[PATCH] riscv: keep interrupts disabled for BREAKPOINT exception

From: Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Guo Ren <guoren@linux.alibaba.com>,
	Masami Hiramatsu <mhiramat@kernel.org>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: keep interrupts disabled for BREAKPOINT exception
Date: Tue, 30 Mar 2021 02:16:24 +0800	[thread overview]
Message-ID: <20210330021624.2b776386@xhacker> (raw)

From: Jisheng Zhang <jszhang@kernel.org>

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")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 arch/riscv/kernel/entry.S | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 744f3209c48d..4114b65698ec 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -130,6 +130,8 @@ skip_context_tracking:
 	 */
 	andi t0, s1, SR_PIE
 	beqz t0, 1f
+	li t0, EXC_BREAKPOINT
+	beq s4, t0, 1f
 #ifdef CONFIG_TRACE_IRQFLAGS
 	call trace_hardirqs_on
 #endif
-- 
2.31.0



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