kernel-ark/arch/powerpc/include/asm/pgtable-ppc64-4k.h

75 lines
2.5 KiB
C
Raw Normal View History

#ifndef _ASM_POWERPC_PGTABLE_PPC64_4K_H
#define _ASM_POWERPC_PGTABLE_PPC64_4K_H
/*
* Entries per page directory level. The PTE level must use a 64b record
* for each page table entry. The PMD and PGD level use a 32b record for
* each entry by assuming that each entry is page aligned.
*/
#define PTE_INDEX_SIZE 9
#define PMD_INDEX_SIZE 7
#define PUD_INDEX_SIZE 7
#define PGD_INDEX_SIZE 9
#ifndef __ASSEMBLY__
#define PTE_TABLE_SIZE (sizeof(pte_t) << PTE_INDEX_SIZE)
#define PMD_TABLE_SIZE (sizeof(pmd_t) << PMD_INDEX_SIZE)
#define PUD_TABLE_SIZE (sizeof(pud_t) << PUD_INDEX_SIZE)
#define PGD_TABLE_SIZE (sizeof(pgd_t) << PGD_INDEX_SIZE)
#endif /* __ASSEMBLY__ */
#define PTRS_PER_PTE (1 << PTE_INDEX_SIZE)
#define PTRS_PER_PMD (1 << PMD_INDEX_SIZE)
#define PTRS_PER_PUD (1 << PMD_INDEX_SIZE)
#define PTRS_PER_PGD (1 << PGD_INDEX_SIZE)
/* PMD_SHIFT determines what a second-level page table entry can map */
#define PMD_SHIFT (PAGE_SHIFT + PTE_INDEX_SIZE)
#define PMD_SIZE (1UL << PMD_SHIFT)
#define PMD_MASK (~(PMD_SIZE-1))
[PATCH] ppc64: Fix bug in SLB miss handler for hugepages This patch, however, should be applied on top of the 64k-page-size patch to fix some problems with hugepage (some pre-existing, another introduced by this patch). The patch fixes a bug in the SLB miss handler for hugepages on ppc64 introduced by the dynamic hugepage patch (commit id c594adad5653491813959277fb87a2fef54c4e05) due to a misunderstanding of the srd instruction's behaviour (mea culpa). The problem arises when a 64-bit process maps some hugepages in the low 4GB of the address space (unusual). In this case, as well as the 256M segment in question being marked for hugepages, other segments at 32G intervals will be incorrectly marked for hugepages. In the process, this patch tweaks the semantics of the hugepage bitmaps to be more sensible. Previously, an address below 4G was marked for hugepages if the appropriate segment bit in the "low areas" bitmask was set *or* if the low bit in the "high areas" bitmap was set (which would mark all addresses below 1TB for hugepage). With this patch, any given address is governed by a single bitmap. Addresses below 4GB are marked for hugepage if and only if their bit is set in the "low areas" bitmap (256M granularity). Addresses between 4GB and 1TB are marked for hugepage iff the low bit in the "high areas" bitmap is set. Higher addresses are marked for hugepage iff their bit in the "high areas" bitmap is set (1TB granularity). To avoid conflicts, this patch must be applied on top of BenH's pending patch for 64k base page size [0]. As such, this patch also addresses a hugepage problem introduced by that patch. That patch allows hugepages of 1MB in size on hardware which supports it, however, that won't work when using 4k pages (4 level pagetable), because in that case hugepage PTEs are stored at the PMD level, and each PMD entry maps 2MB. This patch simply disallows hugepages in that case (we can do something cleverer to re-enable them some other day). Built, booted, and a handful of hugepage related tests passed on POWER5 LPAR (both ARCH=powerpc and ARCH=ppc64). [0] http://gate.crashing.org/~benh/ppc64-64k-pages.diff Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 08:57:52 +00:00
/* With 4k base page size, hugepage PTEs go at the PMD level */
#define MIN_HUGEPTE_SHIFT PMD_SHIFT
/* PUD_SHIFT determines what a third-level page table entry can map */
#define PUD_SHIFT (PMD_SHIFT + PMD_INDEX_SIZE)
#define PUD_SIZE (1UL << PUD_SHIFT)
#define PUD_MASK (~(PUD_SIZE-1))
/* PGDIR_SHIFT determines what a fourth-level page table entry can map */
#define PGDIR_SHIFT (PUD_SHIFT + PUD_INDEX_SIZE)
#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE-1))
/* Bits to mask out from a PMD to get to the PTE page */
#define PMD_MASKED_BITS 0
/* Bits to mask out from a PUD to get to the PMD page */
#define PUD_MASKED_BITS 0
/* Bits to mask out from a PGD to get to the PUD page */
#define PGD_MASKED_BITS 0
powerpc: Use 64k pages without needing cache-inhibited large pages Some POWER5+ machines can do 64k hardware pages for normal memory but not for cache-inhibited pages. This patch lets us use 64k hardware pages for most user processes on such machines (assuming the kernel has been configured with CONFIG_PPC_64K_PAGES=y). User processes start out using 64k pages and get switched to 4k pages if they use any non-cacheable mappings. With this, we use 64k pages for the vmalloc region and 4k pages for the imalloc region. If anything creates a non-cacheable mapping in the vmalloc region, the vmalloc region will get switched to 4k pages. I don't know of any driver other than the DRM that would do this, though, and these machines don't have AGP. When a region gets switched from 64k pages to 4k pages, we do not have to clear out all the 64k HPTEs from the hash table immediately. We use the _PAGE_COMBO bit in the Linux PTE to indicate whether the page was hashed in as a 64k page or a set of 4k pages. If hash_page is trying to insert a 4k page for a Linux PTE and it sees that it has already been inserted as a 64k page, it first invalidates the 64k HPTE before inserting the 4k HPTE. The hash invalidation routines also use the _PAGE_COMBO bit, to determine whether to look for a 64k HPTE or a set of 4k HPTEs to remove. With those two changes, we can tolerate a mix of 4k and 64k HPTEs in the hash table, and they will all get removed when the address space is torn down. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-06-15 00:45:18 +00:00
/*
* 4-level page tables related bits
*/
#define pgd_none(pgd) (!pgd_val(pgd))
#define pgd_bad(pgd) (pgd_val(pgd) == 0)
#define pgd_present(pgd) (pgd_val(pgd) != 0)
#define pgd_clear(pgdp) (pgd_val(*(pgdp)) = 0)
#define pgd_page_vaddr(pgd) (pgd_val(pgd) & ~PGD_MASKED_BITS)
#define pgd_page(pgd) virt_to_page(pgd_page_vaddr(pgd))
#define pud_offset(pgdp, addr) \
(((pud_t *) pgd_page_vaddr(*(pgdp))) + \
(((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1)))
#define pud_ERROR(e) \
printk("%s:%d: bad pud %08lx.\n", __FILE__, __LINE__, pud_val(e))
[POWERPC] Allow drivers to map individual 4k pages to userspace Some drivers have resources that they want to be able to map into userspace that are 4k in size. On a kernel configured with 64k pages we currently end up mapping the 4k we want plus another 60k of physical address space, which could contain anything. This can introduce security problems, for example in the case of an infiniband adaptor where the other 60k could contain registers that some other program is using for its communications. This patch adds a new function, remap_4k_pfn, which drivers can use to map a single 4k page to userspace regardless of whether the kernel is using a 4k or a 64k page size. Like remap_pfn_range, it would typically be called in a driver's mmap function. It only maps a single 4k page, which on a 64k page kernel appears replicated 16 times throughout a 64k page. On a 4k page kernel it reduces to a call to remap_pfn_range. The way this works on a 64k kernel is that a new bit, _PAGE_4K_PFN, gets set on the linux PTE. This alters the way that __hash_page_4K computes the real address to put in the HPTE. The RPN field of the linux PTE becomes the 4k RPN directly rather than being interpreted as a 64k RPN. Since the RPN field is 32 bits, this means that physical addresses being mapped with remap_4k_pfn have to be below 2^44, i.e. 0x100000000000. The patch also factors out the code in arch/powerpc/mm/hash_utils_64.c that deals with demoting a process to use 4k pages into one function that gets called in the various different places where we need to do that. There were some discrepancies between exactly what was done in the various places, such as a call to spu_flush_all_slbs in one case but not in others. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-03 11:24:02 +00:00
/*
* On all 4K setups, remap_4k_pfn() equates to remap_pfn_range() */
[POWERPC] Allow drivers to map individual 4k pages to userspace Some drivers have resources that they want to be able to map into userspace that are 4k in size. On a kernel configured with 64k pages we currently end up mapping the 4k we want plus another 60k of physical address space, which could contain anything. This can introduce security problems, for example in the case of an infiniband adaptor where the other 60k could contain registers that some other program is using for its communications. This patch adds a new function, remap_4k_pfn, which drivers can use to map a single 4k page to userspace regardless of whether the kernel is using a 4k or a 64k page size. Like remap_pfn_range, it would typically be called in a driver's mmap function. It only maps a single 4k page, which on a 64k page kernel appears replicated 16 times throughout a 64k page. On a 4k page kernel it reduces to a call to remap_pfn_range. The way this works on a 64k kernel is that a new bit, _PAGE_4K_PFN, gets set on the linux PTE. This alters the way that __hash_page_4K computes the real address to put in the HPTE. The RPN field of the linux PTE becomes the 4k RPN directly rather than being interpreted as a 64k RPN. Since the RPN field is 32 bits, this means that physical addresses being mapped with remap_4k_pfn have to be below 2^44, i.e. 0x100000000000. The patch also factors out the code in arch/powerpc/mm/hash_utils_64.c that deals with demoting a process to use 4k pages into one function that gets called in the various different places where we need to do that. There were some discrepancies between exactly what was done in the various places, such as a call to spu_flush_all_slbs in one case but not in others. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-04-03 11:24:02 +00:00
#define remap_4k_pfn(vma, addr, pfn, prot) \
remap_pfn_range((vma), (addr), (pfn), PAGE_SIZE, (prot))
#endif /* _ASM_POWERPC_PGTABLE_PPC64_4K_H */