x86: update mptable
make mptable to be consistent with acpi routing, so we could:
1. kexec kernel with acpi=off
2. work around BIOSes where acpi routing is working, but mptable is
not right, so can use kernel/kexec to start other OSes that don't have
good acpi support.
command line: update_mptable
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 0cd9132..cd2b99e 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -739,3 +739,28 @@
return -1UL;
}
+
+/*
+ * pre allocated 4k and reserved it in e820
+ */
+u64 __init early_reserve_e820(u64 startt, u64 sizet, u64 align)
+{
+ u64 size = 0;
+ u64 addr;
+ u64 start;
+
+ start = startt;
+ while (size < sizet)
+ start = find_e820_area_size(start, &size, align);
+
+ if (size < sizet)
+ return 0;
+
+ addr = round_down(start + size - sizet, align);
+ update_memory_range(addr, sizet, E820_RAM, E820_RESERVED);
+ printk(KERN_INFO "update e820 for early_reserve_e820\n");
+ update_e820();
+
+ return addr;
+}
+
