RISC-V: add Zbb extension detection
From: Heiko Stuebner <heiko.stuebner@...> Date: Wed, 19 Oct 2022 15:36:22 +0200
Commit-Message
Add handling for Zbb extension. Zbb provides basic bit-manipulation instructions. As multiple subsequent features want to check for zbb presence, add the extension handling without directly including code using it. Signed-off-by: Heiko Stuebner <heiko.stuebner@...>
Patch-Comment
arch/riscv/Kconfig | 23 +++++++++++++++++++++++ arch/riscv/include/asm/hwcap.h | 1 + arch/riscv/kernel/cpu.c | 1 + arch/riscv/kernel/cpufeature.c | 1 + 4 files changed, 26 insertions(+)
Statistics
- 26 lines added
- 0 lines removed
Changes
------------------------------ arch/riscv/Kconfig ------------------------------
index f4299ba9a843..f4b0e0144516 100644
@@ -426,6 +426,29 @@ config RISCV_ISA_V
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
+ 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
------------------------ arch/riscv/include/asm/hwcap.h ------------------------
index f413db6118e5..c8c69b49f0ad 100644
@@ -59,6 +59,7 @@ enum riscv_isa_ext_id {
RISCV_ISA_EXT_SSTC,
RISCV_ISA_EXT_SVINVAL,
RISCV_ISA_EXT_SVPBMT,
+ RISCV_ISA_EXT_ZBB,
RISCV_ISA_EXT_ZICBOM,
RISCV_ISA_EXT_ZIHINTPAUSE,
RISCV_ISA_EXT_ID_MAX
--------------------------- arch/riscv/kernel/cpu.c ----------------------------
index 0bf1c7f663fc..420228e219f7 100644
@@ -185,6 +185,7 @@ arch_initcall(riscv_cpuinfo_init);
* New entries to this struct should follow the ordering rules described above.
*/
static struct riscv_isa_ext_data isa_ext_arr[] = {
+ __RISCV_ISA_EXT_DATA(zbb, RISCV_ISA_EXT_ZBB),
__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
------------------------ arch/riscv/kernel/cpufeature.c ------------------------
index cbd60e744c09..33938f91cbbf 100644
@@ -234,6 +234,7 @@ printk("!!!! isa-string: %s\n\n\n", isa);
SET_ISA_EXT_MAP("sstc", RISCV_ISA_EXT_SSTC);
SET_ISA_EXT_MAP("svinval", RISCV_ISA_EXT_SVINVAL);
SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT);
+ SET_ISA_EXT_MAP("zbb", RISCV_ISA_EXT_ZBB);
SET_ISA_EXT_MAP("zicbom", RISCV_ISA_EXT_ZICBOM);
SET_ISA_EXT_MAP("zihintpause", RISCV_ISA_EXT_ZIHINTPAUSE);
}