[PATCH 1/3] arm64: fix ID map extension to 52 bits

[Suzuki K Poulose]

On 15/01/18 15:23, Kristina Martsenko wrote:
> Commit fa2a8445b1d3 added support for extending the ID map to 52 bits,
> but accidentally dropped a required change to __cpu_uses_extended_idmap.
> As a result, the kernel fails to boot when VA_BITS = 48 and the ID map
> text is in 52-bit physical memory, because we reduce TCR.T0SZ to cover
> the ID map, but then never set it back to VA_BITS.
> 
> Add back the change, and also clean up some double parentheses.
> 
> Fixes: fa2a8445b1d3 ("arm64: allow ID map to be extended to 52 bits")
> Signed-off-by: Kristina Martsenko <kristina.martsenko at arm.com>
> ---
>   arch/arm64/include/asm/mmu_context.h | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
> index 8f80fcb49252..5aee19905556 100644
> --- a/arch/arm64/include/asm/mmu_context.h
> +++ b/arch/arm64/include/asm/mmu_context.h
> @@ -72,8 +72,7 @@ extern u64 idmap_ptrs_per_pgd;
>   
>   static inline bool __cpu_uses_extended_idmap(void)
>   {
> -	return (!IS_ENABLED(CONFIG_ARM64_VA_BITS_48) &&
> -		unlikely(idmap_t0sz != TCR_T0SZ(VA_BITS)));
> +	return unlikely(idmap_t0sz != TCR_T0SZ(VA_BITS));
>   }
>   
>   /*
> @@ -82,7 +81,7 @@ static inline bool __cpu_uses_extended_idmap(void)
>    */
>   static inline bool __cpu_uses_extended_idmap_level(void)
>   {
> -	return ARM64_HW_PGTABLE_LEVELS((64 - idmap_t0sz)) > CONFIG_PGTABLE_LEVELS;
> +	return ARM64_HW_PGTABLE_LEVELS(64 - idmap_t0sz) > CONFIG_PGTABLE_LEVELS;
>   }
>   
>   /*
> 

Kristina,

Thanks for the fixup.

Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>