[PATCH v2 2/5] riscv: misaligned: enable IRQs while handling misaligned accesses

[Clément Léger]

We can safely reenable IRQs if coming from userspace. This allows to
access user memory that could potentially trigger a page fault.

Fixes: b686ecdeacf6 ("riscv: misaligned: Restrict user access to kernel memory")
Signed-off-by: Clément Léger <cleger at rivosinc.com>
---
 arch/riscv/kernel/traps.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index b1d991c78a23..9c83848797a7 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -220,19 +220,23 @@ static void do_trap_misaligned(struct pt_regs *regs, enum misaligned_access_type
 {
 	irqentry_state_t state;
 
-	if (user_mode(regs))
+	if (user_mode(regs)) {
 		irqentry_enter_from_user_mode(regs);
-	else
+		local_irq_enable();
+	} else {
 		state = irqentry_nmi_enter(regs);
+	}
 
 	if (misaligned_handler[type].handler(regs))
 		do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
 			      misaligned_handler[type].type_str);
 
-	if (user_mode(regs))
+	if (user_mode(regs)) {
+		local_irq_disable();
 		irqentry_exit_to_user_mode(regs);
-	else
+	} else {
 		irqentry_nmi_exit(regs, state);
+	}
 }
 
 asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs)
-- 
2.49.0