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linux/include/asm-xtensa/pgalloc.h

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[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
/*
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
* include/asm-xtensa/pgalloc.h
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
* Copyright (C) 2001-2007 Tensilica Inc.
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
*/
#ifndef _XTENSA_PGALLOC_H
#define _XTENSA_PGALLOC_H
#ifdef __KERNEL__
#include <linux/highmem.h>
/*
* Allocating and freeing a pmd is trivial: the 1-entry pmd is
* inside the pgd, so has no extra memory associated with it.
*/
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
#define pmd_populate_kernel(mm, pmdp, ptep) \
(pmd_val(*(pmdp)) = ((unsigned long)ptep))
#define pmd_populate(mm, pmdp, page) \
(pmd_val(*(pmdp)) = ((unsigned long)page_to_virt(page)))
CONFIG_HIGHPTE vs. sub-page page tables. Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 12:22:04 +00:00
#define pmd_pgtable(pmd) pmd_page(pmd)
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
static inline pgd_t*
pgd_alloc(struct mm_struct *mm)
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
{
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
return (pgd_t*) __get_free_pages(GFP_KERNEL | __GFP_ZERO, PGD_ORDER);
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
}
add mm argument to pte/pmd/pud/pgd_free (with Martin Schwidefsky <schwidefsky@de.ibm.com>) The pgd/pud/pmd/pte page table allocation functions get a mm_struct pointer as first argument. The free functions do not get the mm_struct argument. This is 1) asymmetrical and 2) to do mm related page table allocations the mm argument is needed on the free function as well. [kamalesh@linux.vnet.ibm.com: i386 fix] [akpm@linux-foundation.org: coding-syle fixes] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:14 +00:00
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
{
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
free_page((unsigned long)pgd);
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
}
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
/* Use a slab cache for the pte pages (see also sparc64 implementation) */
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
extern struct kmem_cache *pgtable_cache;
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
unsigned long address)
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
{
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
return kmem_cache_alloc(pgtable_cache, GFP_KERNEL|__GFP_REPEAT);
}
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
[XTENSA] Fix non-existent pte_token_t typedef to pgtable_t This bug was introduced in 2f569afd9ced9ebec9a6eb3dbf6f83429be0a7b4. (CONFIG_HIGHPTE vs. sub-page page tables) Signed-off-by: Chris Zankel <chris@zankel.net>
2008-02-14 00:25:09 +00:00
static inline pgtable_t pte_alloc_one(struct mm_struct *mm,
CONFIG_HIGHPTE vs. sub-page page tables. Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 12:22:04 +00:00
unsigned long addr)
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
{
CONFIG_HIGHPTE vs. sub-page page tables. Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 12:22:04 +00:00
struct page *page;
page = virt_to_page(pte_alloc_one_kernel(mm, addr));
pgtable_page_ctor(page);
return page;
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
}
add mm argument to pte/pmd/pud/pgd_free (with Martin Schwidefsky <schwidefsky@de.ibm.com>) The pgd/pud/pmd/pte page table allocation functions get a mm_struct pointer as first argument. The free functions do not get the mm_struct argument. This is 1) asymmetrical and 2) to do mm related page table allocations the mm argument is needed on the free function as well. [kamalesh@linux.vnet.ibm.com: i386 fix] [akpm@linux-foundation.org: coding-syle fixes] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 06:29:14 +00:00
static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
{
kmem_cache_free(pgtable_cache, pte);
}
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
CONFIG_HIGHPTE vs. sub-page page tables. Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 12:22:04 +00:00
static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
{
CONFIG_HIGHPTE vs. sub-page page tables. Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 12:22:04 +00:00
pgtable_page_dtor(pte);
kmem_cache_free(pgtable_cache, page_address(pte));
[XTENSA] Add support for cache-aliasing Add support for processors that have cache-aliasing issues, such as the Stretch S5000 processor. Cache-aliasing means that the size of the cache (for one way) is larger than the page size, thus, a page can end up in several places in cache depending on the virtual to physical translation. The method used here is to map a user page temporarily through the auto-refill way 0 and of of the DTLB. We probably will want to revisit this issue and use a better approach with kmap/kunmap. Signed-off-by: Chris Zankel <chris@zankel.net>
2007-08-22 17:14:51 +00:00
}
CONFIG_HIGHPTE vs. sub-page page tables. Background: I've implemented 1K/2K page tables for s390. These sub-page page tables are required to properly support the s390 virtualization instruction with KVM. The SIE instruction requires that the page tables have 256 page table entries (pte) followed by 256 page status table entries (pgste). The pgstes are only required if the process is using the SIE instruction. The pgstes are updated by the hardware and by the hypervisor for a number of reasons, one of them is dirty and reference bit tracking. To avoid wasting memory the standard pte table allocation should return 1K/2K (31/64 bit) and 2K/4K if the process is using SIE. Problem: Page size on s390 is 4K, page table size is 1K or 2K. That means the s390 version for pte_alloc_one cannot return a pointer to a struct page. Trouble is that with the CONFIG_HIGHPTE feature on x86 pte_alloc_one cannot return a pointer to a pte either, since that would require more than 32 bit for the return value of pte_alloc_one (and the pte * would not be accessible since its not kmapped). Solution: The only solution I found to this dilemma is a new typedef: a pgtable_t. For s390 pgtable_t will be a (pte *) - to be introduced with a later patch. For everybody else it will be a (struct page *). The additional problem with the initialization of the ptl lock and the NR_PAGETABLE accounting is solved with a constructor pgtable_page_ctor and a destructor pgtable_page_dtor. The page table allocation and free functions need to call these two whenever a page table page is allocated or freed. pmd_populate will get a pgtable_t instead of a struct page pointer. To get the pgtable_t back from a pmd entry that has been installed with pmd_populate a new function pmd_pgtable is added. It replaces the pmd_page call in free_pte_range and apply_to_pte_range. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 12:22:04 +00:00
#define pmd_pgtable(pmd) pmd_page(pmd)
[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6 The attached patches provides part 6 of an architecture implementation for the Tensilica Xtensa CPU series. Signed-off-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-24 05:01:26 +00:00
#endif /* __KERNEL__ */
#endif /* _XTENSA_PGALLOC_H */
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