patch-2.4.10 linux/include/asm-generic/tlb.h

• Lines: 114
• Date: Fri Sep 14 08:41:04 2001
• Orig file: v2.4.9/linux/include/asm-generic/tlb.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.9/linux/include/asm-generic/tlb.h linux/include/asm-generic/tlb.h
@@ -0,0 +1,113 @@
+/* asm-generic/tlb.h
+ *
+ *	Generic TLB shootdown code
+ *
+ * Copyright 2001 Red Hat, Inc.
+ * Based on code from mm/memory.c Copyright Linus Torvalds and others.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#ifndef _ASM_GENERIC__TLB_H
+#define _ASM_GENERIC__TLB_H
+
+#include <linux/config.h>
+
+#ifdef CONFIG_SMP
+/* aim for something that fits in the L1 cache */
+#define FREE_PTE_NR	508
+
+/* mmu_gather_t is an opaque type used by the mm code for passing around any
+ * data needed by arch specific code for tlb_remove_page.  This structure can
+ * be per-CPU or per-MM as the page table lock is held for the duration of TLB
+ * shootdown.
+ */
+typedef struct free_pte_ctx {
+	struct mm_struct	*mm;
+	unsigned long		nr;	/* set to ~0UL means fast mode */
+	unsigned long	start_addr, end_addr;
+	pte_t	ptes[FREE_PTE_NR];
+} mmu_gather_t;
+
+/* Users of the generic TLB shootdown code must declare this storage space. */
+extern mmu_gather_t	mmu_gathers[NR_CPUS];
+
+/* tlb_gather_mmu
+ *	Return a pointer to an initialized mmu_gather_t.
+ */
+static inline mmu_gather_t *tlb_gather_mmu(struct mm_struct *mm)
+{
+	mmu_gather_t *tlb = &mmu_gathers[smp_processor_id()];
+
+	tlb->mm = mm;
+	/* Use fast mode if there is only one user of this mm (this process) */
+	tlb->nr = (atomic_read(&(mm)->mm_users) == 1) ? ~0UL : 0UL;
+	return tlb;
+}
+
+/* void tlb_remove_page(mmu_gather_t *tlb, pte_t *ptep, unsigned long addr)
+ *	Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
+ *	handling the additional races in SMP caused by other CPUs caching valid
+ *	mappings in their TLBs.
+ */
+#define tlb_remove_page(ctxp, pte, addr) do {\
+		/* Handle the common case fast, first. */\
+		if ((ctxp)->nr == ~0UL) {\
+			__free_pte(*(pte));\
+			pte_clear((pte));\
+			break;\
+		}\
+		if (!(ctxp)->nr) \
+			(ctxp)->start_addr = (addr);\
+		(ctxp)->ptes[(ctxp)->nr++] = ptep_get_and_clear(pte);\
+		(ctxp)->end_addr = (addr) + PAGE_SIZE;\
+		if ((ctxp)->nr >= FREE_PTE_NR)\
+			tlb_finish_mmu((ctxp), 0, 0);\
+	} while (0)
+
+/* tlb_finish_mmu
+ *	Called at the end of the shootdown operation to free up any resources
+ *	that were required.  The page talbe lock is still held at this point.
+ */
+static inline void tlb_finish_mmu(struct free_pte_ctx *ctx, unsigned long start, unsigned long end)
+{
+	unsigned long i, nr;
+
+	/* Handle the fast case first. */
+	if (ctx->nr == ~0UL) {
+		flush_tlb_range(ctx->mm, start, end);
+		return;
+	}
+	nr = ctx->nr;
+	ctx->nr = 0;
+	if (nr)
+		flush_tlb_range(ctx->mm, ctx->start_addr, ctx->end_addr);
+	for (i=0; i < nr; i++) {
+		pte_t pte = ctx->ptes[i];
+		__free_pte(pte);
+	}
+}
+
+#else
+
+/* The uniprocessor functions are quite simple and are inline macros in an
+ * attempt to get gcc to generate optimal code since this code is run on each
+ * page in a process at exit.
+ */
+typedef struct mm_struct mmu_gather_t;
+
+#define tlb_gather_mmu(mm)	(mm)
+#define tlb_finish_mmu(tlb, start, end)	flush_tlb_range(tlb, start, end)
+#define tlb_remove_page(tlb, ptep, addr)	do {\
+		pte_t __pte = *(ptep);\
+		pte_clear(ptep);\
+		__free_pte(__pte);\
+	} while (0)
+
+#endif
+
+
+#endif /* _ASM_GENERIC__TLB_H */
+