Re: [PATCH v2 2/2] arm64/mm: Move {tramp_pg_dir, swapper_pg_dir} to .rodata section

[Suzuki K Poulose]

Hi Jun

On 25/06/18 12:39, Jun Yao wrote:

When CONFIG_ARM64_VA_BITS_36/CONFIG_ARM64_VA_BITS_39/
CONFIG_ARM64_VA_BITS_42 are selected, a block-mapping can be
written to swapper_pg_dir. To defend 'KSMA', we move swapper_pg_dir
to .rodata section when these configurations are selected. At the
same time, we update swapper_pg_dir by fixmap.

Signed-off-by: Jun Yao <yaojun8558...@gmail.com>
---
  arch/arm64/include/asm/fixmap.h  |  1 +
  arch/arm64/include/asm/pgalloc.h | 33 ++++++++++++++++++++++++++++++++
  arch/arm64/include/asm/pgtable.h |  5 +++++
  arch/arm64/kernel/head.S         |  6 +++---
  arch/arm64/kernel/vmlinux.lds.S  | 23 ++++++++++++++++++++++
  arch/arm64/mm/mmu.c              |  6 ++++++
  6 files changed, 71 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 62908eeedcdc..881784b43965 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -83,6 +83,7 @@ enum fixed_addresses {
        FIX_PTE,
        FIX_PMD,
        FIX_PUD,
+       FIX_SWAPPER,

__end_of_fixed_addresses

  };
diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 2e05bcd944c8..62512ad9c310 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -49,6 +49,22 @@ static inline void __pud_populate(pud_t *pudp, phys_addr_t 
pmdp, pudval_t prot)

static inline void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp)

  {
+#ifdef CONFIG_ARM64_VA_BITS_39

Could we please use

#ifdef __PAGETABLE_PUD_FOLDED ^^

+       }
+#endif
        __pud_populate(pudp, __pa(pmdp), PMD_TYPE_TABLE);
  }
  #else
@@ -142,6 +158,23 @@ pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, 
pte_t *ptep)
        /*
         * The pmd must be loaded with the physical address of the PTE table
         */
+#if defined(CONFIG_ARM64_VA_BITS_42) || \
+       defined(CONFIG_ARM64_VA_BITS_36)

and

#ifdef __PGTABLE_PMD_FOLDED here ^^

+#if defined(CONFIG_ARM64_VA_BITS_39) || \
+       defined(CONFIG_ARM64_VA_BITS_36) || \
+       defined(CONFIG_ARM64_VA_BITS_42)

and

#ifdef __PGTABLE_PMD_FOLDED ^^ (as it implies
__PGTABLE_PUD_FOLDED )

instead ?


Cheers
Suzuki