Thread (47 messages) 47 messages, 3 authors, 2017-09-28

[PATCHv7 11/19] x86/mm: Make STACK_TOP_MAX dynamic

From: Kirill A. Shutemov <hidden>
Date: 2017-09-18 10:59:41
Also in: lkml
Subsystem: the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

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 <redacted>
---
 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 3fa26a61eabc..fa9300ccce1b 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

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