[PATCH] x86: GDT alignment fix

[net-next-2.6.git] / arch / i386 / kernel / head.S

diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index 4477bb107098c2863ee85a0ef8a27374147ca494..870f20bf33c83325988b28b7343e6464aada4388 100644 (file)
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -17,7 +17,7 @@
 #include <asm/desc.h>
 #include <asm/cache.h>
 #include <asm/thread_info.h>
-#include <asm/asm_offsets.h>
+#include <asm/asm-offsets.h>
 #include <asm/setup.h>
 
 /*
@@ -77,6 +77,32 @@ ENTRY(startup_32)
        subl %edi,%ecx
        shrl $2,%ecx
        rep ; stosl
+/*
+ * Copy bootup parameters out of the way.
+ * Note: %esi still has the pointer to the real-mode data.
+ * With the kexec as boot loader, parameter segment might be loaded beyond
+ * kernel image and might not even be addressable by early boot page tables.
+ * (kexec on panic case). Hence copy out the parameters before initializing
+ * page tables.
+ */
+       movl $(boot_params - __PAGE_OFFSET),%edi
+       movl $(PARAM_SIZE/4),%ecx
+       cld
+       rep
+       movsl
+       movl boot_params - __PAGE_OFFSET + NEW_CL_POINTER,%esi
+       andl %esi,%esi
+       jnz 2f                  # New command line protocol
+       cmpw $(OLD_CL_MAGIC),OLD_CL_MAGIC_ADDR
+       jne 1f
+       movzwl OLD_CL_OFFSET,%esi
+       addl $(OLD_CL_BASE_ADDR),%esi
+2:
+       movl $(saved_command_line - __PAGE_OFFSET),%edi
+       movl $(COMMAND_LINE_SIZE/4),%ecx
+       rep
+       movsl
+1:
 
 /*
  * Initialize page tables.  This creates a PDE and a set of page
@@ -214,28 +240,6 @@ ENTRY(startup_32_smp)
  */
        call setup_idt
 
-/*
- * Copy bootup parameters out of the way.
- * Note: %esi still has the pointer to the real-mode data.
- */
-       movl $boot_params,%edi
-       movl $(PARAM_SIZE/4),%ecx
-       cld
-       rep
-       movsl
-       movl boot_params+NEW_CL_POINTER,%esi
-       andl %esi,%esi
-       jnz 2f                  # New command line protocol
-       cmpw $(OLD_CL_MAGIC),OLD_CL_MAGIC_ADDR
-       jne 1f
-       movzwl OLD_CL_OFFSET,%esi
-       addl $(OLD_CL_BASE_ADDR),%esi
-2:
-       movl $saved_command_line,%edi
-       movl $(COMMAND_LINE_SIZE/4),%ecx
-       rep
-       movsl
-1:
 checkCPUtype:
 
        movl $-1,X86_CPUID              #  -1 for no CPUID initially
@@ -521,3 +525,5 @@ ENTRY(cpu_gdt_table)
        .quad 0x0000000000000000        /* 0xf0 - unused */
        .quad 0x0000000000000000        /* 0xf8 - GDT entry 31: double-fault TSS */
 
+       /* Be sure this is zeroed to avoid false validations in Xen */
+       .fill PAGE_SIZE_asm / 8 - GDT_ENTRIES,8,0