x86 boot : export boot_params via debugfs for debugging

This patch export the boot parameters via debugfs for debugging.

The files added are as follow:

boot_params/data    :  binary file for struct boot_params
boot_params/version :  boot protocol version

This patch is based on 2.6.24-rc5-mm1 and has been tested on i386 and
x86_64 platform.

This patch is based on the Peter Anvin's proposal.

Signed-off-by: Huang Ying <ying.huang@intel.com>

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 65 insertions, 0 deletions

diff --git a/arch/x86/kernel/kdebugfs.c b/arch/x86/kernel/kdebugfs.c
new file mode 100644
index 000000000000..73354302fda7
--- /dev/null
+++ b/arch/x86/kernel/kdebugfs.c
@@ -0,0 +1,65 @@
+/*
+ * Architecture specific debugfs files
+ *
+ * Copyright (C) 2007, Intel Corp.
+ *      Huang Ying <ying.huang@intel.com>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+
+#include <asm/setup.h>
+
+#ifdef CONFIG_DEBUG_BOOT_PARAMS
+static struct debugfs_blob_wrapper boot_params_blob = {
+        .data = &boot_params,
+        .size = sizeof(boot_params),
+};
+
+static int __init boot_params_kdebugfs_init(void)
+{
+        int error;
+        struct dentry *dbp, *version, *data;
+
+        dbp = debugfs_create_dir("boot_params", NULL);
+        if (!dbp) {
+                error = -ENOMEM;
+                goto err_return;
+        }
+        version = debugfs_create_x16("version", S_IRUGO, dbp,
+                                     &boot_params.hdr.version);
+        if (!version) {
+                error = -ENOMEM;
+                goto err_dir;
+        }
+        data = debugfs_create_blob("data", S_IRUGO, dbp,
+                                   &boot_params_blob);
+        if (!data) {
+                error = -ENOMEM;
+                goto err_version;
+        }
+        return 0;
+err_version:
+        debugfs_remove(version);
+err_dir:
+        debugfs_remove(dbp);
+err_return:
+        return error;
+}
+#endif
+
+static int __init arch_kdebugfs_init(void)
+{
+        int error = 0;
+
+#ifdef CONFIG_DEBUG_BOOT_PARAMS
+        error = boot_params_kdebugfs_init();
+#endif
+
+        return error;
+}
+
+arch_initcall(arch_kdebugfs_init);