[PATCH 1/3] Revert "RISC-V: mm: Document mmap changes"

From: Charlie Jenkins
Date: Mon Aug 26 2024 - 12:37:32 EST


This mmap behavior caused unintended breakages so the behavior has been
changed.

Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
---
Documentation/arch/riscv/vm-layout.rst | 16 ----------------
1 file changed, 16 deletions(-)

diff --git a/Documentation/arch/riscv/vm-layout.rst b/Documentation/arch/riscv/vm-layout.rst
index 077b968dcc81..eabec99b5852 100644
--- a/Documentation/arch/riscv/vm-layout.rst
+++ b/Documentation/arch/riscv/vm-layout.rst
@@ -134,19 +134,3 @@ RISC-V Linux Kernel SV57
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | modules, BPF
ffffffff80000000 | -2 GB | ffffffffffffffff | 2 GB | kernel
__________________|____________|__________________|_________|____________________________________________________________
-
-
-Userspace VAs
---------------------
-To maintain compatibility with software that relies on the VA space with a
-maximum of 48 bits the kernel will, by default, return virtual addresses to
-userspace from a 48-bit range (sv48). This default behavior is achieved by
-passing 0 into the hint address parameter of mmap. On CPUs with an address space
-smaller than sv48, the CPU maximum supported address space will be the default.
-
-Software can "opt-in" to receiving VAs from another VA space by providing
-a hint address to mmap. When a hint address is passed to mmap, the returned
-address will never use more bits than the hint address. For example, if a hint
-address of `1 << 40` is passed to mmap, a valid returned address will never use
-bits 41 through 63. If no mappable addresses are available in that range, mmap
-will return `MAP_FAILED`.

--
2.45.0