x86: Fix system crash when loading with "reservetop" parameter

The system will die if the kernel is booted with "reservetop"
parameter, in present code, parse "reservetop" parameter after
early_ioremap_init(), and some function still use
early_ioremap() after it.

The problem is, "reservetop" parameter can modify
'FIXADDR_TOP', then the virtual address got by early_ioremap()
is base on old 'FIXADDR_TOP', but the page mapping is base on
new 'FIXADDR_TOP', it will occur page fault, and the IDT is not
prepare yet, so, the system is dead.

So, put parse_early_param() in the front of
early_ioremap_init() in this patch.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: yinghai@kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4A8D402F.4080805@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 63f32d2..02643cc 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -711,6 +711,11 @@ void __init setup_arch(char **cmdline_p)
        printk(KERN_INFO "Command line: %s\n", boot_command_line);
 #endif
 
+       strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
+       *cmdline_p = command_line;
+
+       parse_early_param();
+
        /* VMI may relocate the fixmap; do this before touching ioremap area */
        vmi_init();
 
@@ -793,11 +798,6 @@ void __init setup_arch(char **cmdline_p)
 #endif
 #endif
 
-       strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
-       *cmdline_p = command_line;
-
-       parse_early_param();
-
 #ifdef CONFIG_X86_64
        check_efer();
 #endif