x86, realmode: Separate real_mode reserve and setup

After we switch to use #PF handler help to set page table, init_level4_pgt
will only have entries set after init_mem_mapping().
We need to move copying init_level4_pgt to trampoline_pgd after that.

So split reserve and setup, and move the setup after init_mem_mapping()
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-11-git-send-email-yinghai@kernel.org
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/include/asm/realmode.h

@@ -58,6 +58,7 @@ extern unsigned char boot_gdt[];
 extern unsigned char secondary_startup_64[];
 #endif
 
-extern void __init setup_real_mode(void);
+void reserve_real_mode(void);
+void setup_real_mode(void);
 
 #endif /* _ARCH_X86_REALMODE_H */

arch/x86/kernel/setup.c

@@ -999,12 +999,14 @@ void __init setup_arch(char **cmdline_p)
 	printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
 			(max_pfn_mapped<<PAGE_SHIFT) - 1);
 
-	setup_real_mode();
+	reserve_real_mode();
 
 	trim_platform_memory_ranges();
 
 	init_mem_mapping();
 
+	setup_real_mode();
+
 	memblock.current_limit = get_max_mapped();
 	dma_contiguous_reserve(0);
 

arch/x86/realmode/init.c

@@ -8,9 +8,26 @@
 struct real_mode_header *real_mode_header;
 u32 *trampoline_cr4_features;
 
-void __init setup_real_mode(void)
+void __init reserve_real_mode(void)
 {
 	phys_addr_t mem;
+	unsigned char *base;
+	size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
+
+	/* Has to be under 1M so we can execute real-mode AP code. */
+	mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
+	if (!mem)
+		panic("Cannot allocate trampoline\n");
+
+	base = __va(mem);
+	memblock_reserve(mem, size);
+	real_mode_header = (struct real_mode_header *) base;
+	printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
+	       base, (unsigned long long)mem, size);
+}
+
+void __init setup_real_mode(void)
+{
 	u16 real_mode_seg;
 	u32 *rel;
 	u32 count;
@@ -25,16 +42,7 @@ void __init setup_real_mode(void)
 	u64 efer;
 #endif
 
-	/* Has to be in very low memory so we can execute real-mode AP code. */
-	mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
-	if (!mem)
-		panic("Cannot allocate trampoline\n");
-
-	base = __va(mem);
-	memblock_reserve(mem, size);
-	real_mode_header = (struct real_mode_header *) base;
-	printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
-	       base, (unsigned long long)mem, size);
+	base = (unsigned char *)real_mode_header;
 
 	memcpy(base, real_mode_blob, size);
 
@@ -84,7 +92,7 @@ void __init setup_real_mode(void)
 }
 
 /*
- * setup_real_mode() gets called very early, to guarantee the
+ * reserve_real_mode() gets called very early, to guarantee the
  * availability of low memory. This is before the proper kernel page
  * tables are set up, so we cannot set page permissions in that
  * function. Also trampoline code will be executed by APs so we