| Message ID | 20200322110028.18279-8-alex@ghiti.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce sv48 support | expand |
On Sun, Mar 22, 2020 at 4:37 PM Alexandre Ghiti <alex@ghiti.fr> wrote: > > Define precisely the size of the user accessible virtual space size > for sv32/39/48 mmu types and explain why the whole virtual address > space is split into 2 equal chunks between kernel and user space. > > Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > --- > arch/riscv/include/asm/pgtable.h | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 06361db3f486..be117a0b4ea1 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -456,8 +456,15 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma, > #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > > /* > - * 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) > -- > 2.20.1 > Looks good to me. Reviewed-by: Anup Patel <anup@brainfault.org> Regards, Anup
On Sun, 22 Mar 2020 04:00:28 PDT (-0700), alex@ghiti.fr wrote: > Define precisely the size of the user accessible virtual space size > for sv32/39/48 mmu types and explain why the whole virtual address > space is split into 2 equal chunks between kernel and user space. > > Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > --- > arch/riscv/include/asm/pgtable.h | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 06361db3f486..be117a0b4ea1 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -456,8 +456,15 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma, > #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > > /* > - * 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) Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
On 4/3/20 11:53 AM, Palmer Dabbelt wrote: > On Sun, 22 Mar 2020 04:00:28 PDT (-0700), alex@ghiti.fr wrote: >> Define precisely the size of the user accessible virtual space size >> for sv32/39/48 mmu types and explain why the whole virtual address >> space is split into 2 equal chunks between kernel and user space. >> >> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> >> --- >> arch/riscv/include/asm/pgtable.h | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >> >> diff --git a/arch/riscv/include/asm/pgtable.h >> b/arch/riscv/include/asm/pgtable.h >> index 06361db3f486..be117a0b4ea1 100644 >> --- a/arch/riscv/include/asm/pgtable.h >> +++ b/arch/riscv/include/asm/pgtable.h >> @@ -456,8 +456,15 @@ static inline int ptep_clear_flush_young(struct >> vm_area_struct *vma, >> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) >> >> /* >> - * 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) > > Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Thanks, Alex
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 06361db3f486..be117a0b4ea1 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -456,8 +456,15 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma, #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) /* - * 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)
Define precisely the size of the user accessible virtual space size for sv32/39/48 mmu types and explain why the whole virtual address space is split into 2 equal chunks between kernel and user space. Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> --- arch/riscv/include/asm/pgtable.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)