LXR linux/arch/ia64/kernel/esi

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