2f569afd9c
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>
232 lines
5.4 KiB
C
232 lines
5.4 KiB
C
#ifndef _M68K_PAGE_H
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#define _M68K_PAGE_H
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#include <linux/const.h>
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/* PAGE_SHIFT determines the page size */
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#ifndef CONFIG_SUN3
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#define PAGE_SHIFT (12)
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#else
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#define PAGE_SHIFT (13)
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#endif
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#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT)
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#define PAGE_MASK (~(PAGE_SIZE-1))
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#include <asm/setup.h>
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#if PAGE_SHIFT < 13
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#define THREAD_SIZE (8192)
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#else
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#define THREAD_SIZE PAGE_SIZE
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#endif
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#ifndef __ASSEMBLY__
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#include <linux/compiler.h>
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#include <asm/module.h>
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#define get_user_page(vaddr) __get_free_page(GFP_KERNEL)
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#define free_user_page(page, addr) free_page(addr)
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/*
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* We don't need to check for alignment etc.
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*/
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#ifdef CPU_M68040_OR_M68060_ONLY
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static inline void copy_page(void *to, void *from)
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{
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unsigned long tmp;
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__asm__ __volatile__("1:\t"
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".chip 68040\n\t"
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"move16 %1@+,%0@+\n\t"
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"move16 %1@+,%0@+\n\t"
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".chip 68k\n\t"
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"dbra %2,1b\n\t"
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: "=a" (to), "=a" (from), "=d" (tmp)
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: "0" (to), "1" (from) , "2" (PAGE_SIZE / 32 - 1)
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);
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}
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static inline void clear_page(void *page)
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{
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unsigned long tmp;
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unsigned long *sp = page;
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*sp++ = 0;
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*sp++ = 0;
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*sp++ = 0;
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*sp++ = 0;
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__asm__ __volatile__("1:\t"
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".chip 68040\n\t"
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"move16 %2@+,%0@+\n\t"
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".chip 68k\n\t"
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"subqw #8,%2\n\t"
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"subqw #8,%2\n\t"
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"dbra %1,1b\n\t"
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: "=a" (sp), "=d" (tmp)
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: "a" (page), "0" (sp),
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"1" ((PAGE_SIZE - 16) / 16 - 1));
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}
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#else
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#define clear_page(page) memset((page), 0, PAGE_SIZE)
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#define copy_page(to,from) memcpy((to), (from), PAGE_SIZE)
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#endif
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#define clear_user_page(addr, vaddr, page) \
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do { clear_page(addr); \
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flush_dcache_page(page); \
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} while (0)
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#define copy_user_page(to, from, vaddr, page) \
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do { copy_page(to, from); \
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flush_dcache_page(page); \
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} while (0)
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/*
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* These are used to make use of C type-checking..
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*/
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typedef struct { unsigned long pte; } pte_t;
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typedef struct { unsigned long pmd[16]; } pmd_t;
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typedef struct { unsigned long pgd; } pgd_t;
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typedef struct { unsigned long pgprot; } pgprot_t;
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typedef struct page *pgtable_t;
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#define pte_val(x) ((x).pte)
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#define pmd_val(x) ((&x)->pmd[0])
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#define pgd_val(x) ((x).pgd)
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#define pgprot_val(x) ((x).pgprot)
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#define __pte(x) ((pte_t) { (x) } )
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#define __pmd(x) ((pmd_t) { (x) } )
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#define __pgd(x) ((pgd_t) { (x) } )
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#define __pgprot(x) ((pgprot_t) { (x) } )
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/* to align the pointer to the (next) page boundary */
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#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK)
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#endif /* !__ASSEMBLY__ */
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#include <asm/page_offset.h>
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#define PAGE_OFFSET (PAGE_OFFSET_RAW)
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#ifndef __ASSEMBLY__
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extern unsigned long m68k_memoffset;
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#ifndef CONFIG_SUN3
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#define WANT_PAGE_VIRTUAL
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static inline unsigned long ___pa(void *vaddr)
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{
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unsigned long paddr;
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asm (
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"1: addl #0,%0\n"
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m68k_fixup(%c2, 1b+2)
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: "=r" (paddr)
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: "0" (vaddr), "i" (m68k_fixup_memoffset));
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return paddr;
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}
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#define __pa(vaddr) ___pa((void *)(vaddr))
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static inline void *__va(unsigned long paddr)
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{
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void *vaddr;
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asm (
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"1: subl #0,%0\n"
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m68k_fixup(%c2, 1b+2)
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: "=r" (vaddr)
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: "0" (paddr), "i" (m68k_fixup_memoffset));
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return vaddr;
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}
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#else /* !CONFIG_SUN3 */
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/* This #define is a horrible hack to suppress lots of warnings. --m */
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#define __pa(x) ___pa((unsigned long)(x))
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static inline unsigned long ___pa(unsigned long x)
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{
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if(x == 0)
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return 0;
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if(x >= PAGE_OFFSET)
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return (x-PAGE_OFFSET);
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else
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return (x+0x2000000);
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}
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static inline void *__va(unsigned long x)
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{
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if(x == 0)
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return (void *)0;
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if(x < 0x2000000)
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return (void *)(x+PAGE_OFFSET);
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else
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return (void *)(x-0x2000000);
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}
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#endif /* CONFIG_SUN3 */
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/*
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* NOTE: virtual isn't really correct, actually it should be the offset into the
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* memory node, but we have no highmem, so that works for now.
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* TODO: implement (fast) pfn<->pgdat_idx conversion functions, this makes lots
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* of the shifts unnecessary.
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*/
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#define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
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#define pfn_to_virt(pfn) __va((pfn) << PAGE_SHIFT)
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extern int m68k_virt_to_node_shift;
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#ifdef CONFIG_SINGLE_MEMORY_CHUNK
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#define __virt_to_node(addr) (&pg_data_map[0])
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#else
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extern struct pglist_data *pg_data_table[];
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static inline __attribute_const__ int __virt_to_node_shift(void)
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{
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int shift;
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asm (
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"1: moveq #0,%0\n"
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m68k_fixup(%c1, 1b)
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: "=d" (shift)
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: "i" (m68k_fixup_vnode_shift));
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return shift;
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}
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#define __virt_to_node(addr) (pg_data_table[(unsigned long)(addr) >> __virt_to_node_shift()])
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#endif
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#define virt_to_page(addr) ({ \
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pfn_to_page(virt_to_pfn(addr)); \
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})
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#define page_to_virt(page) ({ \
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pfn_to_virt(page_to_pfn(page)); \
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})
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#define pfn_to_page(pfn) ({ \
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unsigned long __pfn = (pfn); \
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struct pglist_data *pgdat; \
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pgdat = __virt_to_node((unsigned long)pfn_to_virt(__pfn)); \
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pgdat->node_mem_map + (__pfn - pgdat->node_start_pfn); \
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})
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#define page_to_pfn(_page) ({ \
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struct page *__p = (_page); \
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struct pglist_data *pgdat; \
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pgdat = &pg_data_map[page_to_nid(__p)]; \
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((__p) - pgdat->node_mem_map) + pgdat->node_start_pfn; \
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})
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#define virt_addr_valid(kaddr) ((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory)
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#define pfn_valid(pfn) virt_addr_valid(pfn_to_virt(pfn))
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#endif /* __ASSEMBLY__ */
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#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#include <asm-generic/page.h>
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#endif /* _M68K_PAGE_H */
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