linux/arch/sh/mm/pmb.c
Paul Mundt d01447b319 sh: Merge legacy and dynamic PMB modes.
This implements a bit of rework for the PMB code, which permits us to
kill off the legacy PMB mode completely. Rather than trusting the boot
loader to do the right thing, we do a quick verification of the PMB
contents to determine whether to have the kernel setup the initial
mappings or whether it needs to mangle them later on instead.

If we're booting from legacy mappings, the kernel will now take control
of them and make them match the kernel's initial mapping configuration.
This is accomplished by breaking the initialization phase out in to
multiple steps: synchronization, merging, and resizing. With the recent
rework, the synchronization code establishes page links for compound
mappings already, so we build on top of this for promoting mappings and
reclaiming unused slots.

At the same time, the changes introduced for the uncached helpers also
permit us to dynamically resize the uncached mapping without any
particular headaches. The smallest page size is more than sufficient for
mapping all of kernel text, and as we're careful not to jump to any far
off locations in the setup code the mapping can safely be resized
regardless of whether we are executing from it or not.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2010-02-18 18:13:51 +09:00

762 lines
16 KiB
C

/*
* arch/sh/mm/pmb.c
*
* Privileged Space Mapping Buffer (PMB) Support.
*
* Copyright (C) 2005 - 2010 Paul Mundt
* Copyright (C) 2010 Matt Fleming
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/rwlock.h>
#include <asm/sizes.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
struct pmb_entry;
struct pmb_entry {
unsigned long vpn;
unsigned long ppn;
unsigned long flags;
unsigned long size;
spinlock_t lock;
/*
* 0 .. NR_PMB_ENTRIES for specific entry selection, or
* PMB_NO_ENTRY to search for a free one
*/
int entry;
/* Adjacent entry link for contiguous multi-entry mappings */
struct pmb_entry *link;
};
static void pmb_unmap_entry(struct pmb_entry *, int depth);
static DEFINE_RWLOCK(pmb_rwlock);
static struct pmb_entry pmb_entry_list[NR_PMB_ENTRIES];
static DECLARE_BITMAP(pmb_map, NR_PMB_ENTRIES);
static __always_inline unsigned long mk_pmb_entry(unsigned int entry)
{
return (entry & PMB_E_MASK) << PMB_E_SHIFT;
}
static __always_inline unsigned long mk_pmb_addr(unsigned int entry)
{
return mk_pmb_entry(entry) | PMB_ADDR;
}
static __always_inline unsigned long mk_pmb_data(unsigned int entry)
{
return mk_pmb_entry(entry) | PMB_DATA;
}
static int pmb_alloc_entry(void)
{
int pos;
pos = find_first_zero_bit(pmb_map, NR_PMB_ENTRIES);
if (pos >= 0 && pos < NR_PMB_ENTRIES)
__set_bit(pos, pmb_map);
else
pos = -ENOSPC;
return pos;
}
static struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
unsigned long flags, int entry)
{
struct pmb_entry *pmbe;
unsigned long irqflags;
void *ret = NULL;
int pos;
write_lock_irqsave(&pmb_rwlock, irqflags);
if (entry == PMB_NO_ENTRY) {
pos = pmb_alloc_entry();
if (unlikely(pos < 0)) {
ret = ERR_PTR(pos);
goto out;
}
} else {
if (__test_and_set_bit(entry, pmb_map)) {
ret = ERR_PTR(-ENOSPC);
goto out;
}
pos = entry;
}
write_unlock_irqrestore(&pmb_rwlock, irqflags);
pmbe = &pmb_entry_list[pos];
memset(pmbe, 0, sizeof(struct pmb_entry));
spin_lock_init(&pmbe->lock);
pmbe->vpn = vpn;
pmbe->ppn = ppn;
pmbe->flags = flags;
pmbe->entry = pos;
return pmbe;
out:
write_unlock_irqrestore(&pmb_rwlock, irqflags);
return ret;
}
static void pmb_free(struct pmb_entry *pmbe)
{
__clear_bit(pmbe->entry, pmb_map);
pmbe->entry = PMB_NO_ENTRY;
pmbe->link = NULL;
}
/*
* Ensure that the PMB entries match our cache configuration.
*
* When we are in 32-bit address extended mode, CCR.CB becomes
* invalid, so care must be taken to manually adjust cacheable
* translations.
*/
static __always_inline unsigned long pmb_cache_flags(void)
{
unsigned long flags = 0;
#if defined(CONFIG_CACHE_WRITETHROUGH)
flags |= PMB_C | PMB_WT | PMB_UB;
#elif defined(CONFIG_CACHE_WRITEBACK)
flags |= PMB_C;
#endif
return flags;
}
/*
* Must be run uncached.
*/
static void __set_pmb_entry(struct pmb_entry *pmbe)
{
writel_uncached(pmbe->vpn | PMB_V, mk_pmb_addr(pmbe->entry));
writel_uncached(pmbe->ppn | pmbe->flags | PMB_V,
mk_pmb_data(pmbe->entry));
}
static void __clear_pmb_entry(struct pmb_entry *pmbe)
{
unsigned long addr, data;
unsigned long addr_val, data_val;
addr = mk_pmb_addr(pmbe->entry);
data = mk_pmb_data(pmbe->entry);
addr_val = __raw_readl(addr);
data_val = __raw_readl(data);
/* Clear V-bit */
writel_uncached(addr_val & ~PMB_V, addr);
writel_uncached(data_val & ~PMB_V, data);
}
static void set_pmb_entry(struct pmb_entry *pmbe)
{
unsigned long flags;
spin_lock_irqsave(&pmbe->lock, flags);
__set_pmb_entry(pmbe);
spin_unlock_irqrestore(&pmbe->lock, flags);
}
static struct {
unsigned long size;
int flag;
} pmb_sizes[] = {
{ .size = SZ_512M, .flag = PMB_SZ_512M, },
{ .size = SZ_128M, .flag = PMB_SZ_128M, },
{ .size = SZ_64M, .flag = PMB_SZ_64M, },
{ .size = SZ_16M, .flag = PMB_SZ_16M, },
};
long pmb_remap(unsigned long vaddr, unsigned long phys,
unsigned long size, pgprot_t prot)
{
struct pmb_entry *pmbp, *pmbe;
unsigned long wanted;
int pmb_flags, i;
long err;
u64 flags;
flags = pgprot_val(prot);
pmb_flags = PMB_WT | PMB_UB;
/* Convert typical pgprot value to the PMB equivalent */
if (flags & _PAGE_CACHABLE) {
pmb_flags |= PMB_C;
if ((flags & _PAGE_WT) == 0)
pmb_flags &= ~(PMB_WT | PMB_UB);
}
pmbp = NULL;
wanted = size;
again:
for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) {
unsigned long flags;
if (size < pmb_sizes[i].size)
continue;
pmbe = pmb_alloc(vaddr, phys, pmb_flags | pmb_sizes[i].flag,
PMB_NO_ENTRY);
if (IS_ERR(pmbe)) {
err = PTR_ERR(pmbe);
goto out;
}
spin_lock_irqsave(&pmbe->lock, flags);
__set_pmb_entry(pmbe);
phys += pmb_sizes[i].size;
vaddr += pmb_sizes[i].size;
size -= pmb_sizes[i].size;
pmbe->size = pmb_sizes[i].size;
/*
* Link adjacent entries that span multiple PMB entries
* for easier tear-down.
*/
if (likely(pmbp)) {
spin_lock(&pmbp->lock);
pmbp->link = pmbe;
spin_unlock(&pmbp->lock);
}
pmbp = pmbe;
/*
* Instead of trying smaller sizes on every iteration
* (even if we succeed in allocating space), try using
* pmb_sizes[i].size again.
*/
i--;
spin_unlock_irqrestore(&pmbe->lock, flags);
}
if (size >= SZ_16M)
goto again;
return wanted - size;
out:
pmb_unmap_entry(pmbp, NR_PMB_ENTRIES);
return err;
}
void pmb_unmap(unsigned long addr)
{
struct pmb_entry *pmbe = NULL;
int i;
read_lock(&pmb_rwlock);
for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
if (test_bit(i, pmb_map)) {
pmbe = &pmb_entry_list[i];
if (pmbe->vpn == addr)
break;
}
}
read_unlock(&pmb_rwlock);
pmb_unmap_entry(pmbe, NR_PMB_ENTRIES);
}
static bool pmb_can_merge(struct pmb_entry *a, struct pmb_entry *b)
{
return (b->vpn == (a->vpn + a->size)) &&
(b->ppn == (a->ppn + a->size)) &&
(b->flags == a->flags);
}
static bool pmb_size_valid(unsigned long size)
{
int i;
for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++)
if (pmb_sizes[i].size == size)
return true;
return false;
}
static int pmb_size_to_flags(unsigned long size)
{
int i;
for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++)
if (pmb_sizes[i].size == size)
return pmb_sizes[i].flag;
return 0;
}
static void __pmb_unmap_entry(struct pmb_entry *pmbe, int depth)
{
do {
struct pmb_entry *pmblink = pmbe;
/*
* We may be called before this pmb_entry has been
* entered into the PMB table via set_pmb_entry(), but
* that's OK because we've allocated a unique slot for
* this entry in pmb_alloc() (even if we haven't filled
* it yet).
*
* Therefore, calling __clear_pmb_entry() is safe as no
* other mapping can be using that slot.
*/
__clear_pmb_entry(pmbe);
pmbe = pmblink->link;
pmb_free(pmblink);
} while (pmbe && --depth);
}
static void pmb_unmap_entry(struct pmb_entry *pmbe, int depth)
{
unsigned long flags;
if (unlikely(!pmbe))
return;
write_lock_irqsave(&pmb_rwlock, flags);
__pmb_unmap_entry(pmbe, depth);
write_unlock_irqrestore(&pmb_rwlock, flags);
}
static __always_inline unsigned int pmb_ppn_in_range(unsigned long ppn)
{
return ppn >= __pa(memory_start) && ppn < __pa(memory_end);
}
static void __init pmb_notify(void)
{
int i;
pr_info("PMB: boot mappings:\n");
read_lock(&pmb_rwlock);
for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
struct pmb_entry *pmbe;
if (!test_bit(i, pmb_map))
continue;
pmbe = &pmb_entry_list[i];
pr_info(" 0x%08lx -> 0x%08lx [ %4ldMB %2scached ]\n",
pmbe->vpn >> PAGE_SHIFT, pmbe->ppn >> PAGE_SHIFT,
pmbe->size >> 20, (pmbe->flags & PMB_C) ? "" : "un");
}
read_unlock(&pmb_rwlock);
}
/*
* Sync our software copy of the PMB mappings with those in hardware. The
* mappings in the hardware PMB were either set up by the bootloader or
* very early on by the kernel.
*/
static void __init pmb_synchronize(void)
{
struct pmb_entry *pmbp = NULL;
int i, j;
/*
* Run through the initial boot mappings, log the established
* ones, and blow away anything that falls outside of the valid
* PPN range. Specifically, we only care about existing mappings
* that impact the cached/uncached sections.
*
* Note that touching these can be a bit of a minefield; the boot
* loader can establish multi-page mappings with the same caching
* attributes, so we need to ensure that we aren't modifying a
* mapping that we're presently executing from, or may execute
* from in the case of straddling page boundaries.
*
* In the future we will have to tidy up after the boot loader by
* jumping between the cached and uncached mappings and tearing
* down alternating mappings while executing from the other.
*/
for (i = 0; i < NR_PMB_ENTRIES; i++) {
unsigned long addr, data;
unsigned long addr_val, data_val;
unsigned long ppn, vpn, flags;
unsigned long irqflags;
unsigned int size;
struct pmb_entry *pmbe;
addr = mk_pmb_addr(i);
data = mk_pmb_data(i);
addr_val = __raw_readl(addr);
data_val = __raw_readl(data);
/*
* Skip over any bogus entries
*/
if (!(data_val & PMB_V) || !(addr_val & PMB_V))
continue;
ppn = data_val & PMB_PFN_MASK;
vpn = addr_val & PMB_PFN_MASK;
/*
* Only preserve in-range mappings.
*/
if (!pmb_ppn_in_range(ppn)) {
/*
* Invalidate anything out of bounds.
*/
writel_uncached(addr_val & ~PMB_V, addr);
writel_uncached(data_val & ~PMB_V, data);
continue;
}
/*
* Update the caching attributes if necessary
*/
if (data_val & PMB_C) {
data_val &= ~PMB_CACHE_MASK;
data_val |= pmb_cache_flags();
writel_uncached(data_val, data);
}
size = data_val & PMB_SZ_MASK;
flags = size | (data_val & PMB_CACHE_MASK);
pmbe = pmb_alloc(vpn, ppn, flags, i);
if (IS_ERR(pmbe)) {
WARN_ON_ONCE(1);
continue;
}
spin_lock_irqsave(&pmbe->lock, irqflags);
for (j = 0; j < ARRAY_SIZE(pmb_sizes); j++)
if (pmb_sizes[j].flag == size)
pmbe->size = pmb_sizes[j].size;
if (pmbp) {
spin_lock(&pmbp->lock);
/*
* Compare the previous entry against the current one to
* see if the entries span a contiguous mapping. If so,
* setup the entry links accordingly. Compound mappings
* are later coalesced.
*/
if (pmb_can_merge(pmbp, pmbe))
pmbp->link = pmbe;
spin_unlock(&pmbp->lock);
}
pmbp = pmbe;
spin_unlock_irqrestore(&pmbe->lock, irqflags);
}
}
static void __init pmb_merge(struct pmb_entry *head)
{
unsigned long span, newsize;
struct pmb_entry *tail;
int i = 1, depth = 0;
span = newsize = head->size;
tail = head->link;
while (tail) {
span += tail->size;
if (pmb_size_valid(span)) {
newsize = span;
depth = i;
}
/* This is the end of the line.. */
if (!tail->link)
break;
tail = tail->link;
i++;
}
/*
* The merged page size must be valid.
*/
if (!pmb_size_valid(newsize))
return;
head->flags &= ~PMB_SZ_MASK;
head->flags |= pmb_size_to_flags(newsize);
head->size = newsize;
__pmb_unmap_entry(head->link, depth);
__set_pmb_entry(head);
}
static void __init pmb_coalesce(void)
{
unsigned long flags;
int i;
write_lock_irqsave(&pmb_rwlock, flags);
for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
struct pmb_entry *pmbe;
if (!test_bit(i, pmb_map))
continue;
pmbe = &pmb_entry_list[i];
/*
* We're only interested in compound mappings
*/
if (!pmbe->link)
continue;
/*
* Nothing to do if it already uses the largest possible
* page size.
*/
if (pmbe->size == SZ_512M)
continue;
pmb_merge(pmbe);
}
write_unlock_irqrestore(&pmb_rwlock, flags);
}
#ifdef CONFIG_UNCACHED_MAPPING
static void __init pmb_resize(void)
{
int i;
/*
* If the uncached mapping was constructed by the kernel, it will
* already be a reasonable size.
*/
if (uncached_size == SZ_16M)
return;
read_lock(&pmb_rwlock);
for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
struct pmb_entry *pmbe;
unsigned long flags;
if (!test_bit(i, pmb_map))
continue;
pmbe = &pmb_entry_list[i];
if (pmbe->vpn != uncached_start)
continue;
/*
* Found it, now resize it.
*/
spin_lock_irqsave(&pmbe->lock, flags);
pmbe->size = SZ_16M;
pmbe->flags &= ~PMB_SZ_MASK;
pmbe->flags |= pmb_size_to_flags(pmbe->size);
uncached_resize(pmbe->size);
__set_pmb_entry(pmbe);
spin_unlock_irqrestore(&pmbe->lock, flags);
}
read_lock(&pmb_rwlock);
}
#endif
void __init pmb_init(void)
{
/* Synchronize software state */
pmb_synchronize();
/* Attempt to combine compound mappings */
pmb_coalesce();
#ifdef CONFIG_UNCACHED_MAPPING
/* Resize initial mappings, if necessary */
pmb_resize();
#endif
/* Log them */
pmb_notify();
writel_uncached(0, PMB_IRMCR);
/* Flush out the TLB */
__raw_writel(__raw_readl(MMUCR) | MMUCR_TI, MMUCR);
ctrl_barrier();
}
bool __in_29bit_mode(void)
{
return (__raw_readl(PMB_PASCR) & PASCR_SE) == 0;
}
static int pmb_seq_show(struct seq_file *file, void *iter)
{
int i;
seq_printf(file, "V: Valid, C: Cacheable, WT: Write-Through\n"
"CB: Copy-Back, B: Buffered, UB: Unbuffered\n");
seq_printf(file, "ety vpn ppn size flags\n");
for (i = 0; i < NR_PMB_ENTRIES; i++) {
unsigned long addr, data;
unsigned int size;
char *sz_str = NULL;
addr = __raw_readl(mk_pmb_addr(i));
data = __raw_readl(mk_pmb_data(i));
size = data & PMB_SZ_MASK;
sz_str = (size == PMB_SZ_16M) ? " 16MB":
(size == PMB_SZ_64M) ? " 64MB":
(size == PMB_SZ_128M) ? "128MB":
"512MB";
/* 02: V 0x88 0x08 128MB C CB B */
seq_printf(file, "%02d: %c 0x%02lx 0x%02lx %s %c %s %s\n",
i, ((addr & PMB_V) && (data & PMB_V)) ? 'V' : ' ',
(addr >> 24) & 0xff, (data >> 24) & 0xff,
sz_str, (data & PMB_C) ? 'C' : ' ',
(data & PMB_WT) ? "WT" : "CB",
(data & PMB_UB) ? "UB" : " B");
}
return 0;
}
static int pmb_debugfs_open(struct inode *inode, struct file *file)
{
return single_open(file, pmb_seq_show, NULL);
}
static const struct file_operations pmb_debugfs_fops = {
.owner = THIS_MODULE,
.open = pmb_debugfs_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init pmb_debugfs_init(void)
{
struct dentry *dentry;
dentry = debugfs_create_file("pmb", S_IFREG | S_IRUGO,
sh_debugfs_root, NULL, &pmb_debugfs_fops);
if (!dentry)
return -ENOMEM;
if (IS_ERR(dentry))
return PTR_ERR(dentry);
return 0;
}
postcore_initcall(pmb_debugfs_init);
#ifdef CONFIG_PM
static int pmb_sysdev_suspend(struct sys_device *dev, pm_message_t state)
{
static pm_message_t prev_state;
int i;
/* Restore the PMB after a resume from hibernation */
if (state.event == PM_EVENT_ON &&
prev_state.event == PM_EVENT_FREEZE) {
struct pmb_entry *pmbe;
read_lock(&pmb_rwlock);
for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
if (test_bit(i, pmb_map)) {
pmbe = &pmb_entry_list[i];
set_pmb_entry(pmbe);
}
}
read_unlock(&pmb_rwlock);
}
prev_state = state;
return 0;
}
static int pmb_sysdev_resume(struct sys_device *dev)
{
return pmb_sysdev_suspend(dev, PMSG_ON);
}
static struct sysdev_driver pmb_sysdev_driver = {
.suspend = pmb_sysdev_suspend,
.resume = pmb_sysdev_resume,
};
static int __init pmb_sysdev_init(void)
{
return sysdev_driver_register(&cpu_sysdev_class, &pmb_sysdev_driver);
}
subsys_initcall(pmb_sysdev_init);
#endif