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>

diff --git a/arch/x86/kernel/doublefault_32.c b/arch/x86/kernel/doublefault_32.c
index 395acb12b0d1bfe1a5e1764d00ef4271b00a7e2f..b4f14c6c09d9b12971c1673ebac761515e91a4be 100644 (file)
--- a/arch/x86/kernel/doublefault_32.c
+++ b/arch/x86/kernel/doublefault_32.c
@@ -66,6 +66,6 @@ struct tss_struct doublefault_tss __cacheline_aligned = {
                .ds             = __USER_DS,
                .fs             = __KERNEL_PERCPU,
 
-               .__cr3          = __phys_addr_const((unsigned long)swapper_pg_dir)
+               .__cr3          = __pa_nodebug(swapper_pg_dir),
        }
 };

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 7fb737c6b54f1b6edb005cbfa28a55da45556e8d..8876220d906b89bec29f8fff5d873a6d47550cb7 100644 (file)
--- 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)

diff --git a/include/asm-x86/page.h b/include/asm-x86/page.h
index c91574776751396207f1aa2ce903e15a82239d47..d4f1d5791fc186f29a9a60d4fe182d80f05038e4 100644 (file)
--- a/include/asm-x86/page.h
+++ b/include/asm-x86/page.h
@@ -179,6 +179,7 @@ static inline pteval_t native_pte_flags(pte_t pte)
 #endif /* CONFIG_PARAVIRT */
 
 #define __pa(x)                __phys_addr((unsigned long)(x))
+#define __pa_nodebug(x)        __phys_addr_nodebug((unsigned long)(x))
 /* __pa_symbol should be used for C visible symbols.
    This seems to be the official gcc blessed way to do such arithmetic. */
 #define __pa_symbol(x) __pa(__phys_reloc_hide((unsigned long)(x)))
@@ -188,9 +189,14 @@ static inline pteval_t native_pte_flags(pte_t pte)
 #define __boot_va(x)           __va(x)
 #define __boot_pa(x)           __pa(x)
 
+/*
+ * virt_to_page(kaddr) returns a valid pointer if and only if
+ * virt_addr_valid(kaddr) returns true.
+ */
 #define virt_to_page(kaddr)    pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define pfn_to_kaddr(pfn)      __va((pfn) << PAGE_SHIFT)
-#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
+extern bool __virt_addr_valid(unsigned long kaddr);
+#define virt_addr_valid(kaddr) __virt_addr_valid((unsigned long) (kaddr))
 
 #endif /* __ASSEMBLY__ */
 

diff --git a/include/asm-x86/page_32.h b/include/asm-x86/page_32.h
index 9c5a737a9af9878ee128d15a90505afd6f733737..5d6a68a1067ac90bb32a4008b026fd6c87c59e6c 100644 (file)
--- a/include/asm-x86/page_32.h
+++ b/include/asm-x86/page_32.h
@@ -73,11 +73,11 @@ typedef struct page *pgtable_t;
 #endif
 
 #ifndef __ASSEMBLY__
-#define __phys_addr_const(x)   ((x) - PAGE_OFFSET)
+#define __phys_addr_nodebug(x) ((x) - PAGE_OFFSET)
 #ifdef CONFIG_DEBUG_VIRTUAL
 extern unsigned long __phys_addr(unsigned long);
 #else
-#define __phys_addr(x)         ((x) - PAGE_OFFSET)
+#define __phys_addr(x)         __phys_addr_nodebug(x)
 #endif
 #define __phys_reloc_hide(x)   RELOC_HIDE((x), 0)