Messages in this thread | | | Date | Thu, 18 Feb 2016 11:58:24 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH] arm64: add architecture specified current_pt_regs |
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On Thu, Feb 18, 2016 at 07:48:35PM +0800, Zhi-zhou Zhang wrote: > From: zhizhou <zhizhou.zh@gmail.com> > > This patch is based on the implementation of arm. The generic > current_pt_regs is implemented with current->stack. It need to access > memory that would be too expensive.
Do you have any performance numbers?
> diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h > index e9e5467..1865d54 100644 > --- a/arch/arm64/include/asm/ptrace.h > +++ b/arch/arm64/include/asm/ptrace.h > @@ -185,5 +185,9 @@ static inline int valid_user_regs(struct user_pt_regs *regs) > > extern unsigned long profile_pc(struct pt_regs *regs); > > +#define current_pt_regs(void) ({ (struct pt_regs *) \ > + ((current_stack_pointer | (THREAD_SIZE - 1)) - 0xf) - 1; \ > +})
I don't think this works well with the separate IRQ stack that we merged in 4.5-rc1. current_thread_info() explicitly uses "sp_el0" while current_stack_pointer is just "sp" (though I don't think we ever use current_pt_regs in interrupt context).
-- Catalin
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