x86: fix mttr trimming
Pavel Emelyanov reported that his networking card did not work
and bisected it down to:
"
The commit
093af8d7f0ba3c6be1485973508584ef081e9f93
x86_32: trim memory by updating e820
broke my e1000 card: on loading driver says that
e1000: probe of 0000:04:03.0 failed with error -5
and the interface doesn't appear.
"
on a 32-bit kernel, base will overflow when try to do PAGE_SHIFT,
and highest_addr will always less 4G.
So use pfn instead of address to avoid the overflow when more than
4g RAM is installed on a 32-bit kernel.
Many thanks to Pavel Emelyanov for reporting and testing it.
Bisected-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Tested-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 1e27b69..b6e136f 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -659,7 +659,7 @@
*/
int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
{
- unsigned long i, base, size, highest_addr = 0, def, dummy;
+ unsigned long i, base, size, highest_pfn = 0, def, dummy;
mtrr_type type;
u64 trim_start, trim_size;
@@ -682,28 +682,27 @@
mtrr_if->get(i, &base, &size, &type);
if (type != MTRR_TYPE_WRBACK)
continue;
- base <<= PAGE_SHIFT;
- size <<= PAGE_SHIFT;
- if (highest_addr < base + size)
- highest_addr = base + size;
+ if (highest_pfn < base + size)
+ highest_pfn = base + size;
}
/* kvm/qemu doesn't have mtrr set right, don't trim them all */
- if (!highest_addr) {
+ if (!highest_pfn) {
printk(KERN_WARNING "WARNING: strange, CPU MTRRs all blank?\n");
WARN_ON(1);
return 0;
}
- if ((highest_addr >> PAGE_SHIFT) < end_pfn) {
+ if (highest_pfn < end_pfn) {
printk(KERN_WARNING "WARNING: BIOS bug: CPU MTRRs don't cover"
- " all of memory, losing %LdMB of RAM.\n",
- (((u64)end_pfn << PAGE_SHIFT) - highest_addr) >> 20);
+ " all of memory, losing %luMB of RAM.\n",
+ (end_pfn - highest_pfn) >> (20 - PAGE_SHIFT));
WARN_ON(1);
printk(KERN_INFO "update e820 for mtrr\n");
- trim_start = highest_addr;
+ trim_start = highest_pfn;
+ trim_start <<= PAGE_SHIFT;
trim_size = end_pfn;
trim_size <<= PAGE_SHIFT;
trim_size -= trim_start;