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authorArjan van de Ven <arjan@infradead.org>2008-01-30 07:34:06 -0500
committerIngo Molnar <mingo@elte.hu>2008-01-30 07:34:06 -0500
commit75cbade8ea3127a84e3da7c2c15808e54f0df7e8 (patch)
treeb91fd5e8f9f5f8da0da55a7783c70fc3149cbf2d /arch/x86/mm/pageattr.c
parente81d5dc41b67349c06e80658227c9156738f0df1 (diff)
x86: a new API for drivers/etc to control cache and other page attributes
Right now, if drivers or other code want to change, say, a cache attribute of a page, the only API they have is change_page_attr(). c-p-a is a really bad API for this, because it forces the caller to know *ALL* the attributes he wants for the page, not just the 1 thing he wants to change. So code that wants to set a page uncachable, needs to be aware of the NX status as well etc etc etc. This patch introduces a set of new APIs for this, set_pages_<attr> and set_memory_<attr>, that offer a logical change to the user, and leave all attributes not implied by the requested logical change alone. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
-rw-r--r--arch/x86/mm/pageattr.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4208571334db..f3c9510b8d92 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -211,6 +211,8 @@ repeat:
211 * mem_map entry (pfn_valid() is false). 211 * mem_map entry (pfn_valid() is false).
212 * 212 *
213 * See change_page_attr() documentation for more details. 213 * See change_page_attr() documentation for more details.
214 *
215 * Modules and drivers should use the set_memory_* APIs instead.
214 */ 216 */
215 217
216int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot) 218int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
@@ -273,6 +275,8 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
273 * (e.g. in user space) * This function only deals with the kernel linear map. 275 * (e.g. in user space) * This function only deals with the kernel linear map.
274 * 276 *
275 * For MMIO areas without mem_map use change_page_attr_addr() instead. 277 * For MMIO areas without mem_map use change_page_attr_addr() instead.
278 *
279 * Modules and drivers should use the set_pages_* APIs instead.
276 */ 280 */
277int change_page_attr(struct page *page, int numpages, pgprot_t prot) 281int change_page_attr(struct page *page, int numpages, pgprot_t prot)
278{ 282{
@@ -282,6 +286,199 @@ int change_page_attr(struct page *page, int numpages, pgprot_t prot)
282} 286}
283EXPORT_SYMBOL(change_page_attr); 287EXPORT_SYMBOL(change_page_attr);
284 288
289/**
290 * change_page_attr_set - Change page table attributes in the linear mapping.
291 * @addr: Virtual address in linear mapping.
292 * @numpages: Number of pages to change
293 * @prot: Protection/caching type bits to set (PAGE_*)
294 *
295 * Returns 0 on success, otherwise a negated errno.
296 *
297 * This should be used when a page is mapped with a different caching policy
298 * than write-back somewhere - some CPUs do not like it when mappings with
299 * different caching policies exist. This changes the page attributes of the
300 * in kernel linear mapping too.
301 *
302 * Caller must call global_flush_tlb() later to make the changes active.
303 *
304 * The caller needs to ensure that there are no conflicting mappings elsewhere
305 * (e.g. in user space) * This function only deals with the kernel linear map.
306 *
307 * This function is different from change_page_attr() in that only selected bits
308 * are impacted, all other bits remain as is.
309 */
310int change_page_attr_set(unsigned long addr, int numpages, pgprot_t prot)
311{
312 pgprot_t current_prot;
313 int level;
314 pte_t *pte;
315
316 pte = lookup_address(addr, &level);
317 if (pte)
318 current_prot = pte_pgprot(*pte);
319 else
320 pgprot_val(current_prot) = 0;
321
322 pgprot_val(prot) = pgprot_val(current_prot) | pgprot_val(prot);
323
324 return change_page_attr_addr(addr, numpages, prot);
325}
326
327/**
328 * change_page_attr_clear - Change page table attributes in the linear mapping.
329 * @addr: Virtual address in linear mapping.
330 * @numpages: Number of pages to change
331 * @prot: Protection/caching type bits to clear (PAGE_*)
332 *
333 * Returns 0 on success, otherwise a negated errno.
334 *
335 * This should be used when a page is mapped with a different caching policy
336 * than write-back somewhere - some CPUs do not like it when mappings with
337 * different caching policies exist. This changes the page attributes of the
338 * in kernel linear mapping too.
339 *
340 * Caller must call global_flush_tlb() later to make the changes active.
341 *
342 * The caller needs to ensure that there are no conflicting mappings elsewhere
343 * (e.g. in user space) * This function only deals with the kernel linear map.
344 *
345 * This function is different from change_page_attr() in that only selected bits
346 * are impacted, all other bits remain as is.
347 */
348int change_page_attr_clear(unsigned long addr, int numpages, pgprot_t prot)
349{
350 pgprot_t current_prot;
351 int level;
352 pte_t *pte;
353
354 pte = lookup_address(addr, &level);
355 if (pte)
356 current_prot = pte_pgprot(*pte);
357 else
358 pgprot_val(current_prot) = 0;
359
360 pgprot_val(prot) = pgprot_val(current_prot) & ~pgprot_val(prot);
361
362 return change_page_attr_addr(addr, numpages, prot);
363}
364
365
366
367int set_memory_uc(unsigned long addr, int numpages)
368{
369 pgprot_t uncached;
370
371 pgprot_val(uncached) = _PAGE_PCD | _PAGE_PWT;
372 return change_page_attr_set(addr, numpages, uncached);
373}
374EXPORT_SYMBOL(set_memory_uc);
375
376int set_memory_wb(unsigned long addr, int numpages)
377{
378 pgprot_t uncached;
379
380 pgprot_val(uncached) = _PAGE_PCD | _PAGE_PWT;
381 return change_page_attr_clear(addr, numpages, uncached);
382}
383EXPORT_SYMBOL(set_memory_wb);
384
385int set_memory_x(unsigned long addr, int numpages)
386{
387 pgprot_t nx;
388
389 pgprot_val(nx) = _PAGE_NX;
390 return change_page_attr_clear(addr, numpages, nx);
391}
392EXPORT_SYMBOL(set_memory_x);
393
394int set_memory_nx(unsigned long addr, int numpages)
395{
396 pgprot_t nx;
397
398 pgprot_val(nx) = _PAGE_NX;
399 return change_page_attr_set(addr, numpages, nx);
400}
401EXPORT_SYMBOL(set_memory_nx);
402
403int set_memory_ro(unsigned long addr, int numpages)
404{
405 pgprot_t rw;
406
407 pgprot_val(rw) = _PAGE_RW;
408 return change_page_attr_clear(addr, numpages, rw);
409}
410EXPORT_SYMBOL(set_memory_ro);
411
412int set_memory_rw(unsigned long addr, int numpages)
413{
414 pgprot_t rw;
415
416 pgprot_val(rw) = _PAGE_RW;
417 return change_page_attr_set(addr, numpages, rw);
418}
419EXPORT_SYMBOL(set_memory_rw);
420
421int set_pages_uc(struct page *page, int numpages)
422{
423 unsigned long addr = (unsigned long)page_address(page);
424 pgprot_t uncached;
425
426 pgprot_val(uncached) = _PAGE_PCD | _PAGE_PWT;
427 return change_page_attr_set(addr, numpages, uncached);
428}
429EXPORT_SYMBOL(set_pages_uc);
430
431int set_pages_wb(struct page *page, int numpages)
432{
433 unsigned long addr = (unsigned long)page_address(page);
434 pgprot_t uncached;
435
436 pgprot_val(uncached) = _PAGE_PCD | _PAGE_PWT;
437 return change_page_attr_clear(addr, numpages, uncached);
438}
439EXPORT_SYMBOL(set_pages_wb);
440
441int set_pages_x(struct page *page, int numpages)
442{
443 unsigned long addr = (unsigned long)page_address(page);
444 pgprot_t nx;
445
446 pgprot_val(nx) = _PAGE_NX;
447 return change_page_attr_clear(addr, numpages, nx);
448}
449EXPORT_SYMBOL(set_pages_x);
450
451int set_pages_nx(struct page *page, int numpages)
452{
453 unsigned long addr = (unsigned long)page_address(page);
454 pgprot_t nx;
455
456 pgprot_val(nx) = _PAGE_NX;
457 return change_page_attr_set(addr, numpages, nx);
458}
459EXPORT_SYMBOL(set_pages_nx);
460
461int set_pages_ro(struct page *page, int numpages)
462{
463 unsigned long addr = (unsigned long)page_address(page);
464 pgprot_t rw;
465
466 pgprot_val(rw) = _PAGE_RW;
467 return change_page_attr_clear(addr, numpages, rw);
468}
469EXPORT_SYMBOL(set_pages_ro);
470
471int set_pages_rw(struct page *page, int numpages)
472{
473 unsigned long addr = (unsigned long)page_address(page);
474 pgprot_t rw;
475
476 pgprot_val(rw) = _PAGE_RW;
477 return change_page_attr_set(addr, numpages, rw);
478}
479EXPORT_SYMBOL(set_pages_rw);
480
481
285void clflush_cache_range(void *addr, int size) 482void clflush_cache_range(void *addr, int size)
286{ 483{
287 int i; 484 int i;