From 254b2fd02e34a5761cd2a3aad8b24a7ddd8962e1 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 31 Oct 2022 14:11:57 +0100 Subject: [PATCH] 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 Signed-off-by: Alexander Gordeev --- arch/s390/Kconfig | 2 ++ arch/s390/mm/init.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index a006dbb44890..0c154e8bc4f5 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -197,6 +197,7 @@ config S390 select HAVE_RSEQ select HAVE_SAMPLE_FTRACE_DIRECT select HAVE_SAMPLE_FTRACE_DIRECT_MULTI + select HAVE_SETUP_PER_CPU_AREA select HAVE_SOFTIRQ_ON_OWN_STACK select HAVE_SYSCALL_TRACEPOINTS select HAVE_VIRT_CPU_ACCOUNTING @@ -208,6 +209,7 @@ config S390 select MMU_GATHER_MERGE_VMAS select MODULES_USE_ELF_RELA select NEED_DMA_MAP_STATE if PCI + select NEED_PER_CPU_EMBED_FIRST_CHUNK select NEED_SG_DMA_LENGTH if PCI select OLD_SIGACTION select OLD_SIGSUSPEND3 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 #include #include +#include #include #include #include @@ -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