linux-kernel - Re: [PATCH 1/1] x86: don't exclude low BIOS area when allocating address space for non-PCI cards

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Message-ID: <CAErSpo5_wJrA_aHL9Oy3_qq_UUCb2-7ioY_wARKFFUoM9Ag6FQ@mail.gmail.com>
Date:	Wed, 16 Jul 2014 13:00:21 -0600
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	Christoph Schulz <develop@...stov.de>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"x86@...nel.org" <x86@...nel.org>,
	Robert Resch <fli4l@...ert.reschpara.de>
Subject: Re: [PATCH 1/1] x86: don't exclude low BIOS area when allocating
 address space for non-PCI cards

On Wed, Jul 16, 2014 at 2:00 AM, Christoph Schulz <develop@...stov.de> wrote:
> From: Christoph Schulz <develop@...stov.de>
>
> Commit 30919b0bf356a8ee0ef4f7d38ca8ad99b96820b2 ("x86: avoid low BIOS area when
> allocating address space") moved the test for resource allocations that fall
> within the first 1MB of address space from the PCI-specific path to a generic
> path, such that all resource allocations will avoid this area. However, this
> breaks ISA cards which need to allocate a memory region within the first 1MB.
> An example is the i82365 PCMCIA controller and derivatives like the Ricoh
> RF5C296/396 which map part of the PCMCIA socket memory address space into the
> first 1MB of system memory address space. They do not work anymore as no usable
> memory region exists due to this change:
>
> Intel ISA PCIC probe: Ricoh RF5C296/396 ISA-to-PCMCIA at port 0x3e0 ofs 0x00, 2 sockets
> host opts [0]: none
> host opts [1]: none
> ISA irqs (scanned) = 3,4,5,9,10 status change on irq 10
> pcmcia_socket pcmcia_socket1: pccard: PCMCIA card inserted into slot 1
> pcmcia_socket pcmcia_socket0: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
> pcmcia_socket pcmcia_socket0: cs: IO port probe 0xa00-0xaff: clean.
> pcmcia_socket pcmcia_socket0: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
> pcmcia_socket pcmcia_socket0: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
> pcmcia_socket pcmcia_socket0: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
> pcmcia_socket pcmcia_socket0: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
> pcmcia_socket pcmcia_socket0: cs: memory probe 0x0d0000-0x0dffff: clean.
> pcmcia_socket pcmcia_socket0: cs: memory probe 0x0e0000-0x0effff: clean.
> pcmcia_socket pcmcia_socket0: cs: memory probe 0x60000000-0x60ffffff: clean.
> pcmcia_socket pcmcia_socket0: cs: memory probe 0xa0000000-0xa0ffffff: clean.
> pcmcia_socket pcmcia_socket1: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff
> pcmcia_socket pcmcia_socket1: cs: IO port probe 0xa00-0xaff: clean.
> pcmcia_socket pcmcia_socket1: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff
> pcmcia_socket pcmcia_socket1: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff
> pcmcia_socket pcmcia_socket1: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff
> pcmcia_socket pcmcia_socket1: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff
> pcmcia_socket pcmcia_socket1: cs: memory probe 0x0d0000-0x0dffff: clean.
> pcmcia_socket pcmcia_socket1: cs: memory probe 0x0e0000-0x0effff: clean.
> pcmcia_socket pcmcia_socket1: cs: memory probe 0x60000000-0x60ffffff: clean.
> pcmcia_socket pcmcia_socket1: cs: memory probe 0xa0000000-0xa0ffffff: clean.
> pcmcia_socket pcmcia_socket1: cs: memory probe 0x0cc000-0x0effff: excluding 0xe0000-0xeffff
> pcmcia_socket pcmcia_socket1: cs: unable to map card memory!
>
> If filtering out the first 1MB is reverted, everything works as expected.
>
> Signed-off-by: Christoph Schulz <develop@...stov.de>
> Tested-by: Robert Resch <fli4l@...ert.reschpara.de>

I applied this to pci/misc for v3.17, thanks.

This effectively reverts 30919b0bf356 ("x86: avoid low BIOS area when
allocating address space").  I don't see a reference there to a bug
fixed by 30919b0bf356, so hopefully reverting it won't reintroduce a
bug.

> ---
> diff --git a/arch/x86/kernel/resource.c b/arch/x86/kernel/resource.c
> index 2a26819..80eab01 100644
> --- a/arch/x86/kernel/resource.c
> +++ b/arch/x86/kernel/resource.c
> @@ -37,10 +37,12 @@ static void remove_e820_regions(struct resource *avail)
>
>  void arch_remove_reservations(struct resource *avail)
>  {
> -       /* Trim out BIOS areas (low 1MB and high 2MB) and E820 regions */
> +       /*
> +        * Trim out BIOS area (high 2MB) and E820 regions. We do not remove
> +        * the low 1MB unconditionally, as this area is needed for some ISA
> +        * cards requiring a memory range, e.g. the i82365 PCMCIA controller.
> +        */
>         if (avail->flags & IORESOURCE_MEM) {
> -               if (avail->start < BIOS_END)
> -                       avail->start = BIOS_END;
>                 resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
>
>                 remove_e820_regions(avail);
> diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
> index a19ed92..2ae525e 100644
> --- a/arch/x86/pci/i386.c
> +++ b/arch/x86/pci/i386.c
> @@ -162,6 +162,10 @@ pcibios_align_resource(void *data, const struct resource *res,
>                         return start;
>                 if (start & 0x300)
>                         start = (start + 0x3ff) & ~0x3ff;
> +       } else if (res->flags & IORESOURCE_MEM) {
> +               /* The low 1MB range is reserved for ISA cards */
> +               if (start < BIOS_END)
> +                       start = BIOS_END;
>         }
>         return start;
>  }
> --
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