Re: [RFC V2 1/6] loongarch/mm: Stop using pte_ERROR()

On Wed, Aug 12, 2026 at 01:27:54PM +0200, David Hildenbrand (Arm) wrote:

On 8/12/26 13:19, David Hildenbrand (Arm) wrote:

quoted

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

quoted

Directly use pr_err() in __set_fixmap() and drop pte_ERROR() which helps in
eventually dropping pte_ERROR() macro across the tree. In this new printing
__FILE__ and __LINE__ has been dropped because they are always the same and
don't really add any value.

Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: loongarch@lists.linux.dev
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <redacted>
---
 arch/loongarch/include/asm/pgtable.h | 2 --
 arch/loongarch/mm/init.c             | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index 223528c04d73..a32a8fff70c1 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h

@@ -128,8 +128,6 @@ struct vm_area_struct;
 #define ptep_get(ptep) READ_ONCE(*(ptep))
 #define pmdp_get(pmdp) READ_ONCE(*(pmdp))
 
-#define pte_ERROR(e) \
-	pr_err("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 #ifndef __PAGETABLE_PMD_FOLDED
 #define pmd_ERROR(e) \
 	pr_err("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))

diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index 3407030f3e7a..be9b127daef2 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c

@@ -203,7 +203,7 @@ void __init __set_fixmap(enum fixed_addresses idx,
 
 	ptep = populate_kernel_pte(addr);
 	if (!pte_none(ptep_get(ptep))) {
-		pte_ERROR(*ptep);
+		pr_err("bad pte %016lx\n", pte_val(*ptep));
 		return;
 	}
 

Ah, I missed that we want to print actual values, I somehow thought that we
would be printing pte_none() ...

Maybe we should just be more verbose while at it?

Initially thought that these new prints should be right close to the
original via pxd_ERROR() but I guess making them verbose while doing
the replacements should be indeed acceptable.

quoted

pr_err("unexpected set PTE at %ul in __set_fixmap: %016lx\n",
       addr, pte_val(*ptep));

On second thought, why not simply use ptval_to_str() here as well?

Sure will do the required changes - the following builds successfully.

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

@@ -197,13 +197,15 @@ void __init __set_fixmap(enum fixed_addresses idx,
                               phys_addr_t phys, pgprot_t flags)
 {
        unsigned long addr = __fix_to_virt(idx);
+       char str[PTVAL_STR_MAX];
        pte_t *ptep;

        BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);

        ptep = populate_kernel_pte(addr);
        if (!pte_none(ptep_get(ptep))) {
-               pr_err("bad pte %016lx\n", pte_val(*ptep));
+               ptval_to_str(str, pte_val(*ptep));
+               pr_err("unexpected set PTE at %lx in __set_fixmap: %s\n", addr, str);
                return;
        }

-- 
Cheers,

David