diff options
author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2008-12-18 19:13:24 (GMT) |
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committer | Paul Mackerras <paulus@samba.org> | 2008-12-21 03:21:15 (GMT) |
commit | 5e696617c425eb97bd943d781f3941fb1e8f0e5b (patch) | |
tree | 82138fbda2e28fbe8d0e5821f218cb160230ce27 /arch/powerpc/mm/mmu_context_hash64.c | |
parent | 6d2170be4561293a6aa821c773687bd3f18e8206 (diff) | |
download | linux-fsl-qoriq-5e696617c425eb97bd943d781f3941fb1e8f0e5b.tar.xz |
powerpc/mm: Split mmu_context handling
This splits the mmu_context handling between 32-bit hash based
processors, 64-bit hash based processors and everybody else. This is
preliminary work for adding SMP support for BookE processors.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/mm/mmu_context_hash64.c')
-rw-r--r-- | arch/powerpc/mm/mmu_context_hash64.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mmu_context_hash64.c b/arch/powerpc/mm/mmu_context_hash64.c new file mode 100644 index 0000000..dbeb86a --- /dev/null +++ b/arch/powerpc/mm/mmu_context_hash64.c @@ -0,0 +1,78 @@ +/* + * 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/spinlock.h> +#include <linux/idr.h> + +#include <asm/mmu_context.h> + +static DEFINE_SPINLOCK(mmu_context_lock); +static DEFINE_IDR(mmu_context_idr); + +/* + * The proto-VSID space has 2^35 - 1 segments available for user mappings. + * Each segment contains 2^28 bytes. Each context maps 2^44 bytes, + * so we can support 2^19-1 contexts (19 == 35 + 28 - 44). + */ +#define NO_CONTEXT 0 +#define MAX_CONTEXT ((1UL << 19) - 1) + +int init_new_context(struct task_struct *tsk, struct mm_struct *mm) +{ + int index; + int err; + +again: + if (!idr_pre_get(&mmu_context_idr, GFP_KERNEL)) + return -ENOMEM; + + spin_lock(&mmu_context_lock); + err = idr_get_new_above(&mmu_context_idr, NULL, 1, &index); + spin_unlock(&mmu_context_lock); + + if (err == -EAGAIN) + goto again; + else if (err) + return err; + + if (index > MAX_CONTEXT) { + spin_lock(&mmu_context_lock); + idr_remove(&mmu_context_idr, index); + spin_unlock(&mmu_context_lock); + return -ENOMEM; + } + + /* 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 + */ + if (slice_mm_new_context(mm)) + slice_set_user_psize(mm, mmu_virtual_psize); + mm->context.id = index; + + return 0; +} + +void destroy_context(struct mm_struct *mm) +{ + spin_lock(&mmu_context_lock); + idr_remove(&mmu_context_idr, mm->context.id); + spin_unlock(&mmu_context_lock); + + mm->context.id = NO_CONTEXT; +} |