Re: [PATCH x86/mm 6/6] x86-64 ia32 ptrace get/putreg32 current task

[Chuck Ebbert]

On 11/29/2007 01:09 PM, Linus Torvalds wrote:
>>>  	case offsetof(struct user32, regs.gs):
>>>  		*val = child->thread.gsindex;
>>> +		if (child == current)
>>> +			asm("movl %%gs,%0" : "=r" (*val));
>> Won't this return the kernel's GS instead of the user's?
> 
> No, %gs is untouched by the kernel, so it contains user space version, and 
> getting the value directly from %gs looks correct.
> 

But this is x86_64, where swapgs is done on kernel entry.

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