Re: [PATCH 1/1] arm/arm64: add support for folded p4d page tables

Anshuman Khandual
2020-01-09T03:25:06Z

On 12/30/2019 01:57 PM, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Implement primitives necessary for the 4th level folding, add walks of p4d
> level where appropriate, replace 5level-fixup.h with pgtable-nop4d.h and
> remove __ARCH_USE_5LEVEL_HACK.
>
> Since arm and arm64 share kvm memory management bits, make the conversion
> for both variants at once to avoid breaking the builds in the middle.
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> arch/arm/include/asm/kvm_mmu.h | 5 +-
> arch/arm/include/asm/pgtable.h | 1 -
> arch/arm/include/asm/stage2_pgtable.h | 15 +-
> arch/arm/lib/uaccess_with_memcpy.c | 9 +-
> arch/arm/mach-sa1100/assabet.c | 2 +-
> arch/arm/mm/dump.c | 29 +++-
> arch/arm/mm/fault-armv.c | 7 +-
> arch/arm/mm/fault.c | 28 +++-
> arch/arm/mm/idmap.c | 3 +-
> arch/arm/mm/init.c | 2 +-
> arch/arm/mm/ioremap.c | 12 +-
> arch/arm/mm/mm.h | 2 +-
> arch/arm/mm/mmu.c | 35 +++-
> arch/arm/mm/pgd.c | 40 ++++-
> arch/arm64/include/asm/kvm_mmu.h | 10 +-
> arch/arm64/include/asm/pgalloc.h | 10 +-
> arch/arm64/include/asm/pgtable-types.h | 5 +-
> arch/arm64/include/asm/pgtable.h | 37 +++--
> arch/arm64/include/asm/stage2_pgtable.h | 48 ++++--
> arch/arm64/kernel/hibernate.c | 46 +++++-
> arch/arm64/mm/dump.c | 29 +++-
> arch/arm64/mm/fault.c | 9 +-
> arch/arm64/mm/hugetlbpage.c | 15 +-
> arch/arm64/mm/kasan_init.c | 41 ++++-
> arch/arm64/mm/mmu.c | 52 ++++--
> arch/arm64/mm/pageattr.c | 7 +-
> virt/kvm/arm/mmu.c | 209 ++++++++++++++++++++----
> 27 files changed, 565 insertions(+), 143 deletions(-)
>

^^^^^^

> diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
> index f87a32484ea8..fd6220508711 100644
> --- a/arch/arm64/mm/kasan_init.c
> +++ b/arch/arm64/mm/kasan_init.c
> @@ -84,17 +84,32 @@ static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node,
> return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr);
> }
>
> -static pud_t *__init kasan_pud_offset(pgd_t *pgdp, unsigned long addr, int node,
> +static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node,
> bool early)
> {
> - if (pgd_none(READ_ONCE(*pgdp))) {
> + if (p4d_none(READ_ONCE(*p4dp))) {
> phys_addr_t pud_phys = early ?
> __pa_symbol(kasan_early_shadow_pud)
> : kasan_alloc_zeroed_page(node);
> - __pgd_populate(pgdp, pud_phys, PMD_TYPE_TABLE);
> + __p4d_populate(p4dp, pud_phys, PMD_TYPE_TABLE);
> + }
> +
> + return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr);
> +}
> +
> +static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node,
> + bool early)
> +{
> +#ifndef __PAGETABLE_P4D_FOLDED
> + if (pgd_none(READ_ONCE(*pgdp))) {
> + phys_addr_t p4d_phys = early ?
> + __pa_symbol(kasan_early_shadow_p4d)
> + : kasan_alloc_zeroed_page(node);
> + __pgd_populate(pgdp, p4d_phys, PMD_TYPE_TABLE);

We dont have __pgd_populate() definition any more. AFAICS __PAGETABLE_P4D_FOLDED
is always defined because pgtable-nop4d.h gets pulled in for all configurations
via pgtable-nopud.h and pgtable-nopmd.h headers.

> }
> +#endif
>
> - return early ? pud_offset_kimg(pgdp, addr) : pud_offset(pgdp, addr);
> + return early ? p4d_offset_kimg(pgdp, addr) : p4d_offset(pgdp, addr);
> }
>
> static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
> @@ -126,11 +141,11 @@ static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
> } while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
> }
>
> -static void __init kasan_pud_populate(pgd_t *pgdp, unsigned long addr,
> +static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
> unsigned long end, int node, bool early)
> {
> unsigned long next;
> - pud_t *pudp = kasan_pud_offset(pgdp, addr, node, early);
> + pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
>
> do {
> next = pud_addr_end(addr, end);
> @@ -138,6 +153,18 @@ static void __init kasan_pud_populate(pgd_t *pgdp, unsigned long addr,
> } while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
> }
>
> +static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
> + unsigned long end, int node, bool early)
> +{
> + unsigned long next;
> + p4d_t *p4dp = kasan_p4d_offset(pgdp, addr, node, early);
> +
> + do {
> + next = p4d_addr_end(addr, end);
> + kasan_pmd_populate(p4dp, addr, next, node, early);

s/kasan_pmd_populate()/kasan_pud_populate()