syscalls/move_pages.c

   1 /*
   2  * SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
   3         const void __user * __user *, pages,
   4         const int __user *, nodes,
   5         int __user *, status, int, flags)
   6  */
   7
   8 #define MPOL_MF_MOVE    (1<<1)  /* Move pages owned by this process to conform to mapping */
   9 #define MPOL_MF_MOVE_ALL (1<<2) /* Move every page to conform to mapping */
  10
  11 #include <malloc.h>
  12 #include <string.h>
  13 #include <stdlib.h>
  14 #include <unistd.h>
  15 #include <sys/types.h>
  16 #include "arch.h"
  17 #include "maps.h"
  18 #include "random.h"
  19 #include "sanitise.h"
  20 #include "shm.h"
  21 #include "utils.h"      // page_size
  22
  23 static unsigned int count;
  24
  25 #define NOT_SET 0
  26 #define WAS_MALLOC 1
  27 #define WAS_MAP 2
  28 static unsigned char *pagetypes;
  29
  30 /* After a succesful run, ->post calls this, which frees up
  31  * the allocations done by ->sanitise */
  32 static void free_all_pageallocs(unsigned long *page_alloc)
  33 {
  34         unsigned int i = 0;
  35
  36         if (pagetypes == NULL)
  37                 return;
  38
  39         while (pagetypes[i] != NOT_SET) {
  40                 /* we only care about freeing mallocs, ignore the mmaps. */
  41                 if (pagetypes[i] == WAS_MALLOC) {
  42                         free((void *)page_alloc[i]);
  43                         page_alloc[i] = 0;
  44                         pagetypes[i] = NOT_SET;
  45                 }
  46                 i++;
  47         }
  48         free(page_alloc);
  49 }
  50
  51 static void sanitise_move_pages(int childno)
  52 {
  53         struct map *map;
  54         int *nodes;
  55         unsigned long *page_alloc;
  56         unsigned int i;
  57
  58         if (pagetypes == NULL)
  59                 pagetypes = zmalloc(page_size); // The implied memset(0) == NOT_SET
  60
  61         /* number of pages to move */
  62         count = rand() % (page_size / sizeof(void *));
  63         count = max(1, count);
  64         shm->a2[childno] = count;
  65
  66         /* setup array of ptrs to pages to move */
  67         page_alloc = (unsigned long *) zmalloc(page_size);
  68         shm->scratch[childno] = (unsigned long) page_alloc;
  69
  70         for (i = 0; i < count; i++) {
  71                 if (rand_bool()) {
  72                         /* malloc */
  73                         page_alloc[i] = (unsigned long) memalign(page_size, page_size);
  74                         if (!page_alloc[i]) {
  75                                 free_all_pageallocs(page_alloc);
  76                                 return;
  77                         }
  78                         pagetypes[i] = WAS_MALLOC;
  79                 } else {
  80                         /* mapping. */
  81                         map = get_map();
  82                         page_alloc[i] = (unsigned long) map->ptr;
  83                         pagetypes[i] = WAS_MAP;
  84                 }
  85         }
  86         shm->a3[childno] = (unsigned long) page_alloc;
  87
  88         /* nodes = array of ints specifying desired location for each page */
  89         nodes = malloc(count * sizeof(int));
  90         for (i = 0; i < count; i++)
  91                 nodes[i] = (int) rand() % 2;
  92         shm->a4[childno] = (unsigned long) nodes;
  93
  94         /* status = array of ints returning status of each page.*/
  95         shm->a5[childno] = (unsigned long) zmalloc(count * sizeof(int));
  96
  97         /* Needs CAP_SYS_NICE */
  98         if (getuid() != 0)
  99                 shm->a6[childno] &= ~MPOL_MF_MOVE_ALL;
 100 }
 101
 102 static void post_move_pages(int childno)
 103 {
 104         unsigned long *page;
 105
 106         page = (void *) shm->scratch[childno];
 107         if (page == NULL)
 108                 return;
 109
 110         free_all_pageallocs(page);
 111
 112         shm->scratch[childno] = 0;
 113 }
 114
 115 struct syscallentry syscall_move_pages = {
 116         .name = "move_pages",
 117         .num_args = 6,
 118         .arg1name = "pid",
 119         .arg1type = ARG_PID,
 120         .arg2name = "nr_pages",
 121         .arg3name = "pages",
 122         .arg4name = "nodes",
 123         .arg5name = "status",
 124         .arg6name = "flags",
 125         .arg6type = ARG_LIST,
 126         .arg6list = {
 127                 .num = 2,
 128                 .values = { MPOL_MF_MOVE, MPOL_MF_MOVE_ALL },
 129         },
 130         .group = GROUP_VM,
 131         .sanitise = sanitise_move_pages,
 132         .post = post_move_pages,
 133 };