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[LV-kern-commit] CVS: kernel-2.4/include/asm-vax/mm pgalloc.h,1.7,1.8
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From: Andy P. <at...@us...> - 2001-06-26 19:01:16
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Update of /cvsroot/linux-vax/kernel-2.4/include/asm-vax/mm
In directory usw-pr-cvs1:/tmp/cvs-serv19188/mm
Modified Files:
pgalloc.h
Log Message:
machine check implementation
Index: pgalloc.h
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/include/asm-vax/mm/pgalloc.h,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -r1.7 -r1.8
--- pgalloc.h 2001/06/17 12:39:19 1.7
+++ pgalloc.h 2001/06/26 19:01:11 1.8
@@ -166,162 +166,10 @@
#define pgd_free(pgd) free_pgd_slow(pgd)
#define pgd_alloc() get_pgd_fast()
+/* atp jun 01, moved these to arch/vax/mm/pgalloc.c */
/* Allocate a new page for a page table for the kernel */
-/* It is called from mm/vmalloc.c in alloc_area_pmd()
- *
- * It needs to be physically contiguous with the rest of the
- * system page table.
- * Things to consider:
- * If you want to allocate a pagetable to hold a pte for a given
- * new S0 address, (where this address is higher than SBR+SLR) then that
- * new page table page must be allocated at the exact physical page
- * That maps that S0 address. I.e.
- * To map a virtual address X you need to allocate the physical
- * page containing the address
- *
- * PFN = ( (X-PAGE_OFFSET) >> PAGE_SHIFT)
- * PTE address (physical memory) = (PFN*4)+SBR
- * Physical page address = (PTE address) & ~(PAGE_MASK)
- * SLR = ((Physical page address + (1<<PAGE_SHIFT)) - SBR) / 4.
- *
- *
- * If that physical page is already occupied, the contents must
- * be ejected. This takes time, and can lead to deadlock, particularly
- * if a dirty page needs to be written to disk/swap.
- * Also, any physical pages that are in between the previous end of the
- * system page table, and the new end (SBR+SLR) will need to be cleared,
- * otherwise random rubbish will end up in the system page table.
- * One way to do this by "locking up the machine", moving the contents
- * of the physical pages needed to pages on the freelist, rewriting the PTE's
- * to point at the new physical pages, and then allocating and expanding
- * the system page table. No scheduling allowed. Also how you locate all
- * of the references to a given physical page so that you can rewrite them
- * without conducting a thorough search of all page tables (possibly
- * incurring page faults for those P0 page tables that have been swapped out)
- * is not clear.
- *
- *
- * - At present I'm ducking this. We fix the S0 page table size at
- * boot time, and disallow dynamic expansion. atp Feb 2001.
- *
- * - we still need to implement this ... linux still calls it ..
- * - D.A. May 2001.
- */
-extern inline pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)
-{
- pgd_t *pgdptr = (pgd_t *)pmd;
-
- /* note the lr in the system pgd is in PAGELETS.... shift it down to
- give page view */
- if ((address >> PAGE_SHIFT) < (pgdptr->lr>>3))
- return pte_offset(pmd, address);
- else
- return NULL;
-}
-
-/*
- * allocate a page, to hold page table entries.
- * for a user process.
- * We grab a random page. The only catch is that it must be virtually
- * contiguous within the P0 or P1 page tables, which are held in S0
- * space. So, we remap the page table area in S0 space too.
- */
-extern inline pte_t * pte_alloc(pmd_t * pmd, unsigned long address)
-{
- unsigned long pte_number, pte_page, pte_page_offset;
- pgd_t *pgdptr = (pgd_t *)pmd;
- pte_t *newpte= NULL;
-
- /* Deal with P0 vs P1 spaces */
- /* need to handle error cases */
- if (address < 0x40000000)
- {
- pte_number = (address >> PAGE_SHIFT);
- pte_page = (pte_number >> SIZEOF_PTE_LOG2);
- pte_page_offset = pte_number & (PTRS_PER_PTE - 1);
- if ((pte_number) < (pgdptr->lr)) {
- newpte = pte_offset(pmd, address);
- }
- }
- else
- {
- address-=0x40000000;
- pte_number = (address>>PAGE_SHIFT);
- pte_page = (pte_number >> SIZEOF_PTE_LOG2);
- pte_page_offset = pte_number & (PTRS_PER_PTE - 1);
- if ((pte_number) > (pgdptr->lr)) {
- newpte = pte_offset(pmd, address);
- }
-
- }
-
- if (newpte)
- {
- remap_and_clear_pte_page((pgd_t *)pmd, newpte, pte_page);
- /* make sure a page in S0 space is mapped */
-
- }
- return newpte;
-
- /* old 2.2 code commented out for now .. in case it is of any use
- to anyone later - D.A. May 2001 */
-#if 0
- /* calculate the offset of the requested pte in this pagetable page */
- unsigned long pte_number, pte_page, pte_page_offset;
- pgd_t *pgdptr = (pgd_t *)pmd;
- unsigned long t2;
- pte_t *page;
-
- pte_number = (address >> PAGE_SHIFT);
- pte_page = (pte_number >> SIZEOF_PTE_LOG2);
- pte_page_offset = pte_number & (PTRS_PER_PTE - 1);
-
- /* do we have a pgd base and length set ? */
- /* The p0br and p1br should be setup at process initialisation. */
- if (pmd_none(*pmd)) {
- printk("Got pmd_none\n");
- return NULL;
- }
-
- /* do we need to allocate another page(s) */
-
-
- /* this is already inside the page table region, and allocated */
- /* return the virtual address of the pte. (base registers for p0 and p1 */
- /* refer to virtual addresses in S0 space) so no _va() is needed */
- if (pte_number < (pgdptr->lr)) {
- return (pte_t *) (pgdptr->br + pte_number*BYTES_PER_PTE_T);
- }
-
- /* The address lies outside the current page table - by how much?*/
- /* FIXME: Maximum task size, defined by max p0 pagetable size */
-
- /* number of pages to allocate */
- t2 = ((pte_number - pgdptr->lr) >> SIZEOF_PTE_LOG2) + 1 ;
-
- while (t2--) {
- /* grab a page off the quicklist */
- page = get_pte_fast();
- /* or allocate a new one if none left */
- if (!page) page = get_pte_slow(pmd, address);
-
- /* run out of pages - out of memory */
- /* FIXME: is there anything else we need to do to signal failure?*/
- if (!page) {
- printk("%s:%d: run out of free pages building page table at pte %08lx.\n", __FILE__, __LINE__, pgdptr->lr);
- return NULL;
- }
- /* map this page into the S0 page table at the right point */
- remap_and_clear_pte_page((pgd_t *)pmd, page, pte_page);
-
- /* add this page of PTEs to the length register */
- /* FIXME: handle reverse P1 region... */
- pgdptr->lr += PTRS_PER_PTE;
- }
- return (pte_t *)( pgdptr->br + pte_number*BYTES_PER_PTE_T);
-#endif /* if 0 */
-}
-
+extern pte_t *pte_alloc_kernel(pmd_t *pmd, unsigned long address);
+extern pte_t *pte_alloc(pmd_t *pmd, unsigned long address);
/*
* allocating and freeing a pmd is trivial: the 1-entry pmd is
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