Re: [U-Boot] [PATCH 06/30] riscv: add Kconfig entries for the C and A ISA extensions

Hi Lukas,

On Sat, Oct 20, 2018 at 6:09 AM Lukas Auer lukas.auer@aisec.fraunhofer.de wrote:

Add Kconfig entries for the C (compressed instructions) and A (atomic instructions) ISA extensions. Only the C ISA extension is selectable. This matches the configuration in Linux.

The Kconfig entries are not used yet. A follow-up patch will select the appropriate compiler flags based on the Kconfig configuration.

Signed-off-by: Lukas Auer lukas.auer@aisec.fraunhofer.de

arch/riscv/Kconfig | 9 +++++++++ 1 file changed, 9 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index b81e0d990a..e15329c35e 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -38,6 +38,15 @@ config ARCH_RV64I

endchoice

+config RISCV_ISA_C

•   bool "Emit compressed instructions"
  

•   default y
  

•   help
  

•     This enables the compressed instructions ("C") ISA extension.
  

This is a little bit confusing. Can we use Linux kernel's description instead like below?

Adds "C" to the ISA subsets that the toolchain is allowed to emit when building U-Boot, which results in compressed instructions in the U-Boot binary.

+config RISCV_ISA_A

•   def_bool y
  

I do not believe U-Boot need to care about 'A' extension. So this can be dropped?

config 32BIT bool

Regards, Bin