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80851ef2a5
Add a hook so architectures can validate /dev/mem mmap requests.
This is analogous to validation we already perform in the read/write
paths.
The identity mapping scheme used on ia64 requires that each 16MB or
64MB granule be accessed with exactly one attribute (write-back or
uncacheable). This avoids "attribute aliasing", which can cause a
machine check.
Sample problem scenario:
- Machine supports VGA, so it has uncacheable (UC) MMIO at 640K-768K
- efi_memmap_init() discards any write-back (WB) memory in the first granule
- Application (e.g., "hwinfo") mmaps /dev/mem, offset 0
- hwinfo receives UC mapping (the default, since memmap says "no WB here")
- Machine check abort (on chipsets that don't support UC access to WB
memory, e.g., sx1000)
In the scenario above, the only choices are
- Use WB for hwinfo mmap. Can't do this because it causes attribute
aliasing with the UC mapping for the VGA MMIO space.
- Use UC for hwinfo mmap. Can't do this because the chipset may not
support UC for that region.
- Disallow the hwinfo mmap with -EINVAL. That's what this patch does.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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| .. | ||
| cpufreq | ||
| acpi-ext.c | ||
| acpi.c | ||
| asm-offsets.c | ||
| brl_emu.c | ||
| cyclone.c | ||
| efi_stub.S | ||
| efi.c | ||
| entry.h | ||
| entry.S | ||
| fsys.S | ||
| gate-data.S | ||
| gate.lds.S | ||
| gate.S | ||
| head.S | ||
| ia64_ksyms.c | ||
| init_task.c | ||
| iosapic.c | ||
| irq_ia64.c | ||
| irq_lsapic.c | ||
| irq.c | ||
| ivt.S | ||
| jprobes.S | ||
| kprobes.c | ||
| machvec.c | ||
| Makefile | ||
| mca_asm.S | ||
| mca_drv_asm.S | ||
| mca_drv.c | ||
| mca_drv.h | ||
| mca.c | ||
| minstate.h | ||
| module.c | ||
| numa.c | ||
| pal.S | ||
| palinfo.c | ||
| patch.c | ||
| perfmon_default_smpl.c | ||
| perfmon_generic.h | ||
| perfmon_itanium.h | ||
| perfmon_mckinley.h | ||
| perfmon.c | ||
| process.c | ||
| ptrace.c | ||
| sal.c | ||
| salinfo.c | ||
| semaphore.c | ||
| setup.c | ||
| sigframe.h | ||
| signal.c | ||
| smp.c | ||
| smpboot.c | ||
| sys_ia64.c | ||
| time.c | ||
| topology.c | ||
| traps.c | ||
| unaligned.c | ||
| uncached.c | ||
| unwind_decoder.c | ||
| unwind_i.h | ||
| unwind.c | ||
| vmlinux.lds.S | ||