RE: [PATCH v4 3/4] RISC-V: mm: Enable huge page support to kernel_page_present() function

[JeeHeng Sia <jeeheng.sia@starfivetech.com>]

> -----Original Message-----
> From: Andrew Jones <ajones@ventanamicro.com>
> Sent: Thursday, 23 February, 2023 2:57 PM
> To: JeeHeng Sia <jeeheng.sia@starfivetech.com>
> Cc: paul.walmsley@sifive.com; palmer@dabbelt.com; aou@eecs.berkeley.edu; linux-riscv@lists.infradead.org; linux-
> kernel@vger.kernel.org; Leyfoon Tan <leyfoon.tan@starfivetech.com>; Mason Huo <mason.huo@starfivetech.com>
> Subject: Re: [PATCH v4 3/4] RISC-V: mm: Enable huge page support to kernel_page_present() function
> 
> On Tue, Feb 21, 2023 at 10:35:22AM +0800, Sia Jee Heng wrote:
> > Currently kernel_page_present() function doesn't support huge page
> > detection causes the function to mistakenly return false to the
> > hibernation core.
> >
> > Add huge page detection to the function to solve the problem.
> >
> > Fixes tag: commit 9e953cda5cdf ("riscv:
> > Introduce huge page support for 32/64bit kernel")
> 
> This should be formatted as below (no line wrap and no 'tag' in the tag)
> 
> Fixes: 9e953cda5cdf ("riscv: Introduce huge page support for 32/64bit kernel")
> 
> >
> > Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
> > Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
> > Reviewed-by: Mason Huo <mason.huo@starfivetech.com>
> > ---
> >  arch/riscv/mm/pageattr.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
> > index 86c56616e5de..ea3d61de065b 100644
> > --- a/arch/riscv/mm/pageattr.c
> > +++ b/arch/riscv/mm/pageattr.c
> > @@ -217,18 +217,26 @@ bool kernel_page_present(struct page *page)
> >  	pgd = pgd_offset_k(addr);
> >  	if (!pgd_present(*pgd))
> >  		return false;
> > +	if (pgd_leaf(*pgd))
> > +		return true;
> >
> >  	p4d = p4d_offset(pgd, addr);
> >  	if (!p4d_present(*p4d))
> >  		return false;
> > +	if (p4d_leaf(*p4d))
> > +		return true;
> >
> >  	pud = pud_offset(p4d, addr);
> >  	if (!pud_present(*pud))
> >  		return false;
> > +	if (pud_leaf(*pud))
> > +		return true;
> >
> >  	pmd = pmd_offset(pud, addr);
> >  	if (!pmd_present(*pmd))
> >  		return false;
> > +	if (pmd_leaf(*pmd))
> > +		return true;
> >
> >  	pte = pte_offset_kernel(pmd, addr);
> >  	return pte_present(*pte);
> > --
> > 2.34.1
> >
> >
> 
> Otherwise,
> 
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
noted with thanks
> 
> Thanks,
> drew