Commit 9b50ffb0 authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by Tony Luck
Browse files

[IA64] make ioremap avoid unsupported attributes 



Example memory map (from HP sx1000 with VGA enabled):
    0x00000 - 0x9FFFF supports only WB (cacheable) access
    0xA0000 - 0xBFFFF supports only UC (uncacheable) access
    0xC0000 - 0xFFFFF supports only WB (cacheable) access

pci_read_rom() indirectly uses ioremap(0xC0000) to read the shadow VGA option
ROM.  ioremap() used to default to a 16MB or 64MB UC kernel identity mapping,
which would cause an MCA when reading 0xC0000 since only WB is supported there.

X uses reads the option ROM to initialize devices.  A smaller test case is:
  # echo 1 > /sys/bus/pci/devices/0000:aa:03.0/rom
  # cp /sys/bus/pci/devices/0000:aa:03.0/rom x

To avoid this, we can use the same ioremap_page_range() strategy that most
architectures use for all ioremaps.  These page table mappings come out of the
vmalloc area.  On ia64, these are in region 5 (0xA... addresses) and typically
use 16KB or 64KB mappings instead of 16MB or 64MB mappings.  The smaller
mappings give more flexibility to use the correct attributes.

Signed-off-by: default avatarBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent c4add2e5

arch/ia64/mm/ioremap.c

+55 −5
Original line number Diff line number Diff line 
/*

 * (c) Copyright 2006 Hewlett-Packard Development Company, L.P.

 * (c) Copyright 2006, 2007 Hewlett-Packard Development Company, L.P.

 *	Bjorn Helgaas <bjorn.helgaas@hp.com>

 *

 * This program is free software; you can redistribute it and/or modify
@@ -10,11 +10,13 @@ 
#include <linux/compiler.h>

#include <linux/module.h>

#include <linux/efi.h>

#include <linux/io.h>

#include <linux/vmalloc.h>

#include <asm/io.h>

#include <asm/meminit.h>



static inline void __iomem *

__ioremap (unsigned long phys_addr, unsigned long size)

__ioremap (unsigned long phys_addr)

{

	return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);

}
@@ -22,8 +24,13 @@ __ioremap (unsigned long phys_addr, unsigned long size) 
void __iomem *

ioremap (unsigned long phys_addr, unsigned long size)

{

	void __iomem *addr;

	struct vm_struct *area;

	unsigned long offset;

	pgprot_t prot;

	u64 attr;

	unsigned long gran_base, gran_size;

	unsigned long page_base;



	/*

	 * For things in kern_memmap, we must use the same attribute
@@ -34,7 +41,7 @@ ioremap (unsigned long phys_addr, unsigned long size) 
	if (attr & EFI_MEMORY_WB)

		return (void __iomem *) phys_to_virt(phys_addr);

	else if (attr & EFI_MEMORY_UC)

		return __ioremap(phys_addr, size);

		return __ioremap(phys_addr);



	/*

	 * Some chipsets don't support UC access to memory.  If
@@ -45,7 +52,42 @@ ioremap (unsigned long phys_addr, unsigned long size) 
	if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)

		return (void __iomem *) phys_to_virt(phys_addr);



	return __ioremap(phys_addr, size);

	/*

	 * WB is not supported for the whole granule, so we can't use

	 * the region 7 identity mapping.  If we can safely cover the

	 * area with kernel page table mappings, we can use those

	 * instead.

	 */

	page_base = phys_addr & PAGE_MASK;

	size = PAGE_ALIGN(phys_addr + size) - page_base;

	if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB) {

		prot = PAGE_KERNEL;



		/*

		 * Mappings have to be page-aligned

		 */

		offset = phys_addr & ~PAGE_MASK;

		phys_addr &= PAGE_MASK;



		/*

		 * Ok, go for it..

		 */

		area = get_vm_area(size, VM_IOREMAP);

		if (!area)

			return NULL;



		area->phys_addr = phys_addr;

		addr = (void __iomem *) area->addr;

		if (ioremap_page_range((unsigned long) addr,

				(unsigned long) addr + size, phys_addr, prot)) {

			vunmap((void __force *) addr);

			return NULL;

		}



		return (void __iomem *) (offset + (char __iomem *)addr);

	}



	return __ioremap(phys_addr);

}

EXPORT_SYMBOL(ioremap);
@@ -55,6 +97,14 @@ ioremap_nocache (unsigned long phys_addr, unsigned long size) 
	if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)

		return NULL;



	return __ioremap(phys_addr, size);

	return __ioremap(phys_addr);

}

EXPORT_SYMBOL(ioremap_nocache);



void

iounmap (volatile void __iomem *addr)

{

	if (REGION_NUMBER(addr) == RGN_GATE)

		vunmap((void *) ((unsigned long) addr & PAGE_MASK));

}

EXPORT_SYMBOL(iounmap);

include/asm-ia64/io.h

+1 −5
Original line number Diff line number Diff line
@@ -421,11 +421,7 @@ __writeq (unsigned long val, volatile void __iomem *addr) 


extern void __iomem * ioremap(unsigned long offset, unsigned long size);

extern void __iomem * ioremap_nocache (unsigned long offset, unsigned long size);



static inline void

iounmap (volatile void __iomem *addr)

{

}

extern void iounmap (volatile void __iomem *addr);



/* Use normal IO mappings for DMI */

#define dmi_ioremap ioremap

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