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[deliverable/linux.git] / arch / ia64 / kernel / esi_stub.S
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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>
e007c533 38#include <asm/export.h>
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39
40/*
41 * Inputs:
42 * in0 = address of function descriptor of ESI routine to call
43 * in1 = address of array of ESI parameters
44 *
45 * Outputs:
46 * r8 = result returned by called function
47 */
48GLOBAL_ENTRY(esi_call_phys)
49 .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(2)
50 alloc loc1=ar.pfs,2,7,8,0
51 ld8 r2=[in0],8 // load ESI function's entry point
52 mov loc0=rp
53 .body
54 ;;
55 ld8 out0=[in1],8 // ESI params loaded from array
56 ;; // passing all as inputs doesn't work
57 ld8 out1=[in1],8
58 ;;
59 ld8 out2=[in1],8
60 ;;
61 ld8 out3=[in1],8
62 ;;
63 ld8 out4=[in1],8
64 ;;
65 ld8 out5=[in1],8
66 ;;
67 ld8 out6=[in1],8
68 ;;
69 ld8 out7=[in1]
70 mov loc2=gp // save global pointer
71 mov loc4=ar.rsc // save RSE configuration
72 mov ar.rsc=0 // put RSE in enforced lazy, LE mode
73 ;;
74 ld8 gp=[in0] // load ESI function's global pointer
75 movl r16=PSR_BITS_TO_CLEAR
76 mov loc3=psr // save processor status word
77 movl r17=PSR_BITS_TO_SET
78 ;;
79 or loc3=loc3,r17
80 mov b6=r2
81 ;;
82 andcm r16=loc3,r16 // get psr with IT, DT, and RT bits cleared
83 br.call.sptk.many rp=ia64_switch_mode_phys
84.ret0: mov loc5=r19 // old ar.bsp
85 mov loc6=r20 // old sp
86 br.call.sptk.many rp=b6 // call the ESI function
87.ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode
88 mov r16=loc3 // save virtual mode psr
89 mov r19=loc5 // save virtual mode bspstore
90 mov r20=loc6 // save virtual mode sp
91 br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode
92.ret2: mov ar.rsc=loc4 // restore RSE configuration
93 mov ar.pfs=loc1
94 mov rp=loc0
95 mov gp=loc2
96 br.ret.sptk.many rp
97END(esi_call_phys)
e007c533 98EXPORT_SYMBOL_GPL(esi_call_phys)
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