Summary: the 2.2.1 ioremap does not allow mapping of the very top of
physical space (right up to 0xFFFFFFFF). This should fix that problem and
moves two lines of code so that requests that extend past the top of
physical space fail in the intended way.
Eric Seppanen / sepp@primenet.com
--- linux-2.2.1/arch/i386/mm/ioremap.c Fri Nov 27 17:03:14 1998
+++ linux/arch/i386/mm/ioremap.c Fri Feb 19 11:23:38 1999
@@ -96,9 +96,16 @@
unsigned long offset;
/*
+ * Don't allow zero size or mappings that wrap.
+ * Be careful of integer overflows!
+ */
+ if (!size || phys_addr > phys_addr+(size-1))
+ return NULL;
+
+ /*
* Don't remap the low PCI/ISA area, it's always mapped..
*/
- if (phys_addr >= 0xA0000 && (phys_addr+size) <= 0x100000)
+ if (phys_addr >= 0xA0000 && (phys_addr+(size-1)) < 0x100000)
return phys_to_virt(phys_addr);
/*
@@ -113,12 +120,6 @@
offset = phys_addr & ~PAGE_MASK;
phys_addr &= PAGE_MASK;
size = PAGE_ALIGN(size + offset);
-
- /*
- * Don't allow mappings that wrap..
- */
- if (!size || size > phys_addr + size)
- return NULL;
/*
* Ok, go for it..
-
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