diff options
Diffstat (limited to 'Documentation/riscv')
| -rw-r--r-- | Documentation/riscv/patch-acceptance.rst | 22 | ||||
| -rw-r--r-- | Documentation/riscv/vm-layout.rst | 36 |
2 files changed, 50 insertions, 8 deletions
diff --git a/Documentation/riscv/patch-acceptance.rst b/Documentation/riscv/patch-acceptance.rst index dfe0ac5624fb..07d5a5623e2a 100644 --- a/Documentation/riscv/patch-acceptance.rst +++ b/Documentation/riscv/patch-acceptance.rst @@ -20,16 +20,22 @@ Submit Checklist Addendum ------------------------- We'll only accept patches for new modules or extensions if the specifications for those modules or extensions are listed as being -"Frozen" or "Ratified" by the RISC-V Foundation. (Developers may, of -course, maintain their own Linux kernel trees that contain code for -any draft extensions that they wish.) +unlikely to be incompatibly changed in the future. For +specifications from the RISC-V foundation this means "Frozen" or +"Ratified", for the UEFI forum specifications this means a published +ECR. (Developers may, of course, maintain their own Linux kernel trees +that contain code for any draft extensions that they wish.) -Additionally, the RISC-V specification allows implementors to create +Additionally, the RISC-V specification allows implementers to create their own custom extensions. These custom extensions aren't required to go through any review or ratification process by the RISC-V Foundation. To avoid the maintenance complexity and potential performance impact of adding kernel code for implementor-specific -RISC-V extensions, we'll only to accept patches for extensions that -have been officially frozen or ratified by the RISC-V Foundation. -(Implementors, may, of course, maintain their own Linux kernel trees -containing code for any custom extensions that they wish.) +RISC-V extensions, we'll only consider patches for extensions that either: + +- Have been officially frozen or ratified by the RISC-V Foundation, or +- Have been implemented in hardware that is widely available, per standard + Linux practice. + +(Implementers, may, of course, maintain their own Linux kernel trees containing +code for any custom extensions that they wish.) diff --git a/Documentation/riscv/vm-layout.rst b/Documentation/riscv/vm-layout.rst index 5b36e45fef60..3be44e74ec5d 100644 --- a/Documentation/riscv/vm-layout.rst +++ b/Documentation/riscv/vm-layout.rst @@ -97,3 +97,39 @@ RISC-V Linux Kernel SV48 ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel __________________|____________|__________________|_________|____________________________________________________________ + + +RISC-V Linux Kernel SV57 +------------------------ + +:: + + ======================================================================================================================== + Start addr | Offset | End addr | Size | VM area description + ======================================================================================================================== + | | | | + 0000000000000000 | 0 | 00ffffffffffffff | 64 PB | user-space virtual memory, different per mm + __________________|____________|__________________|_________|___________________________________________________________ + | | | | + 0100000000000000 | +64 PB | feffffffffffffff | ~16K PB | ... huge, almost 64 bits wide hole of non-canonical + | | | | virtual memory addresses up to the -64 PB + | | | | starting offset of kernel mappings. + __________________|____________|__________________|_________|___________________________________________________________ + | + | Kernel-space virtual memory, shared between all processes: + ____________________________________________________________|___________________________________________________________ + | | | | + ff1bfffffee00000 | -57 PB | ff1bfffffeffffff | 2 MB | fixmap + ff1bffffff000000 | -57 PB | ff1bffffffffffff | 16 MB | PCI io + ff1c000000000000 | -57 PB | ff1fffffffffffff | 1 PB | vmemmap + ff20000000000000 | -56 PB | ff5fffffffffffff | 16 PB | vmalloc/ioremap space + ff60000000000000 | -40 PB | ffdeffffffffffff | 32 PB | direct mapping of all physical memory + ffdf000000000000 | -8 PB | fffffffeffffffff | 8 PB | kasan + __________________|____________|__________________|_________|____________________________________________________________ + | + | Identical layout to the 39-bit one from here on: + ____________________________________________________________|____________________________________________________________ + | | | | + ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF + ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel + __________________|____________|__________________|_________|____________________________________________________________ |