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.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

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.comSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>
06267eb2 · Palmer Dabbelt · 10f6913c · 06267eb2 · 06267eb2
Commit 06267eb2 authored Jul 28, 2022 by Palmer Dabbelt
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Documentation/riscv/index.rst Documentation/riscv/index.rst +1 -0

Documentation/riscv/uabi.rst Documentation/riscv/uabi.rst +6 -0

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--- 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


--- a/Documentation/riscv/uabi.rst
+++ b/Documentation/riscv/uabi.rst
+.. SPDX-License-Identifier: GPL-2.0
+
+RISC-V Linux User ABI
+=====================
+
+Misaligned accesses are supported in userspace, but they may perform poorly.