/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* EFI call stub.
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*
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* Copyright (C) 1999-2001 Hewlett-Packard Co
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* David Mosberger <davidm@hpl.hp.com>
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*
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* This stub allows us to make EFI calls in physical mode with interrupts
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* turned off. We need this because we can't call SetVirtualMap() until
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* the kernel has booted far enough to allow allocation of struct vma_struct
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* entries (which we would need to map stuff with memory attributes other
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* than uncached or writeback...). Since the GetTime() service gets called
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* earlier than that, we need to be able to make physical mode EFI calls from
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* the kernel.
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*/
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/*
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* PSR settings as per SAL spec (Chapter 8 in the "IA-64 System
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* Abstraction Layer Specification", revision 2.6e). Note that
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* psr.dfl and psr.dfh MUST be cleared, despite what this manual says.
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* Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call
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* (the br.ia instruction fails unless psr.dfl and psr.dfh are
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* cleared). Fortunately, SAL promises not to touch the floating
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* point regs, so at least we don't have to save f2-f127.
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*/
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#define PSR_BITS_TO_CLEAR \
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(IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT | \
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IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED | \
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IA64_PSR_DFL | IA64_PSR_DFH)
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#define PSR_BITS_TO_SET \
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(IA64_PSR_BN)
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#include <asm/processor.h>
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#include <asm/asmmacro.h>
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/*
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* Inputs:
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* in0 = address of function descriptor of EFI routine to call
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* in1..in7 = arguments to routine
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*
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* Outputs:
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* r8 = EFI_STATUS returned by called function
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*/
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GLOBAL_ENTRY(efi_call_phys)
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.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
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alloc loc1=ar.pfs,8,7,7,0
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ld8 r2=[in0],8 // load EFI function's entry point
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mov loc0=rp
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.body
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;;
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mov loc2=gp // save global pointer
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mov loc4=ar.rsc // save RSE configuration
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mov ar.rsc=0 // put RSE in enforced lazy, LE mode
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;;
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ld8 gp=[in0] // load EFI function's global pointer
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movl r16=PSR_BITS_TO_CLEAR
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mov loc3=psr // save processor status word
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movl r17=PSR_BITS_TO_SET
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;;
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or loc3=loc3,r17
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mov b6=r2
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;;
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andcm r16=loc3,r16 // get psr with IT, DT, and RT bits cleared
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br.call.sptk.many rp=ia64_switch_mode_phys
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.ret0: mov out4=in5
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mov out0=in1
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mov out1=in2
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mov out2=in3
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mov out3=in4
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mov out5=in6
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mov out6=in7
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mov loc5=r19
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mov loc6=r20
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br.call.sptk.many rp=b6 // call the EFI function
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.ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode
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mov r16=loc3
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mov r19=loc5
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mov r20=loc6
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br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode
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.ret2: mov ar.rsc=loc4 // restore RSE configuration
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mov ar.pfs=loc1
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mov rp=loc0
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mov gp=loc2
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br.ret.sptk.many rp
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END(efi_call_phys)
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