Commit Graph

618 Commits

Author SHA1 Message Date
Emmanuel Vadot
2a3d5e3364 rk3328: Add support for this SoC
* rk_cru is a cru driver that needs to be subclassed by
  the real CRU driver
* rk_clk_pll handle the pll type clock on RockChip SoC, it's only read
  only for now.
* rk_clk_composite handle the different composite clock types (with gate,
  with mux etc ...)
* rk_clk_gate handle the RockChip gates
* rk_clk_mux handle the RockChip muxes (unused for now)
* Only clocks for supported devices are supported for now, the rest will be
  added when driver support comes
* The assigned-clock* property are not handled for now so we rely a lot on the
  bootloader to setup some initial values for some clocks.
2018-02-26 21:25:50 +00:00
Olivier Houchard
ed8bce2cd5 In do_ast, make sure the interrupts are enabled before calling ast().
We can reach that point with IRQs disabled, and calling ast() with IRQs 
disabled can lead to a deadlock.
This should fix the freezes on arm64 under load.

Reviewed by:	andrew
2018-02-26 13:12:51 +00:00
Patrick Kelsey
18a7530938 Greatly reduce the number of #ifdefs supporting the TCP_RFC7413 kernel option.
The conditional compilation support is now centralized in
tcp_fastopen.h and tcp_var.h. This doesn't provide the minimum
theoretical code/data footprint when TCP_RFC7413 is disabled, but
nearly all the TFO code should wind up being removed by the optimizer,
the additional footprint in the syncache entries is a single pointer,
and the additional overhead in the tcpcb is at the end of the
structure.

This enables the TCP_RFC7413 kernel option by default in amd64 and
arm64 GENERIC.

Reviewed by:	hiren
MFC after:	1 month
Sponsored by:	Limelight Networks
Differential Revision:	https://reviews.freebsd.org/D14048
2018-02-26 03:03:41 +00:00
Andrew Turner
4f3cad09fe Correctly set the 16kB page size field in the ITS BASER register. Some
new arm64 hardware, e.g. ThunderX2, seems to use this page size so was
failing to attach as the register value read back was incorrect.

While here fix the spelling on shareability.

Sponsored by:	DARPA, AFRL
2018-02-24 10:33:31 +00:00
Conrad Meyer
849ce31a82 Remove unused error return from API that cannot fail
No implementation of fpu_kern_enter() can fail, and it was causing needless
error checking boilerplate and confusion. Change the return code to void to
match reality.

(This trivial change took nine days to land because of the commit hook on
sys/dev/random.  Please consider removing the hook or otherwise lowering the
bar -- secteam never seems to have free time to review patches.)

Reported by:	Lachlan McIlroy <Lachlan.McIlroy AT isilon.com>
Reviewed by:	delphij
Approved by:	secteam (delphij)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14380
2018-02-23 20:15:19 +00:00
Warner Losh
ef1fcaf0f5 Do not include float interfaces when using libsa.
We don't support float in the boot loaders, so don't include
interfaces for float or double in systems headers. In addition, take
the unusual step of spiking double and float to prevent any more
accidental seepage.
2018-02-23 04:04:25 +00:00
Konstantin Belousov
2c0f13aa59 vm_wait() rework.
Make vm_wait() take the vm_object argument which specifies the domain
set to wait for the min condition pass.  If there is no object
associated with the wait, use curthread' policy domainset.  The
mechanics of the wait in vm_wait() and vm_wait_domain() is supplied by
the new helper vm_wait_doms(), which directly takes the bitmask of the
domains to wait for passing min condition.

Eliminate pagedaemon_wait().  vm_domain_clear() handles the same
operations.

Eliminate VM_WAIT and VM_WAITPFAULT macros, the direct functions calls
are enough.

Eliminate several control state variables from vm_domain, unneeded
after the vm_wait() conversion.

Scetched and reviewed by:	jeff
Tested by:	pho
Sponsored by:	The FreeBSD Foundation, Mellanox Technologies
Differential revision:	https://reviews.freebsd.org/D14384
2018-02-20 10:13:13 +00:00
Jeff Roberson
e958ad4cf3 Make v_wire_count a per-cpu counter(9) counter. This eliminates a
significant source of cache line contention from vm_page_alloc().  Use
accessors and vm_page_unwire_noq() so that the mechanism can be easily
changed in the future.

Reviewed by:	markj
Discussed with:	kib, glebius
Tested by:	pho (earlier version)
Sponsored by:	Netflix, Dell/EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14273
2018-02-12 22:53:00 +00:00
Warner Losh
62bca77843 Move __va_list and related defines to sys/sys/_types.h
__va_list and related defines are identical in all the
ARCH/include/_types.h files. Move them to sys/sys/_types.h

Sponsored by: Netflix
2018-02-12 14:48:20 +00:00
Mark Johnston
ab7c09f121 Use vm_page_unwire_noq() instead of directly modifying page wire counts.
No functional change intended.

Reviewed by:	alc, kib (previous revision)
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D14266
2018-02-08 19:28:51 +00:00
Andrew Turner
faa3fd222a Only promote userspace mappings to superpages. This was dropped in r328510,
however due to the break-before-make requirement on arm64 is is currently
unsafe to promote kernel pages.

Sponsored by:	DARPA, AFRL
2018-02-01 14:26:26 +00:00
Michal Meloun
2b4c1a7ffc Remove #endif forgotten in r328510.
Pointy hat: mmel
2018-01-28 15:33:32 +00:00
Michal Meloun
89b090f1e6 Fix handling of I-cache sync operations
- pmap_enter_object() can be used for mapping of executable pages, so it's
  necessary to handle I-cache synchronization within it.

- Fix race in I-cache synchronization in pmap_enter(). The current code firstly
  maps given page to target VA and then do I-cache sync on it. This causes
  race, because this mapping become visible to other threads, before I-cache
  is synced.
  Do sync I-cache firstly (by using DMAP VA) and then map it to target VA.

- ARM64 ARM permits implementation of aliased (AIVIVT, VIPT) I-cache, but we
  can use different that final VA for flushing it. So we should use full
  I-cache flush on affected platforms. For now, and as temporary solution,
  use full flush always.
2018-01-28 15:02:49 +00:00
Michal Meloun
116a5567dd Fix pmap_fault().
- special fault handling for break-before-make mechanism should be also
  applied for instruction translation faults, not only for data translation
  faults.

- since arm64_address_translate_...() functions are not atomic,
  use these with disabled interrupts.
2018-01-27 09:49:47 +00:00
Pedro F. Giffuni
ac2fffa4b7 Revert r327828, r327949, r327953, r328016-r328026, r328041:
Uses of mallocarray(9).

The use of mallocarray(9) has rocketed the required swap to build FreeBSD.
This is likely caused by the allocation size attributes which put extra pressure
on the compiler.

Given that most of these checks are superfluous we have to choose better
where to use mallocarray(9). We still have more uses of mallocarray(9) but
hopefully this is enough to bring swap usage to a reasonable level.

Reported by:	wosch
PR:		225197
2018-01-21 15:42:36 +00:00
Nathan Whitehorn
9a8196ce19 Remove SFBUF_OPTIONAL_DIRECT_MAP and such hacks, replacing them across the
kernel by PHYS_TO_DMAP() as previously present on amd64, arm64, riscv, and
powerpc64. This introduces a new MI macro (PMAP_HAS_DMAP) that can be
evaluated at runtime to determine if the architecture has a direct map;
if it does not (or does) unconditionally and PMAP_HAS_DMAP is either 0 or
1, the compiler can remove the conditional logic.

As part of this, implement PHYS_TO_DMAP() on sparc64 and mips64, which had
similar things but spelled differently. 32-bit MIPS has a partial direct-map
that maps poorly to this concept and is unchanged.

Reviewed by:		kib
Suggestions from:	marius, alc, kib
Runtime tested on:	amd64, powerpc64, powerpc, mips64
2018-01-19 17:46:31 +00:00
Ruslan Bukin
9d00c86401 Set the base address of translation table 0.
This fixes operation on Qualcomm Snapdragon and some other platforms.

During boot time on subsystems initialization we have some amount of
kernel threads created, then scheduler gives CPU time to each thread.
Eventually scheduler returns CPU execution back to thread 0. In this
case writing zero to ttbr0 in cpu_switch leads Qualcomm board to
reboot (asynchronously, CPU continues execution).

Similar to other kernel threads install a valid physical address
(kernel pmap) to user page table base register ttbr0.

Reviewed by:	andrew
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D13536
2018-01-18 16:20:09 +00:00
Andrew Turner
7680515c07 Add a pmap invalidate that doesn't call sched_pin.
When demoting DMAP pages curthread may be pointing to data within the
page we are demoting. Create a new invalidate that doesn't pin and use
it in the demote case.

As the demote has both interrupts disabled, and is within a critical section
this is safe from having the scheduler from switching to another CPU.

Reported by:	loos
Reviewed by:	loos
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D13955
2018-01-18 10:52:31 +00:00
Pedro F. Giffuni
a67b3b1621 arm: make some use of mallocarray(9).
Focus on code where we are doing multiplications within malloc(9). None of
these ire likely to overflow, however the change is still useful as some
static checkers can benefit from the allocation attributes we use for
mallocarray.

This initial sweep only covers malloc(9) calls with M_NOWAIT. No good
reason but I started doing the changes before r327796 and at that time it
was convenient to make sure the sorrounding code could handle NULL values.

X-Differential revision: https://reviews.freebsd.org/D13837
2018-01-15 21:09:58 +00:00
Jeff Roberson
6f4acaf4c9 Add support for NUMA domains to bus dma tags. This causes all memory
allocated with a tag to come from the specified domain if it meets the
other constraints provided by the tag.  Automatically create a tag at
the root of each bus specifying the domain local to that bus if
available.

Reviewed by:	jhb, kib
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D13545
2018-01-12 23:34:16 +00:00
Jeff Roberson
ab3185d15e Implement NUMA support in uma(9) and malloc(9). Allocations from specific
domains can be done by the _domain() API variants.  UMA also supports a
first-touch policy via the NUMA zone flag.

The slab layer is now segregated by VM domains and is precise.  It handles
iteration for round-robin directly.  The per-cpu cache layer remains
a mix of domains according to where memory is allocated and freed.  Well
behaved clients can achieve perfect locality with no performance penalty.

The direct domain allocation functions have to visit the slab layer and
so require per-zone locks which come at some expense.

Reviewed by:	Attilio (a slightly older version)
Tested by:	pho
Sponsored by:	Netflix, Dell/EMC Isilon
2018-01-12 23:25:05 +00:00
Andrew Turner
7023544aec Workaround Spectre Variant 2 on arm64.
We need to handle two cases:

1. One process attacking another process.
2. A process attacking the kernel.

For the first case we clear the branch predictor state on context switch
between different processes. For the second we do this when taking an
instruction abort on a non-userspace address.

To clear the branch predictor state a per-CPU function pointer has been
added. This is set by the new cpu errata code based on if the CPU is
known to be affected.

On Cortex-A57, A72, A73, and A75 we call into the PSCI firmware as newer
versions of this will clear the branch predictor state for us.

It has been reported the ThunderX is unaffected, however the ThunderX2 is
vulnerable. The Qualcomm Falkor core is also affected. As FreeBSD doesn't
yet run on the ThunderX2 or Falkor no workaround is included for these CPUs.

MFC after:	3 days
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D13812
2018-01-12 14:01:38 +00:00
Andrew Turner
ee42eb7e5c iAdd ACPI attachments the the GIC and GICv3 interrupt controller drivers.
For each we need to walk the MADT to find which we have, then add the
driver as needed. As each may have a child they will each walk the same
table to find these details.

Reviewed by:	mmel
Obtained from:	ABT Systems Ltd
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D8720
2018-01-11 17:23:24 +00:00
Andrew Turner
224c3776f6 Add the start of INTRNG support for ACPI.
This adds a new acpi_bus interface with a map_intr method. This is similar
to the Open Firmware map_intr method and allows us to create the needed
mapping from ACPI space to INTRNG space.

Obtained from:	ABT Systems Ltd
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D8617
2018-01-11 17:09:12 +00:00
Michal Meloun
e426794f61 Initialize CONTEXTIDR register on secondary cores by zero,
not with undefined value from X1 register.

MFC after:	1 month
2018-01-11 15:03:01 +00:00
Andrew Turner
4bb409fb8d Add a framework to install CPU errata on arm64. Each erratum can encode
a mask and value to compare with the Main ID Register. If these match then a
function is called to handle the installation of the erratum workaround.

No errata are currently handled, however this will change soon in a future
commit.

MFC after:	1 week
Sponsored by:	DARPA, AFRL
2018-01-09 14:33:05 +00:00
Andrew Turner
dde4c2fc9d Only install the new pagetable pointer into ttbr0_el1 when it differs from
the existing value.

MFC after:	1 week
Sponsored by:	DARPA, AFRL
2018-01-08 11:08:45 +00:00
Andrew Turner
45a91d4538 Move some of the common thread switching code into C. This will help with
future optimisations, e.g. using Address Space IDs (asid).

MFC after:	1 week
Sponsored by:	DARPA, AFRL
2018-01-08 10:23:31 +00:00
Kyle Evans
2defb358ea if_awg: Use syscon prop if it exists
The emac bindings that are landing in Linux 4.15 specify a syscon property
on the emac node that point to /soc/syscon. Use this property if it's
specified, but maintain backwards compatibility with the old method.

The older method is still used for boards that we get .dtb from u-boot, such
as pine64, that did not yet have stable emac bindings.

Tested on:	Banana Pi-M3 (a83t)
Tested on:	Pine64 (a64)
Reviewed by:	manu
Differential Revision:	https://reviews.freebsd.org/D13296
2018-01-04 22:37:15 +00:00
Poul-Henning Kamp
8ba749fbe3 Introduce an architecture-agnostic <sys/_stdarg.h> to reduce
platform divergence.

Only architectures which pass arguments in registers (mips)
and platforms which use really weird compilers (any?) would
need to augment the contents of <sys/_stdarg.h>

Convert x86, arm and arm64 architectures to use <sys/_stdarg.h>
2017-12-25 20:54:00 +00:00
Alexander Kabaev
151ba7933a Do pass removing some write-only variables from the kernel.
This reduces noise when kernel is compiled by newer GCC versions,
such as one used by external toolchain ports.

Reviewed by: kib, andrew(sys/arm and sys/arm64), emaste(partial), erj(partial)
Reviewed by: jhb (sys/dev/pci/* sys/kern/vfs_aio.c and sys/kern/kern_synch.c)
Differential Revision: https://reviews.freebsd.org/D10385
2017-12-25 04:48:39 +00:00
Konstantin Belousov
30d4f9e888 Add atomic_load(9) and atomic_store(9) operations.
They provide relaxed-ordered atomic access semantic.  Due to the
FreeBSD memory model, the operations are syntaxical wrappers around
the volatile accesses.  The volatile qualifier is used to ensure that
the access not optimized out and in turn depends on the volatile
semantic as implemented by supported compilers.

The motivation for adding the operation is to help people coming from
other systems or knowing the C11/C++ standards where atomics have
special type and require use of the special access operations.  It is
still the case that FreeBSD requires plain load and stores of aligned
integer types to be atomic.

Suggested by:	jhb
Reviewed by:	alc, jhb
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D13534
2017-12-19 09:59:20 +00:00
Bruce Evans
fb3cc1c37d Move instantiation of msgbufp from 9 MD files to subr_prf.c.
This variable should be pure MI except possibly for reading it in MD
dump routines.  Its initialization was pure MD in 4.4BSD, but FreeBSD
changed this in r36441 in 1998.  There were many imperfections in
r36441.  This commit fixes only a small one, to simplify fixing the
others 1 arch at a time.  (r47678 added support for
special/early/multiple message buffer initialization which I want in
a more general form, but this was too fragile to use because hacking
on the msgbufp global corrupted it, and was only used for 5 hours in
-current...)
2017-12-07 07:55:38 +00:00
Andrew Turner
78f23de54c Use the module pointer to find the address we need to map to in the early
arm64 boot sequence. This will be a virtual address in the kernel space
after the kernel and any modules loaded by loader so we can use this to
find the size of the kernel + modules. We can then add on a level 2 page for
the module data and round up the size to be aligned to a level 2 page.

This allows more than 8 MiB of modules to be loaded by loader, e.g. zfs.ko
and opensolaris.ko.

Reported by:	Shawn Webb
MFC after:	1 week
Sponsored by:	DARPA, AFRL
2017-12-04 11:25:34 +00:00
Ed Schouten
03c132654d Make COMPAT_FREEBSD32 part of GENERIC on arm64.
The cloudabi32.ko kernel modules can only be loaded on AMD64 and ARM64
by kernels built with COMPAT_FREEBSD32. Even though COMPAT_FREEBSD32
does not support the execution of native FreeBSD executables, do add it
to GENERIC, to make cloudabi32.ko usable.

According to size(1), this makes the kernel image approximately 0.7%
larger.

Reviewed by:	andrew, imp, emaste
Differential Revision:	https://reviews.freebsd.org/D13311
2017-12-03 19:26:14 +00:00
Ed Schouten
aea6d042a9 Port cloudabi32.ko to FreeBSD/arm64.
This change adds an implementation of a sysent for running CloudABI
armv6 and armv7 binaries on FreeBSD/arm64. It is a somewhat literal copy
of the armv6 version, except that it's been patched up to use the proper
registers.

Just like for cloudabi32.ko on FreeBSD/amd64, we make use of a vDSO that
automatically pads system call parameters to 64-bit value. These are
stored in a buffer on the stack, meaning we need to use copyin() and
copyout() unconditionally.
2017-11-30 17:58:48 +00:00
Pedro F. Giffuni
796df753f4 SPDX: Consider code from Carnegie-Mellon University.
Interesting cases, most likely from CMU Mach sources.
2017-11-30 15:48:35 +00:00
Andrew Turner
b4cc39e785 Fix the direction we move the instruction to retuirn to after exiting the
kernel debugger. We should skip the breakpoint instruction, not execute the
instruction before it.

Pointy-hat to:	andrew
MFC after:	1 week
Sponsored by:	DARPA, AFRL
2017-11-28 16:26:56 +00:00
Andrew Turner
be84f91cf4 When we exit the kernel debugger having entered because of a breakpoint
instruction we need to jump over the instruction. Without this we will
execute the same instruction again and enter into the debugger again.

PR:		223917
Reported by:	emaste
MFC after:	1 week
Sponsored by:	DARPA, AFRL
2017-11-28 11:04:47 +00:00
Konstantin Belousov
dde5602786 Fix index calculation for the page table pages for efirt 1:1 map.
Stop issuing pre-assigned number to enumerate all page table pages,
the assignment is incorrect.  Instead automatically calculate the next
unused index. This index in fact does not serve any purpose except to
be unique to satisfy vm_page_grab() interface, we do not look up the
page by the index later.

Reported and tested by:	emaste
Reviewed by:	andrew
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
PR:	223906
Differential revision:	https://reviews.freebsd.org/D13273
2017-11-28 09:34:43 +00:00
Andrew Turner
896d821e54 Set the kernel file name so the kern.bootfile sysctl is set. This allows
for the creation of kernel.old when running installkernel.

MFC after:	1 week
Sponsored by:	DARPA, AFRL
2017-11-27 16:19:00 +00:00
Ed Schouten
2b6a8dd52c Add a Saved Process Status Register bit for AArch32 execution mode.
The documentation on the Saved Process Status Register (SPSR) is a bit
weird; the M[4] bit is documented separately from M[3:0]. The M[4] bit
can be toggled to switch to 32-bit execution mode. This functionality is
orthogonal to M[3:0].

Change the definition of PSR_M_MASK to no longer include M[4]. Add a new
definition, PSR_AARCH32 that can be used to toggle 32-bit independently.
This bit will be used by the cloudabi32 code to force execution of
userspace code in 32-bit mode.

Reviewed by:	andrew
Differential Revision:	https://reviews.freebsd.org/D13148
2017-11-26 14:56:23 +00:00
Ed Schouten
2d19a20d5d Correct some more places where TO_PTR() should be used.
These were missed in r326228.

MFC after:	2 weeks
2017-11-26 14:53:56 +00:00
Ed Schouten
ee13ffbe03 Use TO_PTR() to convert integers to pointers.
For FreeBSD/arm64's cloudabi32 support, I'm going to need a TO_PTR() in
this place. Also use it for all of the other source files, so that the
difference remains as minimal as possible.

MFC after:	2 weeks
2017-11-26 14:45:56 +00:00
Ed Schouten
7af24ff710 Make 32-bit system calls end up in svc_handler().
The nice thing about ARM64 is that it's pretty elegant to install
separate trap/exception handlers for 32-bit and 64-bit processes. That
said, for all other architectures (e.g., i386 on amd64) we always let
32-bit counterparts go through the regular system call codepath. Let's
do the same on ARM64.

Reviewed by:	andrew
Differential Revision:	https://reviews.freebsd.org/D13146
2017-11-26 14:28:27 +00:00
Andrew Turner
c4501bdfac Make the arm64 pmap_invalidate functions static inline. This fixes building
with DIAGNOSTIC.

PR:		223874
Reported by:	emaste
MFC after:	1 week
2017-11-26 09:29:34 +00:00
Ed Maste
ccf802cf18 Temporarily disable VIMAGE on arm64
Loading a kernel module with a static VNET_DEFINE'd variable (e.g.
if_lagg) currently results in a kernel panic.

PR:		223670
2017-11-24 19:21:21 +00:00
Ed Schouten
09f966caf7 Set CP15BEN in SCTLR to make memory barriers work in 32-bit mode.
Binaries generated by Clang for ARMv6 may contain these instructions:

  MCR p15, 0, <Rd>, c7, c10, 5

These instructions are deprecated as of ARMv7, which is why modern
processors have a way of toggling support for them. On FreeBSD/arm64 we
currently disable support for these instructions, meaning that if 32-bit
executables with these instructions are run, they would crash with
SIGILL. This is likely not what we want.

Reviewed by:	andrew
Differential Revision:	https://reviews.freebsd.org/D13145
2017-11-24 13:51:59 +00:00
Ed Schouten
9dcf90f8ad Add rudimentary support for building FreeBSD/arm64 with COMPAT_FREEBSD32.
Right now I'm using two Raspberry Pi's (2 and 3) to test CloudABI
support for armv6, armv7 and aarch64. It would be nice if I could
restrict this to just a single instance when testing smaller changes.
This is why I'd like to get COMPAT_CLOUDABI32 to work on arm64.

As COMPAT_CLOUDABI32 depends on COMPAT_FREEBSD32, at least for the ELF
loading, this change adds all of the bits necessary to at least build a
kernel with COMPAT_FREEBSD32. All of the machine dependent system calls
are still stubbed out, for the reason that implementations for these are
only useful if actual support for running FreeBSD binaries is added.
This is outside the scope of this work.

Reviewed by:	andrew
Differential Revision:	https://reviews.freebsd.org/D13144
2017-11-24 13:50:53 +00:00
Ed Schouten
814629dd64 Don't let cpu_set_syscall_retval() clobber exec_setregs().
Upon successful completion, the execve() system call invokes
exec_setregs() to initialize the registers of the initial thread of the
newly executed process. What is weird is that when execve() returns, it
still goes through the normal system call return path, clobbering the
registers with the system call's return value (td->td_retval).

Though this doesn't seem to be problematic for x86 most of the times (as
the value of eax/rax doesn't matter upon startup), this can be pretty
frustrating for architectures where function argument and return
registers overlap (e.g., ARM). On these systems, exec_setregs() also
needs to initialize td_retval.

Even worse are architectures where cpu_set_syscall_retval() sets
registers to values not derived from td_retval. On these architectures,
there is no way cpu_set_syscall_retval() can set registers to the way it
wants them to be upon the start of execution.

To get rid of this madness, let sys_execve() return EJUSTRETURN. This
will cause cpu_set_syscall_retval() to leave registers intact. This
makes process execution easier to understand. It also eliminates the
difference between execution of the initial process and successive ones.
The initial call to sys_execve() is not performed through a system call
context.

Reviewed by:	kib, jhibbits
Differential Revision:	https://reviews.freebsd.org/D13180
2017-11-24 07:35:08 +00:00