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iomem


iomemはiomem_resourceをヘッド(領域)とする、struct resourceで管理されています。struct resourceはtree型の階層構造で、childは新規に管理する領域のオブジェクトとなります。

なお、新規管理領域はchildでリストされてきたobjectというのでなく、siblingで登録されているobjectでも、そのchildに登録されているbjectについても適用されます。
struct resource {
       resource_size_t start;
       resource_size_t end;
       const char *name;
       unsigned long flags;
       struct resource *parent, *sibling, *child;
};

struct resource iomem_resource = {
       .name   = "PCI mem",
       .start  = 0,
       .end    = -1,
       .flags  = IORESOURCE_MEM,
};
a->child = b; b->sibling = c; c->sibling = d; bはaの管理下。cはbの管理下。dはbの管理下。
a->sibling = b; b->sibling = c; c->sibling = d; bはaの管理下。cはaの管理下。dはaの管理下。
a->sibling = b; b->child = c; c->sibling = d; bはaの管理下。cはbの管理下。dはcの管理下。

サンプルは/proc/iomemでオブジェくの名称と領域で、他の属性をも表示したものです。
#include <linux/module.h>

static struct resource *r_next(struct resource *p, int * attr);
static  char    devmemattr[60];

char*   devmem_ok(struct resource *p)
{
       sprintf(devmemattr, "[BUSY:%d] [EXCLU:%d]",
               (p->flags & IORESOURCE_BUSY)? 1: 0,
               (p->flags & IORESOURCE_EXCLUSIVE)? 1: 0);
       return devmemattr;
}

static struct resource *r_next(struct resource *p, int *attr)
{
       (*pos)++;
       *attr = 0;
       if (p->child)
               return p->child;
       while (!p->sibling && p->parent)
               p = p->parent;
       *attr = 1;
       return p->sibling;
}

static void r_get(struct resource *p)
{
       int     attr;
       char    parent[64];

       parent[0] = NULL;
       if (p->parent) {
               strcpy(parent, p->parent->name);
       }
       printk("%s:%08llx-%08llx : %30s: %30s %d.%d %s\n",
                       (!attr)? "child  ": "sible",
                       (unsigned long long) p->start, 
                       (unsigned long long) p->end,
                       p->name ? p->name : "<BAD>",
                       parent,
                       (p->child)? 1: 0,
                       (p->sibling)? 1: 0,
                       devmem_ok(p));
       while ((p = r_next(p, &attr))) {
               parent[0] = NULL;
               if (p->parent) {
                       strcpy(parent, p->parent->name);
               }
               printk("%s:%08llx-%08llx : %30s: %30s %d.%d %s\n",
                       (!attr)? "child  ": "sibling",
                       (unsigned long long) p->start,
                       (unsigned long long) p->end,
                       p->name ? p->name : "<BAD>",
                       parent,
                       (p->child)? 1: 0,
                       (p->sibling)? 1: 0,
                       devmem_ok(p));
        }
}

static int __init babakaka_init( void )
{
       r_get(&iomem_resource);
       return 1;
} 
module_init(babakaka_init);
結果
[root@localhost north]# insmod babakaka.ko
[root@localhost north]# dmesg -c       
child  :00000000-ffffffff :                        PCI mem:                                1.0 [BUSY:0] [EXCLU:0]
child  :00000000-0000ffff :                       reserved:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:00010000-0009f7ff :                     System RAM:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:0009f800-0009ffff :                       reserved:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:000a0000-000bffff :                PCI Bus 0000:00:                        PCI mem 1.1 [BUSY:0] [EXCLU:0]
child  :000a0000-000bffff :                 Video RAM area:                PCI Bus 0000:00 0.0 [BUSY:1] [EXCLU:0]
sibling:000c0000-000c7fff :                      Video ROM:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:000ca000-000cafff :                    Adapter ROM:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:000cb000-000cbfff :                    Adapter ROM:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:000cc000-000cffff :                PCI Bus 0000:00:                        PCI mem 0.1 [BUSY:0] [EXCLU:0]
sibling:000d0000-000d3fff :                PCI Bus 0000:00:                        PCI mem 0.1 [BUSY:0] [EXCLU:0]
sibling:000d4000-000d7fff :                PCI Bus 0000:00:                        PCI mem 0.1 [BUSY:0] [EXCLU:0]
sibling:000d8000-000dbfff :                PCI Bus 0000:00:                        PCI mem 0.1 [BUSY:0] [EXCLU:0]
sibling:000dc000-000fffff :                       reserved:                        PCI mem 1.1 [BUSY:1] [EXCLU:0]
child  :000f0000-000fffff :                     System ROM:                       reserved 0.0 [BUSY:1] [EXCLU:0]
sibling:00100000-1feeffff :                     System RAM:                        PCI mem 1.1 [BUSY:1] [EXCLU:0]
child  :00400000-0093411e :                    Kernel code:                     System RAM 0.1 [BUSY:1] [EXCLU:0]
sibling:0093411f-00bb6e3f :                    Kernel data:                     System RAM 0.1 [BUSY:1] [EXCLU:0]
sibling:00c57000-00d4efff :                     Kernel bss:                     System RAM 0.0 [BUSY:1] [EXCLU:0]
sibling:1fef0000-1fefefff :                    ACPI Tables:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:1feff000-1fefffff :      ACPI Non-volatile Storage:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:1ff00000-1fffffff :                     System RAM:                        PCI mem 0.1 [BUSY:1] [EXCLU:0]
sibling:20000000-febfffff :                PCI Bus 0000:00:                        PCI mem 1.1 [BUSY:0] [EXCLU:0]
child  :20000000-20007fff :                   0000:00:0f.0:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:20008000-2000bfff :                   0000:00:10.0:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e5b00000-e5bfffff :                PCI Bus 0000:22:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e5c00000-e5cfffff :                PCI Bus 0000:1a:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e5d00000-e5dfffff :                PCI Bus 0000:12:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e5e00000-e5efffff :                PCI Bus 0000:0a:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e5f00000-e5ffffff :                PCI Bus 0000:21:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6000000-e60fffff :                PCI Bus 0000:19:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6100000-e61fffff :                PCI Bus 0000:11:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6200000-e62fffff :                PCI Bus 0000:09:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6300000-e63fffff :                PCI Bus 0000:20:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6400000-e64fffff :                PCI Bus 0000:18:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6500000-e65fffff :                PCI Bus 0000:10:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6600000-e66fffff :                PCI Bus 0000:08:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6700000-e67fffff :                PCI Bus 0000:1f:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6800000-e68fffff :                PCI Bus 0000:17:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6900000-e69fffff :                PCI Bus 0000:0f:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6a00000-e6afffff :                PCI Bus 0000:07:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6b00000-e6bfffff :                PCI Bus 0000:1e:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6c00000-e6cfffff :                PCI Bus 0000:16:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6d00000-e6dfffff :                PCI Bus 0000:0e:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6e00000-e6efffff :                PCI Bus 0000:06:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e6f00000-e6ffffff :                PCI Bus 0000:1d:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7000000-e70fffff :                PCI Bus 0000:15:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7100000-e71fffff :                PCI Bus 0000:0d:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7200000-e72fffff :                PCI Bus 0000:05:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7300000-e73fffff :                PCI Bus 0000:1c:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7400000-e74fffff :                PCI Bus 0000:14:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7500000-e75fffff :                PCI Bus 0000:0c:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7600000-e76fffff :                PCI Bus 0000:04:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7700000-e77fffff :                PCI Bus 0000:1b:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7800000-e78fffff :                PCI Bus 0000:13:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7900000-e79fffff :                PCI Bus 0000:0b:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7a00000-e7afffff :                PCI Bus 0000:03:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:e7b00000-e7ffffff :                PCI Bus 0000:02:                PCI Bus 0000:00 1.1 [BUSY:0] [EXCLU:0]
child  :e7b00000-e7b0ffff :                   0000:02:01.0:                PCI Bus 0000:02 0.1 [BUSY:0] [EXCLU:0]
sibling:e7b10000-e7b1ffff :                   0000:02:05.0:                PCI Bus 0000:02 0.0 [BUSY:0] [EXCLU:0]
sibling:e8000000-efffffff :                   0000:00:0f.0:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:f0000000-f7ffffff :  PCI MMCONFIG 0000 [bus 00-7f]:                PCI Bus 0000:00 1.1 [BUSY:1] [EXCLU:0]
child  :f0000000-f7ffffff :                       reserved:  PCI MMCONFIG 0000 [bus 00-7f] 1.0 [BUSY:0] [EXCLU:0]
child  :f0000000-f7ffffff :                      pnp 00:0d:                       reserved 0.0 [BUSY:0] [EXCLU:0]
sibling:fb500000-fb5fffff :                PCI Bus 0000:22:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fb600000-fb6fffff :                PCI Bus 0000:1a:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fb700000-fb7fffff :                PCI Bus 0000:12:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fb800000-fb8fffff :                PCI Bus 0000:0a:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fb900000-fb9fffff :                PCI Bus 0000:21:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fba00000-fbafffff :                PCI Bus 0000:19:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fbb00000-fbbfffff :                PCI Bus 0000:11:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fbc00000-fbcfffff :                PCI Bus 0000:09:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fbd00000-fbdfffff :                PCI Bus 0000:20:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fbe00000-fbefffff :                PCI Bus 0000:18:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fbf00000-fbffffff :                PCI Bus 0000:10:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc000000-fc0fffff :                PCI Bus 0000:08:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc100000-fc1fffff :                PCI Bus 0000:1f:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc200000-fc2fffff :                PCI Bus 0000:17:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc300000-fc3fffff :                PCI Bus 0000:0f:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc400000-fc4fffff :                PCI Bus 0000:07:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc500000-fc5fffff :                PCI Bus 0000:1e:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc600000-fc6fffff :                PCI Bus 0000:16:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc700000-fc7fffff :                PCI Bus 0000:0e:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc800000-fc8fffff :                PCI Bus 0000:06:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fc900000-fc9fffff :                PCI Bus 0000:1d:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fca00000-fcafffff :                PCI Bus 0000:15:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fcb00000-fcbfffff :                PCI Bus 0000:0d:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fcc00000-fccfffff :                PCI Bus 0000:05:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fcd00000-fcdfffff :                PCI Bus 0000:1c:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fce00000-fcefffff :                PCI Bus 0000:14:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fcf00000-fcffffff :                PCI Bus 0000:0c:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fd000000-fd0fffff :                PCI Bus 0000:04:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fd100000-fd1fffff :                PCI Bus 0000:1b:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fd200000-fd2fffff :                PCI Bus 0000:13:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fd300000-fd3fffff :                PCI Bus 0000:0b:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fd400000-fd4fffff :                PCI Bus 0000:03:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fd500000-fdffffff :                PCI Bus 0000:02:                PCI Bus 0000:00 1.1 [BUSY:0] [EXCLU:0]
child  :fd5ff000-fd5fffff :                   0000:02:02.0:                PCI Bus 0000:02 1.0 [BUSY:0] [EXCLU:0]
child  :fd5ff000-fd5fffff :                       ehci_hcd:                   0000:02:02.0 0.0 [BUSY:1] [EXCLU:0]
sibling:fe000000-fe7fffff :                   0000:00:0f.0:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:fe800000-fe9fffff :                      pnp 00:0d:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:febfd000-febfd01f :                   0000:00:10.0:                PCI Bus 0000:00 0.1 [BUSY:0] [EXCLU:0]
sibling:febfe000-febfffff :                   0000:00:07.7:                PCI Bus 0000:00 0.0 [BUSY:0] [EXCLU:0]
sibling:fec00000-fec0ffff :                       reserved:                        PCI mem 1.1 [BUSY:0] [EXCLU:0]
child  :fec00000-fec003ff :                       IOAPIC 0:                       reserved 0.0 [BUSY:1] [EXCLU:0]
sibling:fed00000-fed003ff :                         HPET 0:                        PCI mem 1.1 [BUSY:0] [EXCLU:0]
child  :fed00000-fed003ff :                      pnp 00:08:                         HPET 0 0.0 [BUSY:0] [EXCLU:0]
sibling:fee00000-fee00fff :                     Local APIC:                        PCI mem 1.1 [BUSY:1] [EXCLU:0]
child  :fee00000-fee00fff :                       reserved:                     Local APIC 0.0 [BUSY:0] [EXCLU:0]
sibling:fffe0000-ffffffff :                       reserved:                        PCI mem 0.0 [BUSY:0] [EXCLU:0]

追記

/dev/memのread/writeコールバックは、参照可能かのチェックにiomem_is_exclusive()がコールし、参照領域がiomem領域でIORESOURCE_BUSY/IORESOURCE_EXCLUSIVEなら参照できません。デバイスドライバで、IORESOURCE_EXCLUSIVEをflagにセットして、登録すればドライバが参照中に/dev/memで参照させなくできます。

iomem_resource領域は、0から-1で、/dev/memでの参照のチェックは結果的に全メモリ領域が対象となります。
int iomem_is_exclusive(u64 addr)
{
       struct resource *p = &iomem_resource;
       int err = 0;
       loff_t l;
       int size = PAGE_SIZE;

       if (!strict_iomem_checks)
               return 0;

       addr = addr & PAGE_MASK;

       read_lock(&resource_lock);
       for (p = p->child; p ; p = r_next(NULL, p, &l)) {

               if (p->start >= addr + size)
                       break;
               if (p->end < addr)
                       continue;
               if (p->flags & IORESOURCE_BUSY &&
                    p->flags & IORESOURCE_EXCLUSIVE) {
                       err = 1;
                       break;
               }
       }
       read_unlock(&resource_lock);

       return err;
}


最終更新 2016/05/10 15:14:16 - north
(2016/05/10 15:14:16 作成)