diff options
| 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/kernel | |
| parent | 8e63d38876691756f9bc6930850f1fb77809be1b (diff) | |
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/kernel')
| -rw-r--r-- | arch/arm64/kernel/asm-offsets.c | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/efi.c | 1 |
2 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 8d89cf8dae55..25de8b244961 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -60,7 +60,7 @@ int main(void) DEFINE(S_SYSCALLNO, offsetof(struct pt_regs, syscallno)); DEFINE(S_FRAME_SIZE, sizeof(struct pt_regs)); BLANK(); - DEFINE(MM_CONTEXT_ID, offsetof(struct mm_struct, context.id)); + DEFINE(MM_CONTEXT_ID, offsetof(struct mm_struct, context.id.counter)); BLANK(); DEFINE(VMA_VM_MM, offsetof(struct vm_area_struct, vm_mm)); DEFINE(VMA_VM_FLAGS, offsetof(struct vm_area_struct, vm_flags)); diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c index 4d12926ea40d..a48d1f477b2e 100644 --- a/arch/arm64/kernel/efi.c +++ b/arch/arm64/kernel/efi.c @@ -48,7 +48,6 @@ static struct mm_struct efi_mm = { .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem), .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock), .mmlist = LIST_HEAD_INIT(efi_mm.mmlist), - INIT_MM_CONTEXT(efi_mm) }; static int uefi_debug __initdata; |