHEDULING system calls for FreeBSD and Linux;
Add man pages for _POSIX_PRIORITY_SCHEDULING system calls;
Add options to LINT;
Minor fixes to P1003_1B code during testing.
everything is contained inside #ifdef VM86, so this option must be
present in the config file to use this functionality.
Thanks to Tor Egge, these changes should work on SMP machines. However,
it may not be throughly SMP-safe.
Currently, the only BIOS calls made are memory-sizing routines at bootup,
these replace reading the RTC values.
problems. Tor Egge and others have helped with various VM bugs
lately, but don't blame him -- blame me!!!
pmap.c:
1) Create an object for kernel page table allocations. This
fixes a bogus allocation method previously used for such, by
grabbing pages from the kernel object, using bogus pindexes.
(This was a code cleanup, and perhaps a minor system stability
issue.)
pmap.c:
2) Pre-set the modify and accessed bits when prudent. This will
decrease bus traffic under certain circumstances.
vfs_bio.c, vfs_cluster.c:
3) Rather than calculating the beginning virtual byte offset
multiple times, stick the offset into the buffer header, so
that the calculated offset can be reused. (Long long multiplies
are often expensive, and this is a probably unmeasurable performance
improvement, and code cleanup.)
vfs_bio.c:
4) Handle write recursion more intelligently (but not perfectly) so
that it is less likely to cause a system panic, and is also
much more robust.
vfs_bio.c:
5) getblk incorrectly wrote out blocks that are incorrectly sized.
The problem is fixed, and writes blocks out ONLY when B_DELWRI
is true.
vfs_bio.c:
6) Check that already constituted buffers have fully valid pages. If
not, then make sure that the B_CACHE bit is not set. (This was
a major source of Sig-11 type problems.)
vfs_bio.c:
7) Fix a potential system deadlock due to an incorrectly specified
sleep priority while waiting for a buffer write operation. The
change that I made opens the system up to serious problems, and
we need to examine the issue of process sleep priorities.
vfs_cluster.c, vfs_bio.c:
8) Make clustered reads work more correctly (and more completely)
when buffers are already constituted, but not fully valid.
(This was another system reliability issue.)
vfs_subr.c, ffs_inode.c:
9) Create a vtruncbuf function, which is used by filesystems that
can truncate files. The vinvalbuf forced a file sync type operation,
while vtruncbuf only invalidates the buffers past the new end of file,
and also invalidates the appropriate pages. (This was a system reliabiliy
and performance issue.)
10) Modify FFS to use vtruncbuf.
vm_object.c:
11) Make the object rundown mechanism for OBJT_VNODE type objects work
more correctly. Included in that fix, create pager entries for
the OBJT_DEAD pager type, so that paging requests that might slip
in during race conditions are properly handled. (This was a system
reliability issue.)
vm_page.c:
12) Make some of the page validation routines be a little less picky
about arguments passed to them. Also, support page invalidation
change the object generation count so that we handle generation
counts a little more robustly.
vm_pageout.c:
13) Further reduce pageout daemon activity when the system doesn't
need help from it. There should be no additional performance
decrease even when the pageout daemon is running. (This was
a significant performance issue.)
vnode_pager.c:
14) Teach the vnode pager to handle race conditions during vnode
deallocations.
on the IOAPIC being connected to the 8254 timer interrupt.
Verify that timer interrupts are delivered. If they aren't, attempt
a fallback to mixed mode (i.e. routing the timer interrupt via the 8259 PIC).
previous commit. Opportunities to clean pages were often missed,
and leaving of the idle state was sometimes delayed until the next
interrupt (after any that occurred while cleaning).
Fixed an unstaticization, a syntax error and a style bug in the
previous commit.
slice number passed in by the bootblocks. This means the kernel will
not use the compatability slice to obtain the root filesystem when
booting from a sliced disk.
Use the extraction macros from reboot.h rather than stating them in full
again.
has been some bitrot and incorrect assumptions in the vfs_bio code. These
problems have manifest themselves worse on NFS type filesystems, but can
still affect local filesystems under certain circumstances. Most of
the problems have involved mmap consistancy, and as a side-effect broke
the vfs.ioopt code. This code might have been committed seperately, but
almost everything is interrelated.
1) Allow (pmap_object_init_pt) prefaulting of buffer-busy pages that
are fully valid.
2) Rather than deactivating erroneously read initial (header) pages in
kern_exec, we now free them.
3) Fix the rundown of non-VMIO buffers that are in an inconsistent
(missing vp) state.
4) Fix the disassociation of pages from buffers in brelse. The previous
code had rotted and was faulty in a couple of important circumstances.
5) Remove a gratuitious buffer wakeup in vfs_vmio_release.
6) Remove a crufty and currently unused cluster mechanism for VBLK
files in vfs_bio_awrite. When the code is functional, I'll add back
a cleaner version.
7) The page busy count wakeups assocated with the buffer cache usage were
incorrectly cleaned up in a previous commit by me. Revert to the
original, correct version, but with a cleaner implementation.
8) The cluster read code now tries to keep data associated with buffers
more aggressively (without breaking the heuristics) when it is presumed
that the read data (buffers) will be soon needed.
9) Change to filesystem lockmgr locks so that they use LK_NOPAUSE. The
delay loop waiting is not useful for filesystem locks, due to the
length of the time intervals.
10) Correct and clean-up spec_getpages.
11) Implement a fully functional nfs_getpages, nfs_putpages.
12) Fix nfs_write so that modifications are coherent with the NFS data on
the server disk (at least as well as NFS seems to allow.)
13) Properly support MS_INVALIDATE on NFS.
14) Properly pass down MS_INVALIDATE to lower levels of the VM code from
vm_map_clean.
15) Better support the notion of pages being busy but valid, so that
fewer in-transit waits occur. (use p->busy more for pageouts instead
of PG_BUSY.) Since the page is fully valid, it is still usable for
reads.
16) It is possible (in error) for cached pages to be busy. Make the
page allocation code handle that case correctly. (It should probably
be a printf or panic, but I want the system to handle coding errors
robustly. I'll probably add a printf.)
17) Correct the design and usage of vm_page_sleep. It didn't handle
consistancy problems very well, so make the design a little less
lofty. After vm_page_sleep, if it ever blocked, it is still important
to relookup the page (if the object generation count changed), and
verify it's status (always.)
18) In vm_pageout.c, vm_pageout_clean had rotted, so clean that up.
19) Push the page busy for writes and VM_PROT_READ into vm_pageout_flush.
20) Fix vm_pager_put_pages and it's descendents to support an int flag
instead of a boolean, so that we can pass down the invalidate bit.
f00f_hack has run.
Use the global r_idt descriptor in f00f_hack when in SMP mode,
so the APs find the relocated interrupt descriptor table.
Submitted by: Partially from David A Adkins <adkin003@tc.umn.edu>
interrupts are masked, and EOI is sent iff the corresponding ISR bit
is set in the local apic. If the CPU cannot obtain the interrupt
service lock (currently the global kernel lock) the interrupt is
forwarded to the CPU holding that lock.
Clock interrupts now have higher priority than other slow interrupts.
the signal handling latency for cpu-bound processes that performs very
few system calls.
The IPI for forcing an additional software trap is no longer dependent upon
BETTER_CLOCK being defined.
than rolling it's own. This means that it now uses the "safe"
exec_map_first_page() to get the ld.so headers rather than risking a panic
on a page fault failure (eg: NFS server goes down).
Since all the ELF tools go to a lot of trouble to make sure everything
lives in the first page for executables, this is a win. I have not seen
any ELF executable on any system where all the headers didn't fit in the
first page with lots of room to spare.
I have been running variations of this code for some time on my pure ELF
systems.
2) Do not unnecessarily force page blocking when paging
pages out.
3) Further improve swap pager performance and correctness,
including fixing the paging in progress deadlock (except
in severe I/O error conditions.)
4) Enable vfs_ioopt=1 as a default.
5) Fix and enable the page prezeroing in SMP mode.
All in all, SMP systems especially should show a significant
improvement in "snappyness."
it runs at a constant frequency. This was less of an issue before,
because the TSC only interpolated in the HZ intervals, but now where
the timecounter is used all the way, this becomes much more visible.
Nit: Fix a printf which triggered the bde-filter.
in a way identically as before.) I had problems with the system properly
handling the number of vnodes when there is alot of system memory, and the
default VM_KMEM_SIZE. Two new options "VM_KMEM_SIZE_SCALE" and
"VM_KMEM_SIZE_MAX" have been added to support better auto-sizing for systems
with greater than 128MB.
Add some accouting for vm_zone memory allocations, and provide properly
for vm_zone allocations out of the kmem_map. Also move the vm_zone
allocation stats to the VM OID tree from the KERN OID tree.
Highlights:
* Simple model for underlying hardware.
* Hardware basis for timekeeping can be changed on the fly.
* Only one hardware clock responsible for TOD keeping.
* Provides a real nanotime() function.
* Time granularity: .232E-18 seconds.
* Frequency granularity: .238E-12 s/s
* Frequency adjustment is continuous in time.
* Less overhead for frequency adjustment.
* Improves xntpd performance.
Reviewed by: bde, bde, bde
is "acquired". This fixes a TSC biasing error of about 10 msec when
pcaudio is active.
Update `time' before calling hardclock() when timer0 is being released.
This is not known to be important.
Added some delays in writertc(). Efficiency is not critical here, unlike
in rtcin(), and we already use conservative delays there.
Don't touch the hardware when machdep.i8254_freq is being changed but
the maximum count wouldn't change. This fixes jitter of up to 10 msec
for most small adjustments to machdep.i8254_freq. When the maximum
count needs to change, the hardware should be adjusted more carefully.
i386_set_ioperm(). Don't use a magic number for the bound.
Fixed missing bounds checking in i386_get_ioperm(). Don't use a
magic number for the bound elsewhere in this function.
Removed some bogus initializers.
actually faster (more than 20% faster for zeroing 1 MB at boot time).
This fixes pessimized copying and zeroing on K6's and perhaps on other
CPUs that are misclassified as i586's.
of the various ad-hoc schemes.
2) When bringing in UPAGES, the pmap code needs to do another vm_page_lookup.
3) When appropriate, set the PG_A or PG_M bits a-priori to both avoid some
processor errata, and to minimize redundant processor updating of page
tables.
4) Modify pmap_protect so that it can only remove permissions (as it
originally supported.) The additional capability is not needed.
5) Streamline read-only to read-write page mappings.
6) For pmap_copy_page, don't enable write mapping for source page.
7) Correct and clean-up pmap_incore.
8) Cluster initial kern_exec pagin.
9) Removal of some minor lint from kern_malloc.
10) Correct some ioopt code.
11) Remove some dead code from the MI swapout routine.
12) Correct vm_object_deallocate (to remove backing_object ref.)
13) Fix dead object handling, that had problems under heavy memory load.
14) Add minor vm_page_lookup improvements.
15) Some pages are not in objects, and make sure that the vm_page.c can
properly support such pages.
16) Add some more page deficit handling.
17) Some minor code readability improvements.
MUST be PG_BUSY. It is bogus to free a page that isn't busy,
because it is in a state of being "unavailable" when being
freed. The additional advantage is that the page_remove code
has a better cross-check that the page should be busy and
unavailable for other use. There were some minor problems
with the collapse code, and this plugs those subtile "holes."
Also, the vfs_bio code wasn't checking correctly for PG_BUSY
pages. I am going to develop a more consistant scheme for
grabbing pages, busy or otherwise. For now, we are stuck
with the current morass.
If you want to play with it, you can find the final version of the
code in the repository the tag LFS_RETIREMENT.
If somebody makes LFS work again, adding it back is certainly
desireable, but as it is now nobody seems to care much about it,
and it has suffered considerable bitrot since its somewhat haphazard
integration.
R.I.P
available. If there isn't bounce space available, the bounce code
is disabled. This will allow most large systems to run properly
when the bounce space is mistakenly allocated above 16MB.
6x86MX CPU is enabled (BIOS should not disable it), some BIOS disables
it via CCR4. In this case, cpu variable becomes CPU_486 and
identblue() is called. Because Cyrix 6x86MX has MSR and doesn't have
MSR1002, wrmsr instruction generates general protection fault.
Tested by: Simon Coggins <chaos@ultra.net.au>
This introduce an xxxFS_BOOT for each of the rootable filesystems.
(Presently not required, but encouraged to allow a smooth move of option *FS
to opt_dontuse.h later.)
LFS is temporarily disabled, and will be re-enabled tomorrow.
1) Start using TSM.
Struct procs continue to point to upages structure, after being freed.
Struct vmspace continues to point to pte object and kva space for kstack.
u_map is now superfluous.
2) vm_map's don't need to be reference counted. They always exist either
in the kernel or in a vmspace. The vmspaces are managed by reference
counts.
3) Remove the "wired" vm_map nonsense.
4) No need to keep a cache of kernel stack kva's.
5) Get rid of strange looking ++var, and change to var++.
6) Change more data structures to use our "zone" allocator. Added
struct proc, struct vmspace and struct vnode. This saves a significant
amount of kva space and physical memory. Additionally, this enables
TSM for the zone managed memory.
7) Keep ioopt disabled for now.
8) Remove the now bogus "single use" map concept.
9) Use generation counts or id's for data structures residing in TSM, where
it allows us to avoid unneeded restart overhead during traversals, where
blocking might occur.
10) Account better for memory deficits, so the pageout daemon will be able
to make enough memory available (experimental.)
11) Fix some vnode locking problems. (From Tor, I think.)
12) Add a check in ufs_lookup, to avoid lots of unneeded calls to bcmp.
(experimental.)
13) Significantly shrink, cleanup, and make slightly faster the vm_fault.c
code. Use generation counts, get rid of unneded collpase operations,
and clean up the cluster code.
14) Make vm_zone more suitable for TSM.
This commit is partially as a result of discussions and contributions from
other people, including DG, Tor Egge, PHK, and probably others that I
have forgotten to attribute (so let me know, if I forgot.)
This is not the infamous, final cleanup of the vnode stuff, but a necessary
step. Vnode mgmt should be correct, but things might still change, and
there is still some missing stuff (like ioopt, and physical backing of
non-merged cache files, debugging of layering concepts.)
Move sigjmp_buf and jmp_buf structure definitions to machine/setjmp.h
so that i386 can continue to use int as the basic register type and
alpha can use long. Bruce was concerned about possible differing
alignment. I've left the definition of _JBLEN in machine/setjmp.h
even though Bruce's example used the number directly. I don't know if
any other code relies on _JBLEN, so I left it to avoid potential
breakage.
config option in pmap. Fix a problem with faulting in pages. Clean-up
some loose ends in swap pager memory management.
The system should be much more stable, but all subtile bugs aren't fixed yet.
This is Junichi's v1.0 driver.
NOTE: Major device numbers have been changed to avoid conflict with other
FreeBSD 3.0 devices. The new numbers should be considered "official."
This driver is still considered "beta" quality, although we have been
playing with it. Please submit bugs to junichi and myself.
Submitted by: junichi@astec.co.jp
address range. They may have been trashed earlier in the boot
process, or the directory header may simply be bogus.
PR: 5140
Submitted by: Joel Faedi <Joel.Faedi@esial.u-nancy.fr>
Brought-to-attention-by: Derek Inksetter <derek@saidev.com>, bde
used, and caused a reference to an uninitialised variable (state).
I think I've fixed it now, but since nothing in the tree seems to use it,
I'm not sure.
It failed to recognize the PCI bus in a system that had only an
old chip-set (class code 000000) and a Cyclom multiport serial
card on PCI bus 0, but no VGA card or disk or network controller.
PR: i386/5300
Submitted by: Nickolay N. Dudorov <nnd@itfs.nsk.su>
- A nonprofiling version of s_lock (called s_lock_np) is used
by mcount.
- When profiling is active, more registers are clobbered in
seemingly simple assembly routines. This means that some
callers needed to save/restore extra registers.
- The stack pointer must have space for a 'fake' return address
in idle, to avoid stack underflow.
noticed some major enhancements available for UP situations. The number
of UP TLB flushes is decreased much more than significantly with these
changes. Since a TLB flush appears to cost minimally approx 80 cycles,
this is a "nice" enhancement, equiv to eliminating between 40 and 160
instructions per TLB flush.
Changes include making sure that kernel threads all use the same PTD,
and eliminate unneeded PTD switches at context switch time.
Wrappered and enabled by the define BETTER_CLOCK (on by default in smpyests.h)
apic_vector.s also contains a small change I (smp) made to eliminate
the double level INT problem. It seems stable, but I haven't the tools
in place to prove it fixes the problem.
Reviewed by: smp@csn.net
Submitted by: Tor Egge <Tor.Egge@idi.ntnu.no>
workaround. Note that this currently eats up two pages extra in the system;
this could be alleviated by aligning idt correctly, and then only dealing with
that (as opposed to the current method of allocated two pages and copying the
IDT table to that, and then setting that to be the IDT table).
make isa_dmacascade, isa_dmastart, isa_dmadone, and find_isadev MUCH
easier to be found by starting them at the beginging of the line...
remove braces inside of ifdef RESOURCE_CHECK... found by % in vi...
"high resolution" profiling. The available clocks are:
- the i8254 clock
- on non-SMP i586's and i686's: the TSC
- on systems with I586_PMC_GUPROF configured, and PERFMON configured
and available: all the performance counters.
This is unfinshed (there are problems with locking out the PERFMON
device driver, and with losing calibration after switching the clock),
but better than static configuration or writing to kmem.
Changed ifdefs to avoid generating code for non-working option
combinations.
time, but was left at 0. This caused the "can't happen" case in
splz_swi to happen for panics when tsleep() calls splx(safepri)
and there is a SWI_AST pending. This was harmless because the
the error handling happens to be right. Debugging this was tricky
because debugger traps force SWI_AST_MASK on in `cpl'.
there is a natural place to initialize `safepri' in a future commit.
Spinoffs:
- spl0() gets called in the unlikely event that isa is not configured.
- configure() has better control over enabling interrupts.
- it is now less unclear that interrupts aren't actually enabled early.
Rev.1.48 of autoconf.c seems to have done the opposite of what was
intended - moving the isa_configure() call delayed the spl0() side
effect.
Added some comments about the bogons. Removed the splhigh() call since
it is a no-op.
interval [VM_MIN_KERNEL_ADDRESS, etext] was used instead of
[btext, etext). Added a comment about this being completely
wrong for LKMs. This only affects interpreting the instructions
after the return to attempt decide the number of args. The
attempt usually fails anyway.
checking was mostly wrong at the boundaries. For the lower limit,
VM_MIN_KERNEL_ADDRESS was used instead of btext and there was an
off-by-(`size' - 1) error. For the upper limit, &etext was used
instead of etext and there was an off-by-1 error. The bugs were
harmless because `size' is not too large and some memory is mapped
just beyond the ends. We still depend on the former to avoid
having to handle the case where the memory range covers the whole
text section, and on the latter to prevent problems when we map
just beyond an end to allow writing an address range that overlaps
the end.
Fixed placement of a nearby comment.
one traditionally reserved for swap devices. The restrictions
should now be the same as the ones for dumpsys(). The restriction
on the partition should be removed someday, and dumpsys() shouldn't
repeat all the checks.
