[PATCH 4.9 08/97] arm64: dont open code page table entry creation

Greg Kroah-Hartman
2020-01-22T09:34:03Z

From: Kristina Martsenko <kristina.martsenko@arm.com>

commit 193383043f14a398393dc18bae8380f7fe665ec3 upstream.

Instead of open coding the generation of page table entries, use the
macros/functions that exist for this - pfn_p*d and p*d_populate. Most
code in the kernel already uses these macros, this patch tries to fix
up the few places that don't. This is useful for the next patch in this
series, which needs to change the page table entry logic, and it's
better to have that logic in one place.

The KVM extended ID map is special, since we're creating a level above
CONFIG_PGTABLE_LEVELS and the required function isn't available. Leave
it as is and add a comment to explain it. (The normal kernel ID map code
doesn't need this change because its page tables are created in assembly
(__create_page_tables)).

Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/include/asm/kvm_mmu.h | 5 +++++
arch/arm64/include/asm/pgtable.h | 1 +
arch/arm64/kernel/hibernate.c | 3 +--
arch/arm64/mm/mmu.c | 14 +++++++++-----
4 files changed, 16 insertions(+), 7 deletions(-)

--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -300,6 +300,11 @@ static inline bool __kvm_cpu_uses_extend
return __cpu_uses_extended_idmap();
}

+/*
+ * Can't use pgd_populate here, because the extended idmap adds an extra level
+ * above CONFIG_PGTABLE_LEVELS (which is 2 or 3 if we're using the extended
+ * idmap), and pgd_populate is only available if CONFIG_PGTABLE_LEVELS = 4.
+ */
static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd,
pgd_t *hyp_pgd,
pgd_t *merged_hyp_pgd,
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -353,6 +353,7 @@ static inline int pmd_protnone(pmd_t pmd

#define pud_write(pud) pte_write(pud_pte(pud))
#define pud_pfn(pud) (((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
+#define pfn_pud(pfn,prot) (__pud(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))

#define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))

--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -247,8 +247,7 @@ static int create_safe_exec_page(void *s
}

pte = pte_offset_kernel(pmd, dst_addr);
- set_pte(pte, __pte(virt_to_phys((void *)dst) |
- pgprot_val(PAGE_KERNEL_EXEC)));
+ set_pte(pte, pfn_pte(virt_to_pfn(dst), PAGE_KERNEL_EXEC));

/*
* Load our new page tables. A strict BBM approach requires that we
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -495,8 +495,8 @@ static void __init map_kernel(pgd_t *pgd
* entry instead.
*/
BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
- set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
- __pud(__pa(bm_pmd) | PUD_TYPE_TABLE));
+ pud_populate(&init_mm, pud_set_fixmap_offset(pgd, FIXADDR_START),
+ lm_alias(bm_pmd));
pud_clear_fixmap();
} else {
BUG();
@@ -611,7 +611,7 @@ int __meminit vmemmap_populate(unsigned
if (!p)
return -ENOMEM;

- set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
+ pmd_set_huge(pmd, __pa(p), __pgprot(PROT_SECT_NORMAL));
} else
vmemmap_verify((pte_t *)pmd, node, addr, next);
} while (addr = next, addr != end);
@@ -797,15 +797,19 @@ int __init arch_ioremap_pmd_supported(vo

int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
{
+ pgprot_t sect_prot = __pgprot(PUD_TYPE_SECT |
+ pgprot_val(mk_sect_prot(prot)));
BUG_ON(phys & ~PUD_MASK);
- set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
+ set_pud(pud, pfn_pud(__phys_to_pfn(phys), sect_prot));
return 1;
}

int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
{
+ pgprot_t sect_prot = __pgprot(PMD_TYPE_SECT |
+ pgprot_val(mk_sect_prot(prot)));
BUG_ON(phys & ~PMD_MASK);
- set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
+ set_pmd(pmd, pfn_pmd(__phys_to_pfn(phys), sect_prot));
return 1;
}