[PATCH 12/18] x86/asm: Add task_top_of_stack() to find the top of a task's stack

Andy Lutomirski
2017-10-26T08:29:32Z

This will let us get rid of a few places that hardcode accesses to
thread.sp0.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/include/asm/processor.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 064b84722166..ad59cec14239 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -795,6 +795,8 @@ static inline void spin_lock_prefetch(const void *x)
#define TOP_OF_INIT_STACK ((unsigned long)&init_stack + sizeof(init_stack) - \
TOP_OF_KERNEL_STACK_PADDING)

+#define task_top_of_stack(task) ((unsigned long)(task_pt_regs(task) + 1))
+
#ifdef CONFIG_X86_32
/*
* User space process size: 3GB (default).
--
2.13.6