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>

9 files changed, 0 insertions, 509 deletions

diff --git a/arch/nds32/kernel/vdso/.gitignore b/arch/nds32/kernel/vdso/.gitignore
deleted file mode 100644
index 652e31d82582..000000000000
--- a/arch/nds32/kernel/vdso/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-vdso.lds
diff --git a/arch/nds32/kernel/vdso/Makefile b/arch/nds32/kernel/vdso/Makefile
deleted file mode 100644
index 55df25ef0057..000000000000
--- a/arch/nds32/kernel/vdso/Makefile
+++ /dev/null
@@ -1,79 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-#
-# Building a vDSO image for AArch64.
-#
-# Author: Will Deacon <will.deacon@arm.com>
-# Heavily based on the vDSO Makefiles for other archs.
-#
-
-obj-vdso := note.o datapage.o sigreturn.o gettimeofday.o
-
-# Build rules
-targets := $(obj-vdso) vdso.so vdso.so.dbg
-obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
-
-ccflags-y := -shared -fno-common -fno-builtin -nostdlib -fPIC -Wl,-shared -g \
-	-Wl,-soname=linux-vdso.so.1 -Wl,--hash-style=sysv
-
-# Disable gcov profiling for VDSO code
-GCOV_PROFILE := n
-
-
-obj-y += vdso.o
-targets += vdso.lds
-CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
-
-# Force dependency
-$(obj)/vdso.o : $(obj)/vdso.so
-
-# Link rule for the .so file, .lds has to be first
-$(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE
-	$(call if_changed,vdsold)
-
-
-# Strip rule for the .so file
-$(obj)/%.so: OBJCOPYFLAGS := -S
-$(obj)/%.so: $(obj)/%.so.dbg FORCE
-	$(call if_changed,objcopy)
-
-# Generate VDSO offsets using helper script
-gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
-quiet_cmd_vdsosym = VDSOSYM $@
-      cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
-
-include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
-	$(call if_changed,vdsosym)
-
-
-
-# Assembly rules for the .S files
-
-sigreturn.o : sigreturn.S
-	$(call if_changed_dep,vdsoas)
-
-note.o : note.S
-	$(call if_changed_dep,vdsoas)
-
-datapage.o : datapage.S
-	$(call if_changed_dep,vdsoas)
-
-gettimeofday.o : gettimeofday.c FORCE
-	$(call if_changed_dep,vdsocc)
-
-# Actual build commands
-quiet_cmd_vdsold = VDSOL   $@
-      cmd_vdsold = $(CC) $(c_flags) -Wl,-n -Wl,-T $(real-prereqs) -o $@
-quiet_cmd_vdsoas = VDSOA   $@
-      cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $<
-quiet_cmd_vdsocc = VDSOA   $@
-      cmd_vdsocc = $(CC) $(c_flags) -c -o $@ $<
-
-# Install commands for the unstripped file
-quiet_cmd_vdso_install = INSTALL $@
-      cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
-
-vdso.so: $(obj)/vdso.so.dbg
-	@mkdir -p $(MODLIB)/vdso
-	$(call cmd,vdso_install)
-
-vdso_install: vdso.so
diff --git a/arch/nds32/kernel/vdso/datapage.S b/arch/nds32/kernel/vdso/datapage.S
deleted file mode 100644
index 4a62c3cab1c8..000000000000
--- a/arch/nds32/kernel/vdso/datapage.S
+++ /dev/null
@@ -1,21 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#include <linux/linkage.h>
-#include <asm/page.h>
-
-ENTRY(__get_timerpage)
-	sethi	$r0, hi20(. + PAGE_SIZE + 8)
-	ori	$r0, $r0, lo12(. + PAGE_SIZE + 4)
-	mfusr	$r1, $pc
-	sub	$r0, $r1, $r0
-	ret
-ENDPROC(__get_timerpage)
-
-ENTRY(__get_datapage)
-	sethi	$r0, hi20(. + 2*PAGE_SIZE + 8)
-	ori	$r0, $r0, lo12(. + 2*PAGE_SIZE + 4)
-	mfusr	$r1, $pc
-	sub	$r0, $r1, $r0
-	ret
-ENDPROC(__get_datapage)
diff --git a/arch/nds32/kernel/vdso/gen_vdso_offsets.sh b/arch/nds32/kernel/vdso/gen_vdso_offsets.sh
deleted file mode 100755
index 01924ff071ad..000000000000
--- a/arch/nds32/kernel/vdso/gen_vdso_offsets.sh
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/bin/sh
-
-#
-# Match symbols in the DSO that look like VDSO_*; produce a header file
-# of constant offsets into the shared object.
-#
-# Doing this inside the Makefile will break the $(filter-out) function,
-# causing Kbuild to rebuild the vdso-offsets header file every time.
-#
-# Author: Will Deacon <will.deacon@arm.com
-#
-
-LC_ALL=C
-sed -n -e 's/^00*/0/' -e \
-'s/^\([0-9a-fA-F]*\) . VDSO_\([a-zA-Z0-9_]*\)$/\#define vdso_offset_\2\t0x\1/p'
diff --git a/arch/nds32/kernel/vdso/gettimeofday.c b/arch/nds32/kernel/vdso/gettimeofday.c
deleted file mode 100644
index 9ec03cf0ec54..000000000000
--- a/arch/nds32/kernel/vdso/gettimeofday.c
+++ /dev/null
@@ -1,269 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#include <linux/compiler.h>
-#include <linux/hrtimer.h>
-#include <linux/time.h>
-#include <asm/io.h>
-#include <asm/barrier.h>
-#include <asm/bug.h>
-#include <asm/page.h>
-#include <asm/unistd.h>
-#include <asm/vdso_datapage.h>
-#include <asm/vdso_timer_info.h>
-#include <asm/asm-offsets.h>
-
-#define X(x) #x
-#define Y(x) X(x)
-
-extern struct vdso_data *__get_datapage(void);
-extern struct vdso_data *__get_timerpage(void);
-
-static notrace unsigned int __vdso_read_begin(const struct vdso_data *vdata)
-{
-	u32 seq;
-repeat:
-	seq = READ_ONCE(vdata->seq_count);
-	if (seq & 1) {
-		cpu_relax();
-		goto repeat;
-	}
-	return seq;
-}
-
-static notrace unsigned int vdso_read_begin(const struct vdso_data *vdata)
-{
-	unsigned int seq;
-
-	seq = __vdso_read_begin(vdata);
-
-	smp_rmb();		/* Pairs with smp_wmb in vdso_write_end */
-	return seq;
-}
-
-static notrace int vdso_read_retry(const struct vdso_data *vdata, u32 start)
-{
-	smp_rmb();		/* Pairs with smp_wmb in vdso_write_begin */
-	return vdata->seq_count != start;
-}
-
-static notrace long clock_gettime_fallback(clockid_t _clkid,
-					   struct __kernel_old_timespec *_ts)
-{
-	register struct __kernel_old_timespec *ts asm("$r1") = _ts;
-	register clockid_t clkid asm("$r0") = _clkid;
-	register long ret asm("$r0");
-
-	asm volatile ("movi	$r15, %3\n"
-		      "syscall 	0x0\n"
-		      :"=r" (ret)
-		      :"r"(clkid), "r"(ts), "i"(__NR_clock_gettime)
-		      :"$r15", "memory");
-
-	return ret;
-}
-
-static notrace int do_realtime_coarse(struct __kernel_old_timespec *ts,
-				      struct vdso_data *vdata)
-{
-	u32 seq;
-
-	do {
-		seq = vdso_read_begin(vdata);
-
-		ts->tv_sec = vdata->xtime_coarse_sec;
-		ts->tv_nsec = vdata->xtime_coarse_nsec;
-
-	} while (vdso_read_retry(vdata, seq));
-	return 0;
-}
-
-static notrace int do_monotonic_coarse(struct __kernel_old_timespec *ts,
-				       struct vdso_data *vdata)
-{
-	u32 seq;
-	u64 ns;
-
-	do {
-		seq = vdso_read_begin(vdata);
-
-		ts->tv_sec = vdata->xtime_coarse_sec + vdata->wtm_clock_sec;
-		ns = vdata->xtime_coarse_nsec + vdata->wtm_clock_nsec;
-
-	} while (vdso_read_retry(vdata, seq));
-
-	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
-	ts->tv_nsec = ns;
-
-	return 0;
-}
-
-static notrace inline u64 vgetsns(struct vdso_data *vdso)
-{
-	u32 cycle_now;
-	u32 cycle_delta;
-	u32 *timer_cycle_base;
-
-	timer_cycle_base =
-	    (u32 *) ((char *)__get_timerpage() + vdso->cycle_count_offset);
-	cycle_now = readl_relaxed(timer_cycle_base);
-	if (true == vdso->cycle_count_down)
-		cycle_now = ~(*timer_cycle_base);
-	cycle_delta = cycle_now - (u32) vdso->cs_cycle_last;
-	return ((u64) cycle_delta & vdso->cs_mask) * vdso->cs_mult;
-}
-
-static notrace int do_realtime(struct __kernel_old_timespec *ts, struct vdso_data *vdata)
-{
-	unsigned count;
-	u64 ns;
-	do {
-		count = vdso_read_begin(vdata);
-		ts->tv_sec = vdata->xtime_clock_sec;
-		ns = vdata->xtime_clock_nsec;
-		ns += vgetsns(vdata);
-		ns >>= vdata->cs_shift;
-	} while (vdso_read_retry(vdata, count));
-
-	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
-	ts->tv_nsec = ns;
-
-	return 0;
-}
-
-static notrace int do_monotonic(struct __kernel_old_timespec *ts, struct vdso_data *vdata)
-{
-	u64 ns;
-	u32 seq;
-
-	do {
-		seq = vdso_read_begin(vdata);
-
-		ts->tv_sec = vdata->xtime_clock_sec;
-		ns = vdata->xtime_clock_nsec;
-		ns += vgetsns(vdata);
-		ns >>= vdata->cs_shift;
-
-		ts->tv_sec += vdata->wtm_clock_sec;
-		ns += vdata->wtm_clock_nsec;
-
-	} while (vdso_read_retry(vdata, seq));
-
-	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
-	ts->tv_nsec = ns;
-
-	return 0;
-}
-
-notrace int __vdso_clock_gettime(clockid_t clkid, struct __kernel_old_timespec *ts)
-{
-	struct vdso_data *vdata;
-	int ret = -1;
-
-	vdata = __get_datapage();
-	if (vdata->cycle_count_offset == EMPTY_REG_OFFSET)
-		return clock_gettime_fallback(clkid, ts);
-
-	switch (clkid) {
-	case CLOCK_REALTIME_COARSE:
-		ret = do_realtime_coarse(ts, vdata);
-		break;
-	case CLOCK_MONOTONIC_COARSE:
-		ret = do_monotonic_coarse(ts, vdata);
-		break;
-	case CLOCK_REALTIME:
-		ret = do_realtime(ts, vdata);
-		break;
-	case CLOCK_MONOTONIC:
-		ret = do_monotonic(ts, vdata);
-		break;
-	default:
-		break;
-	}
-
-	if (ret)
-		ret = clock_gettime_fallback(clkid, ts);
-
-	return ret;
-}
-
-static notrace int clock_getres_fallback(clockid_t _clk_id,
-					  struct __kernel_old_timespec *_res)
-{
-	register clockid_t clk_id asm("$r0") = _clk_id;
-	register struct __kernel_old_timespec *res asm("$r1") = _res;
-	register int ret asm("$r0");
-
-	asm volatile ("movi	$r15, %3\n"
-		      "syscall	0x0\n"
-		      :"=r" (ret)
-		      :"r"(clk_id), "r"(res), "i"(__NR_clock_getres)
-		      :"$r15", "memory");
-
-	return ret;
-}
-
-notrace int __vdso_clock_getres(clockid_t clk_id, struct __kernel_old_timespec *res)
-{
-	struct vdso_data *vdata = __get_datapage();
-
-	if (res == NULL)
-		return 0;
-	switch (clk_id) {
-	case CLOCK_REALTIME:
-	case CLOCK_MONOTONIC:
-	case CLOCK_MONOTONIC_RAW:
-		res->tv_sec = 0;
-		res->tv_nsec = vdata->hrtimer_res;
-		break;
-	case CLOCK_REALTIME_COARSE:
-	case CLOCK_MONOTONIC_COARSE:
-		res->tv_sec = 0;
-		res->tv_nsec = CLOCK_COARSE_RES;
-		break;
-	default:
-		return clock_getres_fallback(clk_id, res);
-	}
-	return 0;
-}
-
-static notrace inline int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
-						struct timezone *_tz)
-{
-	register struct __kernel_old_timeval *tv asm("$r0") = _tv;
-	register struct timezone *tz asm("$r1") = _tz;
-	register int ret asm("$r0");
-
-	asm volatile ("movi	$r15, %3\n"
-		      "syscall	0x0\n"
-		      :"=r" (ret)
-		      :"r"(tv), "r"(tz), "i"(__NR_gettimeofday)
-		      :"$r15", "memory");
-
-	return ret;
-}
-
-notrace int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
-{
-	struct __kernel_old_timespec ts;
-	struct vdso_data *vdata;
-	int ret;
-
-	vdata = __get_datapage();
-
-	if (vdata->cycle_count_offset == EMPTY_REG_OFFSET)
-		return gettimeofday_fallback(tv, tz);
-
-	ret = do_realtime(&ts, vdata);
-
-	if (tv) {
-		tv->tv_sec = ts.tv_sec;
-		tv->tv_usec = ts.tv_nsec / 1000;
-	}
-	if (tz) {
-		tz->tz_minuteswest = vdata->tz_minuteswest;
-		tz->tz_dsttime = vdata->tz_dsttime;
-	}
-
-	return ret;
-}
diff --git a/arch/nds32/kernel/vdso/note.S b/arch/nds32/kernel/vdso/note.S
deleted file mode 100644
index 0aeaa19b05f0..000000000000
--- a/arch/nds32/kernel/vdso/note.S
+++ /dev/null
@@ -1,11 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2012 ARM Limited
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#include <linux/uts.h>
-#include <linux/version.h>
-#include <linux/elfnote.h>
-
-ELFNOTE_START(Linux, 0, "a")
-	.long LINUX_VERSION_CODE
-ELFNOTE_END
diff --git a/arch/nds32/kernel/vdso/sigreturn.S b/arch/nds32/kernel/vdso/sigreturn.S
deleted file mode 100644
index 67e4d1d1612a..000000000000
--- a/arch/nds32/kernel/vdso/sigreturn.S
+++ /dev/null
@@ -1,19 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2012 ARM Limited
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#include <linux/linkage.h>
-#include <asm/unistd.h>
-
-	.text
-
-ENTRY(__kernel_rt_sigreturn)
-	.cfi_startproc
-	movi $r15, __NR_rt_sigreturn
-	/*
-	 * The SWID of syscall should be __NR_rt_sigreturn to synchronize
-	 * the unwinding scheme in gcc
-	 */
-	syscall	__NR_rt_sigreturn
-	.cfi_endproc
-ENDPROC(__kernel_rt_sigreturn)
diff --git a/arch/nds32/kernel/vdso/vdso.S b/arch/nds32/kernel/vdso/vdso.S
deleted file mode 100644
index 16737c11e55b..000000000000
--- a/arch/nds32/kernel/vdso/vdso.S
+++ /dev/null
@@ -1,18 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2012 ARM Limited
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#include <linux/init.h>
-#include <linux/linkage.h>
-#include <linux/const.h>
-#include <asm/page.h>
-
-	.globl vdso_start, vdso_end
-	.section .rodata
-	.balign PAGE_SIZE
-vdso_start:
-	.incbin "arch/nds32/kernel/vdso/vdso.so"
-	.balign PAGE_SIZE
-vdso_end:
-
-	.previous
diff --git a/arch/nds32/kernel/vdso/vdso.lds.S b/arch/nds32/kernel/vdso/vdso.lds.S
deleted file mode 100644
index 1f2b16004594..000000000000
--- a/arch/nds32/kernel/vdso/vdso.lds.S
+++ /dev/null
@@ -1,75 +0,0 @@
-/*
- * SPDX-License-Identifier: GPL-2.0
- * Copyright (C) 2005-2017 Andes Technology Corporation
- */
-
-
-#include <linux/const.h>
-#include <asm/page.h>
-#include <asm/vdso.h>
-
-OUTPUT_ARCH(nds32)
-
-SECTIONS
-{
-	. = SIZEOF_HEADERS;
-
-	.hash		: { *(.hash) }			:text
-	.gnu.hash	: { *(.gnu.hash) }
-	.dynsym		: { *(.dynsym) }
-	.dynstr		: { *(.dynstr) }
-	.gnu.version	: { *(.gnu.version) }
-	.gnu.version_d	: { *(.gnu.version_d) }
-	.gnu.version_r	: { *(.gnu.version_r) }
-
-	.note		: { *(.note.*) }		:text	:note
-
-
-	.text		: { *(.text*) }			:text
-
-	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
-	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
-
-	.dynamic	: { *(.dynamic) }		:text	:dynamic
-
-	.rodata		: { *(.rodata*) }		:text
-
-
-	/DISCARD/	: {
-		*(.note.GNU-stack)
-		*(.data .data.* .gnu.linkonce.d.* .sdata*)
-		*(.bss .sbss .dynbss .dynsbss)
-	}
-}
-
-/*
- * We must supply the ELF program headers explicitly to get just one
- * PT_LOAD segment, and set the flags explicitly to make segments read-only.
- */
-PHDRS
-{
-	text		PT_LOAD		FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
-	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
-	note		PT_NOTE		FLAGS(4);		/* PF_R */
-	eh_frame_hdr	PT_GNU_EH_FRAME;
-}
-
-/*
- * This controls what symbols we export from the DSO.
- */
-VERSION
-{
-	LINUX_4 {
-	global:
-		__kernel_rt_sigreturn;
-		__vdso_gettimeofday;
-		__vdso_clock_getres;
-		__vdso_clock_gettime;
-	local: *;
-	};
-}
-
-/*
- * Make the rt_sigreturn code visible to the kernel.
- */
-VDSO_rt_sigtramp	= __kernel_rt_sigreturn;