x86: convert to the new dynamic percpu allocator

Impact: use new dynamic allocator, unified access to static/dynamic
        percpu memory

Convert to the new dynamic percpu allocator.

* implement populate_extra_pte() for both 32 and 64
* update setup_per_cpu_areas() to use pcpu_setup_static()
* define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr()
* define config HAVE_DYNAMIC_PER_CPU_AREA

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 40 insertions, 22 deletions

diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index d992e6cff73..2dce4355821 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -61,38 +61,56 @@ static inline void setup_percpu_segment(int cpu)
  */
 void __init setup_per_cpu_areas(void)
 {
-        ssize_t size;
-        char *ptr;
-        int cpu;
-
-        /* Copy section for each CPU (we discard the original) */
-        size = roundup(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
+        ssize_t size = __per_cpu_end - __per_cpu_start;
+        unsigned int nr_cpu_pages = DIV_ROUND_UP(size, PAGE_SIZE);
+        static struct page **pages;
+        size_t pages_size;
+        unsigned int cpu, i, j;
+        unsigned long delta;
+        size_t pcpu_unit_size;
 
         pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
                 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
+        pr_info("PERCPU: Allocating %zd bytes for static per cpu data\n", size);
 
-        pr_info("PERCPU: Allocating %zd bytes of per cpu data\n", size);
+        pages_size = nr_cpu_pages * num_possible_cpus() * sizeof(pages[0]);
+        pages = alloc_bootmem(pages_size);
 
+        j = 0;
         for_each_possible_cpu(cpu) {
+                void *ptr;
+
+                for (i = 0; i < nr_cpu_pages; i++) {
 #ifndef CONFIG_NEED_MULTIPLE_NODES
-                ptr = alloc_bootmem_pages(size);
+                        ptr = alloc_bootmem_pages(PAGE_SIZE);
 #else
-                int node = early_cpu_to_node(cpu);
-                if (!node_online(node) || !NODE_DATA(node)) {
-                        ptr = alloc_bootmem_pages(size);
-                        pr_info("cpu %d has no node %d or node-local memory\n",
-                                cpu, node);
-                        pr_debug("per cpu data for cpu%d at %016lx\n",
-                                 cpu, __pa(ptr));
-                } else {
-                        ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);
-                        pr_debug("per cpu data for cpu%d on node%d at %016lx\n",
-                                cpu, node, __pa(ptr));
-                }
+                        int node = early_cpu_to_node(cpu);
+
+                        if (!node_online(node) || !NODE_DATA(node)) {
+                                ptr = alloc_bootmem_pages(PAGE_SIZE);
+                                pr_info("cpu %d has no node %d or node-local "
+                                        "memory\n", cpu, node);
+                                pr_debug("per cpu data for cpu%d at %016lx\n",
+                                         cpu, __pa(ptr));
+                        } else {
+                                ptr = alloc_bootmem_pages_node(NODE_DATA(node),
+                                                               PAGE_SIZE);
+                                pr_debug("per cpu data for cpu%d on node%d "
+                                         "at %016lx\n", cpu, node, __pa(ptr));
+                        }
 #endif
+                        memcpy(ptr, __per_cpu_load + i * PAGE_SIZE, PAGE_SIZE);
+                        pages[j++] = virt_to_page(ptr);
+                }
+        }
+
+        pcpu_unit_size = pcpu_setup_static(populate_extra_pte, pages, size);
 
-                memcpy(ptr, __per_cpu_load, __per_cpu_end - __per_cpu_start);
-                per_cpu_offset(cpu) = ptr - __per_cpu_start;
+        free_bootmem(__pa(pages), pages_size);
+
+        delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
+        for_each_possible_cpu(cpu) {
+                per_cpu_offset(cpu) = delta + cpu * pcpu_unit_size;
                 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
                 per_cpu(cpu_number, cpu) = cpu;
                 setup_percpu_segment(cpu);