On 01/31/2018 09:31 PM, Christophe LEROY wrote:
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
yes.
We did similar fixup for book3s radix
in 9690c15742688e9cb5ee4aa0b08e458551ceea13 (powerpc/mm/radix: Fix
always false comparison against MMU_NO_CONTEXT
)
-aneesh
