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