I14 is also a kind of immediate operand in instruction, like I8/I12/I16/
I21/I26, add it in the Chinese documentation.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

I14 is also a kind of immediate operand in instruction, like I8/I12/I16/
I21/I26, add it in the English documentation.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1, Add NVME related options;
2, Add compressed firmware support;
3, Add virtio drivers in order to run in qemu.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

To get the best stacktrace output, you can compile your userspace
programs with frame pointers (at least glibc + the app you are tracing).

1, export "CC = gcc -fno-omit-frame-pointer";
2, compile your programs with "CC";
3, use uprobe to get stacktrace output.

...
     echo 'p:malloc /usr/lib64/libc.so.6:0x0a4704 size=%r4:u64' > uprobe_events
     echo 'p:free /usr/lib64/libc.so.6:0x0a4d50 ptr=%r4:x64' >> uprobe_events
     echo 'comm == "demo"' > ./events/uprobes/malloc/filter
     echo 'comm == "demo"' > ./events/uprobes/free/filter
     echo 1 > ./options/userstacktrace
     echo 1 > ./options/sym-userobj
...
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1. Use common arch_stack_walk() infrastructure to avoid duplicated code
   and avoid taking care of the stack storage and filtering.
2. Add sched_ra (means sched return address) and sched_cfa (means sched
   call frame address) to thread_info, and store them in switch_to().
3. Add __get_wchan() implementation.

Now we can print the process stack and wait channel by cat /proc/*/stack
and /proc/*/wchan.
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

It unwind the stack frame based on prologue code analyze.
CONFIG_KALLSYMS is needed, at least the address and length
of each function.

Three stages when we do unwind,
  1) unwind_start(), the prapare of unwinding, fill unwind_state.
  2) unwind_done(), judge whether the unwind process is finished or not.
  3) unwind_next_frame(), unwind the next frame.

Dividing unwinder helps to add new unwinders in the future, e.g.:
unwinder_frame, unwinder_orc, .etc.
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Name "guess unwinder" comes from x86, it scans the stack and reports
every kernel text address it finds.

Unwinders can be used by dump_stack() and other stacktrace functions.

Three stages when we do unwind,
  1) unwind_start(), the prapare of unwinding, fill unwind_state.
  2) unwind_done(), judge whether the unwind process is finished or not.
  3) unwind_next_frame(), unwind the next frame.

Add get_stack_info() to get stack info. At present we have irq stack and
task stack. The next_sp is the key info between two types of stacks.

Dividing unwinder helps to add new unwinders in the future.
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

We test 20 million times of getcpu(), the real syscall version take 25
seconds, while the vsyscall version take only 2.4 seconds.
Signed-off-by: Rui Wang <wangrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Loongson64 based systems are PC-like systems which use PCI/PCIe as its
I/O bus, This patch adds the PCI host controller support for LoongArch.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Parse MADT to get multi-processor information, in order to fix the boot
problem and cpu-hotplug problem for SMP platform.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

The kernel entry points of both boot CPU (i.e., kernel_entry) and non-
boot CPUs (i.e., smpboot_entry) may be physical address from BootLoader
(in DA mode or identity-mapping PG mode). So we should jump to the link
address before PG enabled (because DA is disabled at the same time) and
just after DMW configured.

Specifically: With some older firmwares, non-boot CPUs started with PG
enabled, but this need firmware cooperation in the form of a temporary
page table, which is deemed unnecessary. OTOH, latest firmware versions
configure the non-boot CPUs to start in DA mode, so kernel-side changes
are needed.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

This fix a warning when "make C=2":
arch/loongarch/kernel/ptrace.c: note: in included file (through include/linux/uaccess.h, include/linux/sched/task.h, include/linux/sched/signal.h, include/linux/ptrace.h, include/linux/audit.h):
./arch/loongarch/include/asm/uaccess.h:232:32: warning: incorrect type in argument 2 (different address spaces)
./arch/loongarch/include/asm/uaccess.h:232:32:    expected void const *from
./arch/loongarch/include/asm/uaccess.h:232:32:    got void const [noderef] __user *from
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

The return value from the call to get_timer_irq() is int, which can be
a negative error code. However, the return value is being assigned to an
unsigned int variable 'irq', so making 'irq' an int.

Eliminate the following coccicheck warning:
./arch/loongarch/kernel/time.c:146:5-8: WARNING: Unsigned expression compared with zero: irq < 0
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1, ACPI, EFI and SMP are mandatories for LoongArch, select them
unconditionally to avoid various build errors for 'make randconfig'.
2, Move the MMU_GATHER_MERGE_VMAS selection to the correct place.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

When CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS is selected,
cpu_max_bits_warn() generates a runtime warning similar as below while
we show /proc/cpuinfo. Fix this by using nr_cpu_ids (the runtime limit)
instead of NR_CPUS to iterate CPUs.

[    3.052463] ------------[ cut here ]------------
[    3.059679] WARNING: CPU: 3 PID: 1 at include/linux/cpumask.h:108 show_cpuinfo+0x5e8/0x5f0
[    3.070072] Modules linked in: efivarfs autofs4
[    3.076257] CPU: 0 PID: 1 Comm: systemd Not tainted 5.19-rc5+ #1052
[    3.084034] Hardware name: Loongson Loongson-3A5000-7A1000-1w-V0.1-CRB/Loongson-LS3A5000-7A1000-1w-EVB-V1.21, BIOS Loongson-UDK2018-V2.0.04082-beta7 04/27
[    3.099465] Stack : 9000000100157b08 9000000000f18530 9000000000cf846c 9000000100154000
[    3.109127]         9000000100157a50 0000000000000000 9000000100157a58 9000000000ef7430
[    3.118774]         90000001001578e8 0000000000000040 0000000000000020 ffffffffffffffff
[    3.128412]         0000000000aaaaaa 1ab25f00eec96a37 900000010021de80 900000000101c890
[    3.138056]         0000000000000000 0000000000000000 0000000000000000 0000000000aaaaaa
[    3.147711]         ffff8000339dc220 0000000000000001 0000000006ab4000 0000000000000000
[    3.157364]         900000000101c998 0000000000000004 9000000000ef7430 0000000000000000
[    3.167012]         0000000000000009 000000000000006c 0000000000000000 0000000000000000
[    3.176641]         9000000000d3de08 9000000001639390 90000000002086d8 00007ffff0080286
[    3.186260]         00000000000000b0 0000000000000004 0000000000000000 0000000000071c1c
[    3.195868]         ...
[    3.199917] Call Trace:
[    3.203941] [<90000000002086d8>] show_stack+0x38/0x14c
[    3.210666] [<9000000000cf846c>] dump_stack_lvl+0x60/0x88
[    3.217625] [<900000000023d268>] __warn+0xd0/0x100
[    3.223958] [<9000000000cf3c90>] warn_slowpath_fmt+0x7c/0xcc
[    3.231150] [<9000000000210220>] show_cpuinfo+0x5e8/0x5f0
[    3.238080] [<90000000004f578c>] seq_read_iter+0x354/0x4b4
[    3.245098] [<90000000004c2e90>] new_sync_read+0x17c/0x1c4
[    3.252114] [<90000000004c5174>] vfs_read+0x138/0x1d0
[    3.258694] [<90000000004c55f8>] ksys_read+0x70/0x100
[    3.265265] [<9000000000cfde9c>] do_syscall+0x7c/0x94
[    3.271820] [<9000000000202fe4>] handle_syscall+0xc4/0x160
[    3.281824] ---[ end trace 8b484262b4b8c24c ]---

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

LoongArch architecture changes for 5.20 depend on the irqchip and pci
changes to work, so merge them to create a base.

Pull clk fix from Stephen Boyd:
 "One-liner fix of a NULL pointer deref in the Allwinner clk driver"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: sunxi-ng: Fix H6 RTC clock definition

Pull x86 fixes from Borislav Petkov:

 - Update the 'mitigations=' kernel param documentation

 - Check the IBPB feature flag before enabling IBPB in firmware calls
   because cloud vendors' fantasy when it comes to creating guest
   configurations is unlimited

 - Unexport sev_es_ghcb_hv_call() before 5.19 releases now that HyperV
   doesn't need it anymore

 - Remove dead CONFIG_* items

* tag 'x86_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  docs/kernel-parameters: Update descriptions for "mitigations=" param with retbleed
  x86/bugs: Do not enable IBPB at firmware entry when IBPB is not available
  Revert "x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV"
  x86/configs: Update configs in x86_debug.config

Pull locking fix from Borislav Petkov:

 - Avoid rwsem lockups in certain situations when handling the handoff
   bit

* tag 'locking_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/rwsem: Allow slowpath writer to ignore handoff bit if not set by first waiter

Pull EDAC fixes from Borislav Petkov:

 - Relax the condition under which the DIMM label in ghes_edac is set in
   order to accomodate an HPE BIOS which sets only the device but not
   the bank

 - Two forgotten fixes to synopsys_edac when handling error interrupts

* tag 'edac_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/ghes: Set the DIMM label unconditionally
  EDAC/synopsys: Re-enable the error interrupts on v3 hw
  EDAC/synopsys: Use the correct register to disable the error interrupt on v3 hw

Pull ARM fixes from Russell King:
 "Last set of ARM fixes for 5.19:

   - fix for MAX_DMA_ADDRESS overflow

   - fix for find_*_bit performing an out of bounds memory access"

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: findbit: fix overflowing offset
  ARM: 9216/1: Fix MAX_DMA_ADDRESS overflow

With commit d257cc8c ("locking/rwsem: Make handoff bit handling more
consistent"), the writer that sets the handoff bit can be interrupted
out without clearing the bit if the wait queue isn't empty. This disables
reader and writer optimistic lock spinning and stealing.

Now if a non-first writer in the queue is somehow woken up or a new
waiter enters the slowpath, it can't acquire the lock.  This is not the
case before commit d257cc8c as the writer that set the handoff bit
will clear it when exiting out via the out_nolock path. This is less
efficient as the busy rwsem stays in an unlock state for a longer time.

In some cases, this new behavior may cause lockups as shown in [1] and
[2].

This patch allows a non-first writer to ignore the handoff bit if it
is not originally set or initiated by the first waiter. This patch is
shown to be effective in fixing the lockup problem reported in [1].

[1] https://lore.kernel.org/lkml/20220617134325.GC30825@techsingularity.net/
[2] https://lore.kernel.org/lkml/3f02975c-1a9d-be20-32cf-f1d8e3dfafcc@oracle.com/

Fixes: d257cc8c ("locking/rwsem: Make handoff bit handling more consistent")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Donnelly <john.p.donnelly@oracle.com>
Tested-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20220622200419.778799-1-longman@redhat.com

Pull misc fixes from Andrew Morton:
 "Two hotfixes, both cc:stable"

* tag 'mm-hotfixes-stable-2022-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/hmm: fault non-owner device private entries
  page_alloc: fix invalid watermark check on a negative value

Pull block fix from Jens Axboe:
 "Just a single fix for NVMe, yet another quirk addition"

* tag 'block-5.19-2022-07-29' of git://git.kernel.dk/linux-block:
  nvme-pci: Crucial P2 has bogus namespace ids

Pull more drm fixes from Dave Airlie:
 "Maxime had the dog^Wmailing list server eat his homework^Wmisc pull
  request.

  Two more small fixes, one in nouveau svm code and the other in
  simpledrm.

  nouveau:
   - page migration fix

  simpledrm:
   - fix mode_valid return value"

* tag 'drm-fixes-2022-07-30' of git://anongit.freedesktop.org/drm/drm:
  nouveau/svm: Fix to migrate all requested pages
  drm/simpledrm: Fix return type of simpledrm_simple_display_pipe_mode_valid()

One fix to fix simpledrm mode_valid return value, and one for page
migration in nouveau
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220729094514.sfzhc3gqjgwgal62@penduick

Pull SCSI fixes from James Bottomley:
 "Four fixes, three in drivers.

  The two biggest fixes are ufs and the remaining driver and core fix
  are small and obvious (and the core fix is low risk)"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: ufs: core: Fix a race condition related to device management
  scsi: core: Fix warning in scsi_alloc_sgtables()
  scsi: ufs: host: Hold reference returned by of_parse_phandle()
  scsi: mpt3sas: Stop fw fault watchdog work item during system shutdown

Updates descriptions for "mitigations=off" and "mitigations=auto,nosmt"
with the respective retbleed= settings.
Signed-off-by: Eiichi Tsukata <eiichi.tsukata@nutanix.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: corbet@lwn.net
Link: https://lore.kernel.org/r/20220728043907.165688-1-eiichi.tsukata@nutanix.com

If hmm_range_fault() is called with the HMM_PFN_REQ_FAULT flag and a
device private PTE is found, the hmm_range::dev_private_owner page is used
to determine if the device private page should not be faulted in. 
However, if the device private page is not owned by the caller,
hmm_range_fault() returns an error instead of calling migrate_to_ram() to
fault in the page.

For example, if a page is migrated to GPU private memory and a RDMA fault
capable NIC tries to read the migrated page, without this patch it will
get an error.  With this patch, the page will be migrated back to system
memory and the NIC will be able to read the data.

Link: https://lkml.kernel.org/r/20220727000837.4128709-2-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20220725183615.4118795-2-rcampbell@nvidia.com
Fixes: 08ddddda ("mm/hmm: check the device private page owner in hmm_range_fault()")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reported-by: Felix Kuehling <felix.kuehling@amd.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Philip Yang <Philip.Yang@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

There was a report that a task is waiting at the
throttle_direct_reclaim. The pgscan_direct_throttle in vmstat was
increasing.

This is a bug where zone_watermark_fast returns true even when the free
is very low. The commit f27ce0e1 ("page_alloc: consider highatomic
reserve in watermark fast") changed the watermark fast to consider
highatomic reserve. But it did not handle a negative value case which
can be happened when reserved_highatomic pageblock is bigger than the
actual free.

If watermark is considered as ok for the negative value, allocating
contexts for order-0 will consume all free pages without direct reclaim,
and finally free page may become depleted except highatomic free.

Then allocating contexts may fall into throttle_direct_reclaim. This
symptom may easily happen in a system where wmark min is low and other
reclaimers like kswapd does not make free pages quickly.

Handle the negative case by using MIN.

Link: https://lkml.kernel.org/r/20220725095212.25388-1-jaewon31.kim@samsung.com
Fixes: f27ce0e1 ("page_alloc: consider highatomic reserve in watermark fast")
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Reported-by: GyeongHwan Hong <gh21.hong@samsung.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yong-Taek Lee <ytk.lee@samsung.com>
Cc: <stable@vger.kerenl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge tag 'perf-tools-fixes-for-v5.19-2022-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull perf tools fixes from Arnaldo Carvalho de Melo:

 - Fix addresses for bss symbols, describing variables used in resolving
   data access in tools such as 'perf c2c' and 'perf mem'.

 - Skip symbols if SHF_ALLOC flag is not set, a technique used for
   listing deprecated symbols, its addresses are zeros, so not useful.

 - Remove undefined behavior from bpf_perf_object__next() when dealing
   with an empty bpf_objects_list list.

 - Make a ARM CoreSight disasm script work with both python2 and
   python3.

 - Sync x86's cpufeatures header with with the kernel sources.

* tag 'perf-tools-fixes-for-v5.19-2022-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
  perf bpf: Remove undefined behavior from bpf_perf_object__next()
  perf symbol: Skip symbols if SHF_ALLOC flag is not set
  perf symbol: Correct address for bss symbols
  perf scripts python: Let script to be python2 compliant
  tools headers cpufeatures: Sync with the kernel sources

Pull workqueue fix from Tejun Heo:
 "Just one commit to suppress a spurious warning added during the 5.19
  cycle"

* tag 'wq-for-5.19-rc8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Avoid a false warning in unbind_workers()

Pull power management fix from Rafael Wysocki:
 "Make some false positive RCU splats resulting from a recent intel_idle
  driver change go away (Waiman Long)"

* tag 'pm-5.19-rc9' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  intel_idle: Fix false positive RCU splats due to incorrect hardirqs state

Doing set_cpus_allowed_ptr() with wq_unbound_cpumask can be possible
fails and trigger the false warning.

Use cpu_possible_mask instead when wq_unbound_cpumask has no active CPUs.

It is very easy to trigger the warning:
  Set wq_unbound_cpumask to a small set of CPUs.
  Offline all the CPUs of wq_unbound_cpumask.
  Offline an extra CPU and trigger the warning.

Fixes: 10a5a651 ("workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs")
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Pull RISC-V fix from Palmer Dabbelt:
 "A build fix for 'make vdso_install' that avoids an issue trying to
  install the compat VDSO"

* tag 'riscv-for-linus-5.19-rc9' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: compat: vdso: Fix vdso_install target

Merge tag 'loongarch-fixes-5.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:

 - Fix cache size calculation, stack protection attributes, ptrace's
   fpr_set and "ROM Size" in boardinfo

 - Some cleanups and improvements of assembly

 - Some cleanups of unused code and useless code

* tag 'loongarch-fixes-5.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  LoongArch: Fix wrong "ROM Size" of boardinfo
  LoongArch: Fix missing fcsr in ptrace's fpr_set
  LoongArch: Fix shared cache size calculation
  LoongArch: Disable executable stack by default
  LoongArch: Remove unused variables
  LoongArch: Remove clock setting during cpu hotplug stage
  LoongArch: Remove useless header compiler.h
  LoongArch: Remove several syntactic sugar macros for branches
  LoongArch: Re-tab the assembly files
  LoongArch: Simplify "BGT foo, zero" with BGTZ
  LoongArch: Simplify "BLT foo, zero" with BLTZ
  LoongArch: Simplify "BEQ/BNE foo, zero" with BEQZ/BNEZ
  LoongArch: Use the "move" pseudo-instruction where applicable
  LoongArch: Use the "jr" pseudo-instruction where applicable
  LoongArch: Use ABI names of registers where appropriate

When building OpenRISC PCI, which has no ioport_map(), we get the following
build error:

  lib/pci_iomap.c: In function 'pci_iomap_range':
    CC      drivers/i2c/i2c-core-base.o
  ./include/asm-generic/pci_iomap.h:29:41: error: implicit declaration of function 'ioport_map'; did you mean 'ioremap'? [-Werror=implicit-function-declaration]
     29 | #define __pci_ioport_map(dev, port, nr) ioport_map((port), (nr))
	|                                         ^~~~~~~~~~
  lib/pci_iomap.c:44:24: note: in expansion of macro '__pci_ioport_map'
     44 |                 return __pci_ioport_map(dev, start, len);
	|                        ^~~~~~~~~~~~~~~~

Add a NULL definition of __pci_ioport_map() for architectures that do not
support ioport_map().
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220722212248.802500-1-shorne@gmail.comSigned-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Pull powerpc fixes from Michael Ellerman:

 - Re-enable the new amdgpu display engine for powerpc, as long as the
   compiler is correctly configured.

 - Disable stack variable initialisation in prom_init to fix GCC 12
   allmodconfig.

Thanks to Dan Horák and Sudip Mukherjee.

* tag 'powerpc-5.19-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  drm/amdgpu: Re-enable DCN for 64-bit powerpc
  powerpc/64s: Disable stack variable initialisation for prom_init

We can see the "ROM Size" is different in the following outputs:

[root@linux loongson]# cat /sys/firmware/loongson/boardinfo
BIOS Information
Vendor                  : Loongson
Version                 : vUDK2018-LoongArch-V2.0.pre-beta8
ROM Size                : 63 KB
Release Date            : 06/15/2022

Board Information
Manufacturer            : Loongson
Board Name              : Loongson-LS3A5000-7A1000-1w-A2101
Family                  : LOONGSON64

[root@linux loongson]# dmidecode | head -11
...
Handle 0x0000, DMI type 0, 26 bytes
BIOS Information
	Vendor: Loongson
	Version: vUDK2018-LoongArch-V2.0.pre-beta8
	Release Date: 06/15/2022
	ROM Size: 4 MB

According to "BIOS Information (Type 0) structure" in the SMBIOS
Reference Specification [1], it shows 64K * (n+1) is the size of
the physical device containing the BIOS if the size is less than
16M.

Additionally, we can see the related code in dmidecode [2]:

  u64 s = { .l = (code1 + 1) << 6 };

So the output of dmidecode is correct, the output of boardinfo
is wrong, fix it.

By the way, at present no need to consider the size is 16M or
greater on LoongArch, because it is usually 4M or 8M which is
enough to use.

[1] https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.6.0.pdf
[2] https://git.savannah.nongnu.org/cgit/dmidecode.git/tree/dmidecode.c#n347

Fixes: 628c3bb4 ("LoongArch: Add boot and setup routines")
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>