[PATCH] riscv: Reset pmm when PR_TAGGED_ADDR_ENABLE is not set

[Zishun Yi <vulab@iscas.ac.cn>]

In set_tagged_addr_ctrl(), when PR_TAGGED_ADDR_ENABLE is not set, pmlen
is correctly set to 0, but it forgets to reset pmm. This results in the
CPU pmm state not corresponding to the software pmlen state.

Fix this by resetting pmm along with pmlen.

Fixes: 2e1743085887 ("riscv: Add support for the tagged address ABI")
Signed-off-by: Zishun Yi <vulab@iscas.ac.cn>
---
 arch/riscv/kernel/process.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index aacb23978f93..5957effab57c 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -347,8 +347,10 @@ long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg)
 	if (arg & PR_TAGGED_ADDR_ENABLE && (tagged_addr_disabled || !pmlen))
 		return -EINVAL;
 
-	if (!(arg & PR_TAGGED_ADDR_ENABLE))
+	if (!(arg & PR_TAGGED_ADDR_ENABLE)) {
 		pmlen = PMLEN_0;
+		pmm = ENVCFG_PMM_PMLEN_0;
+	}
 
 	if (mmap_write_lock_killable(mm))
 		return -EINTR;
-- 
2.51.2