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authorWill Deacon <will.deacon@arm.com>2015-10-06 20:46:24 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2015-10-07 13:55:41 +0300
commit5aec715d7d3122f77cabaa7578d9d25a0c1ed20e (patch)
tree8d75ae3f1f72bfa8ee77fdea406b6c9dcfaf4e60 /arch/arm64/kernel/efi.c
parent8e63d38876691756f9bc6930850f1fb77809be1b (diff)
downloadlinux-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/kernel/efi.c')
-rw-r--r--arch/arm64/kernel/efi.c1
1 files changed, 0 insertions, 1 deletions
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;