[v1, 2/3] RISC-V: vector: export VLENB csr in __sc_riscv_v_state

[Andy Chiu]

VLENB is critical for callers of ptrace to reconstruct Vector register
files from the register dump of NT_RISCV_VECTOR. Also, future systems
may will have a writable VLENB, so add it now to potentially save future
compatibility issue.

Fixes: 0c59922c769a ("riscv: Add ptrace vector support")
Signed-off-by: Andy Chiu <andy.chiu at sifive.com>
---
 arch/riscv/include/asm/vector.h      | 3 ++-
 arch/riscv/include/uapi/asm/ptrace.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
index 3d78930cab51..c5ee07b3df07 100644
--- a/arch/riscv/include/asm/vector.h
+++ b/arch/riscv/include/asm/vector.h
@@ -70,8 +70,9 @@ static __always_inline void __vstate_csr_save(struct __riscv_v_ext_state *dest)
 		"csrr	%1, " __stringify(CSR_VTYPE) "\n\t"
 		"csrr	%2, " __stringify(CSR_VL) "\n\t"
 		"csrr	%3, " __stringify(CSR_VCSR) "\n\t"
+		"csrr	%4, " __stringify(CSR_VLENB) "\n\t"
 		: "=r" (dest->vstart), "=r" (dest->vtype), "=r" (dest->vl),
-		  "=r" (dest->vcsr) : :);
+		  "=r" (dest->vcsr), "=r" (dest->vlenb) : :);
 }
 
 static __always_inline void __vstate_csr_restore(struct __riscv_v_ext_state *src)
diff --git a/arch/riscv/include/uapi/asm/ptrace.h b/arch/riscv/include/uapi/asm/ptrace.h
index e17c550986a6..283800130614 100644
--- a/arch/riscv/include/uapi/asm/ptrace.h
+++ b/arch/riscv/include/uapi/asm/ptrace.h
@@ -97,6 +97,7 @@ struct __riscv_v_ext_state {
 	unsigned long vl;
 	unsigned long vtype;
 	unsigned long vcsr;
+	unsigned long vlenb;
 	void *datap;
 	/*
 	 * In signal handler, datap will be set a correct user stack offset
-- 
2.17.1