blob: 58233bb7976dfa46651f80ef2aaa67df9f8627b4 [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
* EFI call stub.
* Copyright (C) 1999-2001 Hewlett-Packard Co
* David Mosberger <>
* This stub allows us to make EFI calls in physical mode with interrupts
* turned off. We need this because we can't call SetVirtualMap() until
* the kernel has booted far enough to allow allocation of struct vma_struct
* entries (which we would need to map stuff with memory attributes other
* than uncached or writeback...). Since the GetTime() service gets called
* earlier than that, we need to be able to make physical mode EFI calls from
* the kernel.
* PSR settings as per SAL spec (Chapter 8 in the "IA-64 System
* Abstraction Layer Specification", revision 2.6e). Note that
* psr.dfl and psr.dfh MUST be cleared, despite what this manual says.
* Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call
* (the br.ia instruction fails unless psr.dfl and psr.dfh are
* cleared). Fortunately, SAL promises not to touch the floating
* point regs, so at least we don't have to save f2-f127.
(IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT | \
IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED | \
#define PSR_BITS_TO_SET \
#include <asm/processor.h>
#include <asm/asmmacro.h>
* Inputs:
* in0 = address of function descriptor of EFI routine to call
* in1..in7 = arguments to routine
* Outputs:
* r8 = EFI_STATUS returned by called function
alloc loc1=ar.pfs,8,7,7,0
ld8 r2=[in0],8 // load EFI function's entry point
mov loc0=rp
mov loc2=gp // save global pointer
mov loc4=ar.rsc // save RSE configuration
mov ar.rsc=0 // put RSE in enforced lazy, LE mode
ld8 gp=[in0] // load EFI function's global pointer
mov loc3=psr // save processor status word
movl r17=PSR_BITS_TO_SET
or loc3=loc3,r17
mov b6=r2
andcm r16=loc3,r16 // get psr with IT, DT, and RT bits cleared rp=ia64_switch_mode_phys
.ret0: mov out4=in5
mov out0=in1
mov out1=in2
mov out2=in3
mov out3=in4
mov out5=in6
mov out6=in7
mov loc5=r19
mov loc6=r20 rp=b6 // call the EFI function
.ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode
mov r16=loc3
mov r19=loc5
mov r20=loc6 rp=ia64_switch_mode_virt // return to virtual mode
.ret2: mov ar.rsc=loc4 // restore RSE configuration
mov ar.pfs=loc1
mov rp=loc0
mov gp=loc2
br.ret.sptk.many rp