ARM: 7294/1: vectors: use gate_vma for vectors user mapping

The current user mapping for the vectors page is inserted as a `horrible
hack vma' into each task via arch_setup_additional_pages. This causes
problems with the MM subsystem and vm_normal_page, as described here:

https://lkml.org/lkml/2012/1/14/55

Following the suggestion from Hugh in the above thread, this patch uses
the gate_vma for the vectors user mapping, therefore consolidating
the horrible hack VMAs into one.

Acked-and-Tested-by: Nicolas Pitre <nico@linaro.org>

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h
index 97b440c25c58..5838361c48b3 100644
--- a/arch/arm/include/asm/page.h
+++ b/arch/arm/include/asm/page.h
@@ -151,6 +151,8 @@ extern void __cpu_copy_user_highpage(struct page *to, struct page *from,
 #define clear_page(page)        memset((void *)(page), 0, PAGE_SIZE)
 extern void copy_page(void *to, const void *from);
 
+#define __HAVE_ARCH_GATE_AREA 1
+
 #ifdef CONFIG_ARM_LPAE
 #include <asm/pgtable-3level-types.h>
 #else