linux-kernel - Re: ioremap() called early from pnv_pci_init_ioda

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Date:   Sat, 9 May 2020 18:11:37 +1000
From:   "Oliver O'Halloran" <oohall@...il.com>
To:     Qian Cai <cai@....pw>
Cc:     Christophe Leroy <christophe.leroy@....fr>,
        Michael Ellerman <mpe@...erman.id.au>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: ioremap() called early from pnv_pci_init_ioda_phb()

On Sat, May 9, 2020 at 12:41 AM Qian Cai <cai@....pw> wrote:
>
>  Booting POWER9 PowerNV has this message,
>
> "ioremap() called early from pnv_pci_init_ioda_phb+0x420/0xdfc. Use early_ioremap() instead”
>
> but use the patch below will result in leaks because it will never call early_iounmap() anywhere. However, it looks me it was by design that phb->regs mapping would be there forever where it would be used in pnv_ioda_get_inval_reg(), so is just that check_early_ioremap_leak() initcall too strong?

The warning there is junk. The PHBs are setup at boot and never torn
down so we're not "leaking" the mapping. It's supposed to be there for
the lifetime of the kernel.

That said, we could probably move the PCI setup to a point later in
boot where the normal ioremap can be be used. We would have to check
for initcalls which depend on the PHBs being setup and delay those too
though.

Oliver