int curpage;
};
+/*
+ * Serialize cpa() (for !DEBUG_PAGEALLOC which uses large identity mappings)
+ * using cpa_lock. So that we don't allow any other cpu, with stale large tlb
+ * entries change the page attribute in parallel to some other cpu
+ * splitting a large page entry along with changing the attribute.
+ */
+static DEFINE_SPINLOCK(cpa_lock);
+
#define CPA_FLUSHTLB 1
#define CPA_ARRAY 2
static inline unsigned long highmap_end_pfn(void)
{
- return __pa(round_up((unsigned long)_end, PMD_SIZE)) >> PAGE_SHIFT;
+ return __pa(roundup((unsigned long)_end, PMD_SIZE)) >> PAGE_SHIFT;
}
#endif
return do_split;
}
-static LIST_HEAD(page_pool);
-static unsigned long pool_size, pool_pages, pool_low;
-static unsigned long pool_used, pool_failed;
-
-static void cpa_fill_pool(struct page **ret)
-{
- gfp_t gfp = GFP_KERNEL;
- unsigned long flags;
- struct page *p;
-
- /*
- * Avoid recursion (on debug-pagealloc) and also signal
- * our priority to get to these pagetables:
- */
- if (current->flags & PF_MEMALLOC)
- return;
- current->flags |= PF_MEMALLOC;
-
- /*
- * Allocate atomically from atomic contexts:
- */
- if (in_atomic() || irqs_disabled() || debug_pagealloc)
- gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
-
- while (pool_pages < pool_size || (ret && !*ret)) {
- p = alloc_pages(gfp, 0);
- if (!p) {
- pool_failed++;
- break;
- }
- /*
- * If the call site needs a page right now, provide it:
- */
- if (ret && !*ret) {
- *ret = p;
- continue;
- }
- spin_lock_irqsave(&pgd_lock, flags);
- list_add(&p->lru, &page_pool);
- pool_pages++;
- spin_unlock_irqrestore(&pgd_lock, flags);
- }
-
- current->flags &= ~PF_MEMALLOC;
-}
-
-#define SHIFT_MB (20 - PAGE_SHIFT)
-#define ROUND_MB_GB ((1 << 10) - 1)
-#define SHIFT_MB_GB 10
-#define POOL_PAGES_PER_GB 16
-
-void __init cpa_init(void)
-{
- struct sysinfo si;
- unsigned long gb;
-
- si_meminfo(&si);
- /*
- * Calculate the number of pool pages:
- *
- * Convert totalram (nr of pages) to MiB and round to the next
- * GiB. Shift MiB to Gib and multiply the result by
- * POOL_PAGES_PER_GB:
- */
- if (debug_pagealloc) {
- gb = ((si.totalram >> SHIFT_MB) + ROUND_MB_GB) >> SHIFT_MB_GB;
- pool_size = POOL_PAGES_PER_GB * gb;
- } else {
- pool_size = 1;
- }
- pool_low = pool_size;
-
- cpa_fill_pool(NULL);
- printk(KERN_DEBUG
- "CPA: page pool initialized %lu of %lu pages preallocated\n",
- pool_pages, pool_size);
-}
-
static int split_large_page(pte_t *kpte, unsigned long address)
{
unsigned long flags, pfn, pfninc = 1;
pgprot_t ref_prot;
struct page *base;
- /*
- * Get a page from the pool. The pool list is protected by the
- * pgd_lock, which we have to take anyway for the split
- * operation:
- */
- spin_lock_irqsave(&pgd_lock, flags);
- if (list_empty(&page_pool)) {
- spin_unlock_irqrestore(&pgd_lock, flags);
- base = NULL;
- cpa_fill_pool(&base);
- if (!base)
- return -ENOMEM;
- spin_lock_irqsave(&pgd_lock, flags);
- } else {
- base = list_first_entry(&page_pool, struct page, lru);
- list_del(&base->lru);
- pool_pages--;
-
- if (pool_pages < pool_low)
- pool_low = pool_pages;
- }
+ if (!debug_pagealloc)
+ spin_unlock(&cpa_lock);
+ base = alloc_pages(GFP_KERNEL, 0);
+ if (!debug_pagealloc)
+ spin_lock(&cpa_lock);
+ if (!base)
+ return -ENOMEM;
+ spin_lock_irqsave(&pgd_lock, flags);
/*
* Check for races, another CPU might have split this page
* up for us already:
* If we dropped out via the lookup_address check under
* pgd_lock then stick the page back into the pool:
*/
- if (base) {
- list_add(&base->lru, &page_pool);
- pool_pages++;
- } else
- pool_used++;
+ if (base)
+ __free_page(base);
spin_unlock_irqrestore(&pgd_lock, flags);
return 0;
*/
err = split_large_page(kpte, address);
if (!err) {
- cpa->flags |= CPA_FLUSHTLB;
+ /*
+ * Do a global flush tlb after splitting the large page
+ * and before we do the actual change page attribute in the PTE.
+ *
+ * With out this, we violate the TLB application note, that says
+ * "The TLBs may contain both ordinary and large-page
+ * translations for a 4-KByte range of linear addresses. This
+ * may occur if software modifies the paging structures so that
+ * the page size used for the address range changes. If the two
+ * translations differ with respect to page frame or attributes
+ * (e.g., permissions), processor behavior is undefined and may
+ * be implementation-specific."
+ *
+ * We do this global tlb flush inside the cpa_lock, so that we
+ * don't allow any other cpu, with stale tlb entries change the
+ * page attribute in parallel, that also falls into the
+ * just split large page entry.
+ */
+ flush_tlb_all();
goto repeat;
}
if (cpa->flags & CPA_ARRAY)
cpa->numpages = 1;
+ if (!debug_pagealloc)
+ spin_lock(&cpa_lock);
ret = __change_page_attr(cpa, checkalias);
+ if (!debug_pagealloc)
+ spin_unlock(&cpa_lock);
if (ret)
return ret;
cpa_flush_all(cache);
out:
- cpa_fill_pool(NULL);
-
return ret;
}
int set_memory_array_uc(unsigned long *addr, int addrinarray)
{
+ unsigned long start;
+ unsigned long end;
int i;
/*
* for now UC MINUS. see comments in ioremap_nocache()
*/
for (i = 0; i < addrinarray; i++) {
- if (reserve_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE,
- _PAGE_CACHE_UC_MINUS, NULL))
+ start = __pa(addr[i]);
+ for (end = start + PAGE_SIZE; i < addrinarray - 1; end += PAGE_SIZE) {
+ if (end != __pa(addr[i + 1]))
+ break;
+ i++;
+ }
+ if (reserve_memtype(start, end, _PAGE_CACHE_UC_MINUS, NULL))
goto out;
}
return change_page_attr_set(addr, addrinarray,
__pgprot(_PAGE_CACHE_UC_MINUS), 1);
out:
- while (--i >= 0)
- free_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE);
+ for (i = 0; i < addrinarray; i++) {
+ unsigned long tmp = __pa(addr[i]);
+
+ if (tmp == start)
+ break;
+ for (end = tmp + PAGE_SIZE; i < addrinarray - 1; end += PAGE_SIZE) {
+ if (end != __pa(addr[i + 1]))
+ break;
+ i++;
+ }
+ free_memtype(tmp, end);
+ }
return -EINVAL;
}
EXPORT_SYMBOL(set_memory_array_uc);
int set_memory_array_wb(unsigned long *addr, int addrinarray)
{
int i;
- for (i = 0; i < addrinarray; i++)
- free_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE);
+ for (i = 0; i < addrinarray; i++) {
+ unsigned long start = __pa(addr[i]);
+ unsigned long end;
+
+ for (end = start + PAGE_SIZE; i < addrinarray - 1; end += PAGE_SIZE) {
+ if (end != __pa(addr[i + 1]))
+ break;
+ i++;
+ }
+ free_memtype(start, end);
+ }
return change_page_attr_clear(addr, addrinarray,
__pgprot(_PAGE_CACHE_MASK), 1);
}
{
return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW), 0);
}
+EXPORT_SYMBOL_GPL(set_memory_ro);
int set_memory_rw(unsigned long addr, int numpages)
{
return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_RW), 0);
}
+EXPORT_SYMBOL_GPL(set_memory_rw);
int set_memory_np(unsigned long addr, int numpages)
{
.mask_clr = __pgprot(0),
.flags = 0};
- return __change_page_attr_set_clr(&cpa, 1);
+ /*
+ * No alias checking needed for setting present flag. otherwise,
+ * we may need to break large pages for 64-bit kernel text
+ * mappings (this adds to complexity if we want to do this from
+ * atomic context especially). Let's keep it simple!
+ */
+ return __change_page_attr_set_clr(&cpa, 0);
}
static int __set_pages_np(struct page *page, int numpages)
.mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW),
.flags = 0};
- return __change_page_attr_set_clr(&cpa, 1);
+ /*
+ * No alias checking needed for setting not present flag. otherwise,
+ * we may need to break large pages for 64-bit kernel text
+ * mappings (this adds to complexity if we want to do this from
+ * atomic context especially). Let's keep it simple!
+ */
+ return __change_page_attr_set_clr(&cpa, 0);
}
void kernel_map_pages(struct page *page, int numpages, int enable)
/*
* The return value is ignored as the calls cannot fail.
- * Large pages are kept enabled at boot time, and are
- * split up quickly with DEBUG_PAGEALLOC. If a splitup
- * fails here (due to temporary memory shortage) no damage
- * is done because we just keep the largepage intact up
- * to the next attempt when it will likely be split up:
+ * Large pages for identity mappings are not used at boot time
+ * and hence no memory allocations during large page split.
*/
if (enable)
__set_pages_p(page, numpages);
* but that can deadlock->flush only current cpu:
*/
__flush_tlb_all();
-
- /*
- * Try to refill the page pool here. We can do this only after
- * the tlb flush.
- */
- cpa_fill_pool(NULL);
-}
-
-#ifdef CONFIG_DEBUG_FS
-static int dpa_show(struct seq_file *m, void *v)
-{
- seq_puts(m, "DEBUG_PAGEALLOC\n");
- seq_printf(m, "pool_size : %lu\n", pool_size);
- seq_printf(m, "pool_pages : %lu\n", pool_pages);
- seq_printf(m, "pool_low : %lu\n", pool_low);
- seq_printf(m, "pool_used : %lu\n", pool_used);
- seq_printf(m, "pool_failed : %lu\n", pool_failed);
-
- return 0;
-}
-
-static int dpa_open(struct inode *inode, struct file *filp)
-{
- return single_open(filp, dpa_show, NULL);
}
-static const struct file_operations dpa_fops = {
- .open = dpa_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
-
-static int __init debug_pagealloc_proc_init(void)
-{
- struct dentry *de;
-
- de = debugfs_create_file("debug_pagealloc", 0600, NULL, NULL,
- &dpa_fops);
- if (!de)
- return -ENOMEM;
-
- return 0;
-}
-__initcall(debug_pagealloc_proc_init);
-#endif
-
#ifdef CONFIG_HIBERNATION
bool kernel_page_present(struct page *page)
projects / linux-2.6-omap-h63xx.git / blobdiff