Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

include/asm-ia64/tlb.h

@@ -0,0 +1,245 @@
+#ifndef _ASM_IA64_TLB_H
+#define _ASM_IA64_TLB_H
+/*
+ * Based on <asm-generic/tlb.h>.
+ *
+ * Copyright (C) 2002-2003 Hewlett-Packard Co
+ *	David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+/*
+ * Removing a translation from a page table (including TLB-shootdown) is a four-step
+ * procedure:
+ *
+ *	(1) Flush (virtual) caches --- ensures virtual memory is coherent with kernel memory
+ *	    (this is a no-op on ia64).
+ *	(2) Clear the relevant portions of the page-table
+ *	(3) Flush the TLBs --- ensures that stale content is gone from CPU TLBs
+ *	(4) Release the pages that were freed up in step (2).
+ *
+ * Note that the ordering of these steps is crucial to avoid races on MP machines.
+ *
+ * The Linux kernel defines several platform-specific hooks for TLB-shootdown.  When
+ * unmapping a portion of the virtual address space, these hooks are called according to
+ * the following template:
+ *
+ *	tlb <- tlb_gather_mmu(mm, full_mm_flush);	// start unmap for address space MM
+ *	{
+ *	  for each vma that needs a shootdown do {
+ *	    tlb_start_vma(tlb, vma);
+ *	      for each page-table-entry PTE that needs to be removed do {
+ *		tlb_remove_tlb_entry(tlb, pte, address);
+ *		if (pte refers to a normal page) {
+ *		  tlb_remove_page(tlb, page);
+ *		}
+ *	      }
+ *	    tlb_end_vma(tlb, vma);
+ *	  }
+ *	}
+ *	tlb_finish_mmu(tlb, start, end);	// finish unmap for address space MM
+ */
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+
+#include <asm/pgalloc.h>
+#include <asm/processor.h>
+#include <asm/tlbflush.h>
+#include <asm/machvec.h>
+
+#ifdef CONFIG_SMP
+# define FREE_PTE_NR		2048
+# define tlb_fast_mode(tlb)	((tlb)->nr == ~0U)
+#else
+# define FREE_PTE_NR		0
+# define tlb_fast_mode(tlb)	(1)
+#endif
+
+struct mmu_gather {
+	struct mm_struct	*mm;
+	unsigned int		nr;		/* == ~0U => fast mode */
+	unsigned char		fullmm;		/* non-zero means full mm flush */
+	unsigned char		need_flush;	/* really unmapped some PTEs? */
+	unsigned long		freed;		/* number of pages freed */
+	unsigned long		start_addr;
+	unsigned long		end_addr;
+	struct page 		*pages[FREE_PTE_NR];
+};
+
+/* Users of the generic TLB shootdown code must declare this storage space. */
+DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+/*
+ * Flush the TLB for address range START to END and, if not in fast mode, release the
+ * freed pages that where gathered up to this point.
+ */
+static inline void
+ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+	unsigned int nr;
+
+	if (!tlb->need_flush)
+		return;
+	tlb->need_flush = 0;
+
+	if (tlb->fullmm) {
+		/*
+		 * Tearing down the entire address space.  This happens both as a result
+		 * of exit() and execve().  The latter case necessitates the call to
+		 * flush_tlb_mm() here.
+		 */
+		flush_tlb_mm(tlb->mm);
+	} else if (unlikely (end - start >= 1024*1024*1024*1024UL
+			     || REGION_NUMBER(start) != REGION_NUMBER(end - 1)))
+	{
+		/*
+		 * If we flush more than a tera-byte or across regions, we're probably
+		 * better off just flushing the entire TLB(s).  This should be very rare
+		 * and is not worth optimizing for.
+		 */
+		flush_tlb_all();
+	} else {
+		/*
+		 * XXX fix me: flush_tlb_range() should take an mm pointer instead of a
+		 * vma pointer.
+		 */
+		struct vm_area_struct vma;
+
+		vma.vm_mm = tlb->mm;
+		/* flush the address range from the tlb: */
+		flush_tlb_range(&vma, start, end);
+		/* now flush the virt. page-table area mapping the address range: */
+		flush_tlb_range(&vma, ia64_thash(start), ia64_thash(end));
+	}
+
+	/* lastly, release the freed pages */
+	nr = tlb->nr;
+	if (!tlb_fast_mode(tlb)) {
+		unsigned long i;
+		tlb->nr = 0;
+		tlb->start_addr = ~0UL;
+		for (i = 0; i < nr; ++i)
+			free_page_and_swap_cache(tlb->pages[i]);
+	}
+}
+
+/*
+ * Return a pointer to an initialized struct mmu_gather.
+ */
+static inline struct mmu_gather *
+tlb_gather_mmu (struct mm_struct *mm, unsigned int full_mm_flush)
+{
+	struct mmu_gather *tlb = &__get_cpu_var(mmu_gathers);
+
+	tlb->mm = mm;
+	/*
+	 * Use fast mode if only 1 CPU is online.
+	 *
+	 * It would be tempting to turn on fast-mode for full_mm_flush as well.  But this
+	 * doesn't work because of speculative accesses and software prefetching: the page
+	 * table of "mm" may (and usually is) the currently active page table and even
+	 * though the kernel won't do any user-space accesses during the TLB shoot down, a
+	 * compiler might use speculation or lfetch.fault on what happens to be a valid
+	 * user-space address.  This in turn could trigger a TLB miss fault (or a VHPT
+	 * walk) and re-insert a TLB entry we just removed.  Slow mode avoids such
+	 * problems.  (We could make fast-mode work by switching the current task to a
+	 * different "mm" during the shootdown.) --davidm 08/02/2002
+	 */
+	tlb->nr = (num_online_cpus() == 1) ? ~0U : 0;
+	tlb->fullmm = full_mm_flush;
+	tlb->freed = 0;
+	tlb->start_addr = ~0UL;
+	return tlb;
+}
+
+/*
+ * Called at the end of the shootdown operation to free up any resources that were
+ * collected.  The page table lock is still held at this point.
+ */
+static inline void
+tlb_finish_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+	unsigned long freed = tlb->freed;
+	struct mm_struct *mm = tlb->mm;
+	unsigned long rss = get_mm_counter(mm, rss);
+
+	if (rss < freed)
+		freed = rss;
+	add_mm_counter(mm, rss, -freed);
+	/*
+	 * Note: tlb->nr may be 0 at this point, so we can't rely on tlb->start_addr and
+	 * tlb->end_addr.
+	 */
+	ia64_tlb_flush_mmu(tlb, start, end);
+
+	/* keep the page table cache within bounds */
+	check_pgt_cache();
+}
+
+static inline unsigned int
+tlb_is_full_mm(struct mmu_gather *tlb)
+{
+     return tlb->fullmm;
+}
+
+/*
+ * Logically, this routine frees PAGE.  On MP machines, the actual freeing of the page
+ * must be delayed until after the TLB has been flushed (see comments at the beginning of
+ * this file).
+ */
+static inline void
+tlb_remove_page (struct mmu_gather *tlb, struct page *page)
+{
+	tlb->need_flush = 1;
+
+	if (tlb_fast_mode(tlb)) {
+		free_page_and_swap_cache(page);
+		return;
+	}
+	tlb->pages[tlb->nr++] = page;
+	if (tlb->nr >= FREE_PTE_NR)
+		ia64_tlb_flush_mmu(tlb, tlb->start_addr, tlb->end_addr);
+}
+
+/*
+ * Remove TLB entry for PTE mapped at virtual address ADDRESS.  This is called for any
+ * PTE, not just those pointing to (normal) physical memory.
+ */
+static inline void
+__tlb_remove_tlb_entry (struct mmu_gather *tlb, pte_t *ptep, unsigned long address)
+{
+	if (tlb->start_addr == ~0UL)
+		tlb->start_addr = address;
+	tlb->end_addr = address + PAGE_SIZE;
+}
+
+#define tlb_migrate_finish(mm)	platform_tlb_migrate_finish(mm)
+
+#define tlb_start_vma(tlb, vma)			do { } while (0)
+#define tlb_end_vma(tlb, vma)			do { } while (0)
+
+#define tlb_remove_tlb_entry(tlb, ptep, addr)		\
+do {							\
+	tlb->need_flush = 1;				\
+	__tlb_remove_tlb_entry(tlb, ptep, addr);	\
+} while (0)
+
+#define pte_free_tlb(tlb, ptep)				\
+do {							\
+	tlb->need_flush = 1;				\
+	__pte_free_tlb(tlb, ptep);			\
+} while (0)
+
+#define pmd_free_tlb(tlb, ptep)				\
+do {							\
+	tlb->need_flush = 1;				\
+	__pmd_free_tlb(tlb, ptep);			\
+} while (0)
+
+#define pud_free_tlb(tlb, pudp)				\
+do {							\
+	tlb->need_flush = 1;				\
+	__pud_free_tlb(tlb, pudp);			\
+} while (0)
+
+#endif /* _ASM_IA64_TLB_H */