linux/arch/nds32/kernel/vdso.c
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   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (C) 2012 ARM Limited
   3// Copyright (C) 2005-2017 Andes Technology Corporation
   4
   5#include <linux/cache.h>
   6#include <linux/clocksource.h>
   7#include <linux/elf.h>
   8#include <linux/err.h>
   9#include <linux/errno.h>
  10#include <linux/gfp.h>
  11#include <linux/kernel.h>
  12#include <linux/mm.h>
  13#include <linux/sched.h>
  14#include <linux/signal.h>
  15#include <linux/slab.h>
  16#include <linux/timekeeper_internal.h>
  17#include <linux/vmalloc.h>
  18#include <linux/random.h>
  19
  20#include <asm/cacheflush.h>
  21#include <asm/vdso.h>
  22#include <asm/vdso_datapage.h>
  23#include <asm/vdso_timer_info.h>
  24#include <asm/cache_info.h>
  25extern struct cache_info L1_cache_info[2];
  26extern char vdso_start[], vdso_end[];
  27static unsigned long vdso_pages __ro_after_init;
  28static unsigned long timer_mapping_base;
  29
  30struct timer_info_t timer_info = {
  31        .cycle_count_down = true,
  32        .mapping_base = EMPTY_TIMER_MAPPING,
  33        .cycle_count_reg_offset = EMPTY_REG_OFFSET
  34};
  35/*
  36 * The vDSO data page.
  37 */
  38static struct page *no_pages[] = { NULL };
  39
  40static union {
  41        struct vdso_data data;
  42        u8 page[PAGE_SIZE];
  43} vdso_data_store __page_aligned_data;
  44struct vdso_data *vdso_data = &vdso_data_store.data;
  45static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
  46        {
  47         .name = "[vvar]",
  48         .pages = no_pages,
  49         },
  50        {
  51         .name = "[vdso]",
  52         },
  53};
  54
  55static void get_timer_node_info(void)
  56{
  57        timer_mapping_base = timer_info.mapping_base;
  58        vdso_data->cycle_count_offset =
  59                timer_info.cycle_count_reg_offset;
  60        vdso_data->cycle_count_down =
  61                timer_info.cycle_count_down;
  62}
  63
  64static int __init vdso_init(void)
  65{
  66        int i;
  67        struct page **vdso_pagelist;
  68
  69        if (memcmp(vdso_start, "\177ELF", 4)) {
  70                pr_err("vDSO is not a valid ELF object!\n");
  71                return -EINVAL;
  72        }
  73        /* Creat a timer io mapping to get clock cycles counter */
  74        get_timer_node_info();
  75
  76        vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
  77        pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
  78                vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data);
  79
  80        /* Allocate the vDSO pagelist */
  81        vdso_pagelist = kcalloc(vdso_pages, sizeof(struct page *), GFP_KERNEL);
  82        if (vdso_pagelist == NULL)
  83                return -ENOMEM;
  84
  85        for (i = 0; i < vdso_pages; i++)
  86                vdso_pagelist[i] = virt_to_page(vdso_start + i * PAGE_SIZE);
  87        vdso_spec[1].pages = &vdso_pagelist[0];
  88
  89        return 0;
  90}
  91
  92arch_initcall(vdso_init);
  93
  94unsigned long inline vdso_random_addr(unsigned long vdso_mapping_len)
  95{
  96        unsigned long start = current->mm->mmap_base, end, offset, addr;
  97        start = PAGE_ALIGN(start);
  98
  99        /* Round the lowest possible end address up to a PMD boundary. */
 100        end = (start + vdso_mapping_len + PMD_SIZE - 1) & PMD_MASK;
 101        if (end >= TASK_SIZE)
 102                end = TASK_SIZE;
 103        end -= vdso_mapping_len;
 104
 105        if (end > start) {
 106                offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
 107                addr = start + (offset << PAGE_SHIFT);
 108        } else {
 109                addr = start;
 110        }
 111        return addr;
 112}
 113
 114int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 115{
 116        struct mm_struct *mm = current->mm;
 117        unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
 118        struct vm_area_struct *vma;
 119        unsigned long addr = 0;
 120        pgprot_t prot;
 121        int ret, vvar_page_num = 2;
 122
 123        vdso_text_len = vdso_pages << PAGE_SHIFT;
 124
 125        if(timer_mapping_base == EMPTY_VALUE)
 126                vvar_page_num = 1;
 127        /* Be sure to map the data page */
 128        vdso_mapping_len = vdso_text_len + vvar_page_num * PAGE_SIZE;
 129#ifdef CONFIG_CPU_CACHE_ALIASING
 130        vdso_mapping_len += L1_cache_info[DCACHE].aliasing_num - 1;
 131#endif
 132
 133        if (down_write_killable(&mm->mmap_sem))
 134                return -EINTR;
 135
 136        addr = vdso_random_addr(vdso_mapping_len);
 137        vdso_base = get_unmapped_area(NULL, addr, vdso_mapping_len, 0, 0);
 138        if (IS_ERR_VALUE(vdso_base)) {
 139                ret = vdso_base;
 140                goto up_fail;
 141        }
 142
 143#ifdef CONFIG_CPU_CACHE_ALIASING
 144        {
 145                unsigned int aliasing_mask =
 146                    L1_cache_info[DCACHE].aliasing_mask;
 147                unsigned int page_colour_ofs;
 148                page_colour_ofs = ((unsigned int)vdso_data & aliasing_mask) -
 149                    (vdso_base & aliasing_mask);
 150                vdso_base += page_colour_ofs & aliasing_mask;
 151        }
 152#endif
 153
 154        vma = _install_special_mapping(mm, vdso_base, vvar_page_num * PAGE_SIZE,
 155                                       VM_READ | VM_MAYREAD, &vdso_spec[0]);
 156        if (IS_ERR(vma)) {
 157                ret = PTR_ERR(vma);
 158                goto up_fail;
 159        }
 160
 161        /*Map vdata to user space */
 162        ret = io_remap_pfn_range(vma, vdso_base,
 163                                 virt_to_phys(vdso_data) >> PAGE_SHIFT,
 164                                 PAGE_SIZE, vma->vm_page_prot);
 165        if (ret)
 166                goto up_fail;
 167
 168        /*Map timer to user space */
 169        vdso_base += PAGE_SIZE;
 170        prot = __pgprot(_PAGE_V | _PAGE_M_UR_KR | _PAGE_D |  _PAGE_C_DEV);
 171        ret = io_remap_pfn_range(vma, vdso_base, timer_mapping_base >> PAGE_SHIFT,
 172                                 PAGE_SIZE, prot);
 173        if (ret)
 174                goto up_fail;
 175
 176        /*Map vdso to user space */
 177        vdso_base += PAGE_SIZE;
 178        mm->context.vdso = (void *)vdso_base;
 179        vma = _install_special_mapping(mm, vdso_base, vdso_text_len,
 180                                       VM_READ | VM_EXEC |
 181                                       VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 182                                       &vdso_spec[1]);
 183        if (IS_ERR(vma)) {
 184                ret = PTR_ERR(vma);
 185                goto up_fail;
 186        }
 187
 188        up_write(&mm->mmap_sem);
 189        return 0;
 190
 191up_fail:
 192        mm->context.vdso = NULL;
 193        up_write(&mm->mmap_sem);
 194        return ret;
 195}
 196
 197static void vdso_write_begin(struct vdso_data *vdata)
 198{
 199        ++vdso_data->seq_count;
 200        smp_wmb();              /* Pairs with smp_rmb in vdso_read_retry */
 201}
 202
 203static void vdso_write_end(struct vdso_data *vdata)
 204{
 205        smp_wmb();              /* Pairs with smp_rmb in vdso_read_begin */
 206        ++vdso_data->seq_count;
 207}
 208
 209void update_vsyscall(struct timekeeper *tk)
 210{
 211        vdso_write_begin(vdso_data);
 212        vdso_data->cs_mask = tk->tkr_mono.mask;
 213        vdso_data->cs_mult = tk->tkr_mono.mult;
 214        vdso_data->cs_shift = tk->tkr_mono.shift;
 215        vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
 216        vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
 217        vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
 218        vdso_data->xtime_clock_sec = tk->xtime_sec;
 219        vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
 220        vdso_data->xtime_coarse_sec = tk->xtime_sec;
 221        vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >>
 222            tk->tkr_mono.shift;
 223        vdso_data->hrtimer_res = hrtimer_resolution;
 224        vdso_write_end(vdso_data);
 225}
 226
 227void update_vsyscall_tz(void)
 228{
 229        vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
 230        vdso_data->tz_dsttime = sys_tz.tz_dsttime;
 231}
 232