1/* 2 * EFI call stub. 3 * 4 * Copyright (C) 1999-2001 Hewlett-Packard Co 5 * David Mosberger <davidm@hpl.hp.com> 6 * 7 * This stub allows us to make EFI calls in physical mode with interrupts 8 * turned off. We need this because we can't call SetVirtualMap() until 9 * the kernel has booted far enough to allow allocation of struct vma_struct 10 * entries (which we would need to map stuff with memory attributes other 11 * than uncached or writeback...). Since the GetTime() service gets called 12 * earlier than that, we need to be able to make physical mode EFI calls from 13 * the kernel. 14 */ 15 16/* 17 * PSR settings as per SAL spec (Chapter 8 in the "IA-64 System 18 * Abstraction Layer Specification", revision 2.6e). Note that 19 * psr.dfl and psr.dfh MUST be cleared, despite what this manual says. 20 * Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call 21 * (the br.ia instruction fails unless psr.dfl and psr.dfh are 22 * cleared). Fortunately, SAL promises not to touch the floating 23 * point regs, so at least we don't have to save f2-f127. 24 */ 25#define PSR_BITS_TO_CLEAR \ 26 (IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT | \ 27 IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED | \ 28 IA64_PSR_DFL | IA64_PSR_DFH) 29 30#define PSR_BITS_TO_SET \ 31 (IA64_PSR_BN) 32 33#include <asm/processor.h> 34#include <asm/asmmacro.h> 35 36/* 37 * Inputs: 38 * in0 = address of function descriptor of EFI routine to call 39 * in1..in7 = arguments to routine 40 * 41 * Outputs: 42 * r8 = EFI_STATUS returned by called function 43 */ 44 45GLOBAL_ENTRY(efi_call_phys) 46 .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8) 47 alloc loc1=ar.pfs,8,7,7,0 48 ld8 r2=[in0],8 // load EFI function's entry point 49 mov loc0=rp 50 .body 51 ;; 52 mov loc2=gp // save global pointer 53 mov loc4=ar.rsc // save RSE configuration 54 mov ar.rsc=0 // put RSE in enforced lazy, LE mode 55 ;; 56 ld8 gp=[in0] // load EFI function's global pointer 57 movl r16=PSR_BITS_TO_CLEAR 58 mov loc3=psr // save processor status word 59 movl r17=PSR_BITS_TO_SET 60 ;; 61 or loc3=loc3,r17 62 mov b6=r2 63 ;; 64 andcm r16=loc3,r16 // get psr with IT, DT, and RT bits cleared 65 br.call.sptk.many rp=ia64_switch_mode_phys 66.ret0: mov out4=in5 67 mov out0=in1 68 mov out1=in2 69 mov out2=in3 70 mov out3=in4 71 mov out5=in6 72 mov out6=in7 73 mov loc5=r19 74 mov loc6=r20 75 br.call.sptk.many rp=b6 // call the EFI function 76.ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode 77 mov r16=loc3 78 mov r19=loc5 79 mov r20=loc6 80 br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode 81.ret2: mov ar.rsc=loc4 // restore RSE configuration 82 mov ar.pfs=loc1 83 mov rp=loc0 84 mov gp=loc2 85 br.ret.sptk.many rp 86END(efi_call_phys) 87