Messages in this thread | | | Date | Tue, 26 Jan 2010 11:16:42 +0900 | From | Tejun Heo <> | Subject | Re: [PATCH 7/8] percpu: add __percpu sparse annotations to hw_breakpoint |
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On 01/26/2010 11:04 AM, Al Viro wrote: > On Tue, Jan 26, 2010 at 11:06:10AM +0900, Tejun Heo wrote: >> Hello, >> >> On 01/26/2010 10:02 AM, H. Peter Anvin wrote: >>> A cast (using __typeof__) combined with an address space override? >> >> That still puts the address specification at the wrong level. The >> problem is that the __typeof__ would be an array type which itself >> doesn't have address space set but its members are in address space 3. >> So, you need to get *inside* the array type def to change that. :-( > > Could you post the actual definitions in one piece? Would be easier to > discuss what's going on...
Here it is.
# define RELOC_HIDE(ptr, off) \ ({ unsigned long __ptr; \ __ptr = (unsigned long) (ptr); \ (typeof(ptr)) (__ptr + (off)); })
#define __verify_pcpu_ptr(ptr) do { \ const void __percpu *__vpp_verify = (typeof(ptr))NULL; \ (void)__vpp_verify; \ } while (0)
/* Weird cast keeps both GCC and sparse happy. */ #define SHIFT_PERCPU_PTR(__p, __offset) ({ \ __verify_pcpu_ptr((__p)); \ RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \ })
#define per_cpu(var, cpu) \ (*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))
Thanks.
-- tejun
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