Re: [PATCH v4 13/29] arm64: convert protection key into vm_flags and pgprot values

[Amit Daniel Kachhap]

On 5/3/24 18:31, Joey Gouly wrote:

Modify arch_calc_vm_prot_bits() and vm_get_page_prot() such that the pkey
value is set in the vm_flags and then into the pgprot value.

Signed-off-by: Joey Gouly <joey.go...@arm.com>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <w...@kernel.org>
---
  arch/arm64/include/asm/mman.h | 8 +++++++-
  arch/arm64/mm/mmap.c          | 9 +++++++++
  2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h
index 5966ee4a6154..ecb2d18dc4d7 100644
--- a/arch/arm64/include/asm/mman.h
+++ b/arch/arm64/include/asm/mman.h
@@ -7,7 +7,7 @@
  #include <uapi/asm/mman.h>

static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,

-       unsigned long pkey __always_unused)
+       unsigned long pkey)
  {
        unsigned long ret = 0;

@@ -17,6 +17,12 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,

        if (system_supports_mte() && (prot & PROT_MTE))
                ret |= VM_MTE;

+#if defined(CONFIG_ARCH_HAS_PKEYS)

Should there be system_supports_poe() check like above?

Thanks,
Amit

+       ret |= pkey & 0x1 ? VM_PKEY_BIT0 : 0;
+       ret |= pkey & 0x2 ? VM_PKEY_BIT1 : 0;
+       ret |= pkey & 0x4 ? VM_PKEY_BIT2 : 0;
+#endif
+
        return ret;
  }
  #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index 642bdf908b22..86eda6bc7893 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -102,6 +102,15 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags)
        if (vm_flags & VM_MTE)
                prot |= PTE_ATTRINDX(MT_NORMAL_TAGGED);

+#ifdef CONFIG_ARCH_HAS_PKEYS

+       if (vm_flags & VM_PKEY_BIT0)
+               prot |= PTE_PO_IDX_0;
+       if (vm_flags & VM_PKEY_BIT1)
+               prot |= PTE_PO_IDX_1;
+       if (vm_flags & VM_PKEY_BIT2)
+               prot |= PTE_PO_IDX_2;
+#endif
+
        return __pgprot(prot);
  }
  EXPORT_SYMBOL(vm_get_page_prot);