Re: linux-next: build failure in Linus' tree

[Zenghui Yu]

On 2020/2/10 6:57, Marc Zyngier wrote:
> On Sun, 9 Feb 2020 13:24:18 -0800
> Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Stephen, Linus,
>
> > On Sun, Feb 9, 2020 at 1:08 PM Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> > > Just building Linus' tree, today's linux-next build (arm
> > > multi_v7_defconfig) failed like this:
> > >
> > > arm-linux-gnueabi-ld: drivers/irqchip/irq-gic-v3-its.o: in function `its_vpe_irq_domain_alloc':
> > > irq-gic-v3-its.c:(.text+0x3d50): undefined reference to `__aeabi_uldivmod'
> > >
> > > Caused by commit
> > >
> > >    4e6437f12d6e ("irqchip/gic-v4.1: Ensure L2 vPE table is allocated at RD level")
>
> Gniii... Sorry for the breakage.

Sorry, my bad. I'm going to set up my 32bit ARM for tests (before
sending something out in the future).

> > Ahh. 64-bit divides without using do_div() and friends.
> >
> > Is GICv4 even relevant for 32-bit ARM?
>
> Only should someone boot a large 64bit server in 32bit mode and run VMs
> with direct injection of interrupts. And definitely not once we get rid
> of 32bit KVM.
>
> Do you mind applying the following patch on top? It fixes the breakage
> here.
>
> Thanks,
>
> 	M.
>
> > From d06ab34c3491d3cd191e024bf2da1eb9b8caccdd Mon Sep 17 00:00:00 2001
> From: Marc Zyngier <maz@xxxxxxxxxx>
> Date: Sun, 9 Feb 2020 22:48:50 +0000
> Subject: [PATCH] irqchip/gic-v4.1: Avoid 64bit division for the sake of 32bit
>   ARM
>
> In order to allow the GICv4 code to link properly on 32bit ARM,
> make sure we don't use 64bit divisions when it isn't strictly
> necessary.
>
> Fixes: 4e6437f12d6e ("irqchip/gic-v4.1: Ensure L2 vPE table is allocated at RD level")
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
>   drivers/irqchip/irq-gic-v3-its.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 1ee95f546cb0..83b1186ffcad 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -2444,8 +2444,8 @@ static u64 inherit_vpe_l1_table_from_rd(cpumask_t **mask)
>   static bool allocate_vpe_l2_table(int cpu, u32 id)
>   {
>   	void __iomem *base = gic_data_rdist_cpu(cpu)->rd_base;
> -	u64 val, gpsz, npg;
> -	unsigned int psz, esz, idx;
> +	unsigned int psz, esz, idx, npg, gpsz;
> +	u64 val;
>   	struct page *page;
>   	__le64 *table;
>   

And thanks a lot for your help, Marc!


Zenghui