@@ -527,7 +527,8 @@ config RISCV_ISA_C
help
Adds "C" to the ISA subsets that the toolchain is allowed to emit
when building Linux, which results in compressed instructions in the
- Linux binary.
+ Linux binary. This option produces a kernel that will not run on
+ systems that do not support compressed instructions.
If you don't know what to do here, say Y.
@@ -537,8 +538,8 @@ config RISCV_ISA_SVNAPOT
depends on RISCV_ALTERNATIVE
default y
help
- Allow kernel to detect the Svnapot ISA-extension dynamically at boot
- time and enable its usage.
+ Enable support for the Svnapot ISA-extension when it is detected
+ at boot.
The Svnapot extension is used to mark contiguous PTEs as a range
of contiguous virtual-to-physical translations for a naturally
@@ -556,9 +557,8 @@ config RISCV_ISA_SVPBMT
depends on RISCV_ALTERNATIVE
default y
help
- Adds support to dynamically detect the presence of the Svpbmt
- ISA-extension (Supervisor-mode: page-based memory types) and
- enable its usage.
+ Add support for the Svpbmt ISA-extension (Supervisor-mode:
+ page-based memory types) in the kernel when it is detected at boot.
The memory type for a page contains a combination of attributes
that indicate the cacheability, idempotency, and ordering
@@ -577,14 +577,15 @@ config TOOLCHAIN_HAS_V
depends on AS_HAS_OPTION_ARCH
config RISCV_ISA_V
- bool "VECTOR extension support"
+ bool "Vector extension support"
depends on TOOLCHAIN_HAS_V
depends on FPU
select DYNAMIC_SIGFRAME
default y
help
- Say N here if you want to disable all vector related procedure
- in the kernel.
+ Add support for the Vector extension when it is detected at boot.
+ When this option is disabled, neither the kernel nor userspace may
+ use vector procedures.
If you don't know what to do here, say Y.
@@ -667,8 +668,8 @@ config RISCV_ISA_ZBB
depends on RISCV_ALTERNATIVE
default y
help
- Adds support to dynamically detect the presence of the ZBB
- extension (basic bit manipulation) and enable its usage.
+ Add support for enabling optimisations in the kernel when the
+ Zbb extension is detected at boot.
The Zbb extension provides instructions to accelerate a number
of bit-specific operations (count bit population, sign extending,
@@ -707,9 +708,9 @@ config RISCV_ISA_ZICBOM
select RISCV_DMA_NONCOHERENT
select DMA_DIRECT_REMAP
help
- Adds support to dynamically detect the presence of the ZICBOM
- extension (Cache Block Management Operations) and enable its
- usage.
+ Add support for the Zicbom extension (Cache Block Management
+ Operations) and enable its use in the kernel when it is detected
+ at boot.
The Zicbom extension can be used to handle for example
non-coherent DMA support on devices that need it.
@@ -722,7 +723,7 @@ config RISCV_ISA_ZICBOZ
default y
help
Enable the use of the Zicboz extension (cbo.zero instruction)
- when available.
+ in the kernel when it is detected at boot.
The Zicboz extension is used for faster zeroing of memory.
@@ -760,8 +761,9 @@ config FPU
bool "FPU support"
default y
help
- Say N here if you want to disable all floating-point related procedure
- in the kernel.
+ Add support for floating point operations when an FPU is detected at
+ boot. When this option is disabled, neither the kernel nor userspace
+ may use the floating point unit.
If you don't know what to do here, say Y.