linux/arch/arm64/mm
Suzuki K. Poulose dbb4e152b8 arm64: Delay cpu feature capability checks
At the moment we run through the arm64_features capability list for
each CPU and set the capability if one of the CPU supports it. This
could be problematic in a heterogeneous system with differing capabilities.
Delay the CPU feature checks until all the enabled CPUs are up(i.e,
smp_cpus_done(), so that we can make better decisions based on the
overall system capability. Once we decide and advertise the capabilities
the alternatives can be applied. From this state, we cannot roll back
a feature to disabled based on the values from a new hotplugged CPU,
due to the runtime patching and other reasons. So, for all new CPUs,
we need to make sure that they have the established system capabilities.
Failing which, we bring the CPU down, preventing it from turning online.
Once the capabilities are decided, any new CPU booting up goes through
verification to ensure that it has all the enabled capabilities and also
invokes the respective enable() method on the CPU.

The CPU errata checks are not delayed and is still executed per-CPU
to detect the respective capabilities. If we ever come across a non-errata
capability that needs to be checked on each-CPU, we could introduce them via
a new capability table(or introduce a flag), which can be processed per CPU.

The next patch will make the feature checks use the system wide
safe value of a feature register.

NOTE: The enable() methods associated with the capability is scheduled
on all the CPUs (which is the only use case at the moment). If we need
a different type of 'enable()' which only needs to be run once on any CPU,
we should be able to handle that when needed.

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: Dave Martin <Dave.Martin@arm.com>
[catalin.marinas@arm.com: static variable and coding style fixes]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-21 15:35:58 +01:00
..
cache.S arm64: use ENDPIPROC() to annotate position independent assembler routines 2015-10-12 16:19:45 +01:00
context.c arm64: mm: kill mm_cpumask usage 2015-10-07 11:56:29 +01:00
copypage.c arm64: export __cpu_{clear,copy}_user_page functions 2014-07-08 17:30:51 +01:00
dma-mapping.c arm64: dma-mapping: check whether cma area is initialized or not 2015-09-14 12:28:30 +01:00
dump.c arm64: Make the kernel page dump utility aware of the CONT bit 2015-10-08 18:39:57 +01:00
extable.c arm64: MMU fault handling and page table management 2012-09-17 13:41:57 +01:00
fault.c arm64: Delay cpu feature capability checks 2015-10-21 15:35:58 +01:00
flush.c arm64: force CONFIG_SMP=y and remove redundant #ifdefs 2015-07-27 11:08:40 +01:00
hugetlbpage.c arm64: hugetlb: remove paragraph about writing to FSF 2015-07-27 11:08:40 +01:00
init.c ARM64: kasan: print memory assignment 2015-10-12 17:46:43 +01:00
ioremap.c arm64: add ioremap physical address information 2015-01-23 15:29:06 +00:00
kasan_init.c arm64: kasan: fix issues reported by sparse 2015-10-13 14:54:42 +01:00
Makefile arm64: add KASAN support 2015-10-12 17:46:36 +01:00
mm.h arm64: add better page protections to arm64 2015-01-22 14:54:29 +00:00
mmap.c mm: expose arch_mmap_rnd when available 2015-04-14 16:49:05 -07:00
mmu.c arm64: Handle section maps for swapper/idmap 2015-10-19 17:52:36 +01:00
pageattr.c arm64: mm: unexport set_memory_ro and set_memory_rw 2015-03-19 10:43:56 +00:00
pgd.c arm64: move PGD_SIZE definition to pgalloc.h 2015-10-12 17:46:30 +01:00
proc-macros.S arm64: mm: increase VA range of identity map 2015-03-23 11:35:29 +00:00
proc.S arm64: Add 16K page size support 2015-10-19 17:55:12 +01:00