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>

arch/x86/kernel/acpi/boot.c

@@ -1154,6 +1154,28 @@ int mp_register_gsi(u32 gsi, int triggering, int polarity)
 	return gsi;
 }
 
+int mp_config_acpi_gsi(unsigned char number, unsigned int devfn, u8 pin,
+			u32 gsi, int triggering, int polarity)
+{
+	struct mpc_config_intsrc intsrc;
+	int ioapic;
+
+	/* print the entry should happen on mptable identically */
+	intsrc.mpc_type = MP_INTSRC;
+	intsrc.mpc_irqtype = mp_INT;
+	intsrc.mpc_irqflag = (triggering == ACPI_EDGE_SENSITIVE ? 4 : 0x0c) |
+				(polarity == ACPI_ACTIVE_HIGH ? 1 : 3);
+	intsrc.mpc_srcbus = number;
+	intsrc.mpc_srcbusirq = (((devfn >> 3) & 0x1f) << 2) | ((pin - 1) & 3);
+	ioapic = mp_find_ioapic(gsi);
+	intsrc.mpc_dstapic = mp_ioapic_routing[ioapic].apic_id;
+	intsrc.mpc_dstirq = gsi - mp_ioapic_routing[ioapic].gsi_base;
+
+	MP_intsrc_info(&intsrc);
+
+	return 0;
+}
+
 /*
  * Parse IOAPIC related entries in MADT
  * returns 0 on success, < 0 on error

arch/x86/kernel/e820.c

@@ -739,3 +739,28 @@ u64 __init find_e820_area_size(u64 start, u64 *sizep, u64 align)
 	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;
+}
+