为什么我/proc/iomem中的条目都是00000000-00000000？

Question

I /proc/iomem中的所有尝试都是00000000-00000000。

/proc/ioports也是如此。他们都是万-万

比如：

00000000-00000000 : reserved
00000000-00000000 : System RAM
00000000-00000000 : reserved

我正在运行4.103-1-ARCH x86_64

任何关于如何自己找出原因的建议也会受到欢迎，谢谢。

Answer 1

尝试在命令前面使用sudo，如sudo less /proc/io{mem,ports}

Answer 2

补丁解释了这种现象。

diff --git a/kernel/resource.c b/kernel/resource.c
index 2e78ead..9b5f044 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -105,16 +105,25 @@
{
    struct resource *root = m->private;
    struct resource *r = v, *p;
+   unsigned long long start, end;
    int width = root->end < 0x10000 ? 4 : 8;
    int depth;

    for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
        if (p->parent == root)
            break;
+
+   if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
+       start = r->start;
+       end = r->end;
+   } else {
+       start = end = 0;
+   }
+
    seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
            depth * 2, "",
-           width, (unsigned long long) r->start,
-           width, (unsigned long long) r->end,
+           width, start,
+           width, end,
            r->name ? r->name : "<BAD>");
    return 0;
}