ARM: fix __virt_to_idmap build error on !MMU

Fengguang Wu reports that building ARM with !MMU results in the
following build error:

   arch/arm/kernel/built-in.o: In function `__soft_restart':
>> :(.text+0x1624): undefined reference to `arch_virt_to_idmap'

Fix this by adding an appropriate IS_ENABLED(CONFIG_MMU) into the
__virt_to_idmap() inline function.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index 6f225acc07c5..b7f6fb462ea0 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -286,7 +286,7 @@ extern phys_addr_t (*arch_virt_to_idmap)(unsigned long x);
  */
 static inline phys_addr_t __virt_to_idmap(unsigned long x)
 {
-        if (arch_virt_to_idmap)
+        if (IS_ENABLED(CONFIG_MMU) && arch_virt_to_idmap)
                 return arch_virt_to_idmap(x);
         else
                 return __virt_to_phys(x);