x86: fix virt_addr_valid() with CONFIG_DEBUG_VIRTUAL=y, v2

virt_addr_valid() calls __pa(), which calls __phys_addr(). With
CONFIG_DEBUG_VIRTUAL=y, __phys_addr() will kill the kernel if the
address *isn't* valid. That's clearly wrong for virt_addr_valid().

We also incorporate the debugging checks into virt_addr_valid().

Signed-off-by: Vegard Nossum <vegardno@ben.ifi.uio.no>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 34 insertions, 2 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 7fb737c6b54f..8876220d906b 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -45,6 +45,27 @@ unsigned long __phys_addr(unsigned long x)
 }
 EXPORT_SYMBOL(__phys_addr);
 
+bool __virt_addr_valid(unsigned long x)
+{
+        if (x >= __START_KERNEL_map) {
+                x -= __START_KERNEL_map;
+                if (x >= KERNEL_IMAGE_SIZE)
+                        return false;
+                x += phys_base;
+        } else {
+                if (x < PAGE_OFFSET)
+                        return false;
+                x -= PAGE_OFFSET;
+                if (system_state == SYSTEM_BOOTING ?
+                                x > MAXMEM : !phys_addr_valid(x)) {
+                        return false;
+                }
+        }
+
+        return pfn_valid(x >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(__virt_addr_valid);
+
 #else
 
 static inline int phys_addr_valid(unsigned long addr)
@@ -56,13 +77,24 @@ static inline int phys_addr_valid(unsigned long addr)
 unsigned long __phys_addr(unsigned long x)
 {
         /* VMALLOC_* aren't constants; not available at the boot time */
-        VIRTUAL_BUG_ON(x < PAGE_OFFSET || (system_state != SYSTEM_BOOTING &&
-                                        is_vmalloc_addr((void *)x)));
+        VIRTUAL_BUG_ON(x < PAGE_OFFSET);
+        VIRTUAL_BUG_ON(system_state != SYSTEM_BOOTING &&
+                is_vmalloc_addr((void *) x));
         return x - PAGE_OFFSET;
 }
 EXPORT_SYMBOL(__phys_addr);
 #endif
 
+bool __virt_addr_valid(unsigned long x)
+{
+        if (x < PAGE_OFFSET)
+                return false;
+        if (system_state != SYSTEM_BOOTING && is_vmalloc_addr((void *) x))
+                return false;
+        return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
+}
+EXPORT_SYMBOL(__virt_addr_valid);
+
 #endif
 
 int page_is_ram(unsigned long pagenr)