Re: [PATCH 5/5] arm/arm64: KVM: Make default HYP mappings non-excutable

Mark Rutland
2016-06-13T15:29:44Z

Hi,

Nit: typo in subject "excutable" is missing an 'e'.

Mark.

On Mon, Jun 13, 2016 at 03:00:49PM +0100, Marc Zyngier wrote:
> Structures that can be generally written to don't have any requirement
> to be executable (quite the opposite). This includes the kvm and vcpu
> structures, as well as the stacks.
>
> Let's change the default to incorporate the XN flag.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm/include/asm/pgtable.h | 2 +-
> arch/arm64/include/asm/pgtable-prot.h | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
> index 7487bf9..e0d76ba 100644
> --- a/arch/arm/include/asm/pgtable.h
> +++ b/arch/arm/include/asm/pgtable.h
> @@ -97,7 +97,7 @@ extern pgprot_t pgprot_s2_device;
> #define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY)
> #define PAGE_KERNEL _MOD_PROT(pgprot_kernel, L_PTE_XN)
> #define PAGE_KERNEL_EXEC pgprot_kernel
> -#define PAGE_HYP _MOD_PROT(pgprot_kernel, L_PTE_HYP)
> +#define PAGE_HYP _MOD_PROT(pgprot_kernel, L_PTE_HYP | L_PTE_XN)
> #define PAGE_HYP_EXEC _MOD_PROT(pgprot_kernel, L_PTE_HYP | L_PTE_RDONLY)
> #define PAGE_HYP_RO _MOD_PROT(pgprot_kernel, L_PTE_HYP | L_PTE_RDONLY | L_PTE_XN)
> #define PAGE_HYP_DEVICE _MOD_PROT(pgprot_hyp_device, L_PTE_HYP)
> diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
> index 3802048..39f5252 100644
> --- a/arch/arm64/include/asm/pgtable-prot.h
> +++ b/arch/arm64/include/asm/pgtable-prot.h
> @@ -55,7 +55,7 @@
> #define PAGE_KERNEL_EXEC __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
> #define PAGE_KERNEL_EXEC_CONT __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE | PTE_CONT)
>
> -#define PAGE_HYP __pgprot(_PAGE_DEFAULT | PTE_HYP)
> +#define PAGE_HYP __pgprot(_PAGE_DEFAULT | PTE_HYP | PTE_HYP_XN)
> #define PAGE_HYP_EXEC __pgprot(_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY)
> #define PAGE_HYP_RO __pgprot(_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN)
> #define PAGE_HYP_DEVICE __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
> --
> 2.1.4
>