nds32: Remove the architecture

The nds32 architecture, also known as AndeStar V3, is a custom 32-bit
RISC target designed by Andes Technologies. Support was added to the
kernel in 2016 as the replacement RISC-V based V5 processors were
already announced, and maintained by (current or former) Andes
employees.

As explained by Alan Kao, new customers are now all using RISC-V,
and all known nds32 users are already on longterm stable kernels
provided by Andes, with no development work going into mainline
support any more.

While the port is still in a reasonably good shape, it only gets
worse over time without active maintainers, so it seems best
to remove it before it becomes unusable. As always, if it turns
out that there are mainline users after all, and they volunteer
to maintain the port in the future, the removal can be reverted.

Link: https://lore.kernel.org/linux-mm/YhdWNLUhk+x9RAzU@yamatobi.andestech.com/
Link: https://lore.kernel.org/lkml/20220302065213.82702-1-alankao@andestech.com/
Link: https://www.andestech.com/en/products-solutions/andestar-architecture/
Signed-off-by: Alan Kao <alankao@andestech.com>
[arnd: rewrite changelog to provide more background]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 142 deletions

diff --git a/arch/nds32/include/asm/syscall.h b/arch/nds32/include/asm/syscall.h
deleted file mode 100644
index 90aa56c94af1..000000000000
--- a/arch/nds32/include/asm/syscall.h
+++ /dev/null
@@ -1,142 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-// Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#ifndef _ASM_NDS32_SYSCALL_H
-#define _ASM_NDS32_SYSCALL_H	1
-
-#include <uapi/linux/audit.h>
-#include <linux/err.h>
-struct task_struct;
-struct pt_regs;
-
-/**
- * syscall_get_nr - find what system call a task is executing
- * @task:	task of interest, must be blocked
- * @regs:	task_pt_regs() of @task
- *
- * If @task is executing a system call or is at system call
- * tracing about to attempt one, returns the system call number.
- * If @task is not executing a system call, i.e. it's blocked
- * inside the kernel for a fault or signal, returns -1.
- *
- * Note this returns int even on 64-bit machines.  Only 32 bits of
- * system call number can be meaningful.  If the actual arch value
- * is 64 bits, this truncates to 32 bits so 0xffffffff means -1.
- *
- * It's only valid to call this when @task is known to be blocked.
- */
-static inline int
-syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
-{
-	return regs->syscallno;
-}
-
-/**
- * syscall_rollback - roll back registers after an aborted system call
- * @task:	task of interest, must be in system call exit tracing
- * @regs:	task_pt_regs() of @task
- *
- * It's only valid to call this when @task is stopped for system
- * call exit tracing (due to TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT),
- * after tracehook_report_syscall_entry() returned nonzero to prevent
- * the system call from taking place.
- *
- * This rolls back the register state in @regs so it's as if the
- * system call instruction was a no-op.  The registers containing
- * the system call number and arguments are as they were before the
- * system call instruction.  This may not be the same as what the
- * register state looked like at system call entry tracing.
- */
-static inline void
-syscall_rollback(struct task_struct *task, struct pt_regs *regs)
-{
-	regs->uregs[0] = regs->orig_r0;
-}
-
-/**
- * syscall_get_error - check result of traced system call
- * @task:	task of interest, must be blocked
- * @regs:	task_pt_regs() of @task
- *
- * Returns 0 if the system call succeeded, or -ERRORCODE if it failed.
- *
- * It's only valid to call this when @task is stopped for tracing on exit
- * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
- */
-static inline long
-syscall_get_error(struct task_struct *task, struct pt_regs *regs)
-{
-	unsigned long error = regs->uregs[0];
-	return IS_ERR_VALUE(error) ? error : 0;
-}
-
-/**
- * syscall_get_return_value - get the return value of a traced system call
- * @task:	task of interest, must be blocked
- * @regs:	task_pt_regs() of @task
- *
- * Returns the return value of the successful system call.
- * This value is meaningless if syscall_get_error() returned nonzero.
- *
- * It's only valid to call this when @task is stopped for tracing on exit
- * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
- */
-static inline long
-syscall_get_return_value(struct task_struct *task, struct pt_regs *regs)
-{
-	return regs->uregs[0];
-}
-
-/**
- * syscall_set_return_value - change the return value of a traced system call
- * @task:	task of interest, must be blocked
- * @regs:	task_pt_regs() of @task
- * @error:	negative error code, or zero to indicate success
- * @val:	user return value if @error is zero
- *
- * This changes the results of the system call that user mode will see.
- * If @error is zero, the user sees a successful system call with a
- * return value of @val.  If @error is nonzero, it's a negated errno
- * code; the user sees a failed system call with this errno code.
- *
- * It's only valid to call this when @task is stopped for tracing on exit
- * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
- */
-static inline void
-syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
-			 int error, long val)
-{
-	regs->uregs[0] = (long)error ? error : val;
-}
-
-/**
- * syscall_get_arguments - extract system call parameter values
- * @task:	task of interest, must be blocked
- * @regs:	task_pt_regs() of @task
- * @args:	array filled with argument values
- *
- * Fetches 6 arguments to the system call (from 0 through 5). The first
- * argument is stored in @args[0], and so on.
- *
- * It's only valid to call this when @task is stopped for tracing on
- * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
- */
-#define SYSCALL_MAX_ARGS 6
-static inline void
-syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
-		      unsigned long *args)
-{
-	args[0] = regs->orig_r0;
-	args++;
-	memcpy(args, &regs->uregs[0] + 1, 5 * sizeof(args[0]));
-}
-
-static inline int
-syscall_get_arch(struct task_struct *task)
-{
-	return IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)
-		? AUDIT_ARCH_NDS32BE : AUDIT_ARCH_NDS32;
-}
-
-#endif /* _ASM_NDS32_SYSCALL_H */