Re: [PATCH V3 4/4] riscv: mm: Optimize TASK_SIZE definition

Charlie Jenkins
2024-01-24T18:36:32Z

On Fri, Dec 22, 2023 at 06:57:03AM -0500, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Unify the TASK_SIZE definition with VA_BITS for better readability.
> Add COMPAT mode user address space info in the comment.
>
> Reviewed-by: Leonardo Bras <leobras@redhat.com>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
> ---
> arch/riscv/include/asm/pgtable.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index e415582276ec..271565e1956f 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -866,6 +866,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
> * Note that PGDIR_SIZE must evenly divide TASK_SIZE.
> * Task size is:
> * - 0x9fc00000 (~2.5GB) for RV32.
> + * - 0x80000000 ( 2GB) for RV64 compat mode
> * - 0x4000000000 ( 256GB) for RV64 using SV39 mmu
> * - 0x800000000000 ( 128TB) for RV64 using SV48 mmu
> * - 0x100000000000000 ( 64PB) for RV64 using SV57 mmu
> @@ -877,10 +878,10 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
> * Similarly for SV57, bits 63–57 must be equal to bit 56.
> */
> #ifdef CONFIG_64BIT
> -#define TASK_SIZE_64 (PGDIR_SIZE * PTRS_PER_PGD / 2)
> +#define TASK_SIZE_64 (UL(1) << (VA_BITS - 1))
>
> #ifdef CONFIG_COMPAT
> -#define TASK_SIZE_32 (_AC(0x80000000, UL))
> +#define TASK_SIZE_32 (UL(1) << (VA_BITS_SV32 - 1))
> #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \
> TASK_SIZE_32 : TASK_SIZE_64)
> #else
> --
> 2.40.1
>

Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>