linux-stable/arch/arm64/mm
Suzuki K Poulose 05abb595bb arm64: Delay enabling hardware DBM feature
We enable hardware DBM bit in a capable CPU, very early in the
boot via __cpu_setup. This doesn't give us a flexibility of
optionally disable the feature, as the clearing the bit
is a bit costly as the TLB can cache the settings. Instead,
we delay enabling the feature until the CPU is brought up
into the kernel. We use the feature capability mechanism
to handle it.

The hardware DBM is a non-conflicting feature. i.e, the kernel
can safely run with a mix of CPUs with some using the feature
and the others don't. So, it is safe for a late CPU to have
this capability and enable it, even if the active CPUs don't.

To get this handled properly by the infrastructure, we
unconditionally set the capability and only enable it
on CPUs which really have the feature. Also, we print the
feature detection from the "matches" call back to make sure
we don't mislead the user when none of the CPUs could use the
feature.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-03-26 18:01:44 +01:00
..
cache.S arm64: Add support for new control bits CTR_EL0.DIC and CTR_EL0.IDC 2018-03-09 13:57:57 +00:00
context.c arm64: Move BP hardening to check_and_switch_context 2018-01-23 15:40:29 +00:00
copypage.c arm64: Defer dcache flush in __cpu_copy_user_page 2015-12-17 11:07:13 +00:00
dma-mapping.c arm64: Revert L1_CACHE_SHIFT back to 6 (64-byte cache line size) 2018-03-06 18:52:32 +00:00
dump.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
extable.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fault.c arm64: capabilities: Update prototype for enable call back 2018-03-26 18:00:37 +01:00
flush.c arm64: fix pmem interface definition 2017-08-10 18:13:59 +01:00
hugetlbpage.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
init.c arm64: Revert L1_CACHE_SHIFT back to 6 (64-byte cache line size) 2018-03-06 18:52:32 +00:00
ioremap.c arm64: use is_vmalloc_addr 2017-02-09 13:47:56 +00:00
kasan_init.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mmap.c arm64/mmap: properly account for stack randomization in mmap_base 2017-07-12 16:26:03 -07:00
mmu.c arm64: Enforce BBM for huge IO/VMAP mappings 2018-02-22 11:25:53 +00:00
numa.c arm64/numa: Drop duplicate message 2017-07-20 17:03:53 +01:00
pageattr.c arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables 2018-02-16 18:13:57 +00:00
pgd.c arm64: handle 52-bit addresses in TTBR 2017-12-22 17:35:21 +00:00
physaddr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
proc.S arm64: Delay enabling hardware DBM feature 2018-03-26 18:01:44 +01:00
ptdump_debugfs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00