[PATCHv6 11/19] x86/mm: Make STACK_TOP_MAX dynamic

From: Kirill A. Shutemov
Date: Wed Aug 23 2017 - 08:07:19 EST


For boot-time switching between paging modes, we need to be able to
change STACK_TOP_MAX at runtime.

The change is trivial and it doesn't affect kernel image size.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/processor.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c1352771b2f6..981cb956d8bf 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -871,7 +871,7 @@ static inline void spin_lock_prefetch(const void *x)
IA32_PAGE_OFFSET : TASK_SIZE_MAX)

#define STACK_TOP TASK_SIZE_LOW
-#define STACK_TOP_MAX TASK_SIZE_MAX
+#define STACK_TOP_MAX (pgtable_l5_enabled ? TASK_SIZE_MAX : DEFAULT_MAP_WINDOW)

#define INIT_THREAD { \
.sp0 = TOP_OF_INIT_STACK, \
--
2.14.1