--- /dev/null
- index = hash__alloc_context_id();
- if (index < 0)
- return index;
-
+/*
+ * MMU context allocation for 64-bit kernels.
+ *
+ * Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/pkeys.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+#include <linux/export.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+
+static DEFINE_IDA(mmu_context_ida);
+
+static int alloc_context_id(int min_id, int max_id)
+{
+ return ida_alloc_range(&mmu_context_ida, min_id, max_id, GFP_KERNEL);
+}
+
+void hash__reserve_context_id(int id)
+{
+ int result = ida_alloc_range(&mmu_context_ida, id, id, GFP_KERNEL);
+
+ WARN(result != id, "mmu: Failed to reserve context id %d (rc %d)\n", id, result);
+}
+
+int hash__alloc_context_id(void)
+{
+ unsigned long max;
+
+ if (mmu_has_feature(MMU_FTR_68_BIT_VA))
+ max = MAX_USER_CONTEXT;
+ else
+ max = MAX_USER_CONTEXT_65BIT_VA;
+
+ return alloc_context_id(MIN_USER_CONTEXT, max);
+}
+EXPORT_SYMBOL_GPL(hash__alloc_context_id);
+
+void slb_setup_new_exec(void);
+
++static int realloc_context_ids(mm_context_t *ctx)
++{
++ int i, id;
++
++ /*
++ * id 0 (aka. ctx->id) is special, we always allocate a new one, even if
++ * there wasn't one allocated previously (which happens in the exec
++ * case where ctx is newly allocated).
++ *
++ * We have to be a bit careful here. We must keep the existing ids in
++ * the array, so that we can test if they're non-zero to decide if we
++ * need to allocate a new one. However in case of error we must free the
++ * ids we've allocated but *not* any of the existing ones (or risk a
++ * UAF). That's why we decrement i at the start of the error handling
++ * loop, to skip the id that we just tested but couldn't reallocate.
++ */
++ for (i = 0; i < ARRAY_SIZE(ctx->extended_id); i++) {
++ if (i == 0 || ctx->extended_id[i]) {
++ id = hash__alloc_context_id();
++ if (id < 0)
++ goto error;
++
++ ctx->extended_id[i] = id;
++ }
++ }
++
++ /* The caller expects us to return id */
++ return ctx->id;
++
++error:
++ for (i--; i >= 0; i--) {
++ if (ctx->extended_id[i])
++ ida_free(&mmu_context_ida, ctx->extended_id[i]);
++ }
++
++ return id;
++}
++
+static int hash__init_new_context(struct mm_struct *mm)
+{
+ int index;
+
- if (!mm->context.hash_context) {
- ida_free(&mmu_context_ida, index);
+ mm->context.hash_context = kmalloc(sizeof(struct hash_mm_context),
+ GFP_KERNEL);
- }
++ if (!mm->context.hash_context)
+ return -ENOMEM;
- ida_free(&mmu_context_ida, index);
+
+ /*
+ * The old code would re-promote on fork, we don't do that when using
+ * slices as it could cause problem promoting slices that have been
+ * forced down to 4K.
+ *
+ * For book3s we have MMU_NO_CONTEXT set to be ~0. Hence check
+ * explicitly against context.id == 0. This ensures that we properly
+ * initialize context slice details for newly allocated mm's (which will
+ * have id == 0) and don't alter context slice inherited via fork (which
+ * will have id != 0).
+ *
+ * We should not be calling init_new_context() on init_mm. Hence a
+ * check against 0 is OK.
+ */
+ if (mm->context.id == 0) {
+ memset(mm->context.hash_context, 0, sizeof(struct hash_mm_context));
+ slice_init_new_context_exec(mm);
+ } else {
+ /* This is fork. Copy hash_context details from current->mm */
+ memcpy(mm->context.hash_context, current->mm->context.hash_context, sizeof(struct hash_mm_context));
+#ifdef CONFIG_PPC_SUBPAGE_PROT
+ /* inherit subpage prot detalis if we have one. */
+ if (current->mm->context.hash_context->spt) {
+ mm->context.hash_context->spt = kmalloc(sizeof(struct subpage_prot_table),
+ GFP_KERNEL);
+ if (!mm->context.hash_context->spt) {
+ kfree(mm->context.hash_context);
+ return -ENOMEM;
+ }
+ }
+#endif
++ }
+
++ index = realloc_context_ids(&mm->context);
++ if (index < 0) {
++#ifdef CONFIG_PPC_SUBPAGE_PROT
++ kfree(mm->context.hash_context->spt);
++#endif
++ kfree(mm->context.hash_context);
++ return index;
+ }
+
+ pkey_mm_init(mm);
+ return index;
+}
+
+void hash__setup_new_exec(void)
+{
+ slice_setup_new_exec();
+
+ slb_setup_new_exec();
+}
+
+static int radix__init_new_context(struct mm_struct *mm)
+{
+ unsigned long rts_field;
+ int index, max_id;
+
+ max_id = (1 << mmu_pid_bits) - 1;
+ index = alloc_context_id(mmu_base_pid, max_id);
+ if (index < 0)
+ return index;
+
+ /*
+ * set the process table entry,
+ */
+ rts_field = radix__get_tree_size();
+ process_tb[index].prtb0 = cpu_to_be64(rts_field | __pa(mm->pgd) | RADIX_PGD_INDEX_SIZE);
+
+ /*
+ * Order the above store with subsequent update of the PID
+ * register (at which point HW can start loading/caching
+ * the entry) and the corresponding load by the MMU from
+ * the L2 cache.
+ */
+ asm volatile("ptesync;isync" : : : "memory");
+
+ mm->context.npu_context = NULL;
+ mm->context.hash_context = NULL;
+
+ return index;
+}
+
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+ int index;
+
+ if (radix_enabled())
+ index = radix__init_new_context(mm);
+ else
+ index = hash__init_new_context(mm);
+
+ if (index < 0)
+ return index;
+
+ mm->context.id = index;
+
+ mm->context.pte_frag = NULL;
+ mm->context.pmd_frag = NULL;
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+ mm_iommu_init(mm);
+#endif
+ atomic_set(&mm->context.active_cpus, 0);
+ atomic_set(&mm->context.copros, 0);
+
+ return 0;
+}
+
+void __destroy_context(int context_id)
+{
+ ida_free(&mmu_context_ida, context_id);
+}
+EXPORT_SYMBOL_GPL(__destroy_context);
+
+static void destroy_contexts(mm_context_t *ctx)
+{
+ int index, context_id;
+
+ for (index = 0; index < ARRAY_SIZE(ctx->extended_id); index++) {
+ context_id = ctx->extended_id[index];
+ if (context_id)
+ ida_free(&mmu_context_ida, context_id);
+ }
+ kfree(ctx->hash_context);
+}
+
+static void pmd_frag_destroy(void *pmd_frag)
+{
+ int count;
+ struct page *page;
+
+ page = virt_to_page(pmd_frag);
+ /* drop all the pending references */
+ count = ((unsigned long)pmd_frag & ~PAGE_MASK) >> PMD_FRAG_SIZE_SHIFT;
+ /* We allow PTE_FRAG_NR fragments from a PTE page */
+ if (atomic_sub_and_test(PMD_FRAG_NR - count, &page->pt_frag_refcount)) {
+ pgtable_pmd_page_dtor(page);
+ __free_page(page);
+ }
+}
+
+static void destroy_pagetable_cache(struct mm_struct *mm)
+{
+ void *frag;
+
+ frag = mm->context.pte_frag;
+ if (frag)
+ pte_frag_destroy(frag);
+
+ frag = mm->context.pmd_frag;
+ if (frag)
+ pmd_frag_destroy(frag);
+ return;
+}
+
+void destroy_context(struct mm_struct *mm)
+{
+#ifdef CONFIG_SPAPR_TCE_IOMMU
+ WARN_ON_ONCE(!list_empty(&mm->context.iommu_group_mem_list));
+#endif
+ if (radix_enabled())
+ WARN_ON(process_tb[mm->context.id].prtb0 != 0);
+ else
+ subpage_prot_free(mm);
+ destroy_contexts(&mm->context);
+ mm->context.id = MMU_NO_CONTEXT;
+}
+
+void arch_exit_mmap(struct mm_struct *mm)
+{
+ destroy_pagetable_cache(mm);
+
+ if (radix_enabled()) {
+ /*
+ * Radix doesn't have a valid bit in the process table
+ * entries. However we know that at least P9 implementation
+ * will avoid caching an entry with an invalid RTS field,
+ * and 0 is invalid. So this will do.
+ *
+ * This runs before the "fullmm" tlb flush in exit_mmap,
+ * which does a RIC=2 tlbie to clear the process table
+ * entry. See the "fullmm" comments in tlb-radix.c.
+ *
+ * No barrier required here after the store because
+ * this process will do the invalidate, which starts with
+ * ptesync.
+ */
+ process_tb[mm->context.id].prtb0 = 0;
+ }
+}
+
+#ifdef CONFIG_PPC_RADIX_MMU
+void radix__switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
+{
+ mtspr(SPRN_PID, next->context.id);
+ isync();
+}
+#endif
projects / linux-2.6-microblaze.git / commitdiff