new helper: current_user_stack_pointer()
Cross-architecture equivalent of rdusp(); default is user_stack_pointer(current_pt_regs()) - that works for almost all platforms that have usp saved in pt_regs. The only exception from that is ia64 - we want memory stack, not the backing store for register one. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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@@ -78,6 +78,11 @@ static inline long regs_return_value(struct pt_regs *regs)
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unsigned long __ip = instruction_pointer(regs); \
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(__ip & ~3UL) + ((__ip & 3UL) << 2); \
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})
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/*
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* Why not default? Because user_stack_pointer() on ia64 gives register
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* stack backing store instead...
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*/
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#define current_user_stack_pointer() (current_pt_regs()->r12)
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/* given a pointer to a task_struct, return the user's pt_regs */
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# define task_pt_regs(t) (((struct pt_regs *) ((char *) (t) + IA64_STK_OFFSET)) - 1)
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