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-rw-r--r--arch/x86/kernel/setup_percpu.c234
1 files changed, 234 insertions, 0 deletions
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
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index 0000000000..2c97bf7b56
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+++ b/arch/x86/kernel/setup_percpu.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+#include <linux/percpu.h>
+#include <linux/kexec.h>
+#include <linux/crash_dump.h>
+#include <linux/smp.h>
+#include <linux/topology.h>
+#include <linux/pfn.h>
+#include <linux/stackprotector.h>
+#include <asm/sections.h>
+#include <asm/processor.h>
+#include <asm/desc.h>
+#include <asm/setup.h>
+#include <asm/mpspec.h>
+#include <asm/apicdef.h>
+#include <asm/highmem.h>
+#include <asm/proto.h>
+#include <asm/cpumask.h>
+#include <asm/cpu.h>
+
+#ifdef CONFIG_X86_64
+#define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
+#else
+#define BOOT_PERCPU_OFFSET 0
+#endif
+
+DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
+EXPORT_PER_CPU_SYMBOL(this_cpu_off);
+
+unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = {
+ [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
+};
+EXPORT_SYMBOL(__per_cpu_offset);
+
+/*
+ * On x86_64 symbols referenced from code should be reachable using
+ * 32bit relocations. Reserve space for static percpu variables in
+ * modules so that they are always served from the first chunk which
+ * is located at the percpu segment base. On x86_32, anything can
+ * address anywhere. No need to reserve space in the first chunk.
+ */
+#ifdef CONFIG_X86_64
+#define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE
+#else
+#define PERCPU_FIRST_CHUNK_RESERVE 0
+#endif
+
+#ifdef CONFIG_X86_32
+/**
+ * pcpu_need_numa - determine percpu allocation needs to consider NUMA
+ *
+ * If NUMA is not configured or there is only one NUMA node available,
+ * there is no reason to consider NUMA. This function determines
+ * whether percpu allocation should consider NUMA or not.
+ *
+ * RETURNS:
+ * true if NUMA should be considered; otherwise, false.
+ */
+static bool __init pcpu_need_numa(void)
+{
+#ifdef CONFIG_NUMA
+ pg_data_t *last = NULL;
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu) {
+ int node = early_cpu_to_node(cpu);
+
+ if (node_online(node) && NODE_DATA(node) &&
+ last && last != NODE_DATA(node))
+ return true;
+
+ last = NODE_DATA(node);
+ }
+#endif
+ return false;
+}
+#endif
+
+static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
+{
+#ifdef CONFIG_NUMA
+ if (early_cpu_to_node(from) == early_cpu_to_node(to))
+ return LOCAL_DISTANCE;
+ else
+ return REMOTE_DISTANCE;
+#else
+ return LOCAL_DISTANCE;
+#endif
+}
+
+static int __init pcpu_cpu_to_node(int cpu)
+{
+ return early_cpu_to_node(cpu);
+}
+
+void __init pcpu_populate_pte(unsigned long addr)
+{
+ populate_extra_pte(addr);
+}
+
+static inline void setup_percpu_segment(int cpu)
+{
+#ifdef CONFIG_X86_32
+ struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu),
+ 0xFFFFF);
+
+ write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);
+#endif
+}
+
+void __init setup_per_cpu_areas(void)
+{
+ unsigned int cpu;
+ unsigned long delta;
+ int rc;
+
+ pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n",
+ NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
+
+ /*
+ * Allocate percpu area. Embedding allocator is our favorite;
+ * however, on NUMA configurations, it can result in very
+ * sparse unit mapping and vmalloc area isn't spacious enough
+ * on 32bit. Use page in that case.
+ */
+#ifdef CONFIG_X86_32
+ if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
+ pcpu_chosen_fc = PCPU_FC_PAGE;
+#endif
+ rc = -EINVAL;
+ if (pcpu_chosen_fc != PCPU_FC_PAGE) {
+ const size_t dyn_size = PERCPU_MODULE_RESERVE +
+ PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
+ size_t atom_size;
+
+ /*
+ * On 64bit, use PMD_SIZE for atom_size so that embedded
+ * percpu areas are aligned to PMD. This, in the future,
+ * can also allow using PMD mappings in vmalloc area. Use
+ * PAGE_SIZE on 32bit as vmalloc space is highly contended
+ * and large vmalloc area allocs can easily fail.
+ */
+#ifdef CONFIG_X86_64
+ atom_size = PMD_SIZE;
+#else
+ atom_size = PAGE_SIZE;
+#endif
+ rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
+ dyn_size, atom_size,
+ pcpu_cpu_distance,
+ pcpu_cpu_to_node);
+ if (rc < 0)
+ pr_warn("%s allocator failed (%d), falling back to page size\n",
+ pcpu_fc_names[pcpu_chosen_fc], rc);
+ }
+ if (rc < 0)
+ rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
+ pcpu_cpu_to_node);
+ if (rc < 0)
+ panic("cannot initialize percpu area (err=%d)", rc);
+
+ /* alrighty, percpu areas up and running */
+ 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];
+ per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
+ per_cpu(pcpu_hot.cpu_number, cpu) = cpu;
+ setup_percpu_segment(cpu);
+ /*
+ * Copy data used in early init routines from the
+ * initial arrays to the per cpu data areas. These
+ * arrays then become expendable and the *_early_ptr's
+ * are zeroed indicating that the static arrays are
+ * gone.
+ */
+#ifdef CONFIG_X86_LOCAL_APIC
+ per_cpu(x86_cpu_to_apicid, cpu) =
+ early_per_cpu_map(x86_cpu_to_apicid, cpu);
+ per_cpu(x86_cpu_to_acpiid, cpu) =
+ early_per_cpu_map(x86_cpu_to_acpiid, cpu);
+#endif
+#ifdef CONFIG_NUMA
+ per_cpu(x86_cpu_to_node_map, cpu) =
+ early_per_cpu_map(x86_cpu_to_node_map, cpu);
+ /*
+ * Ensure that the boot cpu numa_node is correct when the boot
+ * cpu is on a node that doesn't have memory installed.
+ * Also cpu_up() will call cpu_to_node() for APs when
+ * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
+ * up later with c_init aka intel_init/amd_init.
+ * So set them all (boot cpu and all APs).
+ */
+ set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
+#endif
+ /*
+ * Up to this point, the boot CPU has been using .init.data
+ * area. Reload any changed state for the boot CPU.
+ */
+ if (!cpu)
+ switch_gdt_and_percpu_base(cpu);
+ }
+
+ /* indicate the early static arrays will soon be gone */
+#ifdef CONFIG_X86_LOCAL_APIC
+ early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
+ early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
+#endif
+#ifdef CONFIG_NUMA
+ early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
+#endif
+
+ /* Setup node to cpumask map */
+ setup_node_to_cpumask_map();
+
+ /* Setup cpu initialized, callin, callout masks */
+ setup_cpu_local_masks();
+
+ /*
+ * Sync back kernel address range again. We already did this in
+ * setup_arch(), but percpu data also needs to be available in
+ * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to
+ * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available
+ * there too.
+ *
+ * FIXME: Can the later sync in setup_cpu_entry_areas() replace
+ * this call?
+ */
+ sync_initial_page_table();
+}