Originally, I had adopted sparc64's name, pmap_clear_write(), for the
function that is now pmap_remove_write(). However, this function is more
like pmap_remove_all() than like pmap_clear_modify() or
pmap_clear_reference(), hence, the name change.
The higher-level rationale behind this change is described in
src/sys/amd64/amd64/pmap.c revision 1.567. The short version is that I'm
trying to clean up and fix our support for execute access.
Reviewed by: marcel@ (ia64)
and pc98 MD files. Remove nodevice and nooption lines specific
to sio(4) from ia64, powerpc and sparc64 NOTES. There were no
such lines for arm yet.
sio(4) is usable on less than half the platforms, not counting
a future mips platform. Its presence in MI files is therefore
increasingly becoming a burden.
mark system calls as being MPSAFE:
- Stop conditionally acquiring Giant around system call invocations.
- Remove all of the 'M' prefixes from the master system call files.
- Remove support for the 'M' prefix from the script that generates the
syscall-related files from the master system call files.
- Don't explicitly set SYF_MPSAFE when registering nfssvc.
implementations and adjust some of the checks while I'm here:
- Add a new check to make sure we don't return from a syscall in a critical
section.
- Add a new explicit check before userret() to make sure we don't return
with any locks held. The advantage here is that we can include the
syscall number and name in syscall() whereas that info is not available
in userret().
- Drop the mtx_assert()'s of sched_lock and Giant. They are replaced by
the more general checks just added.
MFC after: 2 weeks
map was obtained from the SMAP. SMAP is trustworthy, and the memory
extending feature is a band-aid for older systems where FreeBSD's methods
of detecting memory were not always trustworthy. This fixes the issue
where using hw.physmem could result in the ACPI tables getting trashed
breaking ACPI.
MFC after: 3 days
Tested on: i386
system's machine-dependent and machine-independent layers. Once
pmap_clear_write() is implemented on all of our supported
architectures, I intend to replace all calls to pmap_page_protect() by
calls to pmap_clear_write(). Why? Both the use and implementation of
pmap_page_protect() in our virtual memory system has subtle errors,
specifically, the management of execute permission is broken on some
architectures. The "prot" argument to pmap_page_protect() should
behave differently from the "prot" argument to other pmap functions.
Instead of meaning, "give the specified access rights to all of the
physical page's mappings," it means "don't take away the specified
access rights from all of the physical page's mappings, but do take
away the ones that aren't specified." However, owing to our i386
legacy, i.e., no support for no-execute rights, all but one invocation
of pmap_page_protect() specifies VM_PROT_READ only, when the intent
is, in fact, to remove only write permission. Consequently, a
faithful implementation of pmap_page_protect(), e.g., ia64, would
remove execute permission as well as write permission. On the other
hand, some architectures that support execute permission have
basically ignored whether or not VM_PROT_EXECUTE is passed to
pmap_page_protect(), e.g., amd64 and sparc64. This change represents
the first step in replacing pmap_page_protect() by the less subtle
pmap_clear_write() that is already implemented on amd64, i386, and
sparc64.
Discussed with: grehan@ and marcel@
pmap_remove_all() before rather than after the pmap is unlocked. At
present, the page queues lock provides sufficient sychronization. In the
future, the page queues lock may not always be held when free_pv_entry() is
called.
install custom pager functions didn't actually happen in practice (they
all just used the simple pager and passed in a local quit pointer). So,
just hardcode the simple pager as the only pager and make it set a global
db_pager_quit flag that db commands can check when the user hits 'q' (or a
suitable variant) at the pager prompt. Also, now that it's easy to do so,
enable paging by default for all ddb commands. Any command that wishes to
honor the quit flag can do so by checking db_pager_quit. Note that the
pager can also be effectively disabled by setting $lines to 0.
Other fixes:
- 'show idt' on i386 and pc98 now actually checks the quit flag and
terminates early.
- 'show intr' now actually checks the quit flag and terminates early.
ibcs2_getdents(), ibcs2_read(), ogetdirentries(), svr4_sys_getdents(),
and svr4_sys_getdents64() similar to that in getdirentries().
- Mark ibcs2_getdents(), ibcs2_read(), linux_getdents(), linux_getdents64(),
linux_readdir(), ogetdirentries(), svr4_sys_getdents(), and
svr4_sys_getdents64() MPSAFE.
to a copied-in copy of the 'union semun' and a uioseg to indicate which
memory space the 'buf' pointer of the union points to. This is then used
in linux_semctl() and svr4_sys_semctl() to eliminate use of the stackgap.
- Mark linux_ipc() and svr4_sys_semsys() MPSAFE.
from going away. mount(2) is now MPSAFE.
- Expand the scope of Giant some in unmount(2) to protect the mp structure
(or rather, to handle concurrent unmount races) from going away.
umount(2) is now MPSAFE, as well as linux_umount() and linux_oldumount().
- nmount(2) and linux_mount() were already MPSAFE.
pmap_copy() if the mapping is VM_INHERIT_SHARE. Suppose the mapping
is also wired. vmspace_fork() clears the wiring attributes in the vm
map entry but pmap_copy() copies the PG_W attribute in the PTE. I
don't think this is catastrophic. It blocks pmap_remove_pages() from
destroying the mapping and corrupts the pmap's wiring count.
This revision fixes the problem by changing pmap_copy() to clear the
PG_W attribute.
Reviewed by: tegge@
This driver was ported from OpenBSD by Shigeaki Tagashira
<shigeaki@se.hiroshima-u.ac.jp> and posted at
http://www.se.hiroshima-u.ac.jp/~shigeaki/software/freebsd-nfe.html
It was additionally cleaned up by me.
It is still a work-in-progress and thus is purposefully not in GENERIC.
And it conflicts with nve(4), so only one should be loaded.
in 1999, and there are changes to the sysctl names compared to PR,
according to that discussion. The description is in sys/conf/NOTES.
Lines in the GENERIC files are added in commented-out form.
I'll attach the test script I've used to PR.
PR: kern/14584
Submitted by: babkin
VM_ALLOC_NORMAL instead of VM_ALLOC_SYSTEM when try is TRUE. In other
words, when get_pv_entry() is permitted to fail, it no longer tries as
hard to allocate a page.
Change pmap_enter_quick_locked() to fail rather than wait if it is
unable to allocate a page table page. This prevents a race between
pmap_enter_object() and the page daemon. Specifically, an inactive
page that is a successor to the page that was given to
pmap_enter_quick_locked() might become a cache page while
pmap_enter_quick_locked() waits and later pmap_enter_object() maps
the cache page violating the invariant that cache pages are never
mapped. Similarly, change
pmap_enter_quick_locked() to call pmap_try_insert_pv_entry() rather
than pmap_insert_entry(). Generally speaking,
pmap_enter_quick_locked() is used to create speculative mappings. So,
it should not try hard to allocate memory if free memory is scarce.
Add an assertion that the object containing m_start is locked in
pmap_enter_object(). Remove a similar assertion from
pmap_enter_quick_locked() because that function no longer accesses the
containing object.
Remove a stale comment.
Reviewed by: ups@
syscalls. This way there will be a log message printed to the console
(this time for real).
Note: UNIMPL should be used for syscalls we do not implement ever, e.g.
syscalls to load linux kernel modules.
Submitted by: rdivacky
Sponsored by: Goole SoC 2006
P4 IDs: 99600, 99602
when we're about to call kdb_trap() because the latter MI
function can disable interrupts by itself now.
Pointed out by: bde
X-MFC remark: depends on kern/subr_kdb.c#1.18
Sponsored by: RiNet (Cronyx Plus LLC)
Use the method described in IA-32 Intel Architecture Software
Developer's Manual chapter 11.6.6 to get valid mxcsr bits,
use the mxcsr mask to clear invalid bits passed by user code.
an explicit comment that it's needed for the linuxolator. This is not the
case anymore. For all other architectures there was only a "KEEP THIS".
I'm (and other people too) running a COMPAT_43-less kernel since it's not
necessary anymore for the linuxolator. Roman is running such a kernel for a
for longer time. No problems so far. And I doubt other (newer than ia32
or alpha) architectures really depend on it.
This may result in a small performance increase for some workloads.
If the removal of COMPAT_43 results in a not working program, please
recompile it and all dependencies and try again before reporting a
problem.
The only place where COMPAT_43 is needed (as in: does not compile without
it) is in the (outdated/not usable since too old) svr4 code.
Note: this does not remove the COMPAT_43TTY option.
Nagging by: rdivacky
There is a race with the current locking scheme and removing
it should have no measurable performance impact.
This fixes page faults leading to panics in pmap_enter_quick_locked()
on amd64/i386.
Reviewed by: alc,jhb,peter,ps
