/* * EFI call stub. * * Copyright (C) 1999-2001 Hewlett-Packard Co * David Mosberger <davidm@hpl.hp.com> * * 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. */ #define PSR_BITS_TO_CLEAR \ (IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT | \ IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED | \ IA64_PSR_DFL | IA64_PSR_DFH) #define PSR_BITS_TO_SET \ (IA64_PSR_BN) #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 */ GLOBAL_ENTRY(efi_call_phys) .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8) alloc loc1=ar.pfs,8,7,7,0 ld8 r2=[in0],8 // load EFI function's entry point mov loc0=rp .body ;; 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 movl r16=PSR_BITS_TO_CLEAR 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 br.call.sptk.many 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 br.call.sptk.many 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 br.call.sptk.many 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 END(efi_call_phys)