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-rw-r--r--arch/riscv/include/asm/switch_to.h6
-rw-r--r--arch/riscv/kernel/process.c11
2 files changed, 15 insertions, 2 deletions
diff --git a/arch/riscv/include/asm/switch_to.h b/arch/riscv/include/asm/switch_to.h
index 853b65ef656d..949d9cd91dec 100644
--- a/arch/riscv/include/asm/switch_to.h
+++ b/arch/riscv/include/asm/switch_to.h
@@ -19,6 +19,12 @@ static inline void __fstate_clean(struct pt_regs *regs)
regs->sstatus |= (regs->sstatus & ~(SR_FS)) | SR_FS_CLEAN;
}
+static inline void fstate_off(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ regs->sstatus = (regs->sstatus & ~SR_FS) | SR_FS_OFF;
+}
+
static inline void fstate_save(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index f23794bd1e90..fb3a082362eb 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -64,8 +64,14 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
unsigned long sp)
{
regs->sstatus = SR_SPIE;
- if (has_fpu)
+ if (has_fpu) {
regs->sstatus |= SR_FS_INITIAL;
+ /*
+ * Restore the initial value to the FP register
+ * before starting the user program.
+ */
+ fstate_restore(current, regs);
+ }
regs->sepc = pc;
regs->sp = sp;
set_fs(USER_DS);
@@ -75,10 +81,11 @@ void flush_thread(void)
{
#ifdef CONFIG_FPU
/*
- * Reset FPU context
+ * Reset FPU state and context
* frm: round to nearest, ties to even (IEEE default)
* fflags: accrued exceptions cleared
*/
+ fstate_off(current, task_pt_regs(current));
memset(&current->thread.fstate, 0, sizeof(current->thread.fstate));
#endif
}