mips: add missing declarations for trap handlers

These exception handlers are all called from assembly code, so they don't
normally need a declaration, but without one we now get warnings:

arch/mips/mm/fault.c:323:17: error: no previous prototype for 'do_page_fault' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:447:17: error: no previous prototype for 'do_be' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:752:17: error: no previous prototype for 'do_ov' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:874:17: error: no previous prototype for 'do_fpe' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1027:17: error: no previous prototype for 'do_bp' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1114:17: error: no previous prototype for 'do_tr' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1151:17: error: no previous prototype for 'do_ri' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1402:17: error: no previous prototype for 'do_cpu' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1507:17: error: no previous prototype for 'do_msa_fpe' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1527:17: error: no previous prototype for 'do_msa' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1548:17: error: no previous prototype for 'do_mdmx' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1560:17: error: no previous prototype for 'do_watch' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1587:17: error: no previous prototype for 'do_mcheck' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1612:17: error: no previous prototype for 'do_mt' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1648:17: error: no previous prototype for 'do_dsp' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1656:17: error: no previous prototype for 'do_reserved' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1832:17: error: no previous prototype for 'cache_parity_error' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1880:17: error: no previous prototype for 'do_ftlb' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1909:17: error: no previous prototype for 'do_gsexc' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1944:6: error: no previous prototype for 'ejtag_exception_handler' [-Werror=missing-prototypes]
arch/mips/kernel/traps.c:1989:17: error: no previous prototype for 'nmi_exception_handler' [-Werror=missing-prototypes]
arch/mips/kernel/unaligned.c:1516:17: error: no previous prototype for 'do_ade' [-Werror=missing-prototypes]

Link: https://lkml.kernel.org/r/20231204115710.2247097-4-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Rothwell <sfr@rothwell.id.au>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch: add do_page_fault prototypes

do_page_fault() is missing a declaration on a couple of architectures:

arch/alpha/mm/fault.c:85:1: error: no previous prototype for 'do_page_fault' [-Werror=missing-prototypes]
arch/csky/mm/fault.c:187:17: error: no previous prototype for 'do_page_fault' [-Werror=missing-prototypes]
arch/mips/mm/fault.c:323:17: error: no previous prototype for 'do_page_fault' [-Werror=missing-prototypes]
arch/nios2/mm/fault.c:43:17: error: no previous prototype for 'do_page_fault' [-Werror=missing-prototypes]
arch/sh/mm/fault.c:389:27: error: no previous prototype for 'do_page_fault' [-Werror=missing-prototypes]

Since the calling conventions are architecture specific here,
add separate prototypes for each one.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

MIPS: Allow modules to set board_be_handler

After making the brcmstb_gisb driver modular with 707a4cdf86e5 ("bus:
brcmstb_gisb: Allow building as module") Guenter reported that mips
allmodconfig failed to link because board_be_handler was referenced.

Thomas indicated that if we were to continue making the brcmstb_gisb
driver modular for MIPS we would need to introduce a function that
allows setting the board_be_handler and export that function towards
modules.

This is what is being done here: board_be_handler is made static and is
now settable with a mips_set_be_handler() function which is exported.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Suggested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Fixes: 707a4cdf86e5 ("bus: brcmstb_gisb: Allow building as module")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: kernel: Reserve exception base early to prevent corruption

BMIPS is one of the few platforms that do change the exception base.
After commit 2dcb39645441 ("memblock: do not start bottom-up allocations
with kernel_end") we started seeing BMIPS boards fail to boot with the
built-in FDT being corrupted.

Before the cited commit, early allocations would be in the [kernel_end,
RAM_END] range, but after commit they would be within [RAM_START +
PAGE_SIZE, RAM_END].

The custom exception base handler that is installed by
bmips_ebase_setup() done for BMIPS5000 CPUs ends-up trampling on the
memory region allocated by unflatten_and_copy_device_tree() thus
corrupting the FDT used by the kernel.

To fix this, we need to perform an early reservation of the custom
exception space. Additional we reserve the first 4k (1k for R3k) for
either normal exception vector space (legacy CPUs) or special vectors
like cache exceptions.

Huge thanks to Serge for analysing and proposing a solution to this
issue.

Fixes: 2dcb39645441 ("memblock: do not start bottom-up allocations with kernel_end")
Reported-by: Kamal Dasu <kdasu.kdev@gmail.com>
Debugged-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: init: move externs to header file

This commit fixes the following checkpatch warnings:

WARNING: externs should be avoided in .c files

This is a warning for placing declarations in a ".c" file.
This fix removes the declaration in ".c" and adds it to
the common header file.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MIPS: Whitespace cleanup.

Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Introduce board_cache_error_setup() hook.

This is used in subsequent patches.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3819/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add board_ebase_setup()

Some systems need to relocate the MIPS exception vector base during
trap initialization. Add a hook to make this possible.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2959/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Add NMI notifier

Allow the board support code to register a raw notifier callback for
NMI, similar to what is done for CU2 exceptions.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2958/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Move headfiles to new location below arch/mips/include

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>