File: dl-trampoline.S

package info (click to toggle)
glibc 2.31-9
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 277,868 kB
  • sloc: ansic: 1,025,198; asm: 256,773; makefile: 12,084; sh: 10,546; python: 9,618; cpp: 5,233; awk: 1,956; perl: 514; yacc: 290; pascal: 182; sed: 73
file content (361 lines) | stat: -rw-r--r-- 10,385 bytes parent folder | download | duplicates (8)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
/* PLT trampolines. hppa version.
   Copyright (C) 2005-2020 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library.  If not, see
   <https://www.gnu.org/licenses/>.  */

#include <sysdep.h>

/* This code gets called via the .plt stub, and is used in
   dl-runtime.c to call the `_dl_fixup' function and then redirect
   to the address it returns. `_dl_fixup' takes two arguments, however
   `_dl_profile_fixup' takes a number of parameters for use with
   library auditing (LA).

   WARNING: This template is also used by gcc's __cffc, and expects
   that the "bl" for _dl_runtime_resolve exist at a particular offset.
   Do not change this template without changing gcc, while the prefix
   "bl" should fix everything so gcc finds the right spot, it will
   slow down __cffc when it attempts to call fixup to resolve function
   descriptor references. Please refer to gcc/gcc/config/pa/fptr.c

   Enter with r19 = reloc offset, r20 = got-8, r21 = fixup ltp, r22 = fp.  */

	/* RELOCATION MARKER: bl to provide gcc's __cffc with fixup loc. */
	.text
	/* THIS CODE DOES NOT EXECUTE */
	bl	_dl_fixup, %r2
        .text
        .global _dl_runtime_resolve
        .type _dl_runtime_resolve,@function
	cfi_startproc
        .align 4
_dl_runtime_resolve:
        .PROC
        .CALLINFO FRAME=128,CALLS,SAVE_RP,ENTRY_GR=3
        .ENTRY
        /* SAVE_RP says we do */
        stw	%rp, -20(%sp)

	/* Save static link register */
	stw	%r29,-16(%sp)
	/* Save argument registers */
	stw	%r26,-36(%sp)
	stw	%r25,-40(%sp)
	stw	%r24,-44(%sp)
	stw	%r23,-48(%sp)

	/* Build a call frame, and save structure pointer. */
	copy	%sp, %r1	/* Copy previous sp */
	/* Save function result address (on entry) */
	stwm	%r28,128(%sp)
	/* Fill in some frame info to follow ABI */
	stw	%r1,-4(%sp)	/* Previous sp */
	stw	%r21,-32(%sp)	/* PIC register value */

	/* Save input floating point registers. This must be done
	   in the new frame since the previous frame doesn't have
	   enough space */
	ldo	-64(%sp),%r1
	fstd,ma	%fr4,-8(%r1)
	fstd,ma	%fr5,-8(%r1)
	fstd,ma	%fr6,-8(%r1)

	/* Test PA_GP_RELOC bit.  */
	bb,>=	%r19,31,2f		/* branch if not reloc offset */
	fstd,ma	%fr7,-8(%r1)

	/* Set up args to fixup func, needs only two arguments  */
	ldw	8+4(%r20),%r26		/* (1) got[1] == struct link_map */
	copy	%r19,%r25		/* (2) reloc offset  */

	/* Call the real address resolver. */
3:	bl	_dl_fixup,%rp
	copy	%r21,%r19		/* set fixup func ltp */

	/* While the linker will set a function pointer to NULL when it
	   encounters an undefined weak function, we need to dynamically
	   detect removed weak functions.  The issue arises because a weak
	   __gmon_start__ function was added to shared executables to work
	   around issues in _init that are now resolved.  The presence of
	   __gmon_start__ in every shared library breaks the linker
	   `--as-needed' option.  This __gmon_start__ function does nothing
	   but removal is tricky.  Depending on the binding, removal can
	   cause an application using it to fault.  The call to _dl_fixup
	   returns NULL when a function isn't resolved.  In order to help
	   with __gmon_start__ removal, we return directly to the caller
	   when _dl_fixup returns NULL.  This check could be removed when
	   BZ 19170 is fixed.  */
	comib,=	0,%r28,1f

	/* Load up the returned func descriptor */
	copy	%r28, %r22
	copy	%r29, %r19

	/* Reload arguments fp args */
	ldo	-64(%sp),%r1
	fldd,ma	-8(%r1),%fr4
	fldd,ma	-8(%r1),%fr5
	fldd,ma	-8(%r1),%fr6
	fldd,ma	-8(%r1),%fr7

	/* Adjust sp, and restore function result address*/
	ldwm	-128(%sp),%r28

	/* Reload static link register */
	ldw	-16(%sp),%r29
	/* Reload general args */
	ldw	-36(%sp),%r26
	ldw	-40(%sp),%r25
	ldw	-44(%sp),%r24
	ldw	-48(%sp),%r23

	/* Jump to new function, but return to previous function */
	bv	%r0(%r22)
	ldw	-20(%sp),%rp

1:
	/* Return to previous function */
	ldw	-148(%sp),%rp
	bv	%r0(%rp)
	ldo	-128(%sp),%sp

2:
	/* Set up args for _dl_fix_reloc_arg.  */
	copy	%r22,%r26		/* (1) function pointer */
	depi	0,31,2,%r26		/* clear least significant bits */
	ldw	8+4(%r20),%r25		/* (2) got[1] == struct link_map */

	/* Save ltp and link map arg for _dl_fixup.  */
	stw	%r21,-56(%sp)		/* ltp */
	stw	%r25,-60(%sp)		/* struct link map */

	/* Find reloc offset. */
	bl	_dl_fix_reloc_arg,%rp
	copy	%r21,%r19		/* set func ltp */

	/* Set up args for _dl_fixup.  */
	ldw	-56(%sp),%r21		/* ltp */
	ldw	-60(%sp),%r26		/* (1) struct link map */
	b	3b
	copy	%ret0,%r25		/* (2) reloc offset */
        .EXIT
        .PROCEND
	cfi_endproc
	.size   _dl_runtime_resolve, . - _dl_runtime_resolve

        .text
        .global _dl_runtime_profile
        .type _dl_runtime_profile,@function
	cfi_startproc
        .align 4
_dl_runtime_profile:
        .PROC
        .CALLINFO FRAME=192,CALLS,SAVE_RP,ENTRY_GR=3
        .ENTRY

        /* SAVE_RP says we do */
        stw	%rp, -20(%sp)
	/* Save static link register */
	stw	%r29,-16(%sp)

	/* Build a call frame, and save structure pointer. */
	copy	%sp, %r1	/* Copy previous sp */
	/* Save function result address (on entry) */
	stwm	%r28,192(%sp)
	/* Fill in some frame info to follow ABI */
	stw	%r1,-4(%sp)	/* Previous sp */
	stw	%r21,-32(%sp)	/* PIC register value */

	/* Create La_hppa_retval */
	/* -140, lrv_r28
           -136, lrv_r29
           -132, 4 byte pad
           -128, lr_fr4 (8 bytes) */

	/* Create save space for _dl_profile_fixup arguments
	   -120, Saved reloc offset
	   -116, Saved struct link_map
	   -112, *framesizep */

	/* Create La_hppa_regs */
	/* 32-bit registers */
	stw	%r26,-108(%sp)
	stw	%r25,-104(%sp)
	stw	%r24,-100(%sp)
	stw	%r23,-96(%sp)
	/* -92, 4 byte pad */
	/* 64-bit floating point registers */
	ldo	-88(%sp),%r1
	fstd,ma	%fr4,8(%r1)
	fstd,ma	%fr5,8(%r1)
	fstd,ma	%fr6,8(%r1)
	fstd,ma	%fr7,8(%r1)

	/* Test PA_GP_RELOC bit.  */
	bb,>=	%r19,31,2f		/* branch if not reloc offset */
	/* 32-bit stack pointer */
	stw	%sp,-56(%sp)

	/* Set up args to fixup func, needs five arguments  */
	ldw	8+4(%r20),%r26		/* (1) got[1] == struct link_map */
	stw	%r26,-116(%sp)		/* Save struct link_map */
	copy	%r19,%r25		/* (2) reloc offset  */
	stw	%r25,-120(%sp)		/* Save reloc offset */
	copy    %rp,%r24		/* (3) profile_fixup needs rp */
	ldo	-56(%sp),%r23		/* (4) La_hppa_regs */
	ldo	-112(%sp), %r1
	stw	%r1, -52(%sp)		/* (5) long int *framesizep */

	/* Call the real address resolver. */
3:	bl	_dl_profile_fixup,%rp
	copy	%r21,%r19		/* set fixup func ltp */

	/* Load up the returned function descriptor */
	copy	%r28, %r22
	copy	%r29, %r19

	/* Restore gr/fr/sp/rp */
	ldw	-108(%sp),%r26
	ldw	-104(%sp),%r25
	ldw	-100(%sp),%r24
	ldw	-96(%sp),%r23
	/* -92, 4 byte pad, skip */
	ldo	-88(%sp),%r1
	fldd,ma	8(%r1),%fr4
	fldd,ma	8(%r1),%fr5
	fldd,ma	8(%r1),%fr6
	fldd,ma	8(%r1),%fr7

	/* Reload rp register -(192+20) without adjusting stack */
	ldw	-212(%sp),%rp

	/* Reload static link register -(192+16) without adjusting stack */
	ldw	-208(%sp),%r29

	/* *framesizep is >= 0 if we have to run pltexit */
	ldw	-112(%sp),%r28
	cmpb,>>=,N %r0,%r28,L(cpe)

	/* Adjust sp, and restore function result address*/
	ldwm	-192(%sp),%r28
	/* Jump to new function, but return to previous function */
	bv	%r0(%r22)
	ldw	-20(%sp),%rp
	/* NO RETURN */

L(nf):
	/* Call the returned function descriptor */
	bv	%r0(%r22)
	nop
	b,n	L(cont)

L(cpe):
	/* We are going to call the resolved function, but we have a
	   stack frame in the middle. We use the value of framesize to
	   guess how much extra frame we need, and how much frame to
	   copy forward. */

	/* Round to nearest multiple of 64 */
	addi	63, %r28, %r28
	depi	0, 27, 6, %r28

	/* Calcualte start of stack copy */
	ldo	-192(%sp),%r2

	/* Increate the stack by *framesizep */
	copy	%sp, %r1
	add	%sp, %r28, %sp
	/* Save stack pointer */
	stw	%r1, -4(%sp)

	/* Single byte copy of prevous stack onto newly allocated stack */
1:	ldb	%r28(%r2), %r1
	add	%r28, %sp, %r26
	stb	%r1, 0(%r26)
	addi,<	-1,%r28,%r28
	b,n	1b

	/* Retore r28 and r27 and r2 already points at -192(%sp) */
	ldw	0(%r2),%r28
	ldw	84(%r2),%r26

	/* Calculate address of L(cont) */
	b,l	L(nf),%r2
	depwi 0,31,2,%r2
L(cont):
	/* Undo fake stack */
	ldw	-4(%sp),%r1
	copy	%r1, %sp

	/* Arguments to _dl_call_pltexit */
	ldw	-116(%sp), %r26		/* (1) got[1] == struct link_map */
	ldw	-120(%sp), %r25		/* (2) reloc offsets */
	ldo	-56(%sp), %r24		/* (3) *La_hppa_regs */
	ldo	-124(%sp), %r23		/* (4) *La_hppa_retval */

	/* Fill *La_hppa_retval */
	stw	%r28,-140(%sp)
	stw	%r29,-136(%sp)
	ldo	-128(%sp), %r1
	fstd	%fr4,0(%r1)

	/* Call _dl_call_pltexit */
	bl	_dl_call_pltexit,%rp
	nop

	/* Restore *La_hppa_retval */
	ldw	-140(%sp), %r28
	ldw	-136(%sp), %r29
	ldo	-128(%sp), %r1
	fldd	0(%r1), %fr4

	/* Unwind the stack */
	ldo	192(%sp),%sp
	/* Retore callers rp */
        ldw -20(%sp),%rp
	/* Return */
	bv,n	0(%r2)

2:
	/* Set up args for _dl_fix_reloc_arg.  */
	copy	%r22,%r26		/* (1) function pointer */
	depi	0,31,2,%r26		/* clear least significant bits */
	ldw	8+4(%r20),%r25		/* (2) got[1] == struct link_map */

	/* Save ltp and link map arg for _dl_fixup.  */
	stw	%r21,-92(%sp)		/* ltp */
	stw	%r25,-116(%sp)		/* struct link map */

	/* Find reloc offset. */
	bl	_dl_fix_reloc_arg,%rp
	copy	%r21,%r19		/* set func ltp */

	 /* Restore fixup ltp.  */
	ldw	-92(%sp),%r21		/* ltp */

	/* Set up args to fixup func, needs five arguments  */
	ldw	-116(%sp),%r26		/* (1) struct link map */
	copy	%ret0,%r25		/* (2) reloc offset  */
	stw	%r25,-120(%sp)		/* Save reloc offset */
	ldw	-212(%sp),%r24		/* (3) profile_fixup needs rp */
	ldo	-56(%sp),%r23		/* (4) La_hppa_regs */
	ldo	-112(%sp), %r1
	b	3b
	stw	%r1, -52(%sp)		/* (5) long int *framesizep */
        .EXIT
        .PROCEND
	cfi_endproc
	.size   _dl_runtime_profile, . - _dl_runtime_profile