[tip:x86/mm2] x86, 64bit: Copy struct boot_params early

[tip-bot for Yinghai Lu <yinghai@kernel.org>]

Commit-ID:  fa2bbce985ca97943305cdc81d9626e6810ed7f2
Gitweb:     http://git.kernel.org/tip/fa2bbce985ca97943305cdc81d9626e6810ed7f2
Author:     Yinghai Lu <yinghai@kernel.org>
AuthorDate: Thu, 24 Jan 2013 12:19:49 -0800
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 29 Jan 2013 15:12:26 -0800

x86, 64bit: Copy struct boot_params early

We want to support struct boot_params (formerly known as the
zero-page, or real-mode data) above the 4 GiB mark.  We will have #PF
handler to set page table for not accessible ram early, but want to
limit it before x86_64_start_reservations to limit the code change to
native path only.

Also we will need the ramdisk info in struct boot_params to access the microcode
blob in ramdisk in x86_64_start_kernel, so copy struct boot_params early makes
it accessing ramdisk info simple.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-9-git-send-email-yinghai@kernel.org
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/kernel/head64.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 849fc9e..7785e668 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -89,6 +89,8 @@ void __init x86_64_start_kernel(char * real_mode_data)
 	}
 	load_idt((const struct desc_ptr *)&idt_descr);
 
+	copy_bootdata(__va(real_mode_data));
+
 	if (console_loglevel == 10)
 		early_printk("Kernel alive\n");
 
@@ -97,7 +99,9 @@ void __init x86_64_start_kernel(char * real_mode_data)
 
 void __init x86_64_start_reservations(char *real_mode_data)
 {
-	copy_bootdata(__va(real_mode_data));
+	/* version is always not zero if it is copied */
+	if (!boot_params.hdr.version)
+		copy_bootdata(__va(real_mode_data));
 
 	memblock_reserve(__pa_symbol(&_text),
 			 __pa_symbol(&__bss_stop) - __pa_symbol(&_text));