[bug report] powerpc/mm/radix: Add tlbflush routines
Christophe LEROY
christophe.leroy at c-s.fr
Thu Feb 1 03:01:04 AEDT 2018
Le 31/01/2018 à 16:45, Dan Carpenter a écrit :
> Hello Aneesh Kumar K.V,
>
> The patch 1a472c9dba6b: "powerpc/mm/radix: Add tlbflush routines"
> from Apr 29, 2016, leads to the following static checker warning:
>
> arch/powerpc/mm/tlb_nohash.c:218 __local_flush_tlb_page()
> warn: always true condition '(pid != ~0) => (0-u32max != u64max)'
>
> arch/powerpc/mm/tlb_nohash.c
> 211 void __local_flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr,
> 212 int tsize, int ind)
> 213 {
> 214 unsigned int pid;
> 215
> 216 preempt_disable();
> 217 pid = mm ? mm->context.id : 0;
> 218 if (pid != MMU_NO_CONTEXT)
> ^^^^^^^^^^^^^^^^^^^^^
> 219 _tlbil_va(vmaddr, pid, tsize, ind);
> 220 preempt_enable();
> 221 }
>
> I don't know very much about PowerPC. The static checker is guessing
> which headers to pull in instead of relying on the build system so there
> are a lot of false positives. It's apparently using the
> arch/powerpc/include/asm/book3s/64/tlbflush.h header which does:
>
> #define MMU_NO_CONTEXT ~0UL
>
> so it's UINT_MAX vs U64_MAX which is making the checker complain.
As far as I can see from arch/powerpc/include/asm/mmu-hash64.h,
mm->context.id is an unsigned long, so pid should also be an unsigned
long, not an unsigned int ?
Christophe
>
> regards,
> dan carpenter
>
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