forked from Minki/linux
5aec715d7d
Our current switch_mm implementation suffers from a number of problems:
(1) The ASID allocator relies on IPIs to synchronise the CPUs on a
rollover event
(2) Because of (1), we cannot allocate ASIDs with interrupts disabled
and therefore make use of a TIF_SWITCH_MM flag to postpone the
actual switch to finish_arch_post_lock_switch
(3) We run context switch with a reserved (invalid) TTBR0 value, even
though the ASID and pgd are updated atomically
(4) We take a global spinlock (cpu_asid_lock) during context-switch
(5) We use h/w broadcast TLB operations when they are not required
(e.g. in flush_context)
This patch addresses these problems by rewriting the ASID algorithm to
match the bitmap-based arch/arm/ implementation more closely. This in
turn allows us to remove much of the complications surrounding switch_mm,
including the ugly thread flag.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
40 lines
1.3 KiB
C
40 lines
1.3 KiB
C
/*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_MMU_H
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#define __ASM_MMU_H
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typedef struct {
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atomic64_t id;
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void *vdso;
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} mm_context_t;
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/*
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* This macro is only used by the TLBI code, which cannot race with an
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* ASID change and therefore doesn't need to reload the counter using
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* atomic64_read.
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*/
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#define ASID(mm) ((mm)->context.id.counter & 0xffff)
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extern void paging_init(void);
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extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
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extern void init_mem_pgprot(void);
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extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
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unsigned long virt, phys_addr_t size,
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pgprot_t prot);
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extern void *fixmap_remap_fdt(phys_addr_t dt_phys);
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#endif
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