1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * ESI call stub. 4 * 5 * Copyright (C) 2005 Hewlett-Packard Co 6 * Alex Williamson <alex.williamson@hp.com> 7 * 8 * Based on EFI call stub by David Mosberger. The stub is virtually 9 * identical to the one for EFI phys-mode calls, except that ESI 10 * calls may have up to 8 arguments, so they get passed to this routine 11 * through memory. 12 * 13 * This stub allows us to make ESI calls in physical mode with interrupts 14 * turned off. ESI calls may not support calling from virtual mode. 15 * 16 * Google for "Extensible SAL specification" for a document describing the 17 * ESI standard. 18 */ 19 20/* 21 * PSR settings as per SAL spec (Chapter 8 in the "IA-64 System 22 * Abstraction Layer Specification", revision 2.6e). Note that 23 * psr.dfl and psr.dfh MUST be cleared, despite what this manual says. 24 * Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call 25 * (the br.ia instruction fails unless psr.dfl and psr.dfh are 26 * cleared). Fortunately, SAL promises not to touch the floating 27 * point regs, so at least we don't have to save f2-f127. 28 */ 29#define PSR_BITS_TO_CLEAR \ 30 (IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT | \ 31 IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED | \ 32 IA64_PSR_DFL | IA64_PSR_DFH) 33 34#define PSR_BITS_TO_SET \ 35 (IA64_PSR_BN) 36 37#include <linux/export.h> 38#include <asm/processor.h> 39#include <asm/asmmacro.h> 40 41/* 42 * Inputs: 43 * in0 = address of function descriptor of ESI routine to call 44 * in1 = address of array of ESI parameters 45 * 46 * Outputs: 47 * r8 = result returned by called function 48 */ 49GLOBAL_ENTRY(esi_call_phys) 50 .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(2) 51 alloc loc1=ar.pfs,2,7,8,0 52 ld8 r2=[in0],8 // load ESI function's entry point 53 mov loc0=rp 54 .body 55 ;; 56 ld8 out0=[in1],8 // ESI params loaded from array 57 ;; // passing all as inputs doesn't work 58 ld8 out1=[in1],8 59 ;; 60 ld8 out2=[in1],8 61 ;; 62 ld8 out3=[in1],8 63 ;; 64 ld8 out4=[in1],8 65 ;; 66 ld8 out5=[in1],8 67 ;; 68 ld8 out6=[in1],8 69 ;; 70 ld8 out7=[in1] 71 mov loc2=gp // save global pointer 72 mov loc4=ar.rsc // save RSE configuration 73 mov ar.rsc=0 // put RSE in enforced lazy, LE mode 74 ;; 75 ld8 gp=[in0] // load ESI function's global pointer 76 movl r16=PSR_BITS_TO_CLEAR 77 mov loc3=psr // save processor status word 78 movl r17=PSR_BITS_TO_SET 79 ;; 80 or loc3=loc3,r17 81 mov b6=r2 82 ;; 83 andcm r16=loc3,r16 // get psr with IT, DT, and RT bits cleared 84 br.call.sptk.many rp=ia64_switch_mode_phys 85.ret0: mov loc5=r19 // old ar.bsp 86 mov loc6=r20 // old sp 87 br.call.sptk.many rp=b6 // call the ESI function 88.ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode 89 mov r16=loc3 // save virtual mode psr 90 mov r19=loc5 // save virtual mode bspstore 91 mov r20=loc6 // save virtual mode sp 92 br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode 93.ret2: mov ar.rsc=loc4 // restore RSE configuration 94 mov ar.pfs=loc1 95 mov rp=loc0 96 mov gp=loc2 97 br.ret.sptk.many rp 98END(esi_call_phys) 99EXPORT_SYMBOL_GPL(esi_call_phys) 100