riscv: keep interrupts disabled for BREAKPOINT exception

Current riscv's kprobe handlers are run with both preemption and
interrupt enabled, this violates kprobe requirements. Fix this issue
by keeping interrupts disabled for BREAKPOINT exception.

Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
Cc: stable@vger.kernel.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
[Palmer: add a comment]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 76274a4a1d8e6596dbf3069df999847a94238a7e..83095faa680e1626a0ff162030bff63989dc79e1 100644 (file)
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -130,6 +130,9 @@ skip_context_tracking:
         */
        andi t0, s1, SR_PIE
        beqz t0, 1f
+       /* kprobes, entered via ebreak, must have interrupts disabled. */
+       li t0, EXC_BREAKPOINT
+       beq s4, t0, 1f
 #ifdef CONFIG_TRACE_IRQFLAGS
        call trace_hardirqs_on
 #endif