csky: Fixup compile error

: error: C++ style comments are not allowed in ISO C90
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
^
error: (this will be reported only once per input file)

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>

csky: Sync riscv mm/fault.c for easy maintenance

Sync arch/riscv/mm/fault.c into arch/csky for easy maintenance.
Here are the patches related to the modification:

cac4d1d "riscv/mm/fault: Move no context handling to no_context()"
ac416a7 "riscv/mm/fault: Move vmalloc fault handling to vmalloc_fault()"
6c11ffb "riscv/mm/fault: Move fault error handling to mm_fault_error()"
afb8c6f "riscv/mm/fault: Move access error check to function"
bda281d "riscv/mm/fault: Simplify fault error handling"
a51271d "riscv/mm/fault: Move bad area handling to bad_area()"

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>

csky: Optimize the trap processing flow

- Seperate different trap functions
- Add trap_no()
- Remove panic code print
- Redesign die_if_kerenl to die with riscv's
- Print exact trap info for app segment fault

[ 17.389321] gzip[126]: unhandled signal 11 code 0x3 at 0x0007835a in busybox[8000+d4000]
[ 17.393882]
[ 17.393882] CURRENT PROCESS:
[ 17.393882]
[ 17.394309] COMM=gzip PID=126
[ 17.394513] TEXT=00008000-000db2e4 DATA=000dcf14-000dd1ad BSS=000dd1ad-000ff000
[ 17.395499] USER-STACK=7f888e50 KERNEL-STACK=bf130300
[ 17.395499]
[ 17.396801] PC: 0x0007835a (0x7835a)
[ 17.397048] LR: 0x000058b4 (0x58b4)
[ 17.397285] SP: 0xbe519f68
[ 17.397555] orig_a0: 0x00002852
[ 17.397886] PSR: 0x00020341
[ 17.398356] a0: 0x00002852 a1: 0x000f2f5a a2: 0x0000d7ae a3: 0x0000005d
[ 17.399289] r4: 0x000de150 r5: 0x00000002 r6: 0x00000102 r7: 0x00007efa
[ 17.399800] r8: 0x7f888bc4 r9: 0x00000001 r10: 0x000002eb r11: 0x0000aac1
[ 17.400166] r12: 0x00002ef2 r13: 0x00000007 r15: 0x000058b4
[ 17.400531] r16: 0x0000004c r17: 0x00000031 r18: 0x000f5816 r19: 0x000e8068
[ 17.401006] r20: 0x000f5818 r21: 0x000e8068 r22: 0x000f5918 r23: 0x90000000
[ 17.401721] r24: 0x00000031 r25: 0x000000c8 r26: 0x00000000 r27: 0x00000000
[ 17.402199] r28: 0x2ac2a000 r29: 0x00000000 r30: 0x00000000 tls: 0x2aadbaa8
[ 17.402686] hi: 0x00120340 lo: 0x7f888bec
/etc/init.ci/ntfs3g_run: line 61: 126 Segmentation fault gzip -c -9 /mnt/test.bin > /mnt/test_bin.gz

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>

csky: Debug and Ptrace GDB

This patch adds arch ptrace implementation, stack dump and bug.h.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>