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linux_dsm_epyc7002/arch/m68k/mm/kmap.c
Peter Zijlstra ef22d8abd8 m68k: mm: Restructure Motorola MMU page-table layout 
The Motorola 68xxx MMUs, 040 (and later) have a fixed 7,7,{5,6}
page-table setup, where the last depends on the page-size selected (8k
vs 4k resp.), and head.S selects 4K pages. For 030 (and earlier) we
explicitly program 7,7,6 and 4K pages in %tc.

However, the current code implements this mightily weird. What it does
is group 16 of those (6 bit) pte tables into one 4k page to not waste
space. The down-side is that that forces pmd_t to be a 16-tuple
pointing to consecutive pte tables.

This breaks the generic code which assumes READ_ONCE(*pmd) will be
word sized.

Therefore implement a straight forward 7,7,6 3 level page-table setup,
with the addition (for 020/030) of (partial) large-page support. For
now this increases the memory footprint for pte-tables 15 fold.

Tested with ARAnyM/68040 emulation.

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.711478295@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2020-02-10 10:57:48 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* linux/arch/m68k/mm/kmap.c
*
* Copyright (C) 1997 Roman Hodek
*
* 10/01/99 cleaned up the code and changing to the same interface
* used by other architectures /Roman Zippel
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/setup.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/io.h>
#undef DEBUG
/*
* For 040/060 we can use the virtual memory area like other architectures,
* but for 020/030 we want to use early termination page descriptors and we
* can't mix this with normal page descriptors, so we have to copy that code
* (mm/vmalloc.c) and return appropriately aligned addresses.
*/
#ifdef CPU_M68040_OR_M68060_ONLY
#define IO_SIZE PAGE_SIZE
static inline struct vm_struct *get_io_area(unsigned long size)
{
return get_vm_area(size, VM_IOREMAP);
}
static inline void free_io_area(void *addr)
{
vfree((void *)(PAGE_MASK & (unsigned long)addr));
}
#else
#define IO_SIZE PMD_SIZE
static struct vm_struct *iolist;
/*
* __free_io_area unmaps nearly everything, so be careful
* Currently it doesn't free pointer/page tables anymore but this
* wasn't used anyway and might be added later.
*/
static void __free_io_area(void *addr, unsigned long size)
{
unsigned long virtaddr = (unsigned long)addr;
pgd_t *pgd_dir;
p4d_t *p4d_dir;
pud_t *pud_dir;
pmd_t *pmd_dir;
pte_t *pte_dir;
while ((long)size > 0) {
pgd_dir = pgd_offset_k(virtaddr);
p4d_dir = p4d_offset(pgd_dir, virtaddr);
pud_dir = pud_offset(p4d_dir, virtaddr);
if (pud_bad(*pud_dir)) {
printk("iounmap: bad pud(%08lx)\n", pud_val(*pud_dir));
pud_clear(pud_dir);
return;
}
pmd_dir = pmd_offset(pud_dir, virtaddr);
#if CONFIG_PGTABLE_LEVELS == 3
if (CPU_IS_020_OR_030) {
int pmd_type = pmd_val(*pmd_dir) & _DESCTYPE_MASK;
if (pmd_type == _PAGE_PRESENT) {
pmd_clear(pmd_dir);
virtaddr += PMD_SIZE;
size -= PMD_SIZE;
} else if (pmd_type == 0)
continue;
}
#endif
if (pmd_bad(*pmd_dir)) {
printk("iounmap: bad pmd (%08lx)\n", pmd_val(*pmd_dir));
pmd_clear(pmd_dir);
return;
}
pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
pte_val(*pte_dir) = 0;
virtaddr += PAGE_SIZE;
size -= PAGE_SIZE;
}
flush_tlb_all();
}
static struct vm_struct *get_io_area(unsigned long size)
{
unsigned long addr;
struct vm_struct **p, *tmp, *area;
area = kmalloc(sizeof(*area), GFP_KERNEL);
if (!area)
return NULL;
addr = KMAP_START;
for (p = &iolist; (tmp = *p) ; p = &tmp->next) {
if (size + addr < (unsigned long)tmp->addr)
break;
if (addr > KMAP_END-size) {
kfree(area);
return NULL;
}
addr = tmp->size + (unsigned long)tmp->addr;
}
area->addr = (void *)addr;
area->size = size + IO_SIZE;
area->next = *p;
*p = area;
return area;
}
static inline void free_io_area(void *addr)
{
struct vm_struct **p, *tmp;
if (!addr)
return;
addr = (void *)((unsigned long)addr & -IO_SIZE);
for (p = &iolist ; (tmp = *p) ; p = &tmp->next) {
if (tmp->addr == addr) {
*p = tmp->next;
/* remove gap added in get_io_area() */
__free_io_area(tmp->addr, tmp->size - IO_SIZE);
kfree(tmp);
return;
}
}
}
#endif
/*
* Map some physical address range into the kernel address space.
*/
/* Rewritten by Andreas Schwab to remove all races. */
void __iomem *__ioremap(unsigned long physaddr, unsigned long size, int cacheflag)
{
struct vm_struct *area;
unsigned long virtaddr, retaddr;
long offset;
pgd_t *pgd_dir;
p4d_t *p4d_dir;
pud_t *pud_dir;
pmd_t *pmd_dir;
pte_t *pte_dir;
/*
* Don't allow mappings that wrap..
*/
if (!size || physaddr > (unsigned long)(-size))
return NULL;
#ifdef CONFIG_AMIGA
if (MACH_IS_AMIGA) {
if ((physaddr >= 0x40000000) && (physaddr + size < 0x60000000)
&& (cacheflag == IOMAP_NOCACHE_SER))
return (void __iomem *)physaddr;
}
#endif
#ifdef CONFIG_COLDFIRE
if (__cf_internalio(physaddr))
return (void __iomem *) physaddr;
#endif
#ifdef DEBUG
printk("ioremap: 0x%lx,0x%lx(%d) - ", physaddr, size, cacheflag);
#endif
/*
* Mappings have to be aligned
*/
offset = physaddr & (IO_SIZE - 1);
physaddr &= -IO_SIZE;
size = (size + offset + IO_SIZE - 1) & -IO_SIZE;
/*
* Ok, go for it..
*/
area = get_io_area(size);
if (!area)
return NULL;
virtaddr = (unsigned long)area->addr;
retaddr = virtaddr + offset;
#ifdef DEBUG
printk("0x%lx,0x%lx,0x%lx", physaddr, virtaddr, retaddr);
#endif
/*
* add cache and table flags to physical address
*/
if (CPU_IS_040_OR_060) {
physaddr |= (_PAGE_PRESENT | _PAGE_GLOBAL040 |
_PAGE_ACCESSED | _PAGE_DIRTY);
switch (cacheflag) {
case IOMAP_FULL_CACHING:
physaddr |= _PAGE_CACHE040;
break;
case IOMAP_NOCACHE_SER:
default:
physaddr |= _PAGE_NOCACHE_S;
break;
case IOMAP_NOCACHE_NONSER:
physaddr |= _PAGE_NOCACHE;
break;
case IOMAP_WRITETHROUGH:
physaddr |= _PAGE_CACHE040W;
break;
}
} else {
physaddr |= (_PAGE_PRESENT | _PAGE_ACCESSED |
_PAGE_DIRTY | _PAGE_READWRITE);
switch (cacheflag) {
case IOMAP_NOCACHE_SER:
case IOMAP_NOCACHE_NONSER:
default:
physaddr |= _PAGE_NOCACHE030;
break;
case IOMAP_FULL_CACHING:
case IOMAP_WRITETHROUGH:
break;
}
}
while ((long)size > 0) {
#ifdef DEBUG
if (!(virtaddr & (PMD_SIZE-1)))
printk ("\npa=%#lx va=%#lx ", physaddr, virtaddr);
#endif
pgd_dir = pgd_offset_k(virtaddr);
p4d_dir = p4d_offset(pgd_dir, virtaddr);
pud_dir = pud_offset(p4d_dir, virtaddr);
pmd_dir = pmd_alloc(&init_mm, pud_dir, virtaddr);
if (!pmd_dir) {
printk("ioremap: no mem for pmd_dir\n");
return NULL;
}
#if CONFIG_PGTABLE_LEVELS == 3
if (CPU_IS_020_OR_030) {
pmd_val(*pmd_dir) = physaddr;
physaddr += PMD_SIZE;
virtaddr += PMD_SIZE;
size -= PMD_SIZE;
} else
#endif
{
pte_dir = pte_alloc_kernel(pmd_dir, virtaddr);
if (!pte_dir) {
printk("ioremap: no mem for pte_dir\n");
return NULL;
}
pte_val(*pte_dir) = physaddr;
virtaddr += PAGE_SIZE;
physaddr += PAGE_SIZE;
size -= PAGE_SIZE;
}
}
#ifdef DEBUG
printk("\n");
#endif
flush_tlb_all();
return (void __iomem *)retaddr;
}
EXPORT_SYMBOL(__ioremap);
/*
* Unmap an ioremap()ed region again
*/
void iounmap(void __iomem *addr)
{
#ifdef CONFIG_AMIGA
if ((!MACH_IS_AMIGA) ||
(((unsigned long)addr < 0x40000000) ||
((unsigned long)addr > 0x60000000)))
free_io_area((__force void *)addr);
#else
#ifdef CONFIG_COLDFIRE
if (cf_internalio(addr))
return;
#endif
free_io_area((__force void *)addr);
#endif
}
EXPORT_SYMBOL(iounmap);
/*
* Set new cache mode for some kernel address space.
* The caller must push data for that range itself, if such data may already
* be in the cache.
*/
void kernel_set_cachemode(void *addr, unsigned long size, int cmode)
{
unsigned long virtaddr = (unsigned long)addr;
pgd_t *pgd_dir;
p4d_t *p4d_dir;
pud_t *pud_dir;
pmd_t *pmd_dir;
pte_t *pte_dir;
if (CPU_IS_040_OR_060) {
switch (cmode) {
case IOMAP_FULL_CACHING:
cmode = _PAGE_CACHE040;
break;
case IOMAP_NOCACHE_SER:
default:
cmode = _PAGE_NOCACHE_S;
break;
case IOMAP_NOCACHE_NONSER:
cmode = _PAGE_NOCACHE;
break;
case IOMAP_WRITETHROUGH:
cmode = _PAGE_CACHE040W;
break;
}
} else {
switch (cmode) {
case IOMAP_NOCACHE_SER:
case IOMAP_NOCACHE_NONSER:
default:
cmode = _PAGE_NOCACHE030;
break;
case IOMAP_FULL_CACHING:
case IOMAP_WRITETHROUGH:
cmode = 0;
}
}
while ((long)size > 0) {
pgd_dir = pgd_offset_k(virtaddr);
p4d_dir = p4d_offset(pgd_dir, virtaddr);
pud_dir = pud_offset(p4d_dir, virtaddr);
if (pud_bad(*pud_dir)) {
printk("iocachemode: bad pud(%08lx)\n", pud_val(*pud_dir));
pud_clear(pud_dir);
return;
}
pmd_dir = pmd_offset(pud_dir, virtaddr);
#if CONFIG_PGTABLE_LEVELS == 3
if (CPU_IS_020_OR_030) {
unsigned long pmd = pmd_val(*pmd_dir);
if ((pmd & _DESCTYPE_MASK) == _PAGE_PRESENT) {
*pmd_dir = __pmd((pmd & _CACHEMASK040) | cmode);
virtaddr += PMD_SIZE;
size -= PMD_SIZE;
continue;
}
}
#endif
if (pmd_bad(*pmd_dir)) {
printk("iocachemode: bad pmd (%08lx)\n", pmd_val(*pmd_dir));
pmd_clear(pmd_dir);
return;
}
pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
pte_val(*pte_dir) = (pte_val(*pte_dir) & _CACHEMASK040) | cmode;
virtaddr += PAGE_SIZE;
size -= PAGE_SIZE;
}
flush_tlb_all();
}
EXPORT_SYMBOL(kernel_set_cachemode);
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