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* ESI call stub.
* Copyright (C) 2005 Hewlett-Packard Co
* Alex Williamson <>
* Based on EFI call stub by David Mosberger. The stub is virtually
* identical to the one for EFI phys-mode calls, except that ESI
* calls may have up to 8 arguments, so they get passed to this routine
* through memory.
* This stub allows us to make ESI calls in physical mode with interrupts
* turned off. ESI calls may not support calling from virtual mode.
* Google for "Extensible SAL specification" for a document describing the
* ESI standard.
* 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>
#include <asm/export.h>
* Inputs:
* in0 = address of function descriptor of ESI routine to call
* in1 = address of array of ESI parameters
* Outputs:
* r8 = result returned by called function
alloc loc1=ar.pfs,2,7,8,0
ld8 r2=[in0],8 // load ESI function's entry point
mov loc0=rp
ld8 out0=[in1],8 // ESI params loaded from array
;; // passing all as inputs doesn't work
ld8 out1=[in1],8
ld8 out2=[in1],8
ld8 out3=[in1],8
ld8 out4=[in1],8
ld8 out5=[in1],8
ld8 out6=[in1],8
ld8 out7=[in1]
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 ESI 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 loc5=r19 // old ar.bsp
mov loc6=r20 // old sp rp=b6 // call the ESI function
.ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode
mov r16=loc3 // save virtual mode psr
mov r19=loc5 // save virtual mode bspstore
mov r20=loc6 // save virtual mode sp 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