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| author | Bjorn Helgaas <bjorn.helgaas@hp.com> | 2007-03-30 20:34:05 +0400 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2007-03-30 20:37:41 +0400 |
| commit | 9b50ffb0c0281bc5a08ccd56ae9bb84296c28f38 (patch) | |
| tree | 85462c93df91c2fdd0c8fc31643158e9e5cf6734 /include/asm-ia64 | |
| parent | c4add2e537e6f60048dce8dc518254e7e605301d (diff) | |
| download | linux-9b50ffb0c0281bc5a08ccd56ae9bb84296c28f38.tar.xz | |
[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: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'include/asm-ia64')
| -rw-r--r-- | include/asm-ia64/io.h | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/include/asm-ia64/io.h b/include/asm-ia64/io.h index 6311e168cd34..eb17a8692967 100644 --- a/include/asm-ia64/io.h +++ b/include/asm-ia64/io.h @@ -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 |