x86, percpu: setup reserved percpu area for x86_64

[deliverable/linux.git] / arch / x86 / kernel / setup_percpu.c

diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index dd4eabc747c8ae13096d7508a050b4c12544785b..efa615f2bf43b6dbd27d0b36ca11657b202ca110 100644 (file)
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -42,6 +42,19 @@ unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
 };
 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
+
 /**
  * pcpu_need_numa - determine percpu allocation needs to consider NUMA
  *
@@ -141,7 +154,7 @@ static ssize_t __init setup_pcpu_remap(size_t static_size)
 {
        static struct vm_struct vm;
        pg_data_t *last;
-       size_t ptrs_size;
+       size_t ptrs_size, dyn_size;
        unsigned int cpu;
        ssize_t ret;
 
@@ -169,12 +182,14 @@ proceed:
         * Currently supports only single page.  Supporting multiple
         * pages won't be too difficult if it ever becomes necessary.
         */
-       pcpur_size = PFN_ALIGN(static_size + PERCPU_DYNAMIC_RESERVE);
+       pcpur_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
+                              PERCPU_DYNAMIC_RESERVE);
        if (pcpur_size > PMD_SIZE) {
                pr_warning("PERCPU: static data is larger than large page, "
                           "can't use large page\n");
                return -EINVAL;
        }
+       dyn_size = pcpur_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
 
        /* allocate pointer array and alloc large pages */
        ptrs_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpur_ptrs[0]));
@@ -217,8 +232,9 @@ proceed:
        pr_info("PERCPU: Remapped at %p with large pages, static data "
                "%zu bytes\n", vm.addr, static_size);
 
-       ret = pcpu_setup_first_chunk(pcpur_get_page, static_size, 0, PMD_SIZE,
-                                    pcpur_size - static_size, vm.addr, NULL);
+       ret = pcpu_setup_first_chunk(pcpur_get_page, static_size,
+                                    PERCPU_FIRST_CHUNK_RESERVE,
+                                    PMD_SIZE, dyn_size, vm.addr, NULL);
        goto out_free_ar;
 
 enomem:
@@ -276,9 +292,10 @@ static ssize_t __init setup_pcpu_embed(size_t static_size)
                return -EINVAL;
 
        /* allocate and copy */
-       pcpue_size = PFN_ALIGN(static_size + PERCPU_DYNAMIC_RESERVE);
+       pcpue_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
+                              PERCPU_DYNAMIC_RESERVE);
        pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
-       dyn_size = pcpue_size - static_size;
+       dyn_size = pcpue_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
 
        pcpue_ptr = pcpu_alloc_bootmem(0, num_possible_cpus() * pcpue_unit_size,
                                       PAGE_SIZE);
@@ -297,7 +314,8 @@ static ssize_t __init setup_pcpu_embed(size_t static_size)
        pr_info("PERCPU: Embedded %zu pages at %p, static data %zu bytes\n",
                pcpue_size >> PAGE_SHIFT, pcpue_ptr, static_size);
 
-       return pcpu_setup_first_chunk(pcpue_get_page, static_size, 0,
+       return pcpu_setup_first_chunk(pcpue_get_page, static_size,
+                                     PERCPU_FIRST_CHUNK_RESERVE,
                                      pcpue_unit_size, dyn_size,
                                      pcpue_ptr, NULL);
 }
@@ -356,8 +374,9 @@ static ssize_t __init setup_pcpu_4k(size_t static_size)
        pr_info("PERCPU: Allocated %d 4k pages, static data %zu bytes\n",
                pcpu4k_nr_static_pages, static_size);
 
-       ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size, 0, -1, -1,
-                                    NULL, pcpu4k_populate_pte);
+       ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size,
+                                    PERCPU_FIRST_CHUNK_RESERVE, -1, -1, NULL,
+                                    pcpu4k_populate_pte);
        goto out_free_ar;
 
 enomem: