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[RFC,3/6] arm64: pad stacks to PAGE_SIZE for VMAP_STACK

Message ID 1499898783-25732-4-git-send-email-mark.rutland@arm.com
State New
Headers show
Series arm64: alternative VMAP_STACK implementation | expand

Commit Message

Mark Rutland July 12, 2017, 10:33 p.m. UTC 
Our THREAD_SIZE may be smaller than PAGE_SIZE. With VMAP_STACK, we can't
allow stacks to share a page with anything else, so may as well pad
up-to PAGE_SIZE, and have 64K stacks when we have 64K pages.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>

---
 arch/arm64/include/asm/thread_info.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

-- 
1.9.1
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Patch

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 6d0c59a..3684f86 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -25,7 +25,13 @@ 
 
 #include <asm/page.h>
 
-#define THREAD_SHIFT		14
+#define __THREAD_SHIFT		14
+
+#if defined(CONFIG_VMAP_STACK) && (__THREAD_SHIFT < PAGE_SHIFT)
+#define THREAD_SHIFT		PAGE_SHIFT
+#else
+#define THREAD_SHIFT		__THREAD_SHIFT
+#endif
 
 #if THREAD_SHIFT >= PAGE_SHIFT
 #define THREAD_SIZE_ORDER	(THREAD_SHIFT - PAGE_SHIFT)