linux-kernel - Re: [PATCH v4 1/4] genirq: define an empty function set_handle_irq() if !GENERIC_IRQ_MULTI

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 17 Sep 2020 11:46:16 +0800
From:   "Leizhen (ThunderTown)" <thunder.leizhen@...wei.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <maz@...nel.org>,
        Rob Herring <robh+dt@...nel.org>, Guo Ren <guoren@...nel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-csky <linux-csky@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
CC:     Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
        Haoyu Lv <lvhaoyu@...wei.com>, Libin <huawei.libin@...wei.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Jianguo Chen <chenjianguo3@...wei.com>
Subject: Re: [PATCH v4 1/4] genirq: define an empty function set_handle_irq()
 if !GENERIC_IRQ_MULTI_HANDLER



On 2020/9/15 16:43, Zhen Lei wrote:
> To avoid compilation error if an irqchip driver references the function
> set_handle_irq() but may not select GENERIC_IRQ_MULTI_HANDLER on some
> systems.

Hi, Marc:
  Do you agree with this method?

  Otherwise, I should use "#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER ... #endif"
to perform the compilation isolation. This may make the code less beautiful.

> 
> For example, the Synopsys DesignWare APB interrupt controller
> (dw_apb_ictl) is used as the secondary interrupt controller on arc, csky,
> arm64, and most arm32 SoCs, and it's also used as the primary interrupt
> controller on Hisilicon SD5203 (an arm32 SoC). The latter need to use
> set_handle_irq() to register the top-level IRQ handler, but this multi
> irq handler registration mechanism is not implemented on arc system.
> 
> The input parameter "handle_irq" maybe defined as static and only
> set_handle_irq() references it. This will trigger "defined but not used"
> warning. So add "(void)handle_irq" to suppress it.
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
> ---
>  include/linux/irq.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index 1b7f4dfee35b397..0848a2aaa9b40b1 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -1252,6 +1252,8 @@ void irq_matrix_free(struct irq_matrix *m, unsigned int cpu,
>   * top-level IRQ handler.
>   */
>  extern void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
> +#else
> +#define set_handle_irq(handle_irq)	do { (void)handle_irq; } while (0)
>  #endif
>  
>  #endif /* _LINUX_IRQ_H */
>