[PATCH v2] powerpc/ptdump: Fix sparse warning in hashpagetable.c

Michael Ellerman mpe at ellerman.id.au
Wed Feb 2 16:30:39 AEDT 2022


As reported by sparse:

  arch/powerpc/mm/ptdump/hashpagetable.c:264:29: warning: restricted __be64 degrades to integer
  arch/powerpc/mm/ptdump/hashpagetable.c:265:49: warning: restricted __be64 degrades to integer
  arch/powerpc/mm/ptdump/hashpagetable.c:267:36: warning: incorrect type in assignment (different base types)
  arch/powerpc/mm/ptdump/hashpagetable.c:267:36:    expected unsigned long long [usertype]
  arch/powerpc/mm/ptdump/hashpagetable.c:267:36:    got restricted __be64 [usertype] v
  arch/powerpc/mm/ptdump/hashpagetable.c:268:36: warning: incorrect type in assignment (different base types)
  arch/powerpc/mm/ptdump/hashpagetable.c:268:36:    expected unsigned long long [usertype]
  arch/powerpc/mm/ptdump/hashpagetable.c:268:36:    got restricted __be64 [usertype] r

The values returned by plpar_pte_read_4() are CPU endian, not __be64, so
assigning them to struct hash_pte confuses sparse. As a minimal fix open
code a struct to hold the values with CPU endian types.

Reported-by: kernel test robot <lkp at intel.com>
Reported-by: Christophe Leroy <christophe.leroy at csgroup.eu>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
---
 arch/powerpc/mm/ptdump/hashpagetable.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

v2: Don't use struct hash_pte at all.

Replaces v1 http://patchwork.ozlabs.org/project/linuxppc-dev/patch/bbc196451dd34521d239023ccca488db35b8fff1.1643567900.git.christophe.leroy@csgroup.eu/

diff --git a/arch/powerpc/mm/ptdump/hashpagetable.c b/arch/powerpc/mm/ptdump/hashpagetable.c
index c7f824d294b2..9a601587836b 100644
--- a/arch/powerpc/mm/ptdump/hashpagetable.c
+++ b/arch/powerpc/mm/ptdump/hashpagetable.c
@@ -238,7 +238,10 @@ static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64
 
 static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
 {
-	struct hash_pte ptes[4];
+	struct {
+		unsigned long v;
+		unsigned long r;
+	} ptes[4];
 	unsigned long vsid, vpn, hash, hpte_group, want_v;
 	int i, j, ssize = mmu_kernel_ssize;
 	long lpar_rc = 0;
-- 
2.34.1



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