[patch] ia64: make PA() work for both physical identity-mapped virtual addresses

[Bjorn Helgaas]

The EFI Runtime Services Table contains pointers to ia64 function
descriptors.  On existing, pre-Tiano, firmware, SetVirtualAddressMap()
converts *all* these pointers from physical to virtual.  On Tiano-based
firmware, the pointer to the SetVirtualAddressMap() function descriptor
is not converted, so it remains a physical pointer.

The ia64 kexec purgatory patches the SetVirtualAddressMap() function
descriptor so that when the new kernel calls SetVirtualAddressMap(), it
never reaches firmware.  Instead, it calls a dummy function that just
returns success.

Purgatory runs in physical mode, so it must convert the pointer from the
RuntimeServicesTable to a physical address.  This patch makes that
conversion work both for old firmware (where the pointer is an identity-
mapped virtual address) and new Tiano firmware (where the pointer is a
physical address).

Without this patch, kexec on Tiano firmware causes an MCA because
ia64_env_setup() subtracts PAGE_OFFSET from a physical address and ends
up with an invalid physical address.  Referencing that address causes
the MCA.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas at hp.com>

diff --git a/purgatory/arch/ia64/purgatory-ia64.c b/purgatory/arch/ia64/purgatory-ia64.c
index b2fe6d4..acacb56 100644
--- a/purgatory/arch/ia64/purgatory-ia64.c
+++ b/purgatory/arch/ia64/purgatory-ia64.c
@@ -147,7 +147,7 @@ setup_arch(void)
 
 inline unsigned long PA(unsigned long addr)
 {
-	return addr - PAGE_OFFSET;
+	return addr & 0x0fffffffffffffffLL;
 }
 
 void