x86, boot: export linked list of struct setup_data via debugfs

Export linked list of struct setup_data via debugfs.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 160 insertions, 5 deletions

diff --git a/arch/x86/kernel/kdebugfs.c b/arch/x86/kernel/kdebugfs.c
index 73354302fda7..c03205991718 100644
--- a/arch/x86/kernel/kdebugfs.c
+++ b/arch/x86/kernel/kdebugfs.c
@@ -6,23 +6,171 @@
  *
  * This file is released under the GPLv2.
  */
-
 #include <linux/debugfs.h>
+#include <linux/uaccess.h>
 #include <linux/stat.h>
 #include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mm.h>
 
 #include <asm/setup.h>
 
 #ifdef CONFIG_DEBUG_BOOT_PARAMS
+struct setup_data_node {
+        u64 paddr;
+        u32 type;
+        u32 len;
+};
+
+static ssize_t
+setup_data_read(struct file *file, char __user *user_buf, size_t count,
+                loff_t *ppos)
+{
+        struct setup_data_node *node = file->private_data;
+        unsigned long remain;
+        loff_t pos = *ppos;
+        struct page *pg;
+        void *p;
+        u64 pa;
+
+        if (pos < 0)
+                return -EINVAL;
+        if (pos >= node->len)
+                return 0;
+
+        if (count > node->len - pos)
+                count = node->len - pos;
+        pa = node->paddr + sizeof(struct setup_data) + pos;
+        pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
+        if (PageHighMem(pg)) {
+                p = ioremap_cache(pa, count);
+                if (!p)
+                        return -ENXIO;
+        } else {
+                p = __va(pa);
+        }
+
+        remain = copy_to_user(user_buf, p, count);
+
+        if (PageHighMem(pg))
+                iounmap(p);
+
+        if (remain)
+                return -EFAULT;
+
+        *ppos = pos + count;
+
+        return count;
+}
+
+static int setup_data_open(struct inode *inode, struct file *file)
+{
+        file->private_data = inode->i_private;
+        return 0;
+}
+
+static const struct file_operations fops_setup_data = {
+        .read =         setup_data_read,
+        .open =         setup_data_open,
+};
+
+static int __init
+create_setup_data_node(struct dentry *parent, int no,
+                       struct setup_data_node *node)
+{
+        struct dentry *d, *type, *data;
+        char buf[16];
+        int error;
+
+        sprintf(buf, "%d", no);
+        d = debugfs_create_dir(buf, parent);
+        if (!d) {
+                error = -ENOMEM;
+                goto err_return;
+        }
+        type = debugfs_create_x32("type", S_IRUGO, d, &node->type);
+        if (!type) {
+                error = -ENOMEM;
+                goto err_dir;
+        }
+        data = debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
+        if (!data) {
+                error = -ENOMEM;
+                goto err_type;
+        }
+        return 0;
+
+err_type:
+        debugfs_remove(type);
+err_dir:
+        debugfs_remove(d);
+err_return:
+        return error;
+}
+
+static int __init create_setup_data_nodes(struct dentry *parent)
+{
+        struct setup_data_node *node;
+        struct setup_data *data;
+        int error, no = 0;
+        struct dentry *d;
+        struct page *pg;
+        u64 pa_data;
+
+        d = debugfs_create_dir("setup_data", parent);
+        if (!d) {
+                error = -ENOMEM;
+                goto err_return;
+        }
+
+        pa_data = boot_params.hdr.setup_data;
+
+        while (pa_data) {
+                node = kmalloc(sizeof(*node), GFP_KERNEL);
+                if (!node) {
+                        error = -ENOMEM;
+                        goto err_dir;
+                }
+                pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
+                if (PageHighMem(pg)) {
+                        data = ioremap_cache(pa_data, sizeof(*data));
+                        if (!data) {
+                                error = -ENXIO;
+                                goto err_dir;
+                        }
+                } else {
+                        data = __va(pa_data);
+                }
+
+                node->paddr = pa_data;
+                node->type = data->type;
+                node->len = data->len;
+                error = create_setup_data_node(d, no, node);
+                pa_data = data->next;
+
+                if (PageHighMem(pg))
+                        iounmap(data);
+                if (error)
+                        goto err_dir;
+                no++;
+        }
+        return 0;
+
+err_dir:
+        debugfs_remove(d);
+err_return:
+        return error;
+}
+
 static struct debugfs_blob_wrapper boot_params_blob = {
-        .data = &boot_params,
-        .size = sizeof(boot_params),
+        .data           = &boot_params,
+        .size           = sizeof(boot_params),
 };
 
 static int __init boot_params_kdebugfs_init(void)
 {
-        int error;
         struct dentry *dbp, *version, *data;
+        int error;
 
         dbp = debugfs_create_dir("boot_params", NULL);
         if (!dbp) {
@@ -41,7 +189,13 @@ static int __init boot_params_kdebugfs_init(void)
                 error = -ENOMEM;
                 goto err_version;
         }
+        error = create_setup_data_nodes(dbp);
+        if (error)
+                goto err_data;
         return 0;
+
+err_data:
+        debugfs_remove(data);
 err_version:
         debugfs_remove(version);
 err_dir:
@@ -61,5 +215,4 @@ static int __init arch_kdebugfs_init(void)
 
         return error;
 }
-
 arch_initcall(arch_kdebugfs_init);
diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index e1a21d6b3671..b04e2c011e1a 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -278,7 +278,9 @@ static void __init parse_setup_data(void)
                 default:
                         break;
                 }
+#ifndef CONFIG_DEBUG_BOOT_PARAMS
                 free_early(pa_data, pa_data+sizeof(*data)+data->len);
+#endif
                 pa_data = data->next;
                 early_iounmap(data, PAGE_SIZE);
         }