Re: [RFC V2 3/6] sh/mm: Stop using pte_ERROR()

On Wed, Aug 12, 2026 at 01:28:23PM +0200, David Hildenbrand (Arm) wrote:
> On 8/11/26 06:21, Anshuman Khandual wrote:
> > Directly use pr_err() in set_pte_phys() 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: Yoshinori Sato <[email protected]>
> > Cc: Rich Felker <[email protected]>
> > Cc: John Paul Adrian Glaubitz <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Anshuman Khandual <[email protected]>
> > ---
> >  arch/sh/include/asm/pgtable_32.h |  5 -----
> >  arch/sh/mm/init.c                | 11 ++++++++++-
> >  2 files changed, 10 insertions(+), 6 deletions(-)
> > 
> > diff --git a/arch/sh/include/asm/pgtable_32.h b/arch/sh/include/asm/pgtable_32.h
> > index 5f51af18997b..c8eb9a7a4c4c 100644
> > --- a/arch/sh/include/asm/pgtable_32.h
> > +++ b/arch/sh/include/asm/pgtable_32.h
> > @@ -401,14 +401,9 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
> >  #define pmd_page(pmd)		(virt_to_page(pmd_val(pmd)))
> >  
> >  #ifdef CONFIG_X2TLB
> > -#define pte_ERROR(e) \
> > -	printk("%s:%d: bad pte %p(%08lx%08lx).\n", __FILE__, __LINE__, \
> > -	       &(e), (e).pte_high, (e).pte_low)
> >  #define pgd_ERROR(e) \
> >  	printk("%s:%d: bad pgd %016llx.\n", __FILE__, __LINE__, pgd_val(e))
> >  #else
> > -#define pte_ERROR(e) \
> > -	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
> >  #define pgd_ERROR(e) \
> >  	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
> >  #endif
> > diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
> > index 110308bdef01..b3c7fd84ceb4 100644
> > --- a/arch/sh/mm/init.c
> > +++ b/arch/sh/mm/init.c
> > @@ -78,13 +78,22 @@ static pte_t *__get_pte_phys(unsigned long addr)
> >  	return pte_offset_kernel(pmd, addr);
> >  }
> >  
> > +static void print_bad_pte(pte_t pte)
> > +{
> > +#ifdef CONFIG_X2TLB
> > +	printk("bad pte %p(%08lx%08lx).\n", &pte, pte.pte_high, pte.pte_low);
> > +#else
> > +	printk("bad pte %08lx.\n", pte_val(pte));
> > +#endif
> 
> I'd avoid that helper if possible, so we don't encourage new users.
> 
> Shouldn't we just switch to pr_err() right away?

Yes we could move from printk() to pr_err(). The above helper
just prevented an ugly #ifdef block inside if(!pte_none(*pte))
conditional block, nothing more. Will just drop it then.

> 
> > +}
> > +
> >  static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
> >  {
> >  	pte_t *pte;
> >  
> >  	pte = __get_pte_phys(addr);
> >  	if (!pte_none(*pte)) {
> > -		pte_ERROR(*pte);
> > +		print_bad_pte(*pte);
> 
> Maybe similar to my reply to patch #1, actually print something more useful than
> just "bad pte" ? And possibly also just use ptval_to_str().

Probably #ifdef could be dropped here as ptval_to_str() should be able to
handle pte with two unsiged long elements in there i.e pte_high, pte_low
along with standard single unsiged long pte_low format.

#ifdef CONFIG_X2TLB
typedef struct { unsigned long pte_low, pte_high; } pte_t;
#define pte_val(x) \
        ((x).pte_low | ((unsigned long long)(x).pte_high << 32))
#define __pte(x) \
        ({ pte_t __pte = {(x), ((unsigned long long)(x)) >> 32}; __pte; })
#else
typedef struct { unsigned long pte_low; } pte_t;
#define pte_val(x)      ((x).pte_low)
#define __pte(x)        ((pte_t) { (x) } )
#endif

static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
{
        pte_t *pte;

        pte = __get_pte_phys(addr);
        if (!pte_none(*pte)) {
                char str[PTVAL_STR_MAX];

                ptval_to_str(str, pte_val(*pte));
                pr_err("unexpected set PTE at %lx in set_pte_phys: bad pte %p(%s).\n",
                        addr, pte, str);
                return;
        }

        set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, prot));
        local_flush_tlb_one(get_asid(), addr);

        if (pgprot_val(prot) & _PAGE_WIRED)
                tlb_wire_entry(NULL, addr, *pte);
}

But if this does not work revert back printing both pte formats separately
like before.

#ifdef CONFIG_X2TLB
               pr_err("unexpected set PTE at %lx in set_pte_phys: bad pte %p(%08lx%08lx).\n",
                       addr, pte, pte->pte_high, pte->pte_low);
#else
               char str[PTVAL_STR_MAX];

               ptval_to_str(str, pte_val(*pte));
               pr_err("unexpected set PTE at %lx in set_pte_phys: bad pte %s.\n", addr, str);
#endif

> 
> -- 
> Cheers,
> 
> David