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>

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 849fc9e63c2ffd875ba23d7bb2ea879ac756c30f..7785e66840a4990f94e83d874938b27f18b7f357 100644 (file)
--- 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));