Hi,
On Thu, Jan 09, 2020 at 07:50:55AM +0100, Helge Deller wrote:
> > The commit d96885e277b5 ("parisc: use pgtable-nopXd instead of
> > 4level-fixup") converted PA-RISC to use folded page tables, but it missed
> > the conversion of pgd_populate() to pud_populate() in maps_pages()
> > function. This caused the upper page table directory to remain empty and
> > the system would crash as a result.
> >
> > Using pud_populate() that actually populates the page table instead of
> > dummy pgd_populate() fixes the issue.
> > ...
> > diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
> > index ddca8287d43b..354cf060b67f 100644
> > --- a/arch/parisc/mm/init.c
> > +++ b/arch/parisc/mm/init.c
> > @@ -401,7 +401,7 @@ static void __init map_pages(unsigned long start_vaddr,
> > pmd = (pmd_t *) __pa(pmd);
> > }
> >
> > - pgd_populate(NULL, pg_dir, __va(pmd));
> > + pud_populate(NULL, (pud_t *)pg_dir, __va(pmd));
> > #endif
>
> Wouldn't the untested patch below be more clean?
>
> Helge
>
> diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
> index ddca8287d43b..73de58f31f5f 100644
> --- a/arch/parisc/mm/init.c
> +++ b/arch/parisc/mm/init.c
> @@ -387,6 +387,8 @@ static void __init map_pages(unsigned long start_vaddr,
> #if PTRS_PER_PMD == 1
> pmd = (pmd_t *)__pa(pg_dir);
> #else
> + p4d_t *p4d;
> + pud_t *pud;
> pmd = (pmd_t *)pgd_address(*pg_dir);
>
> /*
> @@ -401,7 +403,9 @@ static void __init map_pages(unsigned long start_vaddr,
> pmd = (pmd_t *) __pa(pmd);
> }
>
> - pgd_populate(NULL, pg_dir, __va(pmd));
> + p4d = p4d_offset(pg_dir, vaddr);
> + pud = pud_offset(p4d, vaddr);
> + pud_populate(NULL, pud, __va(pmd));
> #endif
> pg_dir++;
I've tried to keep the changes to minimum :)
Otherwise I'd go with something even more surgical:
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 354cf060b67f..94baa4382c29 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -351,7 +351,6 @@ static void __init map_pages(unsigned long start_vaddr,
unsigned long start_paddr, unsigned long size,
pgprot_t pgprot, int force)
{
- pgd_t *pg_dir;
pmd_t *pmd;
pte_t *pg_table;
unsigned long end_paddr;
@@ -372,8 +371,6 @@ static void __init map_pages(unsigned long start_vaddr,
end_paddr = start_paddr + size;
- pg_dir = pgd_offset_k(start_vaddr);
-
#if PTRS_PER_PMD == 1
start_pmd = 0;
#else
@@ -384,50 +381,30 @@ static void __init map_pages(unsigned long start_vaddr,
address = start_paddr;
vaddr = start_vaddr;
while (address < end_paddr) {
-#if PTRS_PER_PMD == 1
- pmd = (pmd_t *)__pa(pg_dir);
-#else
- pmd = (pmd_t *)pgd_address(*pg_dir);
+ pgd_t *pgd = pgd_offset_k(vaddr);
+ p4d_t *p4d = p4d_offset(pgd, vaddr);
+ pud_t *pud = pud_offset(p4d, vaddr);
- /*
- * pmd is physical at this point
- */
-
- if (!pmd) {
+#if CONFIG_PGTABLE_LEVELS == 3
+ if (pud_none(*pud)) {
pmd = memblock_alloc(PAGE_SIZE << PMD_ORDER,
PAGE_SIZE << PMD_ORDER);
if (!pmd)
panic("pmd allocation failed.\n");
- pmd = (pmd_t *) __pa(pmd);
+ pud_populate(NULL, pud, pmd);
}
-
- pud_populate(NULL, (pud_t *)pg_dir, __va(pmd));
#endif
- pg_dir++;
- /* now change pmd to kernel virtual addresses */
-
- pmd = (pmd_t *)__va(pmd) + start_pmd;
+ pmd = pmd_offset(pud, vaddr);
for (tmp1 = start_pmd; tmp1 < PTRS_PER_PMD; tmp1++, pmd++) {
-
- /*
- * pg_table is physical at this point
- */
-
- pg_table = (pte_t *)pmd_address(*pmd);
- if (!pg_table) {
- pg_table = memblock_alloc(PAGE_SIZE,
- PAGE_SIZE);
+ if (pmd_none(*pmd)) {
+ pg_table = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
if (!pg_table)
panic("page table allocation failed\n");
- pg_table = (pte_t *) __pa(pg_table);
+ pmd_populate_kernel(NULL, pmd, pg_table);
}
- pmd_populate_kernel(NULL, pmd, __va(pg_table));
-
- /* now change pg_table to kernel virtual addresses */
-
- pg_table = (pte_t *) __va(pg_table) + start_pte;
+ pg_table = pte_offset_kernel(pmd, vaddr);
for (tmp2 = start_pte; tmp2 < PTRS_PER_PTE; tmp2++, pg_table++) {
pte_t pte;
pgprot_t prot;
--
Sincerely yours,
Mike.
