MFC r335515 (by chuck@):

Fix the Linux kernel version number calculation

The Linux compatibility code was converting the version number (e.g.
2.6.32) in two different ways and then comparing the results.

The linux_map_osrel() function converted MAJOR.MINOR.PATCH similar to
what FreeBSD does natively. I.e. where major=v0, minor=v1, and patch=v2
v = v0 * 1000000 + v1 * 1000 + v2;

The LINUX_KERNVER() macro, on the other hand, converted the value with
bit shifts. I.e. where major=a, minor=b, and patch=c
v = (((a) << 16) + ((b) << 8) + (c))

The Linux kernel uses the later format via the KERNEL_VERSION() macro in
include/generated/uapi/linux/version.h

Fix is to use the LINUX_KERNVER() macro in linux_map_osrel() as well as
in the .trans_osrel functions.

PR: 229209

MFC r332333 (by emaste@):

linuxulator: deduplicate linux_exec_imgact_try

Previously linuxulator had three identical copies of
linux_exec_imgact_try. Deduplicate before adding another arch to
linuxulator.

MFC r331462 (by emaste@):

Remove redundant cast from Linuxulator SYSINITs.

MFC r331356 (by emaste@):

Share Linux errno table with libsysdecode.

MFC r331226 (byu emaste@):

Rename linuxulator functions with linux_ prefix

It's preferable to have a consistent prefix. This also reduces
differences between the three linux*_sysvec.c files.

MFC r331208 (by emaste@):

linux*_sysvec.c: rationalize whitespace and comments

There's a fair amount of duplication between MD linuxulator files.
Make indentation and comments consistent between the three versions of
linux_sysvec.c to reduce diffs when comparing them.

MFC r331056:
Share a single bsd-linux errno table across MD consumers

Three copies of the linuxulator linux_sysvec.c contained identical
BSD to Linux errno translation tables, and future work to support other
architectures will also use the same table. Move the table to a common
file to be used by all. Make it 'const int' to place it in .rodata.

(Some existing Linux architectures use MD errno values, but x86 and Arm
share the generic set.)

This change should introduce no functional change; a followup will add
missing errno values.

MFC r331057:
linux_errno.c: add newer errno values

Also introduce a static assert to ensure the list is kept up to date.

MFC r331060:
Chase r331057 in libsysdecode erno table

MFC r330927 (by emaste@):

Remove stray ; at end of linux_vdso_deinstall()

MFC r330866 (by emaste@):

Use C99 boolean type for translate_osrel

Migrate to modern types before creating MD Linuxolator bits for new
architectures.

MFC r329794, r329801 (by emaste@):

Correct proper nouns in the Linuxulator

- Capitalize Linux
- Spell FreeBSD out in full
- Address some style(9) on changed lines

MFC r328890 (by emaste@):

Linuxolator whitespace cleanup

A version of each of the MD files by necessity exists for each CPU
architecture supported by the Linuxolator. Clean these up so that new
architectures do not inherit whitespace issues.

Clean up shared Linuxolator files while here.

MFC r321728:

Avoid using [LINUX_]SHAREDPAGE constant directly in the vdso code.
This is needed for https://reviews.freebsd.org/D11780.

MFC 332782:
Simplify the code to allocate stack for auxv, argv[], and environment vectors.

Remove auxarg_size as it was only used once right after a confusing
assignment in each of the variants of exec_copyout_strings().

MFC 330823,332335: Cosmetic cleanups to some Linuxulator files.

330823:
Apply some style(9) to Linuxulator linux_sysvec.c comments

332335:
linuxulator: add else case braces to reduce diffs between archs

Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

MFC r329370, r330239: Rationalize license text on Linuxolator files

Many licenses on Linuxolator files contained small variations from the
standard FreeBSD license text. To avoid license proliferation switch to
the standard 2-clause FreeBSD license for those files where I have
permission from each of the listed copyright holders.

Approved by: dchagin, kan, marcel, rdivacky, sos
Sponsored by: The FreeBSD Foundation

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC r326282, r326317:
Remap ENOATTR to ENODATA in the linuxulator.
In the linux ENOADATA is frequently #defined as ENOATTR.
The change is required for an xattrs support implementation.

Sync bsd_to_linux_errno[] table with i386 and amd64 tables in the sys directory.

Discussed with: netchild
Requested by: jhb
Approved by: pfg (mentor)

MFC r319873:
Move struct syscall_args syscall arguments parameters container into
struct thread.

MFC r320595:

Add support for musl consumers to the Linuxulator.

PR: 213809
Submitted by: Yonas Yanfa (for amd64)
Reported by: Yonas Yanfa
Relnotes: yes

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Cleanup redundant parenthesis from existing howmany()/roundup() macro uses.

X86: use our nitems() macro when it is avaliable through param.h.

No functional change, only trivial cases are done in this sweep,

Discussed in: freebsd-current

Add kern.features flags for linux and linux64 modules

kern.features.linux: 1 meaning linux 32 bits binaries are supported
kern.features.linux64: 1 meaning linux 64 bits binaries are supported

The goal here is to help 3rd party applications (including ports) to determine
if the host do support linux emulation

Reviewed by: dchagin
MFC after: 1 week
Relnotes: yes
Differential Revision: D5830

Convert ss_sp in stack_t and sigstack to void *.

POSIX requires these members to be of type void * rather than the
char * inherited from 4BSD. NetBSD and OpenBSD both changed their
fields to void * back in 1998. No new build failures were reported
via an exp-run.

PR: 206503 (exp-run)
Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D5092

Implement AT_SECURE properly.

AT_SECURE auxv entry has been added to the Linux 2.5 kernel to pass a
boolean flag indicating whether secure mode should be enabled. 1 means
that the program has changes its credentials during the execution.
Being exported AT_SECURE used by glibc issetugid() call.

Submitted by: imp, dchagin
Security: FreeBSD-SA-16:10.linux
Security: CVE-2016-1883

Implement vsyscall hack. Prior to 2.13 glibc uses vsyscall
instead of vdso. An upcoming linux_base-c6 needs it.

Differential Revision: https://reviews.freebsd.org/D1090

Reviewed by: kib, trasz
MFC after: 1 week

Remove sv_prepsyscall, sv_sigsize and sv_sigtbl members of the struct
sysent.

sv_prepsyscall is unused.

sv_sigsize and sv_sigtbl translate signal number from the FreeBSD
namespace into the ABI domain. It is only utilized on i386 for iBCS2
binaries. The issue with this approach is that signals for iBCS2 were
delivered with the FreeBSD signal frame layout, which does not follow
iBCS2. The same note is true for any other potential user if
sv_sigtbl. In other words, if ABI needs signal number translation, it
really needs custom sv_sendsig method instead.

Sponsored by: The FreeBSD Foundation

Fix missing semi-colon from r289055.

Obtained from: mjg
Sponsored by: EMC / Isilon Storage Division

linux: fix handling of out-of-bounds syscall attempts

Due to an off by one the code would read an entry past the table, as
opposed to the last entry which contains the nosys handler.

Reported by: Pawel Biernacki <pawel.biernacki gmail.com>

Rework signal code to allow using it by other modules, like linprocfs:

1. Linux sigset always 64 bit on all platforms. In order to move Linux
sigset code to the linux_common module define it as 64 bit int. Move
Linux sigset manipulation routines to the MI path.

2. Move Linux signal number definitions to the MI path. In general, they
are the same on all platforms except for a few signals.

3. Map Linux RT signals to the FreeBSD RT signals and hide signal conversion
tables to avoid conversion errors.

4. Emulate Linux SIGPWR signal via FreeBSD SIGRTMIN signal which is outside
of allowed on Linux signal numbers.

PR: 197216

Call nosys in case when the incorrect syscall number is specified.

Reported by: trinity

Use the BSD_TO_LINUX_SIGNAL() wherever there is no need
to check the ABI as it is known.

Differential Revision: https://reviews.freebsd.org/D1086

Add AT_RANDOM and AT_EXECFN auxiliary vector entries which are used by
glibc. At list since glibc version 2.16 using AT_RANDOM is mandatory.

Differential Revision: https://reviews.freebsd.org/D1080

Introduce a new module linux_common.ko which is intended for the
following primary purposes:

1. Remove the dependency of linsysfs and linprocfs modules from linux.ko,
which will be architecture specific on amd64.

2. Incorporate into linux_common.ko general code for platforms on which
we'll support two Linuxulator modules (for both instruction set - 32 & 64 bit).

3. Move malloc(9) declaration to linux_common.ko, to enable getting memory
usage statistics properly.

Currently linux_common.ko incorporates a code from linux_mib.c and linux_util.c
and linprocfs, linsysfs and linux kernel modules depend on linux_common.ko.

Temporarily remove dtrace garbage from linux_mib.c and linux_util.c

Differential Revision: https://reviews.freebsd.org/D1072
In collaboration with: Vassilis Laganakos.

Reviewed by: trasz

Remove stale comment about a signal trampoline which
is moved to the shared page at r219609.

Differential Revision: https://reviews.freebsd.org/D1063
Reviewed by: trasz

Put linux_platform into the vdso to avoid copying it onto the stack at
every exec.

Differential Revision: https://reviews.freebsd.org/D1062
Reviewed by: trasz

Implement vdso - virtual dynamic shared object. Through vdso Linux
exposes functions from kernel with proper DWARF CFI information so that
it becomes easier to unwind through them.
Using vdso is a mandatory for a thread cancelation && cleanup
on a modern glibc.

Differential Revision: https://reviews.freebsd.org/D1060

Some style(9) && whitespaces fixes. No functional changes.

Differential Revision: https://reviews.freebsd.org/D1041
Reviewed by: emaste

Switch linuxulator to use the native 1:1 threads.

The reasons:
1. Get rid of the stubs/quirks with process dethreading,
process reparent when the process group leader exits and close
to this problems on wait(), waitpid(), etc.
2. Reuse our kernel code instead of writing excessive thread
managment routines in Linuxulator.

Implementation details:

1. The thread is created via kern_thr_new() in the clone() call with
the CLONE_THREAD parameter. Thus, everything else is a process.
2. The test that the process has a threads is done via P_HADTHREADS
bit p_flag of struct proc.
3. Per thread emulator state data structure is now located in the
struct thread and freed in the thread_dtor() hook.
Mandatory holdig of the p_mtx required when referencing emuldata
from the other threads.
4. PID mangling has changed. Now Linux pid is the native tid
and Linux tgid is the native pid, with the exception of the first
thread in the process where tid and pid are one and the same.

Ugliness:

In case when the Linux thread is the initial thread in the thread
group thread id is equal to the process id. Glibc depends on this
magic (assert in pthread_getattr_np.c). So for system calls that
take thread id as a parameter we should use the special method
to reference struct thread.

Differential Revision: https://reviews.freebsd.org/D1039

MFamd64: Move extern declaration of _ucodesel and _udatasel to
<machine/md_var.h>

Revert r266925 as it can lead to instant panic at fexecve():

To allow to run the interpreter itself add a new ELF branding type.

Pointed out by: kib, mjg

To allow to run the interpreter itself add a new ELF branding type.
Allow Linux ABI to run ELF interpreter.

MFC after: 3 days

x86: Allow users to change PSL_RF via ptrace(PT_SETREGS...)

Debuggers may need to change PSL_RF. Note that tf_eflags is already stored
in the signal context during signal handling and PSL_RF previously could be
modified via sigreturn, so this change should not provide any new ability
to userspace.

For background see the thread at:
http://lists.freebsd.org/pipermail/freebsd-i386/2007-September/005910.html

Reviewed by: jhb, kib
Sponsored by: DARPA, AFRL

Reduce duplication between i386/linux/linux.h and amd64/linux32/linux.h
by moving bits that are MI out into headers in compat/linux.

Reviewed by: Chagin Dmitry dmitry | gmail
MFC after: 2 weeks

Revert previous commit...

Pointyhat to: kevlo (myself)

Prefer NULL over 0 for pointers

Do not write to the user address directly, use suword().

Reported by: Bengt Ahlgren <bengta sics se>
MFC after: 1 week

Convert files to UTF-8

Export the correct AT_PLATFORM value.
Since signal trampolines are copied to the shared page do not need to
leave place on the stack for it. Forgotten in the previous commit.

MFC after: 1 Week

Enable shared page use for amd64/linux32 and i386/linux binaries.
Move signal trampoline code from the top of the stack to the shared page.

MFC after: 2 Weeks

Extend struct sysvec with new method sv_schedtail, which is used for an
explicit process at fork trampoline path instead of eventhadler(schedtail)
invocation for each child process.

Remove eventhandler(schedtail) code and change linux ABI to use newly added
sysvec method.

While here replace explicit comparing of module sysentvec structure with the
newly created process sysentvec to detect the linux ABI.

Discussed with: kib

MFC after: 2 Week

Sort include files in the alphabetical order.

Add macro DECLARE_MODULE_TIED to denote a module as requiring the
kernel of exactly the same __FreeBSD_version as the headers module was
compiled against.

Mark our in-tree ABI emulators with DECLARE_MODULE_TIED. The modules
use kernel interfaces that the Release Engineering Team feel are not
stable enough to guarantee they will not change during the life cycle
of a STABLE branch. In particular, the layout of struct sysentvec is
declared to be not part of the STABLE KBI.

Discussed with: bz, rwatson
Approved by: re (bz, kensmith)
MFC after: 2 weeks

The interpreter name should no longer be treated as a buffer that can be
overwritten. (This change should have been included in r210545.)

Submitted by: kib

Reorganize syscall entry and leave handling.

Extend struct sysvec with three new elements:
sv_fetch_syscall_args - the method to fetch syscall arguments from
usermode into struct syscall_args. The structure is machine-depended
(this might be reconsidered after all architectures are converted).
sv_set_syscall_retval - the method to set a return value for usermode
from the syscall. It is a generalization of
cpu_set_syscall_retval(9) to allow ABIs to override the way to set a
return value.
sv_syscallnames - the table of syscall names.

Use sv_set_syscall_retval in kern_sigsuspend() instead of hardcoding
the call to cpu_set_syscall_retval().

The new functions syscallenter(9) and syscallret(9) are provided that
use sv_*syscall* pointers and contain the common repeated code from
the syscall() implementations for the architecture-specific syscall
trap handlers.

Syscallenter() fetches arguments, calls syscall implementation from
ABI sysent table, and set up return frame. The end of syscall
bookkeeping is done by syscallret().

Take advantage of single place for MI syscall handling code and
implement ptrace_lwpinfo pl_flags PL_FLAG_SCE, PL_FLAG_SCX and
PL_FLAG_EXEC. The SCE and SCX flags notify the debugger that the
thread is stopped at syscall entry or return point respectively. The
EXEC flag augments SCX and notifies debugger that the process address
space was changed by one of exec(2)-family syscalls.

The i386, amd64, sparc64, sun4v, powerpc and ia64 syscall()s are
changed to use syscallenter()/syscallret(). MIPS and arm are not
converted and use the mostly unchanged syscall() implementation.

Reviewed by: jhb, marcel, marius, nwhitehorn, stas
Tested by: marcel (ia64), marius (sparc64), nwhitehorn (powerpc),
stas (mips)
MFC after: 1 month

Change the arguments of exec_setregs() so that it receives a pointer
to the image_params struct instead of several members of that struct
individually. This makes it easier to expand its arguments in the future
without touching all platforms.

Reviewed by: jhb

In r197963, a race with thread being selected for signal delivery
while in kernel mode, and later changing signal mask to block the
signal, was fixed for sigprocmask(2) and ptread_exit(3). The same race
exists for sigreturn(2), setcontext(2) and swapcontext(2) syscalls.

Use kern_sigprocmask() instead of direct manipulation of td_sigmask to
reschedule newly blocked signals, closing the race.

Reviewed by: davidxu
Tested by: pho
MFC after: 1 month

Fix handling of .note.ABI-tag section for GNU systems [1].
Handle GNU/Linux according to LSB Core Specification 4.0,
Chapter 11. Object Format, 11.8. ABI note tag.

Also check the first word of desc, not only name, according to
glibc abi-tags specification to distinguish between Linux and
kFreeBSD.

Add explicit handling for Debian GNU/kFreeBSD, which runs
on our kernels as well [2].

In {amd64,i386}/trap.c, when checking osrel of the current process,
also check the ABI to not change the signal behaviour for Linux
binary processes, now that we save an osrel version for all three
from the lists above in struct proc [2].

These changes make it possible to run FreeBSD, Debian GNU/kFreeBSD
and Linux binaries on the same machine again for at least i386 and
amd64, and no longer break kFreeBSD which was detected as GNU(/Linux).

PR: kern/135468
Submitted by: dchagin [1] (initial patch)
Suggested by: kib [2]
Tested by: Petr Salinger (Petr.Salinger seznam.cz) for kFreeBSD
Reviewed by: kib
MFC after: 3 days

Do not export AT_CLKTCK when emulating Linux kernel prior
to 2.4.0, as it has appeared in the 2.4.0-rc7 first time.
Being exported, AT_CLKTCK is returned by sysconf(_SC_CLK_TCK),
glibc falls back to the hard-coded CLK_TCK value when aux entry
is not present.

Glibc versions prior to 2.2.1 always use hard-coded CLK_TCK value.

For older applications/libc's which depends on hard-coded CLK_TCK
value user should set compat.linux.osrelease less than 2.4.0.

Approved by: kib (mentor)

Rework r189362, r191883.
The frequency of the statistics clock is given by stathz.
Use stathz if it is available, otherwise use hz.

Pointed out by: bde

Approved by: kib (mentor)

Move the per-prison Linux MIB from a private one-off pointer to the new
OSD-based jail extensions. This allows the Linux MIB to accessed via
jail_set and jail_get, and serves as a demonstration of adding jail support
to a module.

Reviewed by: dchagin, kib
Approved by: bz (mentor)

Move extern variable definitions to the header file.

Approved by: kib (mentor)
MFC after: 1 month

Reimplement futexes.
Old implemention used Giant to protect the kernel data structures,
but at the same time called malloc(M_WAITOK), that could cause the
calling thread to sleep and lost Giant protection. User-visible
result was the missed wakeup.

New implementation uses one sx lock per futex. The sx protects
the futex structures and allows to sleep while copyin or copyout
are performed.

Unlike linux, we return EINVAL when FUTEX_CMP_REQUEUE operation
is requested and either caller specified futexes are equial or
second futex already exists. This is acceptable since the situation
can only occur from the application error, and glibc falls back to
old FUTEX_WAKE operation when FUTEX_CMP_REQUEUE returns an error.

Approved by: kib (mentor)
MFC after: 1 month

Fix KBI breakage by r190520 which affects older linux.ko binaries:

1) Move the new field (brand_note) to the end of the Brandinfo structure.
2) Add a new flag BI_BRAND_NOTE that indicates that the brand_note pointer
is valid.
3) Use the brand_note field if the flag BI_BRAND_NOTE is set and as old
modules won't have the flag set, so the new field brand_note would be
ignored.

Suggested by: jhb
Reviewed by: jhb
Approved by: kib (mentor)
MFC after: 6 days

Implement new way of branding ELF binaries by looking to a
".note.ABI-tag" section.

The search order of a brand is changed, now first of all the
".note.ABI-tag" is looked through.

Move code which fetch osreldate for ELF binary to check_note() handler.

PR: 118473
Approved by: kib (mentor)

A better fix for handling different FPU initial control words for different
ABIs:
- Store the FPU initial control word in the pcb for each thread.
- When first using the FPU, load the initial control word after restoring
the clean state if it is not the standard control word.
- Provide a correct control word for Linux/i386 binaries under
FreeBSD/amd64.
- Adjust the control word returned for fpugetregs()/npxgetregs() when a
thread hasn't used the FPU yet to reflect the real initial control
word for the current ABI.
- The Linux/i386 ABI for FreeBSD/i386 now properly sets the right control
word instead of trashing whatever the current state of the FPU is.

Reviewed by: bde

Add AT_PLATFORM, AT_HWCAP and AT_CLKTCK auxiliary vector entries which
are used by glibc. This silents the message "2.4+ kernel w/o ELF notes?"
from some programs at start, among them are top and pkill.

Do the assignment of the vector entries in elf_linux_fixup()
as it is done in glibc.

Fix some minor style issues.

Submitted by: Marcin Cieslak <saper at SYSTEM PL>
Approved by: kib (mentor)
MFC after: 1 week

Remove obsolete AT_DEBUG stuff. It never should have been committed
in the first place, let alone migrated to linux emulation.

Reviewed by: peter, rdivacky

Add sv_flags field to struct sysentvec with intention to provide description
of the ABI of the currently executing image. Change some places to test
the flags instead of explicit comparing with address of known sysentvec
structures to determine ABI features.

Discussed with: dchagin, imp, jhb, peter

Correctly fill siginfo for the signals delivered by linux tkill/tgkill.
It is required for async cancellation to work.

Fix PROC_LOCK leak in linux_tgkill when signal delivery attempt is made
to not linux process.

Do not call em_find(p, ...) with p unlocked.

Move common code for linux_tkill() and linux_tgkill() into
linux_do_tkill().

Change linux siginfo_t definition to match actual linux one. Extend
uid fields to 4 bytes from 2. The extension does not change structure
layout and is binary compatible with previous definition, because i386
is little endian, and each uid field has 2 byte padding after it.

Reported by: Nicolas Joly <njoly pasteur fr>
Submitted by: dchangin
MFC after: 1 month

Change the static struct sysentvec and struct Elf_Brandinfo initializers
to the C99 style. At least, it is easier to read sysent definitions
that way, and search for the actual instances of sigcode etc.

Explicitely initialize sysentvec.sv_maxssiz that was missed in most
sysvecs.

No objection from: jhb
MFC after: 1 month

Implement the linux syscalls
openat, mkdirat, mknodat, fchownat, futimesat, fstatat, unlinkat,
renameat, linkat, symlinkat, readlinkat, fchmodat, faccessat.

Submitted by: rdivacky
Sponsored by: Google Summer of Code 2007
Tested by: pho

Add the support for the AT_FDCWD and fd-relative name lookups to the
namei(9).

Based on the submission by rdivacky,
sponsored by Google Summer of Code 2007
Reviewed by: rwatson, rdivacky
Tested by: pho

Since version 4.3, gcc changed its behaviour concerning the i386/amd64
ABI and the direction flag, that is it now assumes that the direction
flag is cleared at the entry of a function and it doesn't clear once
more if needed. This new behaviour conforms to the i386/amd64 ABI.

Modify the signal handler frame setup code to clear the DF {e,r}flags
bit on the amd64/i386 for the signal handlers.

jhb@ noted that it might break old apps if they assumed DF == 1 would be
preserved in the signal handlers, but that such apps should be rare and
that older versions of gcc would not generate such apps.

Submitted by: Aurelien Jarno <aurelien aurel32 net>
PR: 121422
Reviewed by: jhb
MFC after: 2 weeks

Remove kernel support for M:N threading.

While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential. Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.

Fill in cr2 in the signal context from ksi->ksi_addr.
Together with the sys/i386/i386/trap.c rev. 1.306 it fixes the PR.

Submitted by: rdivacky
Suggested by: jhb
Sponsored by: Google Summer of Code 2007
PR: kern/77710
Approved by: re (kensmith)

MFP4: Turn emul_lock into a mutex.

Submitted by: rdivacky

Change futex lock from mutex to sx. Make futex_get atomic (protected by the
futex lock).

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Suggested by: jhb

Move some stuff into headers where they belong.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Noticed by: jhb, ssouhlal

Add the linux 2.6.x stuff (not used by default!):
- TLS - complete
- pid/tid mangling - complete
- thread area - complete
- futexes - complete with issues
- clone() extension - complete with some possible minor issues
- mq*/timer*/clock* stuff - complete but untested and the mq* stuff is
disabled when not build as part of the kernel with native FreeBSD mq*
support (module support for this will come later)

Tested with:
- linux-firefox - works, tested
- linux-opera - works, tested
- linux-realplay - doesnt work, issue with futexes
- linux-skype - doesnt work, issue with futexes
- linux-rt2-demo - works, tested
- linux-acroread - doesnt work, unknown reason (coredump) and sometimes
issue with futexes
- various unix utilities in linux-base-gentoo3 and linux-base-fc4:
everything tried worked

On amd64 not everything is supported like on i386, the catchup is planned for
later when the remaining bugs in the new functions are fixed.

To test this new stuff, you have to run
sysctl compat.linux.osrelease=2.6.16
to switch back use
sysctl compat.linux.osrelease=2.4.2

Don't switch while running a linux program, strange things may or may not
happen.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Some suggestions/help by: jhb, kib, manu@NetBSD.org, netchild

Add some more errno mappings (bsd -> linux) and a comment about the status..

Submitted by: "Intron" <mag@intron.ac>

Enhance the Linux emulation layer to make MegaRAID SAS managements tool happy.
Add back in a scheme to emulate old type major/minor numbers via hooks into
stat, linprocfs to return major/minors that Linux app's expect. Currently
only /dev/null is always registered. Drivers can register via the Linux
type shim similar to the ioctl shim but by using
linux_device_register_handler/linux_device_unregister_handler functions.
The structure is:

struct linux_device_handler {
char *bsd_driver_name;
char *linux_driver_name;
char *bsd_device_name;
char *linux_device_name;
int linux_major;
int linux_minor;
int linux_char_device;
};

Linprocfs uses this to display the major number of the driver. The
soon to be available linsysfs will use it to fill in the driver name.
Linux_stat uses it to translate the major/minor into Linux type values.

Note major numbers are dynamically assigned via passing in a -1 for
the major number so we don't need to keep track of them.

This is somewhat needed due to us switching to our devfs. MegaCli
will not run until I add in the linsysfs and mfi Linux compat changes.

Sponsored by: IronPort Systems

regen after COMPAT_43 removal

Remove kern.elf32.can_exec_dyn sysctl. Instead extend Brandinfo structure
with flags bitfield and set BI_CAN_EXEC_DYN flag for all brands that usually
allow executing elf dynamic binaries (aka shared libraries). When it is
requested to execute ET_DYN elf image check if this flag is on after we
know the elf brand allowing execution if so.

PR: kern/87615
Submitted by: Marcin Koziej <creep@desk.pl>

Remove linux_mib_destroy() (which I actually added in between 5.0 and 5.1)
which existed to cleanup the linux_osname mutex. Now that MTX_SYSINIT()
has grown a SYSUNINIT to destroy mutexes on unload, the extra destroy here
was redundant and resulted in panics in debug kernels.

MFC after: 1 week
Reported by: Goran Gajic ggajic at afrodita dot rcub dot bg dot ac dot yu

The signal code is now an int rather than a long, so update debug printfs.

1. Change prototype of trapsignal and sendsig to use ksiginfo_t *, most
changes in MD code are trivial, before this change, trapsignal and
sendsig use discrete parameters, now they uses member fields of
ksiginfo_t structure. For sendsig, this change allows us to pass
POSIX realtime signal value to user code.

2. Remove cpu_thread_siginfo, it is no longer needed because we now always
generate ksiginfo_t data and feed it to libpthread.

3. Add p_sigqueue to proc structure to hold shared signals which were
blocked by all threads in the proc.

4. Add td_sigqueue to thread structure to hold all signals delivered to
thread.

5. i386 and amd64 now return POSIX standard si_code, other arches will
be fixed.

6. In this sigqueue implementation, pending signal set is kept as before,
an extra siginfo list holds additional siginfo_t data for signals.
kernel code uses psignal() still behavior as before, it won't be failed
even under memory pressure, only exception is when deleting a signal,
we should call sigqueue_delete to remove signal from sigqueue but
not SIGDELSET. Current there is no kernel code will deliver a signal
with additional data, so kernel should be as stable as before,
a ksiginfo can carry more information, for example, allow signal to
be delivered but throw away siginfo data if memory is not enough.
SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
not be caught or masked.
The sigqueue() syscall allows user code to queue a signal to target
process, if resource is unavailable, EAGAIN will be returned as
specification said.
Just before thread exits, signal queue memory will be freed by
sigqueue_flush.
Current, all signals are allowed to be queued, not only realtime signals.

Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64

Move MODULE_DEPEND() statements for SYSVIPC dependencies to linux_ipc.c
so that they aren't duplicated 3 times and are also in the same file as
the code that depends on the SYSVIPC modules.

Use linux_emul_convpath() rather than linux_emul_find() as
linux_emul_find() is going away.

When running Linux binaries, set up the initial FPU state as Linux
would.

PR: 28966

o Split out kernel part of execve(2) syscall into two parts: one that
copies arguments into the kernel space and one that operates
completely in the kernel space;

o use kernel-only version of execve(2) to kill another stackgap in
linuxlator/i386.

Obtained from: DragonFlyBSD (partially)
MFC after: 2 weeks

Axe the semblance of support for PECOFF and Linux a.out core dumps.

Maintain the broken state of backwards compatibilty for a.out (and
PECOFF!) core dumps. None of the old versions of gdb I tried were
able to read a.out core dumps before or after this change.

Reviewed by: arch@

Do a pass over all modules in the kernel and make them return EOPNOTSUPP
for unknown events.

A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".

Change the types of vn_rdwr_inchunks()'s len and aresid arguments to
size_t and size_t *, respectively. Update callers for the new interface.
This is a better fix for overflows that occurred when dumping segments
larger than 2GB to core files.

Make sigaltstack as per-threaded, because per-process sigaltstack state
is useless for threaded programs, multiple threads can not share same
stack.
The alternative signal stack is private for thread, no lock is needed,
the orignal P_ALTSTACK is now moved into td_pflags and renamed to
TDP_ALTSTACK.
For single thread or Linux clone() based threaded program, there is no
semantic changed, because those programs only have one kernel thread
in every process.

Make sigaltstack as per-threaded, because per-process sigaltstack state
is useless for threaded programs, multiple threads can not share same
stack.
The alternative signal stack is private for thread, no lock is needed,
the orignal P_ALTSTACK is now moved into td_pflags and renamed to
TDP_ALTSTACK.
For single thread or Linux clone() based threaded program, there is no
semantic changed, because those programs only have one kernel thread
in every process.

Reviewed by: deischen, dfr

Sorted includes. Removed duplicates exposed by this.

Add an additional field to the elf brandinfo structure to support
quicker exec-time replacement of the elf interpreter on an emulation
environment where an entire /compat/* tree isn't really warranted.

Add sysentvec->sv_fixlimits() hook so that we can catch cases on 64 bit
systems where the data/stack/etc limits are too big for a 32 bit process.

Move the 5 or so identical instances of ELF_RTLD_ADDR() into imgact_elf.c.

Supply an ia32_fixlimits function. Export the clip/default values to
sysctl under the compat.ia32 heirarchy.

Have mmap(0, ...) respect the current p->p_limits[RLIMIT_DATA].rlim_max
value rather than the sysctl tweakable variable. This allows mmap to
place mappings at sensible locations when limits have been reduced.

Have the imgact_elf.c ld-elf.so.1 placement algorithm use the same
method as mmap(0, ...) now does.

Note that we cannot remove all references to the sysctl tweakable
maxdsiz etc variables because /etc/login.conf specifies a datasize
of 'unlimited'. And that causes exec etc to fail since it can no
longer find space to mmap things.

Rename P_THREADED to P_SA. P_SA means a process is using scheduler
activations.

Use __FBSDID().

- Merge struct procsig with struct sigacts.
- Move struct sigacts out of the u-area and malloc() it using the
M_SUBPROC malloc bucket.
- Add a small sigacts_*() API for managing sigacts structures: sigacts_alloc(),
sigacts_free(), sigacts_copy(), sigacts_share(), and sigacts_shared().
- Remove the p_sigignore, p_sigacts, and p_sigcatch macros.
- Add a mutex to struct sigacts that protects all the members of the struct.
- Add sigacts locking.
- Remove Giant from nosys(), kill(), killpg(), and kern_sigaction() now
that sigacts is locked.
- Several in-kernel functions such as psignal(), tdsignal(), trapsignal(),
and thread_stopped() are now MP safe.

Reviewed by: arch@
Approved by: re (rwatson)

Provide exec_linux_setregs() to override exec_setregs().
Linux initializes %gs to 0. Mimic this behavior.

Submitted by: Christian Zander <zander@minion.de>
Reviewed by: jake
Approved by: re

Don't drop the proc lock just to reacquire it after a few simple assignment
statements. Just hold the lock the entire time.

- Move p->p_sigmask to td->td_sigmask. Signal masks will be per thread with
a follow on commit to kern_sig.c
- signotify() now operates on a thread since unmasked pending signals are
stored in the thread.
- PS_NEEDSIGCHK moves to TDF_NEEDSIGCHK.

- Change trapsignal() to accept a thread and not a proc.
- Change all consumers to pass in a thread.

Right now this does not cause any functional changes but it will be important
later when signals can be delivered to specific threads.

Add missing includes from previous commit.

Reported by: des

Add a cleanup function to destroy the osname_lock and call it on module
unload.

Submitted by: gallatin
Reported by: Martin Karlsson <mk-freebsd@bredband.net>

Sync up linux and svr compat elf fixup functions for exec(). These
functions are now all basically identical except that alpha linux uses
Elf64 arguments and svr4 and i386 linux use Elf32. The fixups include
changing the first argument to be a register_t ** to match the prototype
for fixup functions, asserting that the process in the image_params struct
is always curproc and removing unnecessary locking to read credentials as a
result, and a few style fixes.

Clean up whitespace and remove register keyword.

More caddr_t removal, in conjunction with copy{in,out}(9) this time.
Also clean up some egregious casts and incorrect use of sizeof.

Correctly map SIGSYS signal to/from Linux.

Submitted by: "Georg-W. Koltermann" <g.w.k@web.de>

Back out M_* changes, per decision of the TRB.

Approved by: trb

Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.

bzero() the sigframe before we fill it. This was not done at all in
linux_rt_sendsig() and only done for the fpstate in linux_sendsig().

Style(9). Make some function declarations consistent with the rest,
and remove some nearby extraneous {}'s.

Tidy up some loose ends that bde pointed out. caddr_t bad, ok?
Move fill_kinfo_proc to before we copy the results instead of after
the copy and too late.

There is still more to do here.

The true value of how the kernel was configured for KSTACK_PAGES was not
available at module compile time. Do not #include the bogus
opt_kstack_pages.h at this point and instead refer to the variables that
are also exported via sysctl.

Diff reduction in comments for filling the siginfo structure - refer to
filling in the POSIX parts, when doing the same thing in every port of
FreeBSD.

Supposedly linux has added a 6th syscall arg register (%ebp). I am not
100% sure if this is enough, but it will not harm anything.

Give this a self contained a.out coredump routine.
XXX freebsd-aout coredumps for a linux-aout binary is a bit pointless.

Use the new kern_* functions to avoid the need to store arguments
in the stack gap. This converts most VFS and signal related system
calls, as well as select().

Discussed on: -arch
Approved by: marcel

Added fields for VM_MIN_ADDRESS, PS_STRINGS and stack protections to
sysentvec. Initialized all fields of all sysentvecs, which will allow
them to be used instead of constants in more places. Provided stack
fixup routines for emulations that previously used the default.

Infrastructure tweaks to allow having both an Elf32 and an Elf64 executable
handler in the kernel at the same time. Also, allow for the
exec_new_vmspace() code to build a different sized vmspace depending on
the executable environment. This is a big help for execing i386 binaries
on ia64. The ELF exec code grows the ability to map partial pages when
there is a page size difference, eg: emulating 4K pages on 8K or 16K
hardware pages.

Flesh out the i386 emulation support for ia64. At this point, the only
binary that I know of that fails is cvsup, because the cvsup runtime
tries to execute code in pages not marked executable.

Obtained from: dfr (mostly, many tweaks from me).

Fix typo in the BSD copyright: s/withough/without/

Spotted and suggested by: des
MFC after: 3 weeks

Moved signal handling and rescheduling from userret() to ast() so that
they aren't in the usual path of execution for syscalls and traps.
The main complication for this is that we have to set flags to control
ast() everywhere that changes the signal mask.

Avoid locking in userret() in most of the remaining cases.

Submitted by: luoqi (first part only, long ago, reorganized by me)
Reminded by: dillon

Fixed some style bugs in the removal of __P(()). Continuation lines
were not outdented to preserve non-KNF lining up of code with parentheses.
Switch to KNF formatting.

Remove __P.

Eliminate unnecessary calls to grow_stack() and useracc() from linux_sendsig()
and linux_rt_sendsig(). (See i386/i386/machdep.c revisions 1.503 and 1.504.)

Pre-KSE/M3 commit.
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,

Clear the single-step flag for signal handlers. This fixes bogus trace
traps on the first instruction of signal handlers.

In trap.c:syscall(), fake a trace trap if the single-step flag was set
on entry to the kernel, not if it will be set on exit from the kernel.
This fixes bogus trace traps after the last instruction of signal handlers.

gdb-4.18 (the version in FreeBSD) still has problems with the program in
the PR. These seem to be due to bugs in gdb and not in FreeBSD, and are
fixed in gdb-5.1 (the distribution version).

PR: 33262
Tested by: k Macy <kip_macy@yahoo.com>
MFC after: 1 day

Convert BSD trap codes to i386.

Submitted by: F. Gouget <fgouget@free.fr>

Eliminate the prefix parameter to linux_emul_find(), which was always
linux_emul_path anyway. Linux_emul_find() has interesting bugs in its
prefix handling (which luckily are not currently exploitable); this
commit is preliminary to an attempt at cleaning it up.

Approved by: marcel

Oops, these already included sys/lock.h, they just did so after
sys/mutex.h which is too late.

Add missing includes of sys/lock.h.

Add a lock assertion to linux_sendsig() to match other sendsig functions.

KSE Milestone 2
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

Fix LINT breakage caused by previous commit. The linux_rt_sendsig
and linux_sendsig functions guarded their debugging output with
ldebug(sigreturn). This has been mistaken for a cut-n-paste bug,
and was replaced by ldebug(rt_sendsig) and ldebug(sendsig) resp.
Since the sendsig functions are not syscalls, this brokei any
build that defines DEBUG.

The fix maps both functions to the unused syscall 0 so that they
can be enabled/disabled independently from sigreturn, but not
independently from each other.

Round of cleanups and enhancements. These include (in random order):

o Introduce private types for use in linux syscalls for two reasons:
1. establish type independence for ease in porting and,
2. provide a visual queue as to which syscalls have proper
prototypes to further cleanup the i386/alpha split.
Linuxulator types are prefixed by 'l_'. void and char have not
been "virtualized".

o Provide dummy functions for all syscalls and remove dummy functions
or implementations of truely obsolete syscalls.

o Sanitize the shm*, sem* and msg* syscalls.

o Make a first attempt to implement the linux_sysctl syscall. At this
time it only returns one MIB (KERN_VERSION), but most importantly,
it tells us when we need to add additional sysctls :-)

o Bump the kenel version up to 2.4.2 (this is not the same as the
KERN_VERSION MIB, BTW).

o Implement new syscalls, of which most are specific to i386. Our
syscall table is now up to date with Linux 2.4.2. Some highlights:
- Implement the 32-bit uid_t and gid_t bases syscalls.
- Implement a couple of 64-bit file size/offset bases syscalls.

o Fix or improve numerous syscalls and prototypes.

o Reduce style(9) violations while I'm here. Especially indentation
inconsistencies within the same file are addressed. Re-indenting
did not obfuscate actual changes to the extend that it could not
be combined.

NOTE: I spend some time testing these changes and found that if there
were regressions, they were not caused by these changes AFAICT.
It was observed that installing a RH 7.1 runtime environment
did make matters worse. Hangs and/or reboots have been observed
with and without these changes, so when it failed to make life
better in cases it doesn't look like it made it worse.

Call sendsig() with the proc lock held and return with it held.

Remove the MPSAFE keyword from the parser for syscalls.master.
Instead introduce the [M] prefix to existing keywords. e.g.
MSTD is the MP SAFE version of STD. This is prepatory for a
massive Giant lock pushdown. The old MPSAFE keyword made
syscalls.master too messy.

Begin comments MP-Safe procedures with the comment:
/*
* MPSAFE
*/
This comments means that the procedure may be called without
Giant held (The procedure itself may still need to obtain
Giant temporarily to do its thing).

sv_prepsyscall() is now MP SAFE and assumed to be MP SAFE
sv_transtrap() is now MP SAFE and assumed to be MP SAFE

ktrsyscall() and ktrsysret() are now MP SAFE (Giant Pushdown)
trapsignal() is now MP SAFE (Giant Pushdown)

Places which used to do the if (mtx_owned(&Giant)) mtx_unlock(&Giant)
test in syscall[2]() in */*/trap.c now do not. Instead they
explicitly unlock Giant if they previously obtained it, and then
assert that it is no longer held to catch broken system calls.

Rebuild syscall tables.

Add a new MI pointer to the process' trapframe p_frame instead of using
various differently named pointers buried under p_md.

Reviewed by: jake (in principle)

With this commit, I hereby pronounce gensetdefs past its use-by date.

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

o Merge contents of struct pcred into struct ucred. Specifically, add the
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

Introduce a global lock for the vm subsystem (vm_mtx).

vm_mtx does not recurse and is required for most low level
vm operations.

faults can not be taken without holding Giant.

Memory subsystems can now call the base page allocators safely.

Almost all atomic ops were removed as they are covered under the
vm mutex.

Alpha and ia64 now need to catch up to i386's trap handlers.

FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).

Reviewed (partially) by: jake, jhb

Preserve the state of the %gs register when setting up the signal
handler in Linux emulation. According to bde, this is what Linux
does.

Recent versions of linuxthreads use %gs for thread-specific data,
while FreeBSD uses %fs (mostly because WINE uses %gs).

Tested by: drew

Undo part of the tangle of having sys/lock.h and sys/mutex.h included in
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)

Grab the process lock while calling psignal and before calling psignal.

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

MFS: bring the consistent `compat_3_brand' support into -CURRENT
(the work was first done in the RELENG_4 branch near a release
during a MFC to make the code cleaner and more consistent)

Allow debugging output to be controlled on a per-syscall granularity.
Also clean up debugging output in a slightly more uniform fashion.

The default behavior remains the same (all debugging output is turned on)

Proc locking.

The Linuxulator needs sysvipc to work.

Don't use p->p_sigstk.ss_flags to keep state of whether the
process is on the alternate stack or not. For compatibility
with sigstack(2) state is being updated if such is needed.

We now determine whether the process is on the alternate
stack by looking at its stack pointer. This allows a process
to siglongjmp from a signal handler on the alternate stack
to the place of the sigsetjmp on the normal stack. When
maintaining state, this would have invalidated the state
information and causing a subsequent signal to be delivered
on the normal stack instead of the alternate stack.

PR: 22286

Correct a misnamed argument hidden behind a #ifdef DEBUG

Found by: LINT

o Change the argument of linux_sigreturn to be a pointer to a
struct sigframe. We need more than only the signal context.

o Properly convert the signal mask when setting up the signal
frame in linux_sendsig and properly convert it back in
linux_sigreturn.

Do some cleanups and improve style while here.

Don't unregister the ioctl handlers before we verified we
can unload. Doing so leaves the linuxulator in a crippled
state (no ioctl support) when Linux binaries are run at
unload time.

While here, consistently spell ELF in capitals and perform
some minor style improvements.

ELF spelling submitted by: asmodai

fix glaring bugs in rt signals -- copyout the right signal mask in
linux_rt_sendsig() and restore the same signal mask linux does
in rt_sigreturn(). This gets us saving/restoring all 64-bits of the
linux sigset_t in rt signals.

Reviewed by: marcel

Make linux_sendsig and linux_sigreturn use all 64 bits of a
linux_sigset_t by updating the linux_sigframe struct so as to include
linux's "extramask" field. This field contains the upper 32-bits of
the sigset. extramask sits behind a linux_fpstate struct, which I've
defined primarily for padding purposes.

While we're here, define LINUX_NSIG in terms of LINUX_NBPW (32) and
LINUX_NSIG_WORDS (2).

This fixes problems where threaded apps would accumulate a large
number of zombies. This was happening because the exit signal resides
in the upper 32-bits of the sigset and was never getting unmasked by
the manager thread after the first child exited.

PR: misc/18530 (may be related, originator not yet contacted)
Reviewed by: marcel

Revert auto-generation. The Alpha port is broken.
Syncing with it is wrong.

Make MINSIGSTKSZ machine dependent, and have the sigaltstack
syscall compare against a variable sv_minsigstksz in struct
sysentvec as to properly take the size of the machine- and
ABI dependent struct sigframe into account.

The SVR4 and iBCS2 modules continue to have a minsigstksz of
8192 to preserve behavior. The real values (if different) are
not known at this time. Other ABI modules use the real
values.

The native MINSIGSTKSZ is now defined as follows:

Arch MINSIGSTKSZ
---- -----------
alpha 4096
i386 2048
ia64 12288

Reviewed by: mjacob
Suggested by: bde

Sync with Alpha:
Do not use sysent.c, proto.h and syscall.h in source tree;
use auto-generated versions.

A start at an implemention of linux_rt_sendsig & linux_rt_sigreturn
and associated user-level signal trampoline glue.

Without this patch, an SA_SIGINFO style handler can be installed by a linux
app, but if the handler accesses its sip argument, it will get a garbage
pointer and likely segfault.

We currently supply a valid pointer, but its contents are mainly
garbage. Filling this in properly is future work.

This is the second of 3 commits that will get IBM's JDK 1.3 working with
FreeBSD ...

Update include directives for Linuxulator headers after the
MD/MI split.

Remove the only use of SCARG and perform dead code elimination.

Add a version tag for the rtc port to depend on.

Fix #! script exec under linux emulation. If a script is exec'd from a
program running under linux emulation, the script binary is checked for
in /compat/linux first. Without this patch the wrong script binary
(i.e. the FreeBSD binary) will be run instead of the linux binary.
For example, #!/bin/sh, thus breaking out of linux compatibility mode.

This solves a number of problems people have had installing linux
software on FreeBSD boxes.

Remove unneeded <sys/buf.h> includes.

Due to some interesting cpp tricks in lockmgr, the LINT kernel shrinks
by 924 bytes.

Change our ELF binary branding to something more acceptable to the Binutils
maintainers.

After we established our branding method of writing upto 8 characters of
the OS name into the ELF header in the padding; the Binutils maintainers
and/or SCO (as USL) decided that instead the ELF header should grow two new
fields -- EI_OSABI and EI_ABIVERSION. Each of these are an 8-bit unsigned
integer. SCO has assigned official values for the EI_OSABI field. In
addition to this, the Binutils maintainers and NetBSD decided that a better
ELF branding method was to include ABI information in a ".note" ELF
section.

With this set of changes, we will now create ELF binaries branded using
both "official" methods. Due to the complexity of adding a section to a
binary, binaries branded with ``brandelf'' will only brand using the
EI_OSABI method. Also due to the complexity of pulling a section out of an
ELF file vs. poking around in the ELF header, our image activator only
looks at the EI_OSABI header field.

Note that a new kernel can still properly load old binaries except for
Linux static binaries branded in our old method.

*
* For a short period of time, ``ld'' will also brand ELF binaries
* using our old method. This is so people can still use kernel.old
* with a new world. This support will be removed before 5.0-RELEASE,
* and may not last anywhere upto the actual release. My expiration
* time for this is about 6mo.
*

Changed the type used to represent the user stack pointer from `long *'
to `register_t *'. This fixes bugs like misplacement of argc and argv
on the user stack on i386's with 64-bit longs. We still use longs to
represent "words" like argc and argv, and assume that they are on the
stack (and that there is stack). The suword() and fuword() families
should also use register_t.

Implement pluggable ioctl handlers.

Other modules can register and unregister ioctl handlers to extend the
ioctls known by the Linuxulator. A recent application is the vmware
port. The Linuxulator itself uses the new interface to register its
handlers as well. Handlers for the following types of ioctls have been
defined:
cdrom
console (=keyboard and VT handling)
socket
sound
termio

All ioctl related defines and declarations have been moved to a new
file (linux_ioctl.h), except for the pluggable ioctl handler interface
definition.

While there, cleanup linux.h some more.

linux.h and linux_ioctl.[ch] have been made to conform to style(9) as
much as possible.

Inspired and reviewed by: Vladimir N. Silyaev

Change useracc() and kernacc() to use VM_PROT_{READ|WRITE|EXECUTE} for the
"rw" argument, rather than hijacking B_{READ|WRITE}.

Fix two bugs (physio & cam) resulting by the confusion caused by this.

Submitted by: Tor.Egge@fast.no
Reviewed by: alc, ken (partly)

useracc() the prequel:

Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>. This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.

This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.

Add a per-signal flag to mark handlers registered with osigaction, so we
can provide the correct context to each signal handler.

Fix broken sigsuspend(): don't use p_oldsigmask as a flag, use SAS_OLDMASK
as we did before the linuxthreads support merge (submitted by bde).

Move ps_sigstk from to p_sigacts to the main proc structure since signal
stack should not be shared among threads.

Move SAS_OLDMASK and SAS_ALTSTACK flags from sigacts::ps_flags to proc::p_flag.
Move PS_NOCLDSTOP and PS_NOCLDWAIT flags from proc::p_flag to procsig::ps_flag.

Reviewed by: marcel, jdp, bde

sigset_t change (part 4 of 5)
-----------------------------

The compatibility code and/or emulators have been updated:

iBCS2 now mostly uses the older syscalls. SVR4 now properly
handles all signals. This has been achieved by using the
new sigset_t throughout the emulator. The Linuxulator has
been severely updated. Internally the new Linux sigset_t is
made the default. These are then mapped to and from the
new FreeBSD sigset_t.

Also, rt_sigsuspend has been implemented in the Linuxulator.
Implementing this syscall basicly caused all this sigset_t
changing in the first place and the syscall has been used
throughout the change as a means for testing. It basicly is
too much work to undo the implementation so that it can
later be added again.

A special note on the use of sv_sigtbl and sv_sigsize in
struct sysentvec:
Every signal larger than sv_sigsize is not translated and is
passed on to the signal handler unmodified. Signals in the
range 1 upto and including sv_sigsize are translated.
The rationale is that only the system defined signals need to
be translated.

The emulators also have been updated so that the translation
tables are only indexed for valid (system defined) signals.
This change also fixes the translation bug already in the
SVR4 emulator.

$Id$ -> $FreeBSD$

Tweak include ordering so sys/systm.h is before sys/buf.h to keep buf.h's
inlines happy.

Enable vmspace sharing on SMP. Major changes are,
- %fs register is added to trapframe and saved/restored upon kernel entry/exit.
- Per-cpu pages are no longer mapped at the same virtual address.
- Each cpu now has a separate gdt selector table. A new segment selector
is added to point to per-cpu pages, per-cpu global variables are now
accessed through this new selector (%fs). The selectors in gdt table are
rearranged for cache line optimization.
- fask_vfork is now on as default for both UP and SMP.
- Some aio code cleanup.

Reviewed by: Alan Cox <alc@cs.rice.edu>
John Dyson <dyson@iquest.net>
Julian Elischer <julian@whistel.com>
Bruce Evans <bde@zeta.org.au>
David Greenman <dg@root.com>

unifdef -DVM_STACK - it's been on for a while for x86 and was checked
and appeared to be working for the Alpha some time ago.

Added call to elf_brand_inuse() to prevent you from cutting your own
legs out from under you.

Minor cleanup; no more references to LKM's.

Add (but don't activate) code for a special VM option to make
downward growing stacks more general.
Add (but don't activate) code to use the new stack facility
when running threads, (specifically the linux threads support).
This allows people to use both linux compiled linuxthreads, and also the
native FreeBSD linux-threads port.

The code is conditional on VM_STACK. Not using this will
produce the old heavily tested system.

Submitted by: Richard Seaman <dick@tar.com>

Make it compile again.
I have no idea if the new stuff works though.

Broken by: Julian

Reviewed by: Luoqi Chen, Jordan Hubbard
Submitted by: "Richard Seaman, Jr." <lists@tar.com>
Obtained from: linux :-)

Code to allow Linux Threads to run under FreeBSD.

By default not enabled
This code is dependent on the conditional
COMPAT_LINUX_THREADS (suggested by Garret)
This is not yet a 'real' option but will be within some number of hours.

Removed the cast to a pointer in the definition of PS_STRINGS and
adjusted related casts to match (only in the kernel in this commit).
The pointer was only wanted in one place in kern_exec.c. Applications
should use the kern.ps_strings sysctl instead of PS_STRINGS, so they
shouldn't notice this change.

Added 3 new errno values, requred by various standards: EOVERFLOW,
ECANCELED, EILSEQ.

Fixed ibcs2 and especially linux EIDRM and ENOMSG errno mapping.
Reviewed by: Dan Nelson <dnelson@emsphone.com>

Finished updating module event handlers to be compatible with
modeventhand_t.

*gulp*. Jordan specifically OK'ed this..

This is the bulk of the support for doing kld modules. Two linker_sets
were replaced by SYSINIT()'s. VFS's and exec handlers are self registered.
kld is now a superset of lkm. I have converted most of them, they will
follow as a seperate commit as samples.
This all still works as a static a.out kernel using LKM's.

Unregister the glibc2 brand at module unload time.

Change the ELF registration/unregistration scheme to be less error prone.
Adding a new brand requires a single addition to linux_brandlist instead of
modifying linux_load(), linux_unload(), and linux_elf_init().

Approved by: jkh
Reviewed by: msmith

Make async I/O on a socket work.

Although the current Sybase license does not permit running under
emulation, FreeBSD 3.0 is now "Sybase Ready" should the license change.

Add support for glibc consumers using the new ld-linux.so.2 linker.
I can't say this was the most inspired fix, but it matches the design OK.

Add provisions for variant core dump file formats, depending on the
object format of the executable being dumped. This is the first
step toward producing ELF core dumps in the proper format. I will
commit the code to generate the ELF core dumps Real Soon Now. In
the meantime, ELF executables won't dump core at all. That is
probably no less useful than dumping a.out-style core dumps as they
have done until now.

Submitted by: Alex <garbanzo@hooked.net> (with very minor changes by me)

Use [u]intptr_t instead of [u_]long for casts between pointers and
integers. Don't forget to cast to (void *) as well.

Fixed print format errors.

This commit fixes various 64bit portability problems required for
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.

Unbotch whitespace and change switch with two cases to if.

Noticed by: bde

Translate T_PROTFLT to SIGSEGV instead of SIGBUS when running under
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

Added EIDRM & ENOMSG to errno translation table.

Staticized.

De-staticize enough to make all the LKMs work again. Add comments where
deemed relevant.

Staticize.

Back out DIAGNOSTIC changes.

Turn DIAGNOSTIC into a new-style option.

Make COMPAT_43 and COMPAT_SUNOS new-style options.

Move the "retval" (3rd) parameter from all syscall functions and put
it in struct proc instead.

This fixes a boatload of compiler warning, and removes a lot of cruft
from the sources.

I have not removed the /*ARGSUSED*/, they will require some looking at.

libkvm, ps and other userland struct proc frobbing programs will need
recompiled.

Removed unused #includes (<machine/cpu.h> now gives more pollution).

Fixed misplaced declaration.

Revert my previous commit about using CS_SECURE macro.
Requested by: Bruce.

Use CS_SECURE macro.
Reviewed by: John Dyson

Removed unused #includes.

md_regs is a struct trapframe * now, not int []

Removed potentially harmful garbage <vm/lock.h> and fixed bogus
use of it. It was actually harmless because the use was null due
to fortuitous include orders and identical (wrong) idempotency
macros.

Fix the warning when compiling the SYSINIT hook due to function types.

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

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.

Prepare kernel to take advantage of "branded" ELF binaries.

Removed nested include of <sys/proc.h> from <vm/vm_object.h> and fixed
the one place that depended on it. wakeup() is now prototyped in
<sys/systm.h> so that it is normally visible.

Added nested include of <sys/queue.h> in <vm/vm_object.h>. The queue
macros are a more fundamental prerequisite for <vm/vm_object.h> than
the wakeup prototype and previously happened to be included by
namespace pollution from <sys/proc.h> or elsewhere.

Clean-up the new VM map procfs code, and also add support for executable
format file "etype". It contains a description of the binary type for
a process.

Clean up -Wunused warnings.

Reviewed by: bde

Include <sys/buf.h> so that this does't blow up with B_WRITE undefined.
I fully updated my src tree and did a `make includes' in /usr/src before
trying this fix, so I can only presume that Bruce missed something.

Update the linux_sendsig() handler to the new type of the 4th
arg, now unsigned long. This was (harmlessly on i386) conflicting
with the recent 4.4Lite2 changes.

Move the elf linux_interp structure from the lkm stub to here so that it
can be referenced when the linux emulator is statically compiled into the
kernel.

First attempt at FreeBSD & Linux ELF support.

Compile and link a new kernel, that will give native ELF support, and
provide the hooks for other ELF interpreters as well.

To make native ELF binaries use John Polstras elf-kit-1.0.1..
For the time being also use his ld-elf.so.1 and put it in
/usr/libexec.

The Linux emulator has been enhanced to also run ELF binaries, it
is however in its very first incarnation.
Just get some Linux ELF libs (Slackware-3.0) and put them in the
prober place (/compat/linux/...).
I've ben able to run all the Slackware-3.0 binaries I've tried
so far.
(No it won't run quake yet :)

Mega-commit for Linux emulator update.. This has been stress tested under
netscape-2.0 for Linux running all the Java stuff. The scrollbars are now
working, at least on my machine. (whew! :-)

I'm uncomfortable with the size of this commit, but it's too
inter-dependant to easily seperate out.

The main changes:

COMPAT_LINUX is *GONE*. Most of the code has been moved out of the i386
machine dependent section into the linux emulator itself. The int 0x80
syscall code was almost identical to the lcall 7,0 code and a minor tweak
allows them to both be used with the same C code. All kernels can now
just modload the lkm and it'll DTRT without having to rebuild the kernel
first. Like IBCS2, you can statically compile it in with "options LINUX".

A pile of new syscalls implemented, including getdents(), llseek(),
readv(), writev(), msync(), personality(). The Linux-ELF libraries want
to use some of these.

linux_select() now obeys Linux semantics, ie: returns the time remaining
of the timeout value rather than leaving it the original value.

Quite a few bugs removed, including incorrect arguments being used in
syscalls.. eg: mixups between passing the sigset as an int, vs passing
it as a pointer and doing a copyin(), missing return values, unhandled
cases, SIOC* ioctls, etc.

The build for the code has changed. i386/conf/files now knows how
to build linux_genassym and generate linux_assym.h on the fly.

Supporting changes elsewhere in the kernel:

The user-mode signal trampoline has moved from the U area to immediately
below the top of the stack (below PS_STRINGS). This allows the different
binary emulations to have their own signal trampoline code (which gets rid
of the hardwired syscall 103 (sigreturn on BSD, syslog on Linux)) and so
that the emulator can provide the exact "struct sigcontext *" argument to
the program's signal handlers.

The sigstack's "ss_flags" now uses SS_DISABLE and SS_ONSTACK flags, which
have the same values as the re-used SA_DISABLE and SA_ONSTACK which are
intended for sigaction only. This enables the support of a SA_RESETHAND
flag to sigaction to implement the gross SYSV and Linux SA_ONESHOT signal
semantics where the signal handler is reset when it's triggered.

makesyscalls.sh no longer appends the struct sysentvec on the end of the
generated init_sysent.c code. It's a lot saner to have it in a seperate
file rather than trying to update the structure inside the awk script. :-)

At exec time, the dozen bytes or so of signal trampoline code are copied
to the top of the user's stack, rather than obtaining the trampoline code
the old way by getting a clone of the parent's user area. This allows
Linux and native binaries to freely exec each other without getting
trampolines mixed up.