x86-32: use specific __vmalloc_start_set flag in __virt_addr_valid

Rather than relying on the ever-unreliable system_state,
add a specific __vmalloc_start_set flag to indicate whether
the vmalloc area has meaningful boundaries yet, and use that
in x86-32's __phys_addr and __virt_addr_valid.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/pgtable_32_types.h

@@ -25,6 +25,11 @@
  * area for the same reason. ;)
  */
 #define VMALLOC_OFFSET	(8 * 1024 * 1024)
+
+#ifndef __ASSEMBLER__
+extern bool __vmalloc_start_set; /* set once high_memory is set */
+#endif
+
 #define VMALLOC_START	((unsigned long)high_memory + VMALLOC_OFFSET)
 #ifdef CONFIG_X86_PAE
 #define LAST_PKMAP 512

arch/x86/mm/init_32.c

@@ -59,6 +59,8 @@ unsigned long highstart_pfn, highend_pfn;
 
 static noinline int do_test_wp_bit(void);
 
+bool __read_mostly __vmalloc_start_set = false;
+
 static __init void *alloc_low_page(void)
 {
 	unsigned long pfn = e820_table_end++;
@@ -757,6 +759,8 @@ void __init initmem_init(unsigned long start_pfn,
 #ifdef CONFIG_FLATMEM
 	max_mapnr = num_physpages;
 #endif
+	__vmalloc_start_set = true;
+
 	printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 			pages_to_mb(max_low_pfn));
 

arch/x86/mm/ioremap.c

@@ -76,10 +76,9 @@ static inline int phys_addr_valid(unsigned long addr)
 #ifdef CONFIG_DEBUG_VIRTUAL
 unsigned long __phys_addr(unsigned long x)
 {
-	/* VMALLOC_* aren't constants; not available at the boot time */
+	/* VMALLOC_* aren't constants  */
 	VIRTUAL_BUG_ON(x < PAGE_OFFSET);
-	VIRTUAL_BUG_ON(system_state != SYSTEM_BOOTING &&
-		is_vmalloc_addr((void *) x));
+	VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
 	return x - PAGE_OFFSET;
 }
 EXPORT_SYMBOL(__phys_addr);
@@ -89,7 +88,7 @@ bool __virt_addr_valid(unsigned long x)
 {
 	if (x < PAGE_OFFSET)
 		return false;
-	if (system_state != SYSTEM_BOOTING && is_vmalloc_addr((void *) x))
+	if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
 		return false;
 	return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
 }