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// SPDX-License-Identifier: GPL-2.0
/*
* linux/arch/m68k/mm/motorola.c
*
* Routines specific to the Motorola MMU, originally from:
* linux/arch/m68k/init.c
* which are Copyright (C) 1995 Hamish Macdonald
*
* Moved 8/20/1999 Sam Creasey
*/
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/gfp.h>
#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/dma.h>
#ifdef CONFIG_ATARI
#include <asm/atari_stram.h>
#endif
#include <asm/sections.h>
#undef DEBUG
#ifndef mm_cachebits
/*
* Bits to add to page descriptors for "normal" caching mode.
* For 68020/030 this is 0.
* For 68040, this is _PAGE_CACHE040 (cachable, copyback)
*/
unsigned long mm_cachebits;
EXPORT_SYMBOL(mm_cachebits);
#endif
/* Prior to calling these routines, the page should have been flushed
* from both the cache and ATC, or the CPU might not notice that the
* cache setting for the page has been changed. -jskov
*/
static inline void nocache_page(void *vaddr)
{
unsigned long addr = (unsigned long)vaddr;
if (CPU_IS_040_OR_060) {
pgd_t *dir;
p4d_t *p4dp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
dir = pgd_offset_k(addr);
p4dp = p4d_offset(dir, addr);
pudp = pud_offset(p4dp, addr);
pmdp = pmd_offset(pudp, addr);
ptep = pte_offset_kernel(pmdp, addr);
*ptep = pte_mknocache(*ptep);
}
}
static inline void cache_page(void *vaddr)
{
unsigned long addr = (unsigned long)vaddr;
if (CPU_IS_040_OR_060) {
pgd_t *dir;
p4d_t *p4dp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
dir = pgd_offset_k(addr);
p4dp = p4d_offset(dir, addr);
pudp = pud_offset(p4dp, addr);
pmdp = pmd_offset(pudp, addr);
ptep = pte_offset_kernel(pmdp, addr);
*ptep = pte_mkcache(*ptep);
}
}
/*
* Motorola 680x0 user's manual recommends using uncached memory for address
* translation tables.
*
* Seeing how the MMU can be external on (some of) these chips, that seems like
* a very important recommendation to follow. Provide some helpers to combat
* 'variation' amongst the users of this.
*/
void mmu_page_ctor(void *page)
{
__flush_page_to_ram(page);
flush_tlb_kernel_page(page);
nocache_page(page);
}
void mmu_page_dtor(void *page)
{
cache_page(page);
}
/* ++andreas: {get,free}_pointer_table rewritten to use unused fields from
struct page instead of separately kmalloced struct. Stolen from
arch/sparc/mm/srmmu.c ... */
typedef struct list_head ptable_desc;
static struct list_head ptable_list[2] = {
LIST_HEAD_INIT(ptable_list[0]),
LIST_HEAD_INIT(ptable_list[1]),
};
#define PD_PTABLE(page) ((ptable_desc *)&(virt_to_page(page)->lru))
#define PD_PAGE(ptable) (list_entry(ptable, struct page, lru))
#define PD_MARKBITS(dp) (*(unsigned int *)&PD_PAGE(dp)->index)
static const int ptable_shift[2] = {
7+2, /* PGD, PMD */
6+2, /* PTE */
};
#define ptable_size(type) (1U << ptable_shift[type])
#define ptable_mask(type) ((1U << (PAGE_SIZE / ptable_size(type))) - 1)
void __init init_pointer_table(void *table, int type)
{
ptable_desc *dp;
unsigned long ptable = (unsigned long)table;
unsigned long page = ptable & PAGE_MASK;
unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
dp = PD_PTABLE(page);
if (!(PD_MARKBITS(dp) & mask)) {
PD_MARKBITS(dp) = ptable_mask(type);
list_add(dp, &ptable_list[type]);
}
PD_MARKBITS(dp) &= ~mask;
pr_debug("init_pointer_table: %lx, %x\n", ptable, PD_MARKBITS(dp));
/* unreserve the page so it's possible to free that page */
__ClearPageReserved(PD_PAGE(dp));
init_page_count(PD_PAGE(dp));
return;
}
void *get_pointer_table(int type)
{
ptable_desc *dp = ptable_list[type].next;
unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
unsigned int tmp, off;
/*
* For a pointer table for a user process address space, a
* table is taken from a page allocated for the purpose. Each
* page can hold 8 pointer tables. The page is remapped in
* virtual address space to be noncacheable.
*/
if (mask == 0) {
void *page;
ptable_desc *new;
if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
return NULL;
if (type == TABLE_PTE) {
/*
* m68k doesn't have SPLIT_PTE_PTLOCKS for not having
* SMP.
*/
pgtable_pte_page_ctor(virt_to_page(page));
}
mmu_page_ctor(page);
new = PD_PTABLE(page);
PD_MARKBITS(new) = ptable_mask(type) - 1;
list_add_tail(new, dp);
return (pmd_t *)page;
}
for (tmp = 1, off = 0; (mask & tmp) == 0; tmp <<= 1, off += ptable_size(type))
;
PD_MARKBITS(dp) = mask & ~tmp;
if (!PD_MARKBITS(dp)) {
/* move to end of list */
list_move_tail(dp, &ptable_list[type]);
}
return page_address(PD_PAGE(dp)) + off;
}
int free_pointer_table(void *table, int type)
{
ptable_desc *dp;
unsigned long ptable = (unsigned long)table;
unsigned long page = ptable & PAGE_MASK;
unsigned int mask = 1U << ((ptable - page)/ptable_size(type));
dp = PD_PTABLE(page);
if (PD_MARKBITS (dp) & mask)
panic ("table already free!");
PD_MARKBITS (dp) |= mask;
if (PD_MARKBITS(dp) == ptable_mask(type)) {
/* all tables in page are free, free page */
list_del(dp);
mmu_page_dtor((void *)page);
if (type == TABLE_PTE)
pgtable_pte_page_dtor(virt_to_page(page));
free_page (page);
return 1;
} else if (ptable_list[type].next != dp) {
/*
* move this descriptor to the front of the list, since
* it has one or more free tables.
*/
list_move(dp, &ptable_list[type]);
}
return 0;
}
/* size of memory already mapped in head.S */
extern __initdata unsigned long m68k_init_mapped_size;
extern unsigned long availmem;
static pte_t *last_pte_table __initdata = NULL;
static pte_t * __init kernel_page_table(void)
{
pte_t *pte_table = last_pte_table;
if (((unsigned long)last_pte_table & ~PAGE_MASK) == 0) {
pte_table = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
if (!pte_table) {
panic("%s: Failed to allocate %lu bytes align=%lx\n",
__func__, PAGE_SIZE, PAGE_SIZE);
}
clear_page(pte_table);
mmu_page_ctor(pte_table);
last_pte_table = pte_table;
}
last_pte_table += PTRS_PER_PTE;
return pte_table;
}
static pmd_t *last_pmd_table __initdata = NULL;
static pmd_t * __init kernel_ptr_table(void)
{
if (!last_pmd_table) {
unsigned long pmd, last;
int i;
/* Find the last ptr table that was used in head.S and
* reuse the remaining space in that page for further
* ptr tables.
*/
last = (unsigned long)kernel_pg_dir;
for (i = 0; i <
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