diff options
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/resource.c | 61 |
1 files changed, 36 insertions, 25 deletions
diff --git a/kernel/resource.c b/kernel/resource.c index fed052a1bc9f..f150dbbe6f62 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -492,40 +492,51 @@ int __weak page_is_ram(unsigned long pfn) } EXPORT_SYMBOL_GPL(page_is_ram); -/* - * Search for a resouce entry that fully contains the specified region. - * If found, return 1 if it is RAM, 0 if not. - * If not found, or region is not fully contained, return -1 +/** + * region_intersects() - determine intersection of region with known resources + * @start: region start address + * @size: size of region + * @name: name of resource (in iomem_resource) * - * Used by the ioremap functions to ensure the user is not remapping RAM and is - * a vast speed up over walking through the resource table page by page. + * Check if the specified region partially overlaps or fully eclipses a + * resource identified by @name. Return REGION_DISJOINT if the region + * does not overlap @name, return REGION_MIXED if the region overlaps + * @type and another resource, and return REGION_INTERSECTS if the + * region overlaps @type and no other defined resource. Note, that + * REGION_INTERSECTS is also returned in the case when the specified + * region overlaps RAM and undefined memory holes. + * + * region_intersect() is used by memory remapping functions to ensure + * the user is not remapping RAM and is a vast speed up over walking + * through the resource table page by page. */ -int region_is_ram(resource_size_t start, unsigned long size) +int region_intersects(resource_size_t start, size_t size, const char *name) { - struct resource *p; - resource_size_t end = start + size - 1; unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY; - const char *name = "System RAM"; - int ret = -1; + resource_size_t end = start + size - 1; + int type = 0; int other = 0; + struct resource *p; read_lock(&resource_lock); for (p = iomem_resource.child; p ; p = p->sibling) { - if (p->end < start) - continue; - - if (p->start <= start && end <= p->end) { - /* resource fully contains region */ - if ((p->flags != flags) || strcmp(p->name, name)) - ret = 0; - else - ret = 1; - break; - } - if (end < p->start) - break; /* not found */ + bool is_type = strcmp(p->name, name) == 0 && p->flags == flags; + + if (start >= p->start && start <= p->end) + is_type ? type++ : other++; + if (end >= p->start && end <= p->end) + is_type ? type++ : other++; + if (p->start >= start && p->end <= end) + is_type ? type++ : other++; } read_unlock(&resource_lock); - return ret; + + if (other == 0) + return type ? REGION_INTERSECTS : REGION_DISJOINT; + + if (type) + return REGION_MIXED; + + return REGION_DISJOINT; } void __weak arch_remove_reservations(struct resource *avail) |