summaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
authorPalmer Dabbelt <palmer@rivosinc.com>2022-07-28 14:07:15 -0700
committerPalmer Dabbelt <palmer@rivosinc.com>2022-10-12 08:58:10 -0700
commit06267eb2decaa6baac81bbd882265a8e7782dba4 (patch)
tree9759083742d36af3785229f7d98559e4fc9a363f /Documentation
parent10f6913c548b32ecb73801a16b120e761c6957ea (diff)
doc: RISC-V: Document that misaligned accesses are supported
The RISC-V ISA manual used to mandate that misaligned accesses were supported in user mode, but that requirement was removed in 2018 via riscv-isa-manual commit 61cadb9 ("Provide new description of misaligned load/store behavior compatible with privileged architecture."). Since the Linux uABI was already frozen at that point it's just been demoted to part of the uABI, but that was never written down. Link: https://lore.kernel.org/r/20220728210715.17214-1-palmer@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/riscv/index.rst1
-rw-r--r--Documentation/riscv/uabi.rst6
2 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/riscv/index.rst b/Documentation/riscv/index.rst
index e23b876ad6eb..2e5b18fbb145 100644
--- a/Documentation/riscv/index.rst
+++ b/Documentation/riscv/index.rst
@@ -8,6 +8,7 @@ RISC-V architecture
boot-image-header
vm-layout
patch-acceptance
+ uabi
features
diff --git a/Documentation/riscv/uabi.rst b/Documentation/riscv/uabi.rst
new file mode 100644
index 000000000000..21a82cfb6c4d
--- /dev/null
+++ b/Documentation/riscv/uabi.rst
@@ -0,0 +1,6 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+RISC-V Linux User ABI
+=====================
+
+Misaligned accesses are supported in userspace, but they may perform poorly.