From: Christoph Hellwig <hch@infradead.org>
To: Vincent Chen <vincent.chen@sifive.com>
Cc: linux-riscv@lists.infradead.org, palmer@sifive.com,
linux-kernel@vger.kernel.org, aou@eecs.berkeley.edu,
paul.walmsley@sifive.com
Subject: Re: [PATCH 4/4] riscv: remove the switch statement in do_trap_break()
Date: Fri, 27 Sep 2019 15:47:11 -0700 [thread overview]
Message-ID: <20190927224711.GI4700@infradead.org> (raw)
In-Reply-To: <1569199517-5884-5-git-send-email-vincent.chen@sifive.com>
On Mon, Sep 23, 2019 at 08:45:17AM +0800, Vincent Chen wrote:
> To make the code more straightforward, replacing the switch statement
> with if statement.
>
> Suggested-by: Paul Walmsley <paul.walmsley@sifive.com>
> Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
> ---
> arch/riscv/kernel/traps.c | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index dd13bc90aeb6..1ac75f7d0bff 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -124,23 +124,24 @@ static inline unsigned long get_break_insn_length(unsigned long pc)
>
> asmlinkage void do_trap_break(struct pt_regs *regs)
> {
> + if (user_mode(regs)) {
> + force_sig_fault(SIGTRAP, TRAP_BRKPT,
> + (void __user *)(regs->sepc));
> + return;
> + }
> +#ifdef CONFIG_GENERIC_BUG
> + {
> enum bug_trap_type type;
>
> type = report_bug(regs->sepc, regs);
> + if (type == BUG_TRAP_TYPE_WARN) {
> regs->sepc += get_break_insn_length(regs->sepc);
> return;
> }
> +#endif /* CONFIG_GENERIC_BUG */
> +
> + die(regs, "Kernel BUG");
I like where this is going, but I think this can be improved further
given that fact that report_bug has a nice stub for the
!CONFIG_GENERIC_BUG case.
How about:
if (user_mode(regs))
force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->sepc);
else if (report_bug(regs->sepc, regs) == BUG_TRAP_TYPE_WARN)
regs->sepc += get_break_insn_length(regs->sepc);
else
die(regs, "Kernel BUG");
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next prev parent reply other threads:[~2019-09-27 22:47 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-23 0:45 [PATCH 0/4] riscv: correct the do_trap_break() Vincent Chen
2019-09-23 0:45 ` [PATCH 1/4] riscv: avoid kernel hangs when trapped in BUG() Vincent Chen
2019-09-27 22:25 ` Christoph Hellwig
2019-10-04 18:26 ` Paul Walmsley
2019-09-23 0:45 ` [PATCH 2/4] rsicv: avoid sending a SIGTRAP to a user thread trapped in WARN() Vincent Chen
2019-09-27 22:27 ` Christoph Hellwig
2019-09-27 22:56 ` Christoph Hellwig
2019-09-30 0:22 ` Vincent Chen
2019-10-04 18:26 ` Paul Walmsley
2019-09-23 0:45 ` [PATCH 3/4] riscv: Correct the handling of unexpected ebreak in do_trap_break() Vincent Chen
2019-09-27 22:43 ` Christoph Hellwig
2019-10-04 18:28 ` Paul Walmsley
2019-09-23 0:45 ` [PATCH 4/4] riscv: remove the switch statement " Vincent Chen
2019-09-27 22:47 ` Christoph Hellwig [this message]
2019-10-07 16:08 ` Paul Walmsley
2019-10-07 16:10 ` Christoph Hellwig
2019-10-07 16:30 ` Paul Walmsley
2019-10-08 0:14 ` Vincent Chen
2019-10-08 17:07 ` Paul Walmsley
2019-10-09 22:26 ` Paul Walmsley
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