On Fri, Nov 24, 2023 at 04:34:54PM +0000, Joey Gouly wrote:
> arch/arm64/include/asm/mman.h | 8 +++++++-
> arch/arm64/include/asm/page.h | 10 ++++++++++
> arch/arm64/mm/mmap.c | 9 +++++++++
> arch/powerpc/include/asm/page.h | 11 +++++++++++
> arch/x86/include/asm/page.h | 10 ++++++++++
> fs/proc/task_mmu.c | 2 ++
> include/linux/mm.h | 13 -------------
> 7 files changed, 49 insertions(+), 14 deletions(-)
It might be worth splitting out the powerpc/x86/generic parts into a
separate patch.
> 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)
> + ret |= pkey & 0x1 ? VM_PKEY_BIT0 : 0;
> + ret |= pkey & 0x2 ? VM_PKEY_BIT1 : 0;
> + ret |= pkey & 0x4 ? VM_PKEY_BIT2 : 0;
> +#endif
Is there anywhere that rejects pkey & 8 on arm64? Because with 128-bit
PTEs, if we ever support them, we can have 4-bit pkeys.
> #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
> diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
> index 2312e6ee595f..aabfda2516d2 100644
> --- a/arch/arm64/include/asm/page.h
> +++ b/arch/arm64/include/asm/page.h
> @@ -49,6 +49,16 @@ int pfn_is_map_memory(unsigned long pfn);
>
> #define VM_DATA_DEFAULT_FLAGS (VM_DATA_FLAGS_TSK_EXEC | VM_MTE_ALLOWED)
>
> +#if defined(CONFIG_ARCH_HAS_PKEYS)
> +/* A protection key is a 3-bit value */
> +# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_2
> +# define VM_PKEY_BIT0 VM_HIGH_ARCH_2
> +# define VM_PKEY_BIT1 VM_HIGH_ARCH_3
> +# define VM_PKEY_BIT2 VM_HIGH_ARCH_4
> +# define VM_PKEY_BIT3 0
> +# define VM_PKEY_BIT4 0
> +#endif
I think we should start from VM_HIGH_ARCH_BIT_0 and just move the
VM_MTE, VM_MTE_ALLOWED to VM_HIGH_ARCH_BIT_{4,5}.
> diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
> index e5fcc79b5bfb..a5e75ec333ad 100644
> --- a/arch/powerpc/include/asm/page.h
> +++ b/arch/powerpc/include/asm/page.h
> @@ -330,6 +330,17 @@ static inline unsigned long kaslr_offset(void)
> }
>
> #include <asm-generic/memory_model.h>
> +
> +#if defined(CONFIG_ARCH_HAS_PKEYS)
> +# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
> +/* A protection key is a 5-bit value */
> +# define VM_PKEY_BIT0 VM_HIGH_ARCH_0
> +# define VM_PKEY_BIT1 VM_HIGH_ARCH_1
> +# define VM_PKEY_BIT2 VM_HIGH_ARCH_2
> +# define VM_PKEY_BIT3 VM_HIGH_ARCH_3
> +# define VM_PKEY_BIT4 VM_HIGH_ARCH_4
> +#endif /* CONFIG_ARCH_HAS_PKEYS */
> +
> #endif /* __ASSEMBLY__ */
>
> #endif /* _ASM_POWERPC_PAGE_H */
> diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
> index d18e5c332cb9..b770db1a21e7 100644
> --- a/arch/x86/include/asm/page.h
> +++ b/arch/x86/include/asm/page.h
> @@ -87,5 +87,15 @@ static __always_inline u64 __is_canonical_address(u64 vaddr, u8 vaddr_bits)
>
> #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA
>
> +#if defined(CONFIG_ARCH_HAS_PKEYS)
> +# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
> +/* A protection key is a 4-bit value */
> +# define VM_PKEY_BIT0 VM_HIGH_ARCH_0
> +# define VM_PKEY_BIT1 VM_HIGH_ARCH_1
> +# define VM_PKEY_BIT2 VM_HIGH_ARCH_2
> +# define VM_PKEY_BIT3 VM_HIGH_ARCH_3
> +# define VM_PKEY_BIT4 0
> +#endif /* CONFIG_ARCH_HAS_PKEYS */
Rather than moving these to arch code, we could instead keep the generic
definitions with some additional CONFIG_ARCH_HAS_PKEYS_{3,4,5}BIT
selected from the arch code.
--
Catalin
