[RFC PATCH v5 07/13] riscv: Add has_vector/riscv_vsize to save vector features.

[Greentime Hu]

From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

This patch is used to detect vector support status of CPU and use
riscv_vsize to save the size of all the vector registers. It assumes
all harts has the same capabilities in SMP system.

[greentime.hu@xxxxxxxxxx: add support for dynamic vlen]
Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
---
 arch/riscv/kernel/cpufeature.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index c8527d770c98..5a68a926da68 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -16,6 +16,10 @@ unsigned long elf_hwcap __read_mostly;
 #ifdef CONFIG_FPU
 bool has_fpu __read_mostly;
 #endif
+#ifdef CONFIG_VECTOR
+bool has_vector __read_mostly;
+unsigned long riscv_vsize __read_mostly;
+#endif
 
 void riscv_fill_hwcap(void)
 {
@@ -73,4 +77,11 @@ void riscv_fill_hwcap(void)
 	if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
 		has_fpu = true;
 #endif
+
+#ifdef CONFIG_VECTOR
+	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+		has_vector = true;
+		riscv_vsize = csr_read(CSR_VLENB) * 32;
+	}
+#endif
 }
-- 
2.26.2