RISC-V: add helper function to read the vector VLEN
From: Heiko Stuebner <heiko.stuebner@...> Date: Wed, 15 Feb 2023 13:01:29 +0100
Commit-Message
VLEN describes the length of each vector register and some instructions need specific minimal VLENs to work correctly. The vector code already includes a variable riscv_vsize that contains the value of "32 vector registers with vlenb length" that gets filled during boot. vlenb is the value contained in the CSR_VLENB register and the value represents "VLEN / 8". So add riscv_vector_vlen() to return the actual VLEN value for in-kernel users when they need to check the available VLEN. Signed-off-by: Heiko Stuebner <heiko.stuebner@...>
Patch-Comment
arch/riscv/include/asm/vector.h | 11 +++++++++++ 1 file changed, 11 insertions(+)
Statistics
- 11 lines added
- 0 lines removed
Changes
----------------------- arch/riscv/include/asm/vector.h ------------------------
index 202df9ea28d7..e466e7787d25 100644
@@ -178,4 +178,15 @@ static inline bool riscv_v_vstate_query(struct pt_regs *regs) { return false; }
#endif /* CONFIG_RISCV_ISA_V */
+/*
+ * Return the implementation's vlen value.
+ *
+ * riscv_vsize contains the value of "32 vector registers with vlenb length"
+ * so rebuild the vlen value in bits from it.
+ */
+static inline int riscv_vector_vlen(void)
+{
+ return riscv_v_vsize / 32 * 8;
+}
+
#endif /* ! __ASM_RISCV_VECTOR_H */