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author | Heiko Carstens <hca@linux.ibm.com> | 2022-10-31 16:11:57 +0300 |
---|---|---|
committer | Alexander Gordeev <agordeev@linux.ibm.com> | 2022-11-23 18:22:21 +0300 |
commit | 254b2fd02e34a5761cd2a3aad8b24a7ddd8962e1 (patch) | |
tree | 542937306fd49187b34496ef71f76246f046292d /arch/s390/mm/init.c | |
parent | 2e71df94695cdc930fb373575ea4edabd4e4bcc7 (diff) | |
download | linux-254b2fd02e34a5761cd2a3aad8b24a7ddd8962e1.tar.xz |
s390/mm: provide minimal setup_per_cpu_areas() implementation
s390 allows to enable CONFIG_NUMA, mainly to enable a couple of system
calls which are only present if NUMA is enabled. The NUMA specific system
calls are required by a couple of applications, which wouldn't work if the
system calls wouldn't be present.
The NUMA implementation itself maps all CPUs and memory to node 0. A
special case is the generic percpu setup code, which doesn't expect an s390
like implementation and therefore emits a message/warning:
"percpu: cpu 0 has no node -1 or node-local memory".
In order to get rid of this message, and also to provide sane CPU to node
and CPU distance mappings implement a minimal setup_per_cpu_areas()
function, which is very close to the generic variant.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Diffstat (limited to 'arch/s390/mm/init.c')
-rw-r--r-- | arch/s390/mm/init.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 97d66a3e60fb..a28832eefb06 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -31,6 +31,7 @@ #include <linux/cma.h> #include <linux/gfp.h> #include <linux/dma-direct.h> +#include <linux/percpu.h> #include <asm/processor.h> #include <linux/uaccess.h> #include <asm/pgalloc.h> @@ -222,6 +223,41 @@ unsigned long memory_block_size_bytes(void) return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm); } +unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; +EXPORT_SYMBOL(__per_cpu_offset); + +static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) +{ + return LOCAL_DISTANCE; +} + +static int __init pcpu_cpu_to_node(int cpu) +{ + return 0; +} + +void __init setup_per_cpu_areas(void) +{ + unsigned long delta; + unsigned int cpu; + int rc; + + /* + * Always reserve area for module percpu variables. That's + * what the legacy allocator did. + */ + rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, + PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, + pcpu_cpu_distance, + pcpu_cpu_to_node); + if (rc < 0) + panic("Failed to initialize percpu areas."); + + delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; + for_each_possible_cpu(cpu) + __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu]; +} + #ifdef CONFIG_MEMORY_HOTPLUG #ifdef CONFIG_CMA |