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x86: simplify the 32-bit cpa code
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simplify the 32-bit cpa code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Ingo Molnar committed Jan 30, 2008
1 parent a2172e2 commit 78c94ab
Showing 1 changed file with 56 additions and 123 deletions.
179 changes: 56 additions & 123 deletions arch/x86/mm/pageattr_32.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,9 +15,6 @@
#include <asm/uaccess.h>
#include <asm/pgalloc.h>

static DEFINE_SPINLOCK(cpa_lock);
static struct list_head df_list = LIST_HEAD_INIT(df_list);

pte_t *lookup_address(unsigned long address, int *level)
{
pgd_t *pgd = pgd_offset_k(address);
Expand Down Expand Up @@ -48,19 +45,14 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
pte_t *pbase;
int i;

spin_unlock_irq(&cpa_lock);
base = alloc_pages(GFP_KERNEL, 0);
spin_lock_irq(&cpa_lock);
if (!base)
return NULL;

/*
* page_private is used to track the number of entries in
* the page table page that have non standard attributes.
*/
SetPagePrivate(base);
page_private(base) = 0;

address = __pa(address);
addr = address & LARGE_PAGE_MASK;
pbase = (pte_t *)page_address(base);
Expand All @@ -73,36 +65,6 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
return base;
}

static void cache_flush_page(struct page *p)
{
void *addr = page_address(p);
int i;

for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size)
clflush(addr + i);
}

static void flush_kernel_map(void *arg)
{
struct list_head *lh = (struct list_head *)arg;
struct page *p;

/*
* Flush all to work around Errata in early athlons regarding
* large page flushing.
*/
__flush_tlb_all();

/* High level code is not ready for clflush yet */
if (0 && cpu_has_clflush) {
list_for_each_entry(p, lh, lru)
cache_flush_page(p);
} else {
if (boot_cpu_data.x86_model >= 4)
wbinvd();
}
}

static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
{
unsigned long flags;
Expand All @@ -127,36 +89,12 @@ static void set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
spin_unlock_irqrestore(&pgd_lock, flags);
}

/*
* No more special protections in this 2/4MB area - revert to a large
* page again.
*/
static inline void revert_page(struct page *kpte_page, unsigned long address)
{
pgprot_t ref_prot;
pte_t *linear;

ref_prot =
((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
? PAGE_KERNEL_LARGE_EXEC : PAGE_KERNEL_LARGE;

linear = (pte_t *)
pmd_offset(pud_offset(pgd_offset_k(address), address), address);
set_pmd_pte(linear, address,
pfn_pte((__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT,
ref_prot));
}

static inline void save_page(struct page *kpte_page)
{
if (!test_and_set_bit(PG_arch_1, &kpte_page->flags))
list_add(&kpte_page->lru, &df_list);
}

static int __change_page_attr(struct page *page, pgprot_t prot)
{
pgprot_t ref_prot = PAGE_KERNEL;
struct page *kpte_page;
unsigned long address;
pgprot_t oldprot;
pte_t *kpte;
int level;

Expand All @@ -167,58 +105,41 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
if (!kpte)
return -EINVAL;

oldprot = pte_pgprot(*kpte);
kpte_page = virt_to_page(kpte);
BUG_ON(PageLRU(kpte_page));
BUG_ON(PageCompound(kpte_page));

if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
if (level == 3) {
set_pte_atomic(kpte, mk_pte(page, prot));
} else {
struct page *split;
pgprot_t ref_prot;

ref_prot =
((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
? PAGE_KERNEL_EXEC : PAGE_KERNEL;
split = split_large_page(address, prot, ref_prot);
if (!split)
return -ENOMEM;

set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
kpte_page = split;
}
page_private(kpte_page)++;
} else {
if (level == 3) {
set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
BUG_ON(page_private(kpte_page) == 0);
page_private(kpte_page)--;
} else
BUG();
}

/*
* If the pte was reserved, it means it was created at boot
* time (not via split_large_page) and in turn we must not
* replace it with a largepage.
* Better fail early if someone sets the kernel text to NX.
* Does not cover __inittext
*/
BUG_ON(address >= (unsigned long)&_text &&
address < (unsigned long)&_etext &&
(pgprot_val(prot) & _PAGE_NX));

save_page(kpte_page);
if (!PageReserved(kpte_page)) {
if (cpu_has_pse && (page_private(kpte_page) == 0)) {
paravirt_release_pt(page_to_pfn(kpte_page));
revert_page(kpte_page, address);
}
if ((address & LARGE_PAGE_MASK) < (unsigned long)&_etext)
ref_prot = PAGE_KERNEL_EXEC;

ref_prot = canon_pgprot(ref_prot);
prot = canon_pgprot(prot);

if (level == 3) {
set_pte_atomic(kpte, mk_pte(page, prot));
} else {
struct page *split;
split = split_large_page(address, prot, ref_prot);
if (!split)
return -ENOMEM;

/*
* There's a small window here to waste a bit of RAM:
*/
set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
}
return 0;
}

static inline void flush_map(struct list_head *l)
{
on_each_cpu(flush_kernel_map, l, 1, 1);
}

/*
* Change the page attributes of an page in the linear mapping.
*
Expand All @@ -234,40 +155,52 @@ static inline void flush_map(struct list_head *l)
*/
int change_page_attr(struct page *page, int numpages, pgprot_t prot)
{
unsigned long flags;
int err = 0, i;

spin_lock_irqsave(&cpa_lock, flags);
for (i = 0; i < numpages; i++, page++) {
err = __change_page_attr(page, prot);
if (err)
break;
}
spin_unlock_irqrestore(&cpa_lock, flags);

return err;
}
EXPORT_SYMBOL(change_page_attr);

void global_flush_tlb(void)
int change_page_attr_addr(unsigned long addr, int numpages, pgprot_t prot)
{
struct page *pg, *next;
struct list_head l;
int i;
unsigned long pfn = (addr >> PAGE_SHIFT);

for (i = 0; i < numpages; i++) {
if (!pfn_valid(pfn + i)) {
break;
} else {
int level;
pte_t *pte = lookup_address(addr + i*PAGE_SIZE, &level);
BUG_ON(pte && !pte_none(*pte));
}
}
return change_page_attr(virt_to_page(addr), i, prot);
}

static void flush_kernel_map(void *arg)
{
/*
* Flush all to work around Errata in early athlons regarding
* large page flushing.
*/
__flush_tlb_all();

if (boot_cpu_data.x86_model >= 4)
wbinvd();
}

void global_flush_tlb(void)
{
BUG_ON(irqs_disabled());

spin_lock_irq(&cpa_lock);
list_replace_init(&df_list, &l);
spin_unlock_irq(&cpa_lock);
flush_map(&l);
list_for_each_entry_safe(pg, next, &l, lru) {
list_del(&pg->lru);
clear_bit(PG_arch_1, &pg->flags);
if (PageReserved(pg) || !cpu_has_pse || page_private(pg) != 0)
continue;
ClearPagePrivate(pg);
__free_page(pg);
}
on_each_cpu(flush_kernel_map, NULL, 1, 1);
}
EXPORT_SYMBOL(global_flush_tlb);

Expand Down

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