[PATCH] x86: cap iomem_resource to addressable physical memory

[H . Peter Anvin]

iomem_resource is by default initialized to -1, which means 64 bits of
physical address space if 64-bit resources are enabled.  However, x86
CPUs cannot address 64 bits of physical address space.  Thus, we want
to cap the physical address space to what the union of all CPU can
actually address.

Without this patch, we may end up assigning inaccessible values to
uninitialized 64-bit PCI memory resources.

Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Matthew Wilcox <matthew@xxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Cc: Martin Mares <mj@xxxxxx>
Cc: stable@xxxxxxxxxx
---
 arch/x86/kernel/cpu/common.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 77848d9..de8a49c 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -839,6 +839,9 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
 #if defined(CONFIG_NUMA) && defined(CONFIG_X86_64)
 	numa_add_cpu(smp_processor_id());
 #endif
+
+	/* Cap the iomem address space to what is addressable on all CPUs */
+	iomem_resource.end &= (1ULL << c->x86_phys_bits) - 1;
 }
 
 #ifdef CONFIG_X86_64
-- 
1.6.0.6


--------------080009000602050700000706--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/