diff options
Diffstat (limited to 'arch/riscv/include/asm/pgtable.h')
| -rw-r--r-- | arch/riscv/include/asm/pgtable.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 2ab6650d3926..d0a96b507561 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -685,6 +685,15 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, /* * Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32. * Note that PGDIR_SIZE must evenly divide TASK_SIZE. + * Task size is: + * - 0x9fc00000 (~2.5GB) for RV32. + * - 0x4000000000 ( 256GB) for RV64 using SV39 mmu + * - 0x800000000000 ( 128TB) for RV64 using SV48 mmu + * + * Note that PGDIR_SIZE must evenly divide TASK_SIZE since "RISC-V + * Instruction Set Manual Volume II: Privileged Architecture" states that + * "load and store effective addresses, which are 64bits, must have bits + * 63–48 all equal to bit 47, or else a page-fault exception will occur." */ #ifdef CONFIG_64BIT #define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2) |