[PATCH v4] riscv: fix pfn_to_virt err in do_page_fault().

[fuyao]

Shaohua:
	sorry, i read it wrong. this patch is right.

On Tue, Oct 27, 2020 at 10:59:52AM +0800, fuyao wrote:
> have you seen the main line?
> 
> it already corrected.
> 
> On Mon, Oct 26, 2020 at 08:46:08PM +0800, liush wrote:
> > From: Shaohua Liu <liush at allwinnertech.com>
> > 
> > The argument to pfn_to_virt() should be pfn not the value of CSR_SATP.
> > 
> > Reviewed-by: Palmer Dabbelt <palmerdabbelt at google.com>
> > Reviewed-by: Anup Patel <anup at brainfault.org>
> > Signed-off-by: liush <liush at allwinnertech.com>
> > ---
> >  arch/riscv/mm/fault.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> > index 1359e21..3c8b9e4 100644
> > --- a/arch/riscv/mm/fault.c
> > +++ b/arch/riscv/mm/fault.c
> > @@ -86,6 +86,7 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
> >  	pmd_t *pmd, *pmd_k;
> >  	pte_t *pte_k;
> >  	int index;
> > +	unsigned long pfn;
> >  
> >  	/* User mode accesses just cause a SIGSEGV */
> >  	if (user_mode(regs))
> > @@ -100,7 +101,8 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
> >  	 * of a task switch.
> >  	 */
> >  	index = pgd_index(addr);
> > -	pgd = (pgd_t *)pfn_to_virt(csr_read(CSR_SATP)) + index;
> > +	pfn = csr_read(CSR_SATP) & SATP_PPN;
> > +	pgd = (pgd_t *)pfn_to_virt(pfn) + index;
> >  	pgd_k = init_mm.pgd + index;
> >  
> >  	if (!pgd_present(*pgd_k)) {