[kernel][pmm] convert pmm_alloc_range() to returning a status instead of count

Tested: runtests on x86 and arm

Change-Id: Id3b550ee9affa742707b2c98ec4c543f1cca7c85

[kernel] WITH_DEV_PCIE -> WITH_KERNEL_PCIE

Hard-code this in KERNEL_DEFINES rather than relying on the
magic predefine based on the presence of the dev/pcie module.

Test: CQ & manual verification that kernel text size didn't change
Change-Id: Id827a8a93bc61ac8b1d7727f51a18f53277a7a16

[kernel][debuglog] Kernel param to print to serial

Add a kernel cmdline parameter (kernel.bypass-debuglog) which if set to
true, behaves exactly as enabling ENABLE_KERNEL_LL_DEBUG. setting the
former to true (or enabling the latter) forces prints to go straight to
the serial console (unbuffered, bypassing debuglog). The reason for
retaining the compile time switch is to control the behavior of prints
that might happen very early in boot, before cmdline is parsed. The
compile time switch overrides the kernel cmdline parameter, and
secondly, both of these settings have the side effect of disabling irq
driver uart tx. Later, we can investigate turning this into a switch
that we can enable/disable at run time (via devmgr perhaps), so we can
control buffering for kernel printfs after boot, if necessary.

Test: Added internal state in the uart drivers, examine that for various
scenarios (bypass-debuglog on and off), ENABLE_KERNEL_LL_DEBUG on, which
should override the kernel cmdline parameter. Also tested using the uart
bulk print tests.

ZX-2301.

Change-Id: I075836313a13ff33077180bd01ebdf40d11e46fc

[kernel] Add feature flag to disable kernel PCI

When ENABLE_USER_PCI=1 is passed to the build zircon
will build with pci syscalls stubbed out and initialize
a new, mostly-empty userspace pci process.

Test: core-tests

Change-Id: I9f35715a7c4374072491c91592966815c6d0c667

Revert "[kernel][debuglog] Add a kernel cmdline parameter to force prints to serial console."

This reverts commit 5427fd8bea3a465778a91bf84d0515a83e40616f.

Reason for revert: Debug and fix a crash.

Original change's description:
> [kernel][debuglog] Add a kernel cmdline parameter to force prints to serial console.
>
> Add a kernel cmdline parameter (kernel.bypass-debuglog) which if set to
> true, behaves exactly as enabling ENABLE_KERNEL_LL_DEBUG. setting the
> former to true (or enabling the latter) forces prints to go straight to
> the serial console (unbuffered, bypassing debuglog). The reason for
> retaining the compile time switch is to control the behavior of prints
> that might happen very early in boot, before cmdline is parsed. The
> compile time switch overrides the kernel cmdline parameter, and
> secondly, both of these settings have the side effect of disabling irq
> driver uart tx. Later, we can investigate turning this into a switch
> that we can enable/disable at run time (via devmgr perhaps), so we can
> control buffering for kernel printfs after boot, if necessary.
>
> Test: Added internal state in the uart drivers, examine that for various
> scenarios (bypass-debuglog on and off), ENABLE_KERNEL_LL_DEBUG on, which
> should override the kernel cmdline parameter.
>
> ZX-2301.
>
> Change-Id: If14620511575d7dd6c3ed0347efbc412ec13a6d6

TBR=voydanoff@google.com,cpu@google.com,travisg@google.com,swetland@google.com,srmohan@google.com

Change-Id: Ie3883cba76347ab195ae3525696d35827ba08adf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true

[kernel][debuglog] Add a kernel cmdline parameter to force prints to serial console.

Add a kernel cmdline parameter (kernel.bypass-debuglog) which if set to
true, behaves exactly as enabling ENABLE_KERNEL_LL_DEBUG. setting the
former to true (or enabling the latter) forces prints to go straight to
the serial console (unbuffered, bypassing debuglog). The reason for
retaining the compile time switch is to control the behavior of prints
that might happen very early in boot, before cmdline is parsed. The
compile time switch overrides the kernel cmdline parameter, and
secondly, both of these settings have the side effect of disabling irq
driver uart tx. Later, we can investigate turning this into a switch
that we can enable/disable at run time (via devmgr perhaps), so we can
control buffering for kernel printfs after boot, if necessary.

Test: Added internal state in the uart drivers, examine that for various
scenarios (bypass-debuglog on and off), ENABLE_KERNEL_LL_DEBUG on, which
should override the kernel cmdline parameter.

ZX-2301.

Change-Id: If14620511575d7dd6c3ed0347efbc412ec13a6d6

[kernel][mexec] Fix hangs during mexec

We were seeing hangs in mexec due to
1) Forcefully stopping the other cores which may have been holding
locks, and
2) Acquiring mutexes after we've disabled interrupts, potentially
leading to unexpected behavior

ZX-2339 #done
ZX-2344 #done

Test: Ran a lot of mexec cycles, didn't see anymore hangs

Change-Id: I5b7cf565cebe2a95a34b1a5694880f56528f7a97

[netboot][zbi] Support complete ZBI booting

When netboot receives only a "kernel.bin" and no "ramdisk.bin",
it expects the single file to be a complete ZBI. It splits the
kernel from the data ZBI and passes both to mexec.

The BOOTLOADER_VERSION is bumped to 0.7.9 for this change, to
indicate a netboot that's capable of booting a complete ZBI.
This means that with this change, new and old zedboot images and
host-side bootserver tools will be incompatible. (That is,
bootserver will refuse to serve a differently-versioned zedboot
even though in this case it would work as long as either the old
method with separate ramdisk image was being used, or the zedboot
was a new one.)

Test: CQ + manual netboot with both old and new methods
Change-Id: I63ff688e491e5f956ffc46f7284f613bad2d3633

[kernel] Gracefully stop secondary CPUs when shutting down

Prior to this change...

... on x64, ZX_SYSTEM_POWERCTL_SHUTDOWN would aggressively shutdown
secondary CPUs without giving them a chance to complete critical
sections and release spinlocks. This led to hangs during shutdown (see
INTK-390).

... on arm64, the shutdown of secondary CPUs was more controlled as
they were first parked by having each CPU halt itself. However,
runqueues, DPCs, and timers were not properly handled. For example, a
DPC could fire after its CPU has been offlined, resulting in an
assertion failure (ZX-2232).

This change:

- Updates x64 and arm64 to more gracefully shutdown secondary CPUs
- Unifies the graceful shutdown paths for arm64 and x64.
- Implements arch_mp_cpu_unplug, arch_mp_prep_cpu_unplug, and
arch_flush_state_and_halt on arm64
- Changes arm64 to use mp_unplug_cpu_mask_single_locked
- Removes a workaround from userboot/start.c (INTK-390)
- Renames platform_halt_helper to platform_graceful_halt
- Removes unused enum values from platform_halt_reason
- Updates comments for platform_halt and platform_halt_secondary_cpus

Tested: Manually, observed no hangs, no panics. Details below...

- Boot looped 300,000 times ('userboot=bin/ps userboot.shutdown=true')
- qemu/arm64/gicv2
- qemu/arm64/gicv3
- qemu/x64
- Flashed vim2, netbooted, ran 'dm reboot' a few times
- Flashed eve, netbooted, ran 'dm reboot' a few times

ZX-2232 #done

ZX-2228 #comment progress

Change-Id: Ib667b272f516dc2e663aa393c1ec78837535041f

[zircon][boot] Rename memory.h to e820.h

This is so that it can be used by higher layers, specifically by Machina
on x86 platforms.

Test: Built Zircon and Garnet and ran "fx run -k".
Change-Id: Ia5039ba8d06751ce2fd72e3573f825a9188d3a77

[ulib][zbi] Rename zbi to libzbi

This is to avoid the naming collision with the zbi tool, so that the
ulib can be exported for use by upper layers.

Test: Built Zircon and Garnet, then ran using "fx run -k".
Change-Id: Ib3f495f908791f6808fa4a399d087f24ec501a88

[libzbi] Addresses some additional CR comments

+ Change zbi_result_t to an enum
+ Remove const from a number of function arguments

Change-Id: I226423b0ce523546779848abb853a02082a8d653

[libzbi] Reapply libzbi append bootdata change

This change was previously reverted due to a bug which
has since been fixed.

Change-Id: I9237fe9ae999b03c394120bbab29537e72da9108

[libzbi] Revert zbi append section change

Unbreaks paver boot loop that some folks are experiencing

This reverts commit da1e998d28d776b3706589af28c6a900081f7f7d.

Change-Id: Ibcc856dc0feba31aae5811ce4ee03f035081912d

[libzbi] migrate bootdata_append_section to libzbi

libzbi implements Zbi::CreateSection and Zbi::AppendSection
which duplicate the functionality of bootdata_append_section.

bootdata_append_section had several problems:
+ It was implemented in syscalls/system.cpp which isn't
really an appropriate place for that utility function.
+ It was only available in the kernel so there was no
way to share that code in userspace, libzbi is shared
with userspace.
+ Tests for bootdata_append_section lived in the
syscalls/... folder which isn't really an appropriate
place for those tests.

Change-Id: I4c9c9481919b8c57b74e5d944520687ca4a03733

[libzbi] Implement zbi_create_section.

Divides zbi_append_section into two seperate
methods:

zbi_create_section creates an empty section at
the end of the ZBI and passes a pointer to the
payload back to the client.

zbi_append_section maintains its current
functionality.

Change-Id: I14a887eb874c3d9dce45cf68e24c8ecf2f21c79a

[pc][zbi] Migrate PC bootdata processing to libzbi

This helps us share ZBI parsing code between our
two supported platforms and factors the common
elements into a shared library.

I've also temporarily removed the CRC validation
code and I feel that it also belongs in libzbi
where both platforms can take advantage of it.

Change-Id: If82aeb356e73ad8dbaf8a08f7536ea212076fe5b

[zbi][kernel] Remove all references to bootdata

Convert the kernel from bootdata to zbi with a few
notable exceptions:
+ Process bootdata on x86/PC was not converted
because we intend to migrate that to using
libzbi in a future patch.
+ syscalls_system.cpp/mexec weren't migrated for
the same reason as above.

bootdata_unittest.cpp was also removed because it
tests the bootdata append functionality which is
redundant with libzbi functionality and slated
to be removed.

Tested by booting on the following platforms:
+ QEMU ARM
+ QEMU x86 (KVM)
+ Vim2
+ UEFI based x86 system

Change-Id: Ifcf803b16a20a70ecd2f4aae930b0304e9cb3437

[debuglog] Enable debuglog with the early gfx console

Change-Id: I05f713cf4ec9d21ecd252e9271e9f6dc9ee14fd2

[kernel][pmm] first pass overhaul of the PMM

-Add a new PmmNode class that represents a pmm for a single NUMA node.
-Move main free queues into PmmNode.
-Make PmmArena be a child of PmmNode.
-Refactor the vm_page structure a bit to change how queues work. Make
the main queue node be intrinsic to the page, instead of per state.
-Move some per page helper routines into the page struct.
-Remove the KMAP flags, since they're not used on 64bit machines.

TODO:
-Make use of the LO_MEM flag for <4GB allocations
-Make use of the new active/inactive/wired queues in PmmNode
-Add support for multiple nodes in a NUMA system
-Keep page state count in PmmNode class to make page state counting less
expensive

Change-Id: I0ca5e55aad0bb2f393d2dc590b02f160e4740398

[kernel][pc] Switch to using smbios library

ZX-2003 #comment Make kernel use library

Change-Id: I5b27d8dbd0f11d29a28efbc636985c9324b5d18c

[kernel][uart] Add a cmdline for overriding bootdata settings

Passing kernel.serial=none will turn serial off.
Passing kernel.serial=legacy on x64 will use the legacy COM1 port.
Not passing kernel.serial will fallback to the bootdata settings.
If no bootdata serial setting is provided, the system on x64
currently defaults to the legacy port.

This also updates the run-zircon script to take a --no-serial
argument for disabling serial. If this option is not provided,
run-zircon will pass kernel.serial=legacy to the kernel.

ZX-1901 #comment Add the cmdline argument

Change-Id: Ied0b159ce0c6ba0542f2a5087c63013f8324e9bc

[pc][smbios] Enumerate the struct type values

Change-Id: Ia1ef472aad298d643ef46008d1109f2a48c36ace

[kernel][pc] On QEMU, shutdown with debug exit device

ZX-1567 #comment

Change-Id: I6fd8aab6b71ded97f641e1a50e0f93c3ec1103ba

[pc][smbios] Implement a subset of SMBIOS support

This will let us retrieve system information such as product names,
SKUs, and firmware revisions that may be useful for logging in bug
reports.

Change-Id: Ia42d1ec715a5f8898165070e243ec163bfe89a98

[kernel][x86][topology] add node level to topology decode, add logic for multi-node AMD cpus

This threadripper is actually a numa multinode machine on a single
socket. Add the appropriate logic to decode this from the AMD specific
topology leaf.

Add a node level, which is currently only used for informational
purposes and never filled in on intel machines.

Change-Id: I2f928f75bdc536c0c0a5298c779690143d0d90be

[kernel][platform] switch PC and ARM platform over to using the boot memory reservation system

Instead of tracking reserved memory in this layer, add reserved ranges
to the boot reserve system prior to adding arenas to the PMM. This
should allow the pmm to allocate memory out of itself without stepping
on reserved memory.

Change-Id: I98921ccbec90bf89decd597c90b219f164aefd07

[kernel][platform] run clang-fmt on all of kernel/platform

Change-Id: I8dcc6ca434f0c77e4fa7c23c202772abf03e1f1d

[platform][pc] Report LAST_CRASHLOG the same way as an NVRAM log

This unifies the reporting mechanisms on PC which should let us keep the
forwarding-across-mexec behavior simple.

ZX-1485 #comment unifying reporting mechanisms

Change-Id: I437609c4e817a0d79413d0c348ac0584031f65f9

[kernel][pc] Propagate NVRAM panic log location across mexec

We were failing to copy the bootdata info over.

ZX-1485 #comment Fix part of /boot/log/last-panic.txt issue.

Change-Id: I8d18c7fd3a6cc0867145563af12ca3e8880917bf

[platform][pc] Give better names to pc internal functions

Change-Id: Ifd2def5a5b5f97f924eefe3dbbc0ff5c4d1934d4

[kernel][arm] use the peripheral memory map from the mdi, remove the use of mmu_initial_map

Multiple smaller changes here that were too hard to split:
-Switch arm code to mapping the peripheral map based on the mdi
-Construct a peripheral map reserve region after the fact when the vm comes up
-Remove the mmu_initial_map for both arm and x86
-Construct the physmap reserve region from the physmap #defines instead of the table
-Change arm start.S to map the first 512GB of physical space for the physmap

Change-Id: I345c521f38fde88cfabffbdaae6331e6b8ebd323

[api] start normalizing ZX_PIXEL_FORMAT_*

- encode byte-size of pixels in the format for easy extraction
(replace a bunch of redundant switch statements with the new
ZX_PIXEL_FORMAT_BYTES(pf) macro)
- define legacy kernel GFX and DISPLAY pixel formats in terms
of the ZX_PIXEL_FORMAT constants
- Convert legacy values to new values when reading bootdata
to maintain bootloader backward compatibility.

Change-Id: I4f9cc579ef08fcd86701ae8b8e082030091435ca

[pc][suspend] Mark UART as stopped during suspend

Otherwise if a print occurs before the UART comes up, the system may
hang.

Change-Id: I0af64289c476f43b029a57dd47e0d77c73aca33f

[bootdata] remove all support for v1 bootdata

- combine bootdata and bootextra headers into a common header
- FLAG_EXTRA becomes FLAG_V2 and required everywhere
- all backward compatibility processing is removed
- all backward compatible generation is removed

Change-Id: Iaca0e7cdc8297f981f9594df0528b87765032050

[pc][suspend] Implement platform_{suspend, resume}

This allows us to restore timers after resume from suspend-to-RAM.

ZX-1184

Change-Id: Ia63d1403c8011fa7b6d7ba8b5b75f3791b621051

[pc][bootdata] Store SMBIOS entry point given by bootloader

Change-Id: Iac5cc487075379fe8a7038cbe0da5316e35ff14e

[kernel][memory] refactor some physical<->virtual routines, formally naming the BKM physmap

This mostly just rearranges the names of things, but add an actual name
for the big kernel map and add some bounds checking to usage.

This should let us be a bit more dynamic about the physmap in the
future, including placing it at a random location and/or giving it a
more complex mapping.

Change-Id: I062d3f0483f27436252b9607174e10b852f0f832

[mexec] support "new" bootdata extra data records

Change-Id: I8382b97fff9ce31bfef778f6c08e95b5c704ca65

[pc] Use a unique_ptr to hold apic_ids

Change-Id: I3c1fe1ca8013e8e13f91c353431daed6ce1cd91d

[kernel][arch] remove KERNEL_LOAD_OFFSET from the kernel link address

-ARM64 kernels are now linked to run precisely at -4GB with no load
offset baked into the address.
-bake KERNEL_LOAD_OFFSET into KERNEL_BASE for x86 so that the initial
mmu table setup still works.
-remove PHYS_HEADER_LOAD_OFFSET which is no longer used

Change-Id: I33b293653346afbfc9aeaae5d2a433ef3a4be0b1

[zedboot] Reinstate hack to disable PCI before Zedboot

Leaving PCI (specifically DMA) devices running during Mexec was causing
memory corruption.

Disabling PCI devices caused graphics to not start up
on some devices.

While we work on a longer term fix I'm going to re-enable this hack to see
what the impact is on the Acer. I'll also investigate why graphics fails to
start on other devices.

This reverts commit 8250a9e1cf3f383d94a950f0182d6c71a9cd082a.

Change-Id: I50af57fbc1d367db18815eb495e28fd54475716e

[kernel] Make mmu_initial_mappings const

Everything that can be const should be const.

Change-Id: If4ee54756a4ba932e242aea844477b8e35187310

[kernel][x86] Stash the BSP APIC ID

We can later use this to assign all IOAPIC IRQs and MSIs to the
same core (until we have a more sophisticated assignment mechanism).

Change-Id: Idb4f5b8913e62c19418b071171ce03d76cfacb77

[zedboot][mexec] Add more logging to cmdline patch failures

Also increases auxiliary data size for passing structs to the next kernel by 2x
since we're now passing more data along.

Change-Id: I70fee3ae4f1a793a2fd5dea22fde991fa86285a0

[kernel][sched] thread's cpu affinity is now a bitmask instead of a number

-Can specify the mask of which cpus a thread is allowed to run on
-thread_set_cpu_affinity() will now do what is needed to migrate a
thread between cores, even if the thread is currently running on another
cpu.

Change-Id: I5dfc9f8e1c23d63ed749c84bc3dfa4118470b8e6

[zedboot] Remove hack to disable PCI before Zedboot

This hack seems to be causing some trouble recently:

+ UART fails to initialize with this hack present after a zedboot.
+ This hack was causing Zedboot to hang reliably for me.

Furthermore, I haven't seen any instances of devices failing to initialize
after a zedboot so I think it's better that we remove this hack for now.

Change-Id: I6ddba184dbf64ce21d06f2183f679e7ab9aa702f

[pc][mexec][uart] Pass UART parameters via bootdata during mexec

Patch the bootdata with the BOOTDATA_DEBUG_UART section to inform the next
kernel about the UART config.

Change-Id: Iaa31647c78a11a1a196c2d3d071cbe274d51b1e0

[kernel][platform] Convert kernel/platform to use zx_status_t

Change-Id: If07f3ab0f67f7c3408fc520d48d9cde1b7d735be

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[zircon][mxtl->fbl] Rename mxtl to fbl

Change-Id: Ie21b6498e1bfb0a7fa0315e40b9e5c3ee78646be

[kernel][vm] move kernel/kernel/vm to just kernel/vm

Change-Id: I8f724a9f8a61415712661d1fdd3dc4e1c70cf620

[bootdata] further movement toward new bootdata headers

- bootloader, kernel, userboot, and devmgr now support FLAG_EXTRA
for container headers as well as item headers
- bootloader generates new style headers for prepended bootdata
items when it detects a new style container header
- mkbootfs generates large container headers when generating
bootdata images with crc32 enabled
- bootloader version bumped to 0.6.0 to mark the point of
compatibility needed for kernels once we throw the switch
to use new headers exclusively

Change-Id: Ifcb78d62f882ddd869da8d73ffe774a0f7937bc0

[kernel][options] tidy up some kernel cmdline options

- Renamed kernel.halt_on_panic to .halt-on-panic
- Renamed smp.cpus to kernel.smp.cpus
- Renamed smp.ht to kernel.smp.ht
- Renamed timer.wallclock to kernel.wallclock
- Removed docs for nonexistent option superceded by virtcon.*

Change-Id: I59245798805731cfeca07ba142da88cbb8fbd91d

[kernel][bootdata][pc] check crc32 on bootdata items that have it

Only when DEBUG_BOOT_DATA is set, since normally the output from
this stage is not usefully visible. This is intended to debug
data corruption during bootloader -> kernel handoff.

Change-Id: I2826da837f6eea89493288d0393ee79eec34236f

[pc][pci] Tear down PCI devices before mexec()

As noted in comments, this is a workaround until we have a more mature
driver destruction handler.

Change-Id: I97b99beb144cdf6921f3a7210668f23cc5873176

[mexec][cmdline] Pass cmdline to next kernel via mexec

Adds an argument to the mexec syscall for passing kernel
command line arguments to the next kernel.

Change-Id: I405bbe041865715a7de001d864c49bf20a42aa7c

[x86][pc] Implements mexec for Intel x86 PC

Change-Id: Id257568884e91056bbaab64d8d4650ddfd49ddda

[platform] Implements halt_secondaries and thread_migrate_cpu

Implements two new APIs in the kernel:

(1) platform_halt_secondary_cpus

Halt any CPU cores that are not designated as the boot cpu
as the platform sees fit.

This call is intended to bring the system back into the state
it was in when it booted in order to fascilitate mexec.
This patch implements this call for x86.

(2) thread_migrate_cpu

Pins the current thread on a target CPU and ensures that the
migration has succeded.

In addition, this patch refactors mexec to use the new APIs

Change-Id: Ic05b76dd117e50fdb08f98ce92ccec443c870004

[pc][crashlog] add platform_recover_crashlog() and nvram crashlog support

- platform_recover_crashlog() provides a way to obtain the crashlog
contents in situations where it will not be located and passed in
via the bootloader
- arm gets a do-nothing implementation
- pc gets an implementation that works with the nvram crashlog
bootdata item, and its platform_stow_crashlog() now favors the
nvram crashlog over the efi variable crashlog if both are
available
- pc: change chipset level reset to a hard reset from a full reset,
to avoid multi-second system-wide reset that could impact memory
integrity

Change-Id: I6b600249e6504f14269dc2fc0f87e6c765073854

[kernel][x86][smp] clean up a little bit of boot spew regarding x86 boot

Also early terminate the x86_bringup_aps() routine if theres no work to
be done.

Change-Id: I9676d409b2dbaf0fd87c4c5891ec8505194d1d4e

[pc][bootdata] wire up new bootdata items, tidy things

- simplify bootloader struct by sharing sub-structs with
bootinfo, which also simplifies processing bootinfo
- wire up bootdata item for debug uart
- allow specification of irq (otherwise use polling mode)
for debug uart bootdata
- remove no-longer-needed commandline paths for setting
up the sw fb and debug uart
- move bootdata extraction above uart init

Change-Id: Ieff479e5adf372e166e5d8a290ae58a6662fccb7

[kernel][multiboot] fix the multiboot flags table

Turns out the multiboot flags constants have been wrong since forever,
which has caused us to add some workaround code, blaming qemu for
not passing in the multiboot mmap info. It was our fault.

Change-Id: I6ae92c1ad1243d982f53700124e042a4b980c2c5

[magenta][kernel][platform] Use the new MX_ERR_* and MX_OK names

Change-Id: I66e96d82886d10bc497eca0999be9a7e56ba7b16

[kernel][vm] restructure kernel vm headers and remove more legacy routines

Mostly unpack vm.h into a few separate headers.

No functional change

Change-Id: Ifd85506f49596d82a3a0e970fc911a34f3064d70

[kernel] remove the WITH_SMP flag

Always build the kernel with full SMP support.

Change-Id: I105f8e4127a93113c795ae80e1dc4d4b0d43abe8

platform: multiboot: Allow framebuffer configuration on command line

Multiboot bootloaders currently do not have a way to pass the framebuffer
configuration to the kernel. Allow it to be read from the command line
so it can be configured for the current panel.

Change-Id: Id5004e2f50d16d9e6750f04aedc6da851254b068
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>

[cmdline][kernel] Implement appending to kernel cmdline

Calling cmdline_init more than once previously corrupted
the state of the kernel command line.

On ARM we have a scenario now where the kernel command line
can come from the native bootloader as well as through the
bootdata structure.

For now we want to be able to support unioning these two
command lines.

Change-Id: Idf6dc9beaf1bf68d408afbb9a8db408a2d2869af

[kernel] fix some issues with platform_*_crashlog()

Change-Id: I36be328f26ee38bbf01efbb571e89efd6d4711a5

[kernel][gigaboot][devmgr] reliable last crashlog mechanism

Introduce platform_stow_crashlog(), a simple API for the panic
path to pass a textual log to the platform in hopes that it will
find its way to the system after a reboot.

For the PC platform, if there is an EFI System Table, attempt to
use EFI Runtime Services to stash this data in an EFI variable.

Gigaboot will read this EFI variable and pass the crashlog to
the booting system as BOOTDATA_LAST_CRASHLOG, erasing the contents
of the variable afterwards.

Devmgr will unpack BOOTDATA_LAST_CRASHLOG into /boot/log/last-panic.txt

Change-Id: I6cc7602a2e85156f8d3353166f4cbc22413a5ae1

[kernel][pc] Use e820entry_t consistently.

When calling process_bootitem, we should correctly use the size of the
e820entry_t structure.

Change-Id: I633516dcf4a6ee9690cabc29b512297ab1cf472b

[kernel][pc] Remove x86-32 code from platform.

Remove some x86-32 code for the initial MMU mapping.

Change-Id: Ifaccd187af045a06018b7f0955ce50d0f3819c7e

[kernel][vm] Remove defunct min_alloc_gap arguments

Change-Id: I931dd3a70fff34ca2acd157f8fcedd71ba9e44a3

[kernel][vm] Convert most calls of vmm_alloc_physical to C++

Need to convert ACPICA's magenta code to C++ to get rid of the last one.

Change-Id: Ica2103302d5923807e03a30b1b284bb39b3e9d24

[kernel][pc] Finish C++ conversion

Change-Id: Iea6ff5e497597c1b0cd3a914e1a3cdd5b641cf58

[kernel][pc] Rename all C files to CPP

This is a straight rename and breaks the build. The next patch in
this series makes everything build.

Change-Id: I067e3fe1e3a49d2ca217f48b72fd1e768c3332d7