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[220.132.236.182]) by smtp.gmail.com with ESMTPSA id l7sm9139392pjy.12.2019.09.22.17.45.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 22 Sep 2019 17:45:39 -0700 (PDT) From: Vincent Chen To: linux-riscv@lists.infradead.org Cc: paul.walmsley@sifive.com, palmer@sifive.com, aou@eecs.berkeley.edu, linux-kernel@vger.kernel.org, vincent.chen@sifive.com Subject: [PATCH 3/4] riscv: Correct the handling of unexpected ebreak in do_trap_break() Date: Mon, 23 Sep 2019 08:45:16 +0800 Message-Id: <1569199517-5884-4-git-send-email-vincent.chen@sifive.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1569199517-5884-1-git-send-email-vincent.chen@sifive.com> References: <1569199517-5884-1-git-send-email-vincent.chen@sifive.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For the kernel space, all ebreak instructions are determined at compile time because the kernel space debugging module is currently unsupported. Hence, it should be treated as a bug if an ebreak instruction which does not belong to BUG_TRAP_TYPE_WARN or BUG_TRAP_TYPE_BUG is executed in kernel space. For the userspace, debugging module or user problem may intentionally insert an ebreak instruction to trigger a SIGTRAP signal. To approach the above two situations, the do_trap_break() will direct the BUG_TRAP_TYPE_NONE ebreak exception issued in kernel space to die() and will send a SIGTRAP to the trapped process only when the ebreak is in userspace. Signed-off-by: Vincent Chen --- arch/riscv/kernel/traps.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 82f42a55451e..dd13bc90aeb6 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -130,8 +130,6 @@ asmlinkage void do_trap_break(struct pt_regs *regs) type = report_bug(regs->sepc, regs); switch (type) { #ifdef CONFIG_GENERIC_BUG - case BUG_TRAP_TYPE_NONE: - break; case BUG_TRAP_TYPE_WARN: regs->sepc += get_break_insn_length(regs->sepc); return; @@ -140,8 +138,9 @@ asmlinkage void do_trap_break(struct pt_regs *regs) default: die(regs, "Kernel BUG"); } - } - force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc)); + } else + force_sig_fault(SIGTRAP, TRAP_BRKPT, + (void __user *)(regs->sepc)); } #ifdef CONFIG_GENERIC_BUG -- 2.7.4