Re: [RFC V2 4/6] sh/mm: Stop using [p4d|pud|pmd]_ERROR()

On Wed, Aug 12, 2026 at 01:21:28PM +0200, David Hildenbrand (Arm) wrote:

On 8/11/26 06:21, Anshuman Khandual wrote:

quoted

Stop using [p4d|pud|pmd]_ERROR() in __get_pte_phys() as the pgtable entries
are known to be NULL and hence could not really be accessed.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: linux-sh@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <redacted>
---
 arch/sh/mm/init.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index b3c7fd84ceb4..0bb8555568a4 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c

@@ -58,22 +58,16 @@ static pte_t *__get_pte_phys(unsigned long addr)
 	}
 
 	p4d = p4d_alloc(NULL, pgd, addr);
-	if (unlikely(!p4d)) {
-		p4d_ERROR(*p4d);
+	if (unlikely(!p4d))
 		return NULL;
-	}
 
 	pud = pud_alloc(NULL, p4d, addr);
-	if (unlikely(!pud)) {
-		pud_ERROR(*pud);
+	if (unlikely(!pud))
 		return NULL;
-	}
 
 	pmd = pmd_alloc(NULL, pud, addr);
-	if (unlikely(!pmd)) {
-		pmd_ERROR(*pmd);
+	if (unlikely(!pmd))
 		return NULL;
-	}
 
 	return pte_offset_kernel(pmd, addr);
 }

Do we want to print an error like "allocating p4d table failed"?

Sure, will add error prints like the following.

--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c

@@ -56,16 +56,22 @@ static pte_t *__get_pte_phys(unsigned long addr)
                return NULL;

        p4d = p4d_alloc(NULL, pgd, addr);
-       if (unlikely(!p4d))
+       if (unlikely(!p4d)) {
+               pr_err("allocating p4d table failed\n");
                return NULL;
+       }

        pud = pud_alloc(NULL, p4d, addr);
-       if (unlikely(!pud))
+       if (unlikely(!pud)) {
+               pr_err("allocating pud table failed\n");
                return NULL;
+       }

        pmd = pmd_alloc(NULL, pud, addr);
-       if (unlikely(!pmd))
+       if (unlikely(!pmd)) {
+               pr_err("allocating pmd table failed\n");
                return NULL;
+       }

        return pte_offset_kernel(pmd, addr);
 }

Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David