Re: [PATCH] arm64: Fix PIE_E1 mapping for _PAGE_READONLY_EXEC

[Yeo Reum Yun]

Hi Seongsu, 

> diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
> index 161e8660eddd..ca14f61dee81 100644
> --- a/arch/arm64/include/asm/pgtable-prot.h
> +++ b/arch/arm64/include/asm/pgtable-prot.h
> @@ -180,7 +180,7 @@ static inline bool __pure lpa2_is_enabled(void)
>       PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_GCS),           PIE_NONE_O) | \
>       PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_GCS_RO),        PIE_NONE_O) | \
>        PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_EXECONLY),      PIE_NONE_O) | \
> -       PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_READONLY_EXEC), PIE_R)      | \
> +       PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_READONLY_EXEC), PIE_RX)     | \
>        PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_SHARED_EXEC),   PIE_RW)     | \
>       PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_READONLY),      PIE_R)      | \
>        PIRx_ELx_PERM_PREP(pte_pi_index(_PAGE_SHARED),        PIE_RW)     | \


NIT: This looks like it allows executing user code from the kernel.
Why is this necessary?


--  
Sincerely,
Yeoreum Yun