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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> |
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