| blob | 59eb59bb408202043e19b904a46a6928c4beb6eb |
1 /*
2 * Signal trampoline for 64 bits processes in a ppc64 kernel for
3 * use in the vDSO
4 *
5 * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), IBM Corp.
6 * Copyright (C) 2004 Alan Modra (amodra@au.ibm.com)), IBM Corp.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13 #include <asm/processor.h>
14 #include <asm/ppc_asm.h>
15 #include <asm/unistd.h>
16 #include <asm/vdso.h>
17 #include <asm/ptrace.h> /* XXX for __SIGNAL_FRAMESIZE */
19 .text
21 /* The nop here is a hack. The dwarf2 unwind routines subtract 1 from
22 the return address to get an address in the middle of the presumed
23 call instruction. Since we don't have a call here, we artifically
24 extend the range covered by the unwind info by padding before the
25 real start. */
26 nop
27 .balign 8
28 V_FUNCTION_BEGIN(__kernel_sigtramp_rt64)
29 .Lsigrt_start = . - 4
30 addi r1, r1, __SIGNAL_FRAMESIZE
31 li r0,__NR_rt_sigreturn
32 sc
33 .Lsigrt_end:
34 V_FUNCTION_END(__kernel_sigtramp_rt64)
35 /* The ".balign 8" above and the following zeros mimic the old stack
36 trampoline layout. The last magic value is the ucontext pointer,
37 chosen in such a way that older libgcc unwind code returns a zero
38 for a sigcontext pointer. */
39 .long 0,0,0
40 .quad 0,-21*8
42 /* Register r1 can be found at offset 8 of a pt_regs structure.
43 A pointer to the pt_regs is stored in memory at the old sp plus PTREGS. */
44 #define cfa_save \
45 .byte 0x0f; /* DW_CFA_def_cfa_expression */ \
46 .uleb128 9f - 1f; /* length */ \
47 1: \
48 .byte 0x71; .sleb128 PTREGS; /* DW_OP_breg1 */ \
49 .byte 0x06; /* DW_OP_deref */ \
50 .byte 0x23; .uleb128 RSIZE; /* DW_OP_plus_uconst */ \
51 .byte 0x06; /* DW_OP_deref */ \
52 9:
54 /* Register REGNO can be found at offset OFS of a pt_regs structure.
55 A pointer to the pt_regs is stored in memory at the old sp plus PTREGS. */
56 #define rsave(regno, ofs) \
57 .byte 0x10; /* DW_CFA_expression */ \
58 .uleb128 regno; /* regno */ \
59 .uleb128 9f - 1f; /* length */ \
60 1: \
61 .byte 0x71; .sleb128 PTREGS; /* DW_OP_breg1 */ \
62 .byte 0x06; /* DW_OP_deref */ \
63 .ifne ofs; \
64 .byte 0x23; .uleb128 ofs; /* DW_OP_plus_uconst */ \
65 .endif; \
66 9:
68 /* If msr bit 1<<25 is set, then VMX register REGNO is at offset REGNO*16
69 of the VMX reg struct. A pointer to the VMX reg struct is at VREGS in
70 the pt_regs struct. This macro is for REGNO == 0, and contains
71 'subroutines' that the other macros jump to. */
72 #define vsave_msr0(regno) \
73 .byte 0x10; /* DW_CFA_expression */ \
74 .uleb128 regno + 77; /* regno */ \
75 .uleb128 9f - 1f; /* length */ \
76 1: \
77 .byte 0x30 + regno; /* DW_OP_lit0 */ \
78 2: \
79 .byte 0x40; /* DW_OP_lit16 */ \
80 .byte 0x1e; /* DW_OP_mul */ \
81 3: \
82 .byte 0x71; .sleb128 PTREGS; /* DW_OP_breg1 */ \
83 .byte 0x06; /* DW_OP_deref */ \
84 .byte 0x12; /* DW_OP_dup */ \
85 .byte 0x23; /* DW_OP_plus_uconst */ \
86 .uleb128 33*RSIZE; /* msr offset */ \
87 .byte 0x06; /* DW_OP_deref */ \
88 .byte 0x0c; .long 1 << 25; /* DW_OP_const4u */ \
89 .byte 0x1a; /* DW_OP_and */ \
90 .byte 0x12; /* DW_OP_dup, ret 0 if bra taken */ \
91 .byte 0x30; /* DW_OP_lit0 */ \
92 .byte 0x29; /* DW_OP_eq */ \
93 .byte 0x28; .short 0x7fff; /* DW_OP_bra to end */ \
94 .byte 0x13; /* DW_OP_drop, pop the 0 */ \
95 .byte 0x23; .uleb128 VREGS; /* DW_OP_plus_uconst */ \
96 .byte 0x06; /* DW_OP_deref */ \
97 .byte 0x22; /* DW_OP_plus */ \
98 .byte 0x2f; .short 0x7fff; /* DW_OP_skip to end */ \
99 9:
101 /* If msr bit 1<<25 is set, then VMX register REGNO is at offset REGNO*16
102 of the VMX reg struct. REGNO is 1 thru 31. */
103 #define vsave_msr1(regno) \
104 .byte 0x10; /* DW_CFA_expression */ \
105 .uleb128 regno + 77; /* regno */ \
106 .uleb128 9f - 1f; /* length */ \
107 1: \
108 .byte 0x30 + regno; /* DW_OP_lit n */ \
109 .byte 0x2f; .short 2b - 9f; /* DW_OP_skip */ \
110 9:
112 /* If msr bit 1<<25 is set, then VMX register REGNO is at offset OFS of
113 the VMX save block. */
114 #define vsave_msr2(regno, ofs) \
115 .byte 0x10; /* DW_CFA_expression */ \
116 .uleb128 regno + 77; /* regno */ \
117 .uleb128 9f - 1f; /* length */ \
118 1: \
119 .byte 0x0a; .short ofs; /* DW_OP_const2u */ \
120 .byte 0x2f; .short 3b - 9f; /* DW_OP_skip */ \
121 9:
123 /* VMX register REGNO is at offset OFS of the VMX save area. */
124 #define vsave(regno, ofs) \
125 .byte 0x10; /* DW_CFA_expression */ \
126 .uleb128 regno + 77; /* regno */ \
127 .uleb128 9f - 1f; /* length */ \
128 1: \
129 .byte 0x71; .sleb128 PTREGS; /* DW_OP_breg1 */ \
130 .byte 0x06; /* DW_OP_deref */ \
131 .byte 0x23; .uleb128 VREGS; /* DW_OP_plus_uconst */ \
132 .byte 0x06; /* DW_OP_deref */ \
133 .byte 0x23; .uleb128 ofs; /* DW_OP_plus_uconst */ \
134 9:
136 /* This is where the pt_regs pointer can be found on the stack. */
137 #define PTREGS 128+168+56
139 /* Size of regs. */
140 #define RSIZE 8
142 /* Size of CR reg in DWARF unwind info. */
143 #define CRSIZE 4
145 /* This is the offset of the VMX reg pointer. */
146 #define VREGS 48*RSIZE+33*8
148 /* Describe where general purpose regs are saved. */
149 #define EH_FRAME_GEN \
150 cfa_save; \
151 rsave ( 0, 0*RSIZE); \
152 rsave ( 2, 2*RSIZE); \
153 rsave ( 3, 3*RSIZE); \
154 rsave ( 4, 4*RSIZE); \
155 rsave ( 5, 5*RSIZE); \
156 rsave ( 6, 6*RSIZE); \
157 rsave ( 7, 7*RSIZE); \
158 rsave ( 8, 8*RSIZE); \
159 rsave ( 9, 9*RSIZE); \
160 rsave (10, 10*RSIZE); \
161 rsave (11, 11*RSIZE); \
162 rsave (12, 12*RSIZE); \
163 rsave (13, 13*RSIZE); \
164 rsave (14, 14*RSIZE); \
165 rsave (15, 15*RSIZE); \
166 rsave (16, 16*RSIZE); \
167 rsave (17, 17*RSIZE); \
168 rsave (18, 18*RSIZE); \
169 rsave (19, 19*RSIZE); \
170 rsave (20, 20*RSIZE); \
171 rsave (21, 21*RSIZE); \
172 rsave (22, 22*RSIZE); \
173 rsave (23, 23*RSIZE); \
174 rsave (24, 24*RSIZE); \
175 rsave (25, 25*RSIZE); \
176 rsave (26, 26*RSIZE); \
177 rsave (27, 27*RSIZE); \
178 rsave (28, 28*RSIZE); \
179 rsave (29, 29*RSIZE); \
180 rsave (30, 30*RSIZE); \
181 rsave (31, 31*RSIZE); \
182 rsave (67, 32*RSIZE); /* ap, used as temp for nip */ \
183 rsave (65, 36*RSIZE); /* lr */ \
184 rsave (70, 38*RSIZE + (RSIZE - CRSIZE)) /* cr */
186 /* Describe where the FP regs are saved. */
187 #define EH_FRAME_FP \
188 rsave (32, 48*RSIZE + 0*8); \
189 rsave (33, 48*RSIZE + 1*8); \
190 rsave (34, 48*RSIZE + 2*8); \
191 rsave (35, 48*RSIZE + 3*8); \
192 rsave (36, 48*RSIZE + 4*8); \
193 rsave (37, 48*RSIZE + 5*8); \
194 rsave (38, 48*RSIZE + 6*8); \
195 rsave (39, 48*RSIZE + 7*8); \
196 rsave (40, 48*RSIZE + 8*8); \
197 rsave (41, 48*RSIZE + 9*8); \
198 rsave (42, 48*RSIZE + 10*8); \
199 rsave (43, 48*RSIZE + 11*8); \
200 rsave (44, 48*RSIZE + 12*8); \
201 rsave (45, 48*RSIZE + 13*8); \
202 rsave (46, 48*RSIZE + 14*8); \
203 rsave (47, 48*RSIZE + 15*8); \
204 rsave (48, 48*RSIZE + 16*8); \
205 rsave (49, 48*RSIZE + 17*8); \
206 rsave (50, 48*RSIZE + 18*8); \
207 rsave (51, 48*RSIZE + 19*8); \
208 rsave (52, 48*RSIZE + 20*8); \
209 rsave (53, 48*RSIZE + 21*8); \
210 rsave (54, 48*RSIZE + 22*8); \
211 rsave (55, 48*RSIZE + 23*8); \
212 rsave (56, 48*RSIZE + 24*8); \
213 rsave (57, 48*RSIZE + 25*8); \
214 rsave (58, 48*RSIZE + 26*8); \
215 rsave (59, 48*RSIZE + 27*8); \
216 rsave (60, 48*RSIZE + 28*8); \
217 rsave (61, 48*RSIZE + 29*8); \
218 rsave (62, 48*RSIZE + 30*8); \
219 rsave (63, 48*RSIZE + 31*8)
221 /* Describe where the VMX regs are saved. */
222 #ifdef CONFIG_ALTIVEC
223 #define EH_FRAME_VMX \
224 vsave_msr0 ( 0); \
225 vsave_msr1 ( 1); \
226 vsave_msr1 ( 2); \
227 vsave_msr1 ( 3); \
228 vsave_msr1 ( 4); \
229 vsave_msr1 ( 5); \
230 vsave_msr1 ( 6); \
231 vsave_msr1 ( 7); \
232 vsave_msr1 ( 8); \
233 vsave_msr1 ( 9); \
234 vsave_msr1 (10); \
235 vsave_msr1 (11); \
236 vsave_msr1 (12); \
237 vsave_msr1 (13); \
238 vsave_msr1 (14); \
239 vsave_msr1 (15); \
240 vsave_msr1 (16); \
241 vsave_msr1 (17); \
242 vsave_msr1 (18); \
243 vsave_msr1 (19); \
244 vsave_msr1 (20); \
245 vsave_msr1 (21); \
246 vsave_msr1 (22); \
247 vsave_msr1 (23); \
248 vsave_msr1 (24); \
249 vsave_msr1 (25); \
250 vsave_msr1 (26); \
251 vsave_msr1 (27); \
252 vsave_msr1 (28); \
253 vsave_msr1 (29); \
254 vsave_msr1 (30); \
255 vsave_msr1 (31); \
256 vsave_msr2 (33, 32*16+12); \
257 vsave (32, 33*16)
258 #else
259 #define EH_FRAME_VMX
260 #endif
262 .section .eh_frame,"a",@progbits
263 .Lcie:
264 .long .Lcie_end - .Lcie_start
265 .Lcie_start:
266 .long 0 /* CIE ID */
267 .byte 1 /* Version number */
268 .string "zRS" /* NUL-terminated augmentation string */
269 .uleb128 4 /* Code alignment factor */
270 .sleb128 -8 /* Data alignment factor */
271 .byte 67 /* Return address register column, ap */
272 .uleb128 1 /* Augmentation value length */
273 .byte 0x14 /* DW_EH_PE_pcrel | DW_EH_PE_udata8. */
274 .byte 0x0c,1,0 /* DW_CFA_def_cfa: r1 ofs 0 */
275 .balign 8
276 .Lcie_end:
278 .long .Lfde0_end - .Lfde0_start
279 .Lfde0_start:
280 .long .Lfde0_start - .Lcie /* CIE pointer. */
281 .quad .Lsigrt_start - . /* PC start, length */
282 .quad .Lsigrt_end - .Lsigrt_start
283 .uleb128 0 /* Augmentation */
284 EH_FRAME_GEN
285 EH_FRAME_FP
286 EH_FRAME_VMX
287 # Do we really need to describe the frame at this point? ie. will
288 # we ever have some call chain that returns somewhere past the addi?
289 # I don't think so, since gcc doesn't support async signals.
290 # .byte 0x41 /* DW_CFA_advance_loc 1*4 */
291 #undef PTREGS
292 #define PTREGS 168+56
293 # EH_FRAME_GEN
294 # EH_FRAME_FP
295 # EH_FRAME_VMX
296 .balign 8
297 .Lfde0_end: