1/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <sysdep.h>
19#include <features.h>
20
21#include "ucontext_i.h"
22
23/* __getcontext (ucontext_t *ucp)
24
25 Saves the machine context in UCP such that when it is activated,
26 it appears as if __getcontext() returned again. The only difference
27 is that on a first return, r9 contains 1 and on a subsequent
28 return, it contains 0.
29
30 This implementation in intended to be used for *synchronous* context
31 switches only. Therefore, it does not have to save anything
32 other than the PRESERVED state. */
33
34ENTRY(__getcontext)
35 .prologue
36 .body
37 alloc r11 = ar.pfs, 1, 0, 4, 0
38
39 // sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask):
40
41 mov r3 = SC_MASK
42 mov out0 = SIG_BLOCK
43
44 flushrs // save dirty partition on rbs
45 mov out1 = 0
46 add out2 = r3, in0
47
48 mov out3 = 8 // sizeof kernel sigset_t
49 DO_CALL(__NR_rt_sigprocmask)
50
51 mov.m rFPSR = ar.fpsr
52 mov.m rRSC = ar.rsc
53 add r2 = SC_GR+1*8, r32
54 ;;
55 mov.m rBSP = ar.bsp
56 .prologue
57 .save ar.unat, rUNAT
58 mov.m rUNAT = ar.unat
59 .body
60 add r3 = SC_GR+4*8, r32
61 ;;
62
63.mem.offset 0,0; st8.spill [r2] = r1, (5*8 - 1*8)
64.mem.offset 8,0; st8.spill [r3] = r4, 16
65 mov rPFS = r11
66 ;;
67.mem.offset 0,0; st8.spill [r2] = r5, 16
68.mem.offset 8,0; st8.spill [r3] = r6, 48
69 and rTMP = ~0x3, rRSC
70 ;;
71.mem.offset 0,0; st8.spill [r2] = r7, (SC_FR+2*16-(SC_GR+7*8))
72.mem.offset 8,0; st8.spill [r3] = sp, (SC_FR+3*16-(SC_GR+12*8))
73 ;;
74 mov.m ar.rsc = rTMP // put RSE into enforced lazy mode
75 mov.m rNAT = ar.unat
76 mov.i rLC = ar.lc
77 ;;
78 mov.m rRNAT = ar.rnat
79 mov.m ar.rsc = rRSC // restore RSE mode
80 mov rPR = pr
81
82 /*
83 * Rotate NaT bits by rPOS positions to the right:
84 */
85 stf.spill [r2] = f2, 32
86 stf.spill [r3] = f3, 32
87 add rPOS = SC_GR, r32 // rPOS <- &sc_gr[0]
88 ;;
89 stf.spill [r2] = f4, (16*16-4*16)
90 stf.spill [r3] = f5, (17*16-5*16)
91 extr.u rPOS = rPOS, 3, 6 // get NaT bit number for r0
92 ;;
93 stf.spill [r2] = f16, 32
94 stf.spill [r3] = f17, 32
95 sub rCPOS = 64, rPOS
96 ;;
97 stf.spill [r2] = f18, 32
98 stf.spill [r3] = f19, 32
99 shr.u rTMP = rNAT, rPOS
100 ;;
101 stf.spill [r2] = f20, 32
102 stf.spill [r3] = f21, 32
103 shl rNAT = rNAT, rCPOS
104 ;;
105 stf.spill [r2] = f22, 32
106 stf.spill [r3] = f23, 32
107 or rNAT = rNAT, rTMP
108 ;;
109 stf.spill [r2] = f24, 32
110 stf.spill [r3] = f25, 32
111 mov r8 = 0
112 ;;
113 stf.spill [r2] = f26, 32
114 stf.spill [r3] = f27, 32
115 mov r9 = 1
116 ;;
117 stf.spill [r2] = f28, 32
118 stf.spill [r3] = f29, 32
119 mov rB0 = b0
120 ;;
121 stf.spill [r2] = f30, 32
122 stf.spill [r3] = f31, 32
123 mov rB1 = b1
124 ;;
125 mov ar.unat = rUNAT // we're done spilling integer regs; restore caller's UNaT
126 add r2 = SC_NAT, r32
127 add r3 = SC_BSP, r32
128 ;;
129 st8 [r2] = rNAT, (SC_RNAT-SC_NAT)
130 st8 [r3] = rBSP, (SC_UNAT-SC_BSP)
131 mov rB2 = b2
132 ;;
133 st8 [r2] = rRNAT, (SC_FPSR-SC_RNAT)
134 st8 [r3] = rUNAT, (SC_PFS-SC_UNAT)
135 mov rB3 = b3
136 ;;
137 st8 [r2] = rFPSR, (SC_LC-SC_FPSR)
138 st8 [r3] = rPFS, (SC_PR-SC_PFS)
139 mov rB4 = b4
140 ;;
141 st8 [r2] = rLC, (SC_BR+0*8-SC_LC)
142 st8 [r3] = rPR, (SC_BR+1*8-SC_PR)
143 mov rB5 = b5
144 ;;
145 st8 [r2] = rB0, 16
146 st8 [r3] = rB1, 16
147 ;;
148 st8 [r2] = rB2, 16
149 st8 [r3] = rB3, 16
150 ;;
151 st8 [r2] = rB4
152 st8 [r3] = rB5
153 ret
154END(__getcontext)
155
156weak_alias (__getcontext, getcontext)
157

source code of glibc/sysdeps/unix/sysv/linux/ia64/getcontext.S