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, 263 deletions

diff --git a/arch/nds32/mm/init.c b/arch/nds32/mm/init.c
deleted file mode 100644
index f63f839738c4..000000000000
--- a/arch/nds32/mm/init.c
+++ /dev/null
@@ -1,263 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 1995-2005 Russell King
-// Copyright (C) 2012 ARM Ltd.
-// Copyright (C) 2013-2017 Andes Technology Corporation
-
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/swap.h>
-#include <linux/init.h>
-#include <linux/memblock.h>
-#include <linux/mman.h>
-#include <linux/nodemask.h>
-#include <linux/initrd.h>
-#include <linux/highmem.h>
-
-#include <asm/sections.h>
-#include <asm/setup.h>
-#include <asm/tlb.h>
-#include <asm/page.h>
-
-DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
-DEFINE_SPINLOCK(anon_alias_lock);
-extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
-
-/*
- * empty_zero_page is a special page that is used for
- * zero-initialized data and COW.
- */
-struct page *empty_zero_page;
-EXPORT_SYMBOL(empty_zero_page);
-
-static void __init zone_sizes_init(void)
-{
-	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
-
-	max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
-#ifdef CONFIG_HIGHMEM
-	max_zone_pfn[ZONE_HIGHMEM] = max_pfn;
-#endif
-	free_area_init(max_zone_pfn);
-
-}
-
-/*
- * Map all physical memory under high_memory into kernel's address space.
- *
- * This is explicitly coded for two-level page tables, so if you need
- * something else then this needs to change.
- */
-static void __init map_ram(void)
-{
-	unsigned long v, p, e;
-	pgd_t *pge;
-	p4d_t *p4e;
-	pud_t *pue;
-	pmd_t *pme;
-	pte_t *pte;
-	/* These mark extents of read-only kernel pages...
-	 * ...from vmlinux.lds.S
-	 */
-
-	p = (u32) memblock_start_of_DRAM() & PAGE_MASK;
-	e = min((u32) memblock_end_of_DRAM(), (u32) __pa(high_memory));
-
-	v = (u32) __va(p);
-	pge = pgd_offset_k(v);
-
-	while (p < e) {
-		int j;
-		p4e = p4d_offset(pge, v);
-		pue = pud_offset(p4e, v);
-		pme = pmd_offset(pue, v);
-
-		if ((u32) pue != (u32) pge || (u32) pme != (u32) pge) {
-			panic("%s: Kernel hardcoded for "
-			      "two-level page tables", __func__);
-		}
-
-		/* Alloc one page for holding PTE's... */
-		pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
-		if (!pte)
-			panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
-			      __func__, PAGE_SIZE, PAGE_SIZE);
-		set_pmd(pme, __pmd(__pa(pte) + _PAGE_KERNEL_TABLE));
-
-		/* Fill the newly allocated page with PTE'S */
-		for (j = 0; p < e && j < PTRS_PER_PTE;
-		     v += PAGE_SIZE, p += PAGE_SIZE, j++, pte++) {
-			/* Create mapping between p and v. */
-			/* TODO: more fine grant for page access permission */
-			set_pte(pte, __pte(p + pgprot_val(PAGE_KERNEL)));
-		}
-
-		pge++;
-	}
-}
-static pmd_t *fixmap_pmd_p;
-static void __init fixedrange_init(void)
-{
-	unsigned long vaddr;
-	pmd_t *pmd;
-#ifdef CONFIG_HIGHMEM
-	pte_t *pte;
-#endif /* CONFIG_HIGHMEM */
-
-	/*
-	 * Fixed mappings:
-	 */
-	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1);
-	pmd = pmd_off_k(vaddr);
-	fixmap_pmd_p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
-	if (!fixmap_pmd_p)
-		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
-		      __func__, PAGE_SIZE, PAGE_SIZE);
-	set_pmd(pmd, __pmd(__pa(fixmap_pmd_p) + _PAGE_KERNEL_TABLE));
-
-#ifdef CONFIG_HIGHMEM
-	/*
-	 * Permanent kmaps:
-	 */
-	vaddr = PKMAP_BASE;
-
-	pmd = pmd_off_k(vaddr);
-	pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
-	if (!pte)
-		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
-		      __func__, PAGE_SIZE, PAGE_SIZE);
-	set_pmd(pmd, __pmd(__pa(pte) + _PAGE_KERNEL_TABLE));
-	pkmap_page_table = pte;
-#endif /* CONFIG_HIGHMEM */
-}
-
-/*
- * paging_init() sets up the page tables, initialises the zone memory
- * maps, and sets up the zero page, bad page and bad page tables.
- */
-void __init paging_init(void)
-{
-	int i;
-	void *zero_page;
-
-	pr_info("Setting up paging and PTEs.\n");
-	/* clear out the init_mm.pgd that will contain the kernel's mappings */
-	for (i = 0; i < PTRS_PER_PGD; i++)
-		swapper_pg_dir[i] = __pgd(1);
-
-	map_ram();
-
-	fixedrange_init();
-
-	/* allocate space for empty_zero_page */
-	zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
-	if (!zero_page)
-		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
-		      __func__, PAGE_SIZE, PAGE_SIZE);
-	zone_sizes_init();
-
-	empty_zero_page = virt_to_page(zero_page);
-	flush_dcache_page(empty_zero_page);
-}
-
-static inline void __init free_highmem(void)
-{
-#ifdef CONFIG_HIGHMEM
-	unsigned long pfn;
-	for (pfn = PFN_UP(__pa(high_memory)); pfn < max_pfn; pfn++) {
-		phys_addr_t paddr = (phys_addr_t) pfn << PAGE_SHIFT;
-		if (!memblock_is_reserved(paddr))
-			free_highmem_page(pfn_to_page(pfn));
-	}
-#endif
-}
-
-static void __init set_max_mapnr_init(void)
-{
-	max_mapnr = max_pfn;
-}
-
-/*
- * mem_init() marks the free areas in the mem_map and tells us how much
- * memory is free.  This is done after various parts of the system have
- * claimed their memory after the kernel image.
- */
-void __init mem_init(void)
-{
-	phys_addr_t memory_start = memblock_start_of_DRAM();
-	BUG_ON(!mem_map);
-	set_max_mapnr_init();
-
-	free_highmem();
-
-	/* this will put all low memory onto the freelists */
-	memblock_free_all();
-
-	pr_info("virtual kernel memory layout:\n"
-		"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-#ifdef CONFIG_HIGHMEM
-		"    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-#endif
-		"    consist : 0x%08lx - 0x%08lx   (%4ld MB)\n"
-		"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
-		"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
-		"      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-		"      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
-		"      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
-		FIXADDR_START, FIXADDR_TOP, (FIXADDR_TOP - FIXADDR_START) >> 10,
-#ifdef CONFIG_HIGHMEM
-		PKMAP_BASE, PKMAP_BASE + LAST_PKMAP * PAGE_SIZE,
-		(LAST_PKMAP * PAGE_SIZE) >> 10,
-#endif
-		CONSISTENT_BASE, CONSISTENT_END,
-		((CONSISTENT_END) - (CONSISTENT_BASE)) >> 20, VMALLOC_START,
-		(unsigned long)VMALLOC_END, (VMALLOC_END - VMALLOC_START) >> 20,
-		(unsigned long)__va(memory_start), (unsigned long)high_memory,
-		((unsigned long)high_memory -
-		 (unsigned long)__va(memory_start)) >> 20,
-		(unsigned long)&__init_begin, (unsigned long)&__init_end,
-		((unsigned long)&__init_end -
-		 (unsigned long)&__init_begin) >> 10, (unsigned long)&_etext,
-		(unsigned long)&_edata,
-		((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
-		(unsigned long)&_text, (unsigned long)&_etext,
-		((unsigned long)&_etext - (unsigned long)&_text) >> 10);
-
-	/*
-	 * Check boundaries twice: Some fundamental inconsistencies can
-	 * be detected at build time already.
-	 */
-#ifdef CONFIG_HIGHMEM
-	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > FIXADDR_START);
-	BUILD_BUG_ON((CONSISTENT_END) > PKMAP_BASE);
-#endif
-	BUILD_BUG_ON(VMALLOC_END > CONSISTENT_BASE);
-	BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
-
-#ifdef CONFIG_HIGHMEM
-	BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > FIXADDR_START);
-	BUG_ON(CONSISTENT_END > PKMAP_BASE);
-#endif
-	BUG_ON(VMALLOC_END > CONSISTENT_BASE);
-	BUG_ON(VMALLOC_START >= VMALLOC_END);
-	BUG_ON((unsigned long)high_memory > VMALLOC_START);
-
-	return;
-}
-
-void __set_fixmap(enum fixed_addresses idx,
-			       phys_addr_t phys, pgprot_t flags)
-{
-	unsigned long addr = __fix_to_virt(idx);
-	pte_t *pte;
-
-	BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
-
-	pte = (pte_t *)&fixmap_pmd_p[pte_index(addr)];
-
-	if (pgprot_val(flags)) {
-		set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
-	} else {
-		pte_clear(&init_mm, addr, pte);
-		flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
-	}
-}