uaccess: remove CONFIG_SET_FS

There are no remaining callers of set_fs(), so CONFIG_SET_FS
can be removed globally, along with the thread_info field and
any references to it.

This turns access_ok() into a cheaper check against TASK_SIZE_MAX.

As CONFIG_SET_FS is now gone, drop all remaining references to
set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel().

Acked-by: Sam Ravnborg <sam@ravnborg.org> # for sparc32 changes
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> # for arc changes
Acked-by: Stafford Horne <shorne@gmail.com> # [openrisc, asm-generic]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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: remove unused including <linux/version.h>

Remove including <linux/version.h> that don't need it.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>

csky: add support for TIF_NOTIFY_SIGNAL

Wire up TIF_NOTIFY_SIGNAL handling for csky.

Cc: linux-csky@vger.kernel.org
Acked-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

csky: Add SECCOMP_FILTER supported

secure_computing() is called first in syscall_trace_enter() so that
a system call will be aborted quickly without doing succeeding syscall
tracing if seccomp rules want to deny that system call.

TODO:
- Update https://github.com/seccomp/libseccomp csky support

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

csky: Coding convention in entry.S

There is no fixup or feature in the patch, we only cleanup with:

- Remove unnecessary reg used (r11, r12), just use r9 & r10 &
syscallid regs as temp useage.
- Add _TIF_SYSCALL_WORK and _TIF_WORK_MASK to gather macros.

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

csky: Fixup gdbmacros.txt with name sp in thread_struct

The gdbmacros.txt use sp in thread_struct, but csky use ksp. This
cause bttnobp fail to excute.

TODO:
- Still couldn't display the contents of stack.

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

csky: Fixup calltrace panic

The implementation of show_stack will panic with wrong fp:

addr = *fp++;

because the fp isn't checked properly.

The current implementations of show_stack, wchan and stack_trace
haven't been designed properly, so just deprecate them.

This patch is a reference to riscv's way, all codes are modified from
arm's. The patch is passed with:

- cat /proc/<pid>/stack
- cat /proc/<pid>/wchan
- echo c > /proc/sysrq-trigger

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

csky: Fixup compile error for abiv1 entry.S

This bug is from uprobe signal definition in thread_info.h. The
instruction (andi) of abiv1 immediate is smaller than abiv2, then
it will cause:

AS arch/csky/kernel/entry.o
arch/csky/kernel/entry.S: Assembler messages:
arch/csky/kernel/entry.S:224: Error: Operand 2 immediate is overflow.

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

csky: Add uprobes support

This patch adds support for uprobes on csky architecture.

Just like kprobe, it support single-step and simulate instructions.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>

csky: Update syscall_trace_enter/exit implementation

Previous syscall_trace implementation couldn't support AUDITSYSCALL and
SYSCALL_TRACEPOINTS. Now we redesign it to support audit_syscall
and syscall_tracepoints just like other archs'.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Dmitry V. Levin <ldv@altlinux.org>
Cc: Arnd Bergmann <arnd@arndb.de>

csky: stacktrace supported.

The gcc option "-mbacktrace" will push fp(r8),lr into stack and we could
unwind the stack with:
fp = *fp
lr = (unsigned int *)fp[1]

Signed-off-by: Guo Ren <ren_guo@c-sky.com>

csky: Process management and Signal

This patch adds files related to task_switch, sigcontext, signal,
fpu context switch.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>