Commit | Line | Data |
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90cee759 PB |
1 | /* |
2 | * Copyright (C) 2014 Imagination Technologies | |
3 | * Author: Paul Burton <paul.burton@imgtec.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License as published by the | |
7 | * Free Software Foundation; either version 2 of the License, or (at your | |
8 | * option) any later version. | |
9 | */ | |
10 | ||
1a770b85 | 11 | #include <linux/binfmts.h> |
90cee759 | 12 | #include <linux/elf.h> |
1a770b85 | 13 | #include <linux/export.h> |
90cee759 PB |
14 | #include <linux/sched.h> |
15 | ||
1a770b85 | 16 | #include <asm/cpu-features.h> |
2b5e869e MR |
17 | #include <asm/cpu-info.h> |
18 | ||
503943e0 MR |
19 | /* Whether to accept legacy-NaN and 2008-NaN user binaries. */ |
20 | bool mips_use_nan_legacy; | |
21 | bool mips_use_nan_2008; | |
22 | ||
46490b57 | 23 | /* FPU modes */ |
90cee759 | 24 | enum { |
46490b57 MC |
25 | FP_FRE, |
26 | FP_FR0, | |
27 | FP_FR1, | |
90cee759 PB |
28 | }; |
29 | ||
46490b57 MC |
30 | /** |
31 | * struct mode_req - ABI FPU mode requirements | |
32 | * @single: The program being loaded needs an FPU but it will only issue | |
33 | * single precision instructions meaning that it can execute in | |
34 | * either FR0 or FR1. | |
35 | * @soft: The soft(-float) requirement means that the program being | |
36 | * loaded needs has no FPU dependency at all (i.e. it has no | |
37 | * FPU instructions). | |
38 | * @fr1: The program being loaded depends on FPU being in FR=1 mode. | |
39 | * @frdefault: The program being loaded depends on the default FPU mode. | |
40 | * That is FR0 for O32 and FR1 for N32/N64. | |
41 | * @fre: The program being loaded depends on FPU with FRE=1. This mode is | |
42 | * a bridge which uses FR=1 whilst still being able to maintain | |
43 | * full compatibility with pre-existing code using the O32 FP32 | |
44 | * ABI. | |
45 | * | |
46 | * More information about the FP ABIs can be found here: | |
47 | * | |
48 | * https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking#10.4.1._Basic_mode_set-up | |
49 | * | |
50 | */ | |
51 | ||
52 | struct mode_req { | |
53 | bool single; | |
54 | bool soft; | |
55 | bool fr1; | |
56 | bool frdefault; | |
57 | bool fre; | |
58 | }; | |
59 | ||
60 | static const struct mode_req fpu_reqs[] = { | |
61 | [MIPS_ABI_FP_ANY] = { true, true, true, true, true }, | |
62 | [MIPS_ABI_FP_DOUBLE] = { false, false, false, true, true }, | |
63 | [MIPS_ABI_FP_SINGLE] = { true, false, false, false, false }, | |
64 | [MIPS_ABI_FP_SOFT] = { false, true, false, false, false }, | |
65 | [MIPS_ABI_FP_OLD_64] = { false, false, false, false, false }, | |
66 | [MIPS_ABI_FP_XX] = { false, false, true, true, true }, | |
67 | [MIPS_ABI_FP_64] = { false, false, true, false, false }, | |
68 | [MIPS_ABI_FP_64A] = { false, false, true, false, true } | |
69 | }; | |
70 | ||
71 | /* | |
72 | * Mode requirements when .MIPS.abiflags is not present in the ELF. | |
73 | * Not present means that everything is acceptable except FR1. | |
74 | */ | |
75 | static struct mode_req none_req = { true, true, false, true, true }; | |
76 | ||
90cee759 PB |
77 | int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf, |
78 | bool is_interp, struct arch_elf_state *state) | |
79 | { | |
2ed02dd4 MR |
80 | union { |
81 | struct elf32_hdr e32; | |
82 | struct elf64_hdr e64; | |
83 | } *ehdr = _ehdr; | |
46490b57 MC |
84 | struct elf32_phdr *phdr32 = _phdr; |
85 | struct elf64_phdr *phdr64 = _phdr; | |
90cee759 | 86 | struct mips_elf_abiflags_v0 abiflags; |
2ed02dd4 MR |
87 | bool elf32; |
88 | u32 flags; | |
90cee759 PB |
89 | int ret; |
90 | ||
2ed02dd4 MR |
91 | elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32; |
92 | flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags; | |
93 | ||
4939788e | 94 | /* Let's see if this is an O32 ELF */ |
2ed02dd4 MR |
95 | if (elf32) { |
96 | if (flags & EF_MIPS_FP64) { | |
46490b57 MC |
97 | /* |
98 | * Set MIPS_ABI_FP_OLD_64 for EF_MIPS_FP64. We will override it | |
99 | * later if needed | |
100 | */ | |
101 | if (is_interp) | |
102 | state->interp_fp_abi = MIPS_ABI_FP_OLD_64; | |
103 | else | |
104 | state->fp_abi = MIPS_ABI_FP_OLD_64; | |
105 | } | |
106 | if (phdr32->p_type != PT_MIPS_ABIFLAGS) | |
107 | return 0; | |
108 | ||
109 | if (phdr32->p_filesz < sizeof(abiflags)) | |
110 | return -EINVAL; | |
111 | ||
112 | ret = kernel_read(elf, phdr32->p_offset, | |
113 | (char *)&abiflags, | |
114 | sizeof(abiflags)); | |
115 | } else { | |
46490b57 MC |
116 | if (phdr64->p_type != PT_MIPS_ABIFLAGS) |
117 | return 0; | |
118 | if (phdr64->p_filesz < sizeof(abiflags)) | |
119 | return -EINVAL; | |
120 | ||
121 | ret = kernel_read(elf, phdr64->p_offset, | |
122 | (char *)&abiflags, | |
123 | sizeof(abiflags)); | |
124 | } | |
90cee759 | 125 | |
90cee759 PB |
126 | if (ret < 0) |
127 | return ret; | |
128 | if (ret != sizeof(abiflags)) | |
129 | return -EIO; | |
130 | ||
131 | /* Record the required FP ABIs for use by mips_check_elf */ | |
132 | if (is_interp) | |
133 | state->interp_fp_abi = abiflags.fp_abi; | |
134 | else | |
135 | state->fp_abi = abiflags.fp_abi; | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
eb4bc076 | 140 | int arch_check_elf(void *_ehdr, bool has_interpreter, void *_interp_ehdr, |
90cee759 PB |
141 | struct arch_elf_state *state) |
142 | { | |
2ed02dd4 MR |
143 | union { |
144 | struct elf32_hdr e32; | |
145 | struct elf64_hdr e64; | |
146 | } *ehdr = _ehdr; | |
2b5e869e MR |
147 | union { |
148 | struct elf32_hdr e32; | |
149 | struct elf64_hdr e64; | |
150 | } *iehdr = _interp_ehdr; | |
46490b57 MC |
151 | struct mode_req prog_req, interp_req; |
152 | int fp_abi, interp_fp_abi, abi0, abi1, max_abi; | |
2ed02dd4 MR |
153 | bool elf32; |
154 | u32 flags; | |
155 | ||
156 | elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32; | |
157 | flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags; | |
90cee759 | 158 | |
2b5e869e | 159 | /* |
503943e0 MR |
160 | * Determine the NaN personality, reject the binary if not allowed. |
161 | * Also ensure that any interpreter matches the executable. | |
2b5e869e MR |
162 | */ |
163 | if (flags & EF_MIPS_NAN2008) { | |
503943e0 | 164 | if (mips_use_nan_2008) |
2b5e869e MR |
165 | state->nan_2008 = 1; |
166 | else | |
167 | return -ENOEXEC; | |
168 | } else { | |
503943e0 | 169 | if (mips_use_nan_legacy) |
2b5e869e MR |
170 | state->nan_2008 = 0; |
171 | else | |
172 | return -ENOEXEC; | |
173 | } | |
174 | if (has_interpreter) { | |
175 | bool ielf32; | |
176 | u32 iflags; | |
177 | ||
178 | ielf32 = iehdr->e32.e_ident[EI_CLASS] == ELFCLASS32; | |
179 | iflags = ielf32 ? iehdr->e32.e_flags : iehdr->e64.e_flags; | |
180 | ||
181 | if ((flags ^ iflags) & EF_MIPS_NAN2008) | |
182 | return -ELIBBAD; | |
183 | } | |
184 | ||
97f2645f | 185 | if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT)) |
90cee759 PB |
186 | return 0; |
187 | ||
a49dc427 | 188 | fp_abi = state->fp_abi; |
90cee759 PB |
189 | |
190 | if (has_interpreter) { | |
a49dc427 | 191 | interp_fp_abi = state->interp_fp_abi; |
90cee759 PB |
192 | |
193 | abi0 = min(fp_abi, interp_fp_abi); | |
194 | abi1 = max(fp_abi, interp_fp_abi); | |
195 | } else { | |
196 | abi0 = abi1 = fp_abi; | |
197 | } | |
198 | ||
2ed02dd4 MR |
199 | if (elf32 && !(flags & EF_MIPS_ABI2)) { |
200 | /* Default to a mode capable of running code expecting FR=0 */ | |
201 | state->overall_fp_mode = cpu_has_mips_r6 ? FP_FRE : FP_FR0; | |
620b1550 | 202 | |
2ed02dd4 MR |
203 | /* Allow all ABIs we know about */ |
204 | max_abi = MIPS_ABI_FP_64A; | |
205 | } else { | |
620b1550 PB |
206 | /* MIPS64 code always uses FR=1, thus the default is easy */ |
207 | state->overall_fp_mode = FP_FR1; | |
208 | ||
209 | /* Disallow access to the various FPXX & FP64 ABIs */ | |
210 | max_abi = MIPS_ABI_FP_SOFT; | |
620b1550 | 211 | } |
90cee759 | 212 | |
46490b57 MC |
213 | if ((abi0 > max_abi && abi0 != MIPS_ABI_FP_UNKNOWN) || |
214 | (abi1 > max_abi && abi1 != MIPS_ABI_FP_UNKNOWN)) | |
215 | return -ELIBBAD; | |
216 | ||
217 | /* It's time to determine the FPU mode requirements */ | |
218 | prog_req = (abi0 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi0]; | |
219 | interp_req = (abi1 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi1]; | |
90cee759 | 220 | |
46490b57 MC |
221 | /* |
222 | * Check whether the program's and interp's ABIs have a matching FPU | |
223 | * mode requirement. | |
224 | */ | |
225 | prog_req.single = interp_req.single && prog_req.single; | |
226 | prog_req.soft = interp_req.soft && prog_req.soft; | |
227 | prog_req.fr1 = interp_req.fr1 && prog_req.fr1; | |
228 | prog_req.frdefault = interp_req.frdefault && prog_req.frdefault; | |
229 | prog_req.fre = interp_req.fre && prog_req.fre; | |
230 | ||
231 | /* | |
232 | * Determine the desired FPU mode | |
233 | * | |
234 | * Decision making: | |
235 | * | |
236 | * - We want FR_FRE if FRE=1 and both FR=1 and FR=0 are false. This | |
237 | * means that we have a combination of program and interpreter | |
238 | * that inherently require the hybrid FP mode. | |
239 | * - If FR1 and FRDEFAULT is true, that means we hit the any-abi or | |
240 | * fpxx case. This is because, in any-ABI (or no-ABI) we have no FPU | |
241 | * instructions so we don't care about the mode. We will simply use | |
242 | * the one preferred by the hardware. In fpxx case, that ABI can | |
243 | * handle both FR=1 and FR=0, so, again, we simply choose the one | |
244 | * preferred by the hardware. Next, if we only use single-precision | |
245 | * FPU instructions, and the default ABI FPU mode is not good | |
246 | * (ie single + any ABI combination), we set again the FPU mode to the | |
247 | * one is preferred by the hardware. Next, if we know that the code | |
248 | * will only use single-precision instructions, shown by single being | |
249 | * true but frdefault being false, then we again set the FPU mode to | |
250 | * the one that is preferred by the hardware. | |
251 | * - We want FP_FR1 if that's the only matching mode and the default one | |
252 | * is not good. | |
253 | * - Return with -ELIBADD if we can't find a matching FPU mode. | |
254 | */ | |
255 | if (prog_req.fre && !prog_req.frdefault && !prog_req.fr1) | |
256 | state->overall_fp_mode = FP_FRE; | |
257 | else if ((prog_req.fr1 && prog_req.frdefault) || | |
258 | (prog_req.single && !prog_req.frdefault)) | |
259 | /* Make sure 64-bit MIPS III/IV/64R1 will not pick FR1 */ | |
260 | state->overall_fp_mode = ((current_cpu_data.fpu_id & MIPS_FPIR_F64) && | |
261 | cpu_has_mips_r2_r6) ? | |
262 | FP_FR1 : FP_FR0; | |
263 | else if (prog_req.fr1) | |
264 | state->overall_fp_mode = FP_FR1; | |
265 | else if (!prog_req.fre && !prog_req.frdefault && | |
266 | !prog_req.fr1 && !prog_req.single && !prog_req.soft) | |
90cee759 | 267 | return -ELIBBAD; |
90cee759 PB |
268 | |
269 | return 0; | |
270 | } | |
271 | ||
46490b57 | 272 | static inline void set_thread_fp_mode(int hybrid, int regs32) |
90cee759 | 273 | { |
46490b57 MC |
274 | if (hybrid) |
275 | set_thread_flag(TIF_HYBRID_FPREGS); | |
276 | else | |
90cee759 | 277 | clear_thread_flag(TIF_HYBRID_FPREGS); |
46490b57 MC |
278 | if (regs32) |
279 | set_thread_flag(TIF_32BIT_FPREGS); | |
280 | else | |
90cee759 | 281 | clear_thread_flag(TIF_32BIT_FPREGS); |
46490b57 | 282 | } |
90cee759 | 283 | |
46490b57 MC |
284 | void mips_set_personality_fp(struct arch_elf_state *state) |
285 | { | |
286 | /* | |
287 | * This function is only ever called for O32 ELFs so we should | |
288 | * not be worried about N32/N64 binaries. | |
289 | */ | |
90cee759 | 290 | |
97f2645f | 291 | if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT)) |
46490b57 | 292 | return; |
90cee759 | 293 | |
46490b57 MC |
294 | switch (state->overall_fp_mode) { |
295 | case FP_FRE: | |
296 | set_thread_fp_mode(1, 0); | |
297 | break; | |
298 | case FP_FR0: | |
299 | set_thread_fp_mode(0, 1); | |
300 | break; | |
301 | case FP_FR1: | |
302 | set_thread_fp_mode(0, 0); | |
90cee759 | 303 | break; |
90cee759 | 304 | default: |
90cee759 PB |
305 | BUG(); |
306 | } | |
307 | } | |
2b5e869e MR |
308 | |
309 | /* | |
310 | * Select the IEEE 754 NaN encoding and ABS.fmt/NEG.fmt execution mode | |
311 | * in FCSR according to the ELF NaN personality. | |
312 | */ | |
313 | void mips_set_personality_nan(struct arch_elf_state *state) | |
314 | { | |
315 | struct cpuinfo_mips *c = &boot_cpu_data; | |
316 | struct task_struct *t = current; | |
317 | ||
318 | t->thread.fpu.fcr31 = c->fpu_csr31; | |
319 | switch (state->nan_2008) { | |
320 | case 0: | |
321 | break; | |
322 | case 1: | |
323 | if (!(c->fpu_msk31 & FPU_CSR_NAN2008)) | |
324 | t->thread.fpu.fcr31 |= FPU_CSR_NAN2008; | |
325 | if (!(c->fpu_msk31 & FPU_CSR_ABS2008)) | |
326 | t->thread.fpu.fcr31 |= FPU_CSR_ABS2008; | |
327 | break; | |
328 | default: | |
329 | BUG(); | |
330 | } | |
331 | } | |
1a770b85 PB |
332 | |
333 | int mips_elf_read_implies_exec(void *elf_ex, int exstack) | |
334 | { | |
335 | if (exstack != EXSTACK_DISABLE_X) { | |
336 | /* The binary doesn't request a non-executable stack */ | |
337 | return 1; | |
338 | } | |
339 | ||
340 | if (!cpu_has_rixi) { | |
341 | /* The CPU doesn't support non-executable memory */ | |
342 | return 1; | |
343 | } | |
344 | ||
345 | return 0; | |
346 | } | |
347 | EXPORT_SYMBOL(mips_elf_read_implies_exec); |