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IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR sizes

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Go through the iomem resource tree to check if any of the ioremap()
requests span more than any slot in the iomem resource tree and do
a WARN_ON() if we hit this check.

This will raise a red-flag, if some driver is mapping more than what
is needed. And hopefully identify possible corruptions much earlier.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Suresh Siddha 2008-09-25 18:43:34 -07:00 committed by Ingo Molnar
parent 9a22b6e76b
commit 379daf6290
3 changed files with 40 additions and 0 deletions
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6
arch/x86/mm/ioremap.c
View File

@ -149,6 +149,12 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
if (is_ISA_range(phys_addr, last_addr))
return (__force void __iomem *)phys_to_virt(phys_addr);
/*
* Check if the request spans more than any BAR in the iomem resource
* tree.
*/
WARN_ON(iomem_map_sanity_check(phys_addr, size));
/*
* Don't allow anybody to remap normal RAM that we're using..
*/

1
include/linux/ioport.h
View File

@ -169,6 +169,7 @@ extern struct resource * __devm_request_region(struct device *dev,
extern void __devm_release_region(struct device *dev, struct resource *parent,
resource_size_t start, resource_size_t n);
extern int iomem_map_sanity_check(resource_size_t addr, unsigned long size);
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_IOPORT_H */

33
kernel/resource.c
View File

@ -827,3 +827,36 @@ static int __init reserve_setup(char *str)
}
__setup("reserve=", reserve_setup);
/*
* Check if the requested addr and size spans more than any slot in the
* iomem resource tree.
*/
int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
{
struct resource *p = &iomem_resource;
int err = 0;
loff_t l;
read_lock(&resource_lock);
for (p = p->child; p ; p = r_next(NULL, p, &l)) {
/*
* We can probably skip the resources without
* IORESOURCE_IO attribute?
*/
if (p->start >= addr + size)
continue;
if (p->end < addr)
continue;
if (p->start <= addr && (p->end >= addr + size - 1))
continue;
printk(KERN_WARNING "resource map sanity check conflict: "
"0x%llx 0x%llx 0x%llx 0x%llx %s\n",
addr, addr + size - 1, p->start, p->end, p->name);
err = -1;
break;
}
read_unlock(&resource_lock);
return err;
}