[RFC PATCH 4/6] riscv: vector: do not pass task_struct into riscv_v_vstate_{save,restore}()

[Björn Töpel]

From: Andy Chiu <andy.chiu at sifive.com>

riscv_v_vstate_{save,restore}() can operate only on the knowlege of
struct __riscv_v_ext_state, and struct pt_regs. Let the caller decides
which should be passed into the function. Meanwhile, the kernel-mode
Vector is going to introduce another vstate, so this also makes functions
potentially able to be reused.

Signed-off-by: Andy Chiu <andy.chiu at sifive.com>
---
 arch/riscv/include/asm/entry-common.h  |  2 +-
 arch/riscv/include/asm/vector.h        | 14 +++++---------
 arch/riscv/kernel/kernel_mode_vector.c |  2 +-
 arch/riscv/kernel/ptrace.c             |  2 +-
 arch/riscv/kernel/signal.c             |  2 +-
 5 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/riscv/include/asm/entry-common.h b/arch/riscv/include/asm/entry-common.h
index 52926f4d8d7c..aa1b9e50d6c8 100644
--- a/arch/riscv/include/asm/entry-common.h
+++ b/arch/riscv/include/asm/entry-common.h
@@ -12,7 +12,7 @@ static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
 {
 	if (ti_work & _TIF_RISCV_V_DEFER_RESTORE) {
 		clear_thread_flag(TIF_RISCV_V_DEFER_RESTORE);
-		riscv_v_vstate_restore(current, regs);
+		riscv_v_vstate_restore(&current->thread.vstate, regs);
 	}
 }
 
diff --git a/arch/riscv/include/asm/vector.h b/arch/riscv/include/asm/vector.h
index 768acd517414..9b818aac8a94 100644
--- a/arch/riscv/include/asm/vector.h
+++ b/arch/riscv/include/asm/vector.h
@@ -164,23 +164,19 @@ static inline void riscv_v_vstate_discard(struct pt_regs *regs)
 	__riscv_v_vstate_dirty(regs);
 }
 
-static inline void riscv_v_vstate_save(struct task_struct *task,
+static inline void riscv_v_vstate_save(struct __riscv_v_ext_state *vstate,
 				       struct pt_regs *regs)
 {
 	if ((regs->status & SR_VS) == SR_VS_DIRTY) {
-		struct __riscv_v_ext_state *vstate = &task->thread.vstate;
-
 		__riscv_v_vstate_save(vstate, vstate->datap);
 		__riscv_v_vstate_clean(regs);
 	}
 }
 
-static inline void riscv_v_vstate_restore(struct task_struct *task,
+static inline void riscv_v_vstate_restore(struct __riscv_v_ext_state *vstate,
 					  struct pt_regs *regs)
 {
 	if ((regs->status & SR_VS) != SR_VS_OFF) {
-		struct __riscv_v_ext_state *vstate = &task->thread.vstate;
-
 		__riscv_v_vstate_restore(vstate, vstate->datap);
 		__riscv_v_vstate_clean(regs);
 	}
@@ -201,7 +197,7 @@ static inline void __switch_to_vector(struct task_struct *prev,
 	struct pt_regs *regs;
 
 	regs = task_pt_regs(prev);
-	riscv_v_vstate_save(prev, regs);
+	riscv_v_vstate_save(&prev->thread.vstate, regs);
 	riscv_v_vstate_set_restore(next, task_pt_regs(next));
 }
 
@@ -219,8 +215,8 @@ static inline bool riscv_v_vstate_query(struct pt_regs *regs) { return false; }
 static inline bool riscv_v_vstate_ctrl_user_allowed(void) { return false; }
 #define riscv_v_vsize (0)
 #define riscv_v_vstate_discard(regs)		do {} while (0)
-#define riscv_v_vstate_save(task, regs)		do {} while (0)
-#define riscv_v_vstate_restore(task, regs)	do {} while (0)
+#define riscv_v_vstate_save(vstate, regs)	do {} while (0)
+#define riscv_v_vstate_restore(vstate, regs)	do {} while (0)
 #define __switch_to_vector(__prev, __next)	do {} while (0)
 #define riscv_v_vstate_off(regs)		do {} while (0)
 #define riscv_v_vstate_on(regs)			do {} while (0)
diff --git a/arch/riscv/kernel/kernel_mode_vector.c b/arch/riscv/kernel/kernel_mode_vector.c
index 1c3b32d2b340..d9e097e68937 100644
--- a/arch/riscv/kernel/kernel_mode_vector.c
+++ b/arch/riscv/kernel/kernel_mode_vector.c
@@ -68,7 +68,7 @@ void kernel_vector_begin(void)
 
 	BUG_ON(!may_use_simd());
 
-	riscv_v_vstate_save(current, task_pt_regs(current));
+	riscv_v_vstate_save(&current->thread.vstate, task_pt_regs(current));
 
 	get_cpu_vector_context();
 
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
index 2afe460de16a..2e7e00f4f8e1 100644
--- a/arch/riscv/kernel/ptrace.c
+++ b/arch/riscv/kernel/ptrace.c
@@ -100,7 +100,7 @@ static int riscv_vr_get(struct task_struct *target,
 	 * copying them to membuf.
 	 */
 	if (target == current)
-		riscv_v_vstate_save(current, task_pt_regs(current));
+		riscv_v_vstate_save(&current->thread.vstate, task_pt_regs(current));
 
 	ptrace_vstate.vstart = vstate->vstart;
 	ptrace_vstate.vl = vstate->vl;
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 0fca2c128b5f..75fd8cc05e10 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -86,7 +86,7 @@ static long save_v_state(struct pt_regs *regs, void __user **sc_vec)
 	/* datap is designed to be 16 byte aligned for better performance */
 	WARN_ON(unlikely(!IS_ALIGNED((unsigned long)datap, 16)));
 
-	riscv_v_vstate_save(current, regs);
+	riscv_v_vstate_save(&current->thread.vstate, regs);
 	/* Copy everything of vstate but datap. */
 	err = __copy_to_user(&state->v_state, &current->thread.vstate,
 			     offsetof(struct __riscv_v_ext_state, datap));
-- 
2.39.2