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authorHeiko Stuebner <heiko.stuebner@vrull.eu>2023-01-13 22:23:01 +0100
committerPalmer Dabbelt <palmer@rivosinc.com>2023-01-31 11:43:24 -0800
commitb6fcdb191e36f82336f9b5e126d51c02e7323480 (patch)
tree9478e9f2e5141295105137ec3e62e1aa9e6141d2 /arch/riscv/Kconfig
parent56e0790c7f9e59ba6a0f4b59981d1d6fbf43efb0 (diff)
downloadlwn-b6fcdb191e36f82336f9b5e126d51c02e7323480.tar.gz
lwn-b6fcdb191e36f82336f9b5e126d51c02e7323480.zip
RISC-V: add zbb support to string functions
Add handling for ZBB extension and add support for using it as a variant for optimized string functions. Support for the Zbb-str-variants is limited to the GNU-assembler for now, as LLVM has not yet acquired the functionality to selectively change the arch option in assembler code. This is still under review at https://reviews.llvm.org/D123515 Co-developed-by: Christoph Muellner <christoph.muellner@vrull.eu> Signed-off-by: Christoph Muellner <christoph.muellner@vrull.eu> Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230113212301.3534711-3-heiko@sntech.de Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/Kconfig')
-rw-r--r--arch/riscv/Kconfig24
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index e2b656043abf..7c814fbf9527 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -416,6 +416,30 @@ config RISCV_ISA_SVPBMT
If you don't know what to do here, say Y.
+config TOOLCHAIN_HAS_ZBB
+ bool
+ default y
+ depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zbb)
+ depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zbb)
+ depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
+ depends on AS_IS_GNU
+
+config RISCV_ISA_ZBB
+ bool "Zbb extension support for bit manipulation instructions"
+ depends on TOOLCHAIN_HAS_ZBB
+ depends on !XIP_KERNEL && MMU
+ select RISCV_ALTERNATIVE
+ default y
+ help
+ Adds support to dynamically detect the presence of the ZBB
+ extension (basic bit manipulation) and enable its usage.
+
+ The Zbb extension provides instructions to accelerate a number
+ of bit-specific operations (count bit population, sign extending,
+ bitrotation, etc).
+
+ If you don't know what to do here, say Y.
+
config TOOLCHAIN_HAS_ZICBOM
bool
default y