1 // SPDX-License-Identifier: GPL-2.0-or-later 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* 2 /*
3 * Copyright (C) 2014 Imagination Technologies 3 * Copyright (C) 2014 Imagination Technologies
4 * Author: Paul Burton <paul.burton@mips.com> 4 * Author: Paul Burton <paul.burton@mips.com>
5 */ 5 */
6 6
7 #include <linux/binfmts.h> 7 #include <linux/binfmts.h>
8 #include <linux/elf.h> 8 #include <linux/elf.h>
9 #include <linux/export.h> 9 #include <linux/export.h>
10 #include <linux/sched.h> 10 #include <linux/sched.h>
11 11
12 #include <asm/cpu-features.h> 12 #include <asm/cpu-features.h>
13 #include <asm/cpu-info.h> 13 #include <asm/cpu-info.h>
14 #include <asm/fpu.h> 14 #include <asm/fpu.h>
15 15
16 #ifdef CONFIG_MIPS_FP_SUPPORT 16 #ifdef CONFIG_MIPS_FP_SUPPORT
17 17
18 /* Whether to accept legacy-NaN and 2008-NaN u 18 /* Whether to accept legacy-NaN and 2008-NaN user binaries. */
19 bool mips_use_nan_legacy; 19 bool mips_use_nan_legacy;
20 bool mips_use_nan_2008; 20 bool mips_use_nan_2008;
21 21
22 /* FPU modes */ 22 /* FPU modes */
23 enum { 23 enum {
24 FP_FRE, 24 FP_FRE,
25 FP_FR0, 25 FP_FR0,
26 FP_FR1, 26 FP_FR1,
27 }; 27 };
28 28
29 /** 29 /**
30 * struct mode_req - ABI FPU mode requirements 30 * struct mode_req - ABI FPU mode requirements
31 * @single: The program being loaded needs 31 * @single: The program being loaded needs an FPU but it will only issue
32 * single precision instructions 32 * single precision instructions meaning that it can execute in
33 * either FR0 or FR1. 33 * either FR0 or FR1.
34 * @soft: The soft(-float) requirement m 34 * @soft: The soft(-float) requirement means that the program being
35 * loaded needs has no FPU depend 35 * loaded needs has no FPU dependency at all (i.e. it has no
36 * FPU instructions). 36 * FPU instructions).
37 * @fr1: The program being loaded depen 37 * @fr1: The program being loaded depends on FPU being in FR=1 mode.
38 * @frdefault: The program being loaded depen 38 * @frdefault: The program being loaded depends on the default FPU mode.
39 * That is FR0 for O32 and FR1 fo 39 * That is FR0 for O32 and FR1 for N32/N64.
40 * @fre: The program being loaded depen 40 * @fre: The program being loaded depends on FPU with FRE=1. This mode is
41 * a bridge which uses FR=1 whils 41 * a bridge which uses FR=1 whilst still being able to maintain
42 * full compatibility with pre-ex 42 * full compatibility with pre-existing code using the O32 FP32
43 * ABI. 43 * ABI.
44 * 44 *
45 * More information about the FP ABIs can be f 45 * More information about the FP ABIs can be found here:
46 * 46 *
47 * https://dmz-portal.mips.com/wiki/MIPS_O32_A 47 * https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking#10.4.1._Basic_mode_set-up
48 * 48 *
49 */ 49 */
50 50
51 struct mode_req { 51 struct mode_req {
52 bool single; 52 bool single;
53 bool soft; 53 bool soft;
54 bool fr1; 54 bool fr1;
55 bool frdefault; 55 bool frdefault;
56 bool fre; 56 bool fre;
57 }; 57 };
58 58
59 static const struct mode_req fpu_reqs[] = { 59 static const struct mode_req fpu_reqs[] = {
60 [MIPS_ABI_FP_ANY] = { true, true, 60 [MIPS_ABI_FP_ANY] = { true, true, true, true, true },
61 [MIPS_ABI_FP_DOUBLE] = { false, false, 61 [MIPS_ABI_FP_DOUBLE] = { false, false, false, true, true },
62 [MIPS_ABI_FP_SINGLE] = { true, false, 62 [MIPS_ABI_FP_SINGLE] = { true, false, false, false, false },
63 [MIPS_ABI_FP_SOFT] = { false, true, 63 [MIPS_ABI_FP_SOFT] = { false, true, false, false, false },
64 [MIPS_ABI_FP_OLD_64] = { false, false, 64 [MIPS_ABI_FP_OLD_64] = { false, false, false, false, false },
65 [MIPS_ABI_FP_XX] = { false, false, 65 [MIPS_ABI_FP_XX] = { false, false, true, true, true },
66 [MIPS_ABI_FP_64] = { false, false, 66 [MIPS_ABI_FP_64] = { false, false, true, false, false },
67 [MIPS_ABI_FP_64A] = { false, false, 67 [MIPS_ABI_FP_64A] = { false, false, true, false, true }
68 }; 68 };
69 69
70 /* 70 /*
71 * Mode requirements when .MIPS.abiflags is no 71 * Mode requirements when .MIPS.abiflags is not present in the ELF.
72 * Not present means that everything is accept 72 * Not present means that everything is acceptable except FR1.
73 */ 73 */
74 static struct mode_req none_req = { true, true 74 static struct mode_req none_req = { true, true, false, true, true };
75 75
76 int arch_elf_pt_proc(void *_ehdr, void *_phdr, 76 int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
77 bool is_interp, struct ar 77 bool is_interp, struct arch_elf_state *state)
78 { 78 {
79 union { 79 union {
80 struct elf32_hdr e32; 80 struct elf32_hdr e32;
81 struct elf64_hdr e64; 81 struct elf64_hdr e64;
82 } *ehdr = _ehdr; 82 } *ehdr = _ehdr;
83 struct elf32_phdr *phdr32 = _phdr; 83 struct elf32_phdr *phdr32 = _phdr;
84 struct elf64_phdr *phdr64 = _phdr; 84 struct elf64_phdr *phdr64 = _phdr;
85 struct mips_elf_abiflags_v0 abiflags; 85 struct mips_elf_abiflags_v0 abiflags;
86 bool elf32; 86 bool elf32;
87 u32 flags; 87 u32 flags;
88 int ret; 88 int ret;
89 loff_t pos; 89 loff_t pos;
90 90
91 elf32 = ehdr->e32.e_ident[EI_CLASS] == 91 elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
92 flags = elf32 ? ehdr->e32.e_flags : eh 92 flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
93 93
94 /* Let's see if this is an O32 ELF */ 94 /* Let's see if this is an O32 ELF */
95 if (elf32) { 95 if (elf32) {
96 if (flags & EF_MIPS_FP64) { 96 if (flags & EF_MIPS_FP64) {
97 /* 97 /*
98 * Set MIPS_ABI_FP_OLD 98 * Set MIPS_ABI_FP_OLD_64 for EF_MIPS_FP64. We will override it
99 * later if needed 99 * later if needed
100 */ 100 */
101 if (is_interp) 101 if (is_interp)
102 state->interp_ 102 state->interp_fp_abi = MIPS_ABI_FP_OLD_64;
103 else 103 else
104 state->fp_abi 104 state->fp_abi = MIPS_ABI_FP_OLD_64;
105 } 105 }
106 if (phdr32->p_type != PT_MIPS_ 106 if (phdr32->p_type != PT_MIPS_ABIFLAGS)
107 return 0; 107 return 0;
108 108
109 if (phdr32->p_filesz < sizeof( 109 if (phdr32->p_filesz < sizeof(abiflags))
110 return -EINVAL; 110 return -EINVAL;
111 pos = phdr32->p_offset; 111 pos = phdr32->p_offset;
112 } else { 112 } else {
113 if (phdr64->p_type != PT_MIPS_ 113 if (phdr64->p_type != PT_MIPS_ABIFLAGS)
114 return 0; 114 return 0;
115 if (phdr64->p_filesz < sizeof( 115 if (phdr64->p_filesz < sizeof(abiflags))
116 return -EINVAL; 116 return -EINVAL;
117 pos = phdr64->p_offset; 117 pos = phdr64->p_offset;
118 } 118 }
119 119
120 ret = kernel_read(elf, &abiflags, size 120 ret = kernel_read(elf, &abiflags, sizeof(abiflags), &pos);
121 if (ret < 0) 121 if (ret < 0)
122 return ret; 122 return ret;
123 if (ret != sizeof(abiflags)) 123 if (ret != sizeof(abiflags))
124 return -EIO; 124 return -EIO;
125 125
126 /* Record the required FP ABIs for use 126 /* Record the required FP ABIs for use by mips_check_elf */
127 if (is_interp) 127 if (is_interp)
128 state->interp_fp_abi = abiflag 128 state->interp_fp_abi = abiflags.fp_abi;
129 else 129 else
130 state->fp_abi = abiflags.fp_ab 130 state->fp_abi = abiflags.fp_abi;
131 131
132 return 0; 132 return 0;
133 } 133 }
134 134
135 int arch_check_elf(void *_ehdr, bool has_inter 135 int arch_check_elf(void *_ehdr, bool has_interpreter, void *_interp_ehdr,
136 struct arch_elf_state *stat 136 struct arch_elf_state *state)
137 { 137 {
138 union { 138 union {
139 struct elf32_hdr e32; 139 struct elf32_hdr e32;
140 struct elf64_hdr e64; 140 struct elf64_hdr e64;
141 } *ehdr = _ehdr; 141 } *ehdr = _ehdr;
142 union { 142 union {
143 struct elf32_hdr e32; 143 struct elf32_hdr e32;
144 struct elf64_hdr e64; 144 struct elf64_hdr e64;
145 } *iehdr = _interp_ehdr; 145 } *iehdr = _interp_ehdr;
146 struct mode_req prog_req, interp_req; 146 struct mode_req prog_req, interp_req;
147 int fp_abi, interp_fp_abi, abi0, abi1, 147 int fp_abi, interp_fp_abi, abi0, abi1, max_abi;
148 bool elf32; 148 bool elf32;
149 u32 flags; 149 u32 flags;
150 150
151 elf32 = ehdr->e32.e_ident[EI_CLASS] == 151 elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
152 flags = elf32 ? ehdr->e32.e_flags : eh 152 flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
153 153
154 /* 154 /*
155 * Determine the NaN personality, reje 155 * Determine the NaN personality, reject the binary if not allowed.
156 * Also ensure that any interpreter ma 156 * Also ensure that any interpreter matches the executable.
157 */ 157 */
158 if (flags & EF_MIPS_NAN2008) { 158 if (flags & EF_MIPS_NAN2008) {
159 if (mips_use_nan_2008) 159 if (mips_use_nan_2008)
160 state->nan_2008 = 1; 160 state->nan_2008 = 1;
161 else 161 else
162 return -ENOEXEC; 162 return -ENOEXEC;
163 } else { 163 } else {
164 if (mips_use_nan_legacy) 164 if (mips_use_nan_legacy)
165 state->nan_2008 = 0; 165 state->nan_2008 = 0;
166 else 166 else
167 return -ENOEXEC; 167 return -ENOEXEC;
168 } 168 }
169 if (has_interpreter) { 169 if (has_interpreter) {
170 bool ielf32; 170 bool ielf32;
171 u32 iflags; 171 u32 iflags;
172 172
173 ielf32 = iehdr->e32.e_ident[EI 173 ielf32 = iehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
174 iflags = ielf32 ? iehdr->e32.e 174 iflags = ielf32 ? iehdr->e32.e_flags : iehdr->e64.e_flags;
175 175
176 if ((flags ^ iflags) & EF_MIPS 176 if ((flags ^ iflags) & EF_MIPS_NAN2008)
177 return -ELIBBAD; 177 return -ELIBBAD;
178 } 178 }
179 179
180 if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_S 180 if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT))
181 return 0; 181 return 0;
182 182
183 fp_abi = state->fp_abi; 183 fp_abi = state->fp_abi;
184 184
185 if (has_interpreter) { 185 if (has_interpreter) {
186 interp_fp_abi = state->interp_ 186 interp_fp_abi = state->interp_fp_abi;
187 187
188 abi0 = min(fp_abi, interp_fp_a 188 abi0 = min(fp_abi, interp_fp_abi);
189 abi1 = max(fp_abi, interp_fp_a 189 abi1 = max(fp_abi, interp_fp_abi);
190 } else { 190 } else {
191 abi0 = abi1 = fp_abi; 191 abi0 = abi1 = fp_abi;
192 } 192 }
193 193
194 if (elf32 && !(flags & EF_MIPS_ABI2)) 194 if (elf32 && !(flags & EF_MIPS_ABI2)) {
195 /* Default to a mode capable o 195 /* Default to a mode capable of running code expecting FR=0 */
196 state->overall_fp_mode = cpu_h 196 state->overall_fp_mode = cpu_has_mips_r6 ? FP_FRE : FP_FR0;
197 197
198 /* Allow all ABIs we know abou 198 /* Allow all ABIs we know about */
199 max_abi = MIPS_ABI_FP_64A; 199 max_abi = MIPS_ABI_FP_64A;
200 } else { 200 } else {
201 /* MIPS64 code always uses FR= 201 /* MIPS64 code always uses FR=1, thus the default is easy */
202 state->overall_fp_mode = FP_FR 202 state->overall_fp_mode = FP_FR1;
203 203
204 /* Disallow access to the vari 204 /* Disallow access to the various FPXX & FP64 ABIs */
205 max_abi = MIPS_ABI_FP_SOFT; 205 max_abi = MIPS_ABI_FP_SOFT;
206 } 206 }
207 207
208 if ((abi0 > max_abi && abi0 != MIPS_AB 208 if ((abi0 > max_abi && abi0 != MIPS_ABI_FP_UNKNOWN) ||
209 (abi1 > max_abi && abi1 != MIPS_AB 209 (abi1 > max_abi && abi1 != MIPS_ABI_FP_UNKNOWN))
210 return -ELIBBAD; 210 return -ELIBBAD;
211 211
212 /* It's time to determine the FPU mode 212 /* It's time to determine the FPU mode requirements */
213 prog_req = (abi0 == MIPS_ABI_FP_UNKNOW 213 prog_req = (abi0 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi0];
214 interp_req = (abi1 == MIPS_ABI_FP_UNKN 214 interp_req = (abi1 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi1];
215 215
216 /* 216 /*
217 * Check whether the program's and int 217 * Check whether the program's and interp's ABIs have a matching FPU
218 * mode requirement. 218 * mode requirement.
219 */ 219 */
220 prog_req.single = interp_req.single && 220 prog_req.single = interp_req.single && prog_req.single;
221 prog_req.soft = interp_req.soft && pro 221 prog_req.soft = interp_req.soft && prog_req.soft;
222 prog_req.fr1 = interp_req.fr1 && prog_ 222 prog_req.fr1 = interp_req.fr1 && prog_req.fr1;
223 prog_req.frdefault = interp_req.frdefa 223 prog_req.frdefault = interp_req.frdefault && prog_req.frdefault;
224 prog_req.fre = interp_req.fre && prog_ 224 prog_req.fre = interp_req.fre && prog_req.fre;
225 225
226 /* 226 /*
227 * Determine the desired FPU mode 227 * Determine the desired FPU mode
228 * 228 *
229 * Decision making: 229 * Decision making:
230 * 230 *
231 * - We want FR_FRE if FRE=1 and both 231 * - We want FR_FRE if FRE=1 and both FR=1 and FR=0 are false. This
232 * means that we have a combination 232 * means that we have a combination of program and interpreter
233 * that inherently require the hybri 233 * that inherently require the hybrid FP mode.
234 * - If FR1 and FRDEFAULT is true, tha 234 * - If FR1 and FRDEFAULT is true, that means we hit the any-abi or
235 * fpxx case. This is because, in an 235 * fpxx case. This is because, in any-ABI (or no-ABI) we have no FPU
236 * instructions so we don't care abo 236 * instructions so we don't care about the mode. We will simply use
237 * the one preferred by the hardware 237 * the one preferred by the hardware. In fpxx case, that ABI can
238 * handle both FR=1 and FR=0, so, ag 238 * handle both FR=1 and FR=0, so, again, we simply choose the one
239 * preferred by the hardware. Next, 239 * preferred by the hardware. Next, if we only use single-precision
240 * FPU instructions, and the default 240 * FPU instructions, and the default ABI FPU mode is not good
241 * (ie single + any ABI combination) 241 * (ie single + any ABI combination), we set again the FPU mode to the
242 * one is preferred by the hardware. 242 * one is preferred by the hardware. Next, if we know that the code
243 * will only use single-precision in 243 * will only use single-precision instructions, shown by single being
244 * true but frdefault being false, t 244 * true but frdefault being false, then we again set the FPU mode to
245 * the one that is preferred by the 245 * the one that is preferred by the hardware.
246 * - We want FP_FR1 if that's the only 246 * - We want FP_FR1 if that's the only matching mode and the default one
247 * is not good. 247 * is not good.
248 * - Return with -ELIBADD if we can't 248 * - Return with -ELIBADD if we can't find a matching FPU mode.
249 */ 249 */
250 if (prog_req.fre && !prog_req.frdefaul 250 if (prog_req.fre && !prog_req.frdefault && !prog_req.fr1)
251 state->overall_fp_mode = FP_FR 251 state->overall_fp_mode = FP_FRE;
252 else if ((prog_req.fr1 && prog_req.frd 252 else if ((prog_req.fr1 && prog_req.frdefault) ||
253 (prog_req.single && !prog_req 253 (prog_req.single && !prog_req.frdefault))
254 /* Make sure 64-bit MIPS III/I 254 /* Make sure 64-bit MIPS III/IV/64R1 will not pick FR1 */
255 state->overall_fp_mode = ((raw 255 state->overall_fp_mode = ((raw_current_cpu_data.fpu_id & MIPS_FPIR_F64) &&
256 cpu_ 256 cpu_has_mips_r2_r6) ?
257 FP_F 257 FP_FR1 : FP_FR0;
258 else if (prog_req.fr1) 258 else if (prog_req.fr1)
259 state->overall_fp_mode = FP_FR 259 state->overall_fp_mode = FP_FR1;
260 else if (!prog_req.fre && !prog_req.f 260 else if (!prog_req.fre && !prog_req.frdefault &&
261 !prog_req.fr1 && !prog_req.s 261 !prog_req.fr1 && !prog_req.single && !prog_req.soft)
262 return -ELIBBAD; 262 return -ELIBBAD;
263 263
264 return 0; 264 return 0;
265 } 265 }
266 266
267 static inline void set_thread_fp_mode(int hybr 267 static inline void set_thread_fp_mode(int hybrid, int regs32)
268 { 268 {
269 if (hybrid) 269 if (hybrid)
270 set_thread_flag(TIF_HYBRID_FPR 270 set_thread_flag(TIF_HYBRID_FPREGS);
271 else 271 else
272 clear_thread_flag(TIF_HYBRID_F 272 clear_thread_flag(TIF_HYBRID_FPREGS);
273 if (regs32) 273 if (regs32)
274 set_thread_flag(TIF_32BIT_FPRE 274 set_thread_flag(TIF_32BIT_FPREGS);
275 else 275 else
276 clear_thread_flag(TIF_32BIT_FP 276 clear_thread_flag(TIF_32BIT_FPREGS);
277 } 277 }
278 278
279 void mips_set_personality_fp(struct arch_elf_s 279 void mips_set_personality_fp(struct arch_elf_state *state)
280 { 280 {
281 /* 281 /*
282 * This function is only ever called f 282 * This function is only ever called for O32 ELFs so we should
283 * not be worried about N32/N64 binari 283 * not be worried about N32/N64 binaries.
284 */ 284 */
285 285
286 if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_S 286 if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT))
287 return; 287 return;
288 288
289 switch (state->overall_fp_mode) { 289 switch (state->overall_fp_mode) {
290 case FP_FRE: 290 case FP_FRE:
291 set_thread_fp_mode(1, 0); 291 set_thread_fp_mode(1, 0);
292 break; 292 break;
293 case FP_FR0: 293 case FP_FR0:
294 set_thread_fp_mode(0, 1); 294 set_thread_fp_mode(0, 1);
295 break; 295 break;
296 case FP_FR1: 296 case FP_FR1:
297 set_thread_fp_mode(0, 0); 297 set_thread_fp_mode(0, 0);
298 break; 298 break;
299 default: 299 default:
300 BUG(); 300 BUG();
301 } 301 }
302 } 302 }
303 303
304 /* 304 /*
305 * Select the IEEE 754 NaN encoding and ABS.fm 305 * Select the IEEE 754 NaN encoding and ABS.fmt/NEG.fmt execution mode
306 * in FCSR according to the ELF NaN personalit 306 * in FCSR according to the ELF NaN personality.
307 */ 307 */
308 void mips_set_personality_nan(struct arch_elf_ 308 void mips_set_personality_nan(struct arch_elf_state *state)
309 { 309 {
310 struct cpuinfo_mips *c = &boot_cpu_dat 310 struct cpuinfo_mips *c = &boot_cpu_data;
311 struct task_struct *t = current; 311 struct task_struct *t = current;
312 312
313 /* Do this early so t->thread.fpu.fcr3 313 /* Do this early so t->thread.fpu.fcr31 won't be clobbered in case
314 * we are preempted before the lose_fp 314 * we are preempted before the lose_fpu(0) in start_thread.
315 */ 315 */
316 lose_fpu(0); 316 lose_fpu(0);
317 317
318 t->thread.fpu.fcr31 = c->fpu_csr31; 318 t->thread.fpu.fcr31 = c->fpu_csr31;
319 switch (state->nan_2008) { 319 switch (state->nan_2008) {
320 case 0: 320 case 0:
321 if (!(c->fpu_msk31 & FPU_CSR_N <<
322 t->thread.fpu.fcr31 &= <<
323 if (!(c->fpu_msk31 & FPU_CSR_A <<
324 t->thread.fpu.fcr31 &= <<
325 break; 321 break;
326 case 1: 322 case 1:
327 if (!(c->fpu_msk31 & FPU_CSR_N 323 if (!(c->fpu_msk31 & FPU_CSR_NAN2008))
328 t->thread.fpu.fcr31 |= 324 t->thread.fpu.fcr31 |= FPU_CSR_NAN2008;
329 if (!(c->fpu_msk31 & FPU_CSR_A 325 if (!(c->fpu_msk31 & FPU_CSR_ABS2008))
330 t->thread.fpu.fcr31 |= 326 t->thread.fpu.fcr31 |= FPU_CSR_ABS2008;
331 break; 327 break;
332 default: 328 default:
333 BUG(); 329 BUG();
334 } 330 }
335 } 331 }
336 332
337 #endif /* CONFIG_MIPS_FP_SUPPORT */ 333 #endif /* CONFIG_MIPS_FP_SUPPORT */
338 334
339 int mips_elf_read_implies_exec(void *elf_ex, i 335 int mips_elf_read_implies_exec(void *elf_ex, int exstack)
340 { 336 {
341 /* 337 /*
342 * Set READ_IMPLIES_EXEC only on non-N 338 * Set READ_IMPLIES_EXEC only on non-NX systems that
343 * do not request a specific state via 339 * do not request a specific state via PT_GNU_STACK.
344 */ 340 */
345 return (!cpu_has_rixi && exstack == EX 341 return (!cpu_has_rixi && exstack == EXSTACK_DEFAULT);
346 } 342 }
347 EXPORT_SYMBOL(mips_elf_read_implies_exec); 343 EXPORT_SYMBOL(mips_elf_read_implies_exec);
348 344
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