microblaze: fix typos in comments

Various spelling mistakes in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Link: https://lore.kernel.org/r/20220430191122.8667-1-Julia.Lawall@inria.fr
Signed-off-by: Michal Simek <michal.simek@amd.com>

kgdb/treewide: constify struct kgdb_arch arch_kgdb_ops

checkpatch.pl reports the following:

WARNING: struct kgdb_arch should normally be const
#28: FILE: arch/mips/kernel/kgdb.c:397:
+struct kgdb_arch arch_kgdb_ops = {

This report makes sense, as all other ops struct, this
one should also be const. This patch does the change.

Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

microblaze: Label local function static

Warnings found by sparse:
arch/microblaze/kernel/dma.c:157:5: warning: symbol
'dma_direct_mmap_coherent' was not declared. Should it be static?
arch/microblaze/kernel/kgdb.c:35:14: warning: symbol 'pvr' was not
declared. Should it be static?

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

microblaze: Use unsigned type for "for" loop because of comparison-kgdb.c

This patch removes warnings reported by W=1:
arch/microblaze/kernel/kgdb.c: In function 'pt_regs_to_gdb_regs':
arch/microblaze/kernel/kgdb.c:43:16: warning: comparison between signed
and unsigned integer expressions [-Wsign-compare]
arch/microblaze/kernel/kgdb.c:51:16: warning: comparison between signed
and unsigned integer expressions [-Wsign-compare]
arch/microblaze/kernel/kgdb.c: In function 'gdb_regs_to_pt_regs':
arch/microblaze/kernel/kgdb.c:77:16: warning: comparison between signed
and unsigned integer expressions [-Wsign-compare]
arch/microblaze/kernel/kgdb.c: In function
'sleeping_thread_to_gdb_regs':
arch/microblaze/kernel/kgdb.c:99:16: warning: comparison between signed
and unsigned integer expressions [-Wsign-compare]
arch/microblaze/kernel/kgdb.c:103:16: warning: comparison between signed
and unsigned integer expressions [-Wsign-compare]

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

microblaze: Declare microblaze_kgdb_break in header

This patch removes the warning:
arch/microblaze/kernel/kgdb.c:81:6: warning: no previous prototype for
'microblaze_kgdb_break' [-Wmissing-prototypes]

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

microblaze: Don't mark arch_kgdb_ops as const.

Other architectures don't do it, and it conflicts with the extern'd definition
in include/linux/kgdb.h.

The patch fails checkpatch but it reflects current
functions declaration and solved compilation error.

Signed-off-by: Graeme Smecher <gsmecher@threespeedlogic.com>
CC: Michal Simek <monstr@monstr.eu>
CC: linux-kernel@vger.kernel.org
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

microblaze: Fix coding style issues

Fix coding style issues reported by checkpatch.pl.

Signed-off-by: Michal Simek <monstr@monstr.eu>

microblaze: KGDB little endian support

Just need to use little-endian opcode for brki r16, 0x18

Signed-off-by: Michal Simek <monstr@monstr.eu>
CC: Jason Wessel <jason.wessel@windriver.com>

microblaze: kgdb: Remove unused variable and fix return value

I forget to remove unused variable from kgdb_arch_handle_exception.
Fix return value in microblaze_kgdb_break function.

Error log:
arch/microblaze/kernel/kgdb.c: In function 'microblaze_kgdb_break':
arch/microblaze/kernel/kgdb.c:83: warning: 'return' with a value, in function returning void
arch/microblaze/kernel/kgdb.c: In function 'kgdb_arch_handle_exception':
arch/microblaze/kernel/kgdb.c:119: warning: unused variable 'cpu'

Signed-off-by: Michal Simek <monstr@monstr.eu>

microblaze: Add KGDB support

Kgdb uses brki r16, 0x18 instruction to call
low level _debug_exception function which save
current state to pt_regs and call microblaze_kgdb_break
function. _debug_exception should be called only from
the kernel space. User space calling is not supported
because user application debugging uses different handling.

pt_regs_to_gdb_regs loads additional special registers
which can't be changed

* Enable KGDB in Kconfig
* Remove ancient not-tested KGDB support
* Remove ancient _debug_exception code from entry.S

Only MMU KGDB support is supported.

Signed-off-by: Michal Simek <monstr@monstr.eu>
CC: Jason Wessel <jason.wessel@windriver.com>
CC: John Williams <john.williams@petalogix.com>
CC: Edgar E. Iglesias <edgar.iglesias@petalogix.com>
CC: linux-kernel@vger.kernel.org
Acked-by: Jason Wessel <jason.wessel@windriver.com>