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| author | Will Deacon <will.deacon@arm.com> | 2015-10-06 18:46:24 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-10-07 11:55:41 +0100 |
| commit | 5aec715d7d3122f77cabaa7578d9d25a0c1ed20e (patch) | |
| tree | 8d75ae3f1f72bfa8ee77fdea406b6c9dcfaf4e60 /arch/arm64/mm/proc.S | |
| parent | 8e63d38876691756f9bc6930850f1fb77809be1b (diff) | |
| download | linux-0-day-5aec715d7d3122f77cabaa7578d9d25a0c1ed20e.tar.gz linux-0-day-5aec715d7d3122f77cabaa7578d9d25a0c1ed20e.tar.xz | |
arm64: mm: rewrite ASID allocator and MM context-switching code
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>
Diffstat (limited to 'arch/arm64/mm/proc.S')
| -rw-r--r-- | arch/arm64/mm/proc.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index bbde13d77da5f..91cb2eaac256b 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -130,7 +130,7 @@ ENDPROC(cpu_do_resume) * - pgd_phys - physical address of new TTB */ ENTRY(cpu_do_switch_mm) - mmid w1, x1 // get mm->context.id + mmid x1, x1 // get mm->context.id bfi x0, x1, #48, #16 // set the ASID msr ttbr0_el1, x0 // set TTBR0 isb |