source: trunk/packages/xen-3.1/xen-3.1/xen/arch/ia64/linux/efi_stub.S @ 34

Last change on this file since 34 was 34, checked in by hartmans, 18 years ago

Add xen and xen-common

File size: 2.6 KB
Line 
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)
Note: See TracBrowser for help on using the repository browser.