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v4.6
  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
 
 11#include <linux/elf.h>
 
 12#include <linux/sched.h>
 13
 
 14#include <asm/cpu-info.h>
 15
 16/* Whether to accept legacy-NaN and 2008-NaN user binaries.  */
 17bool mips_use_nan_legacy;
 18bool mips_use_nan_2008;
 19
 20/* FPU modes */
 21enum {
 22	FP_FRE,
 23	FP_FR0,
 24	FP_FR1,
 25};
 26
 27/**
 28 * struct mode_req - ABI FPU mode requirements
 29 * @single:	The program being loaded needs an FPU but it will only issue
 30 *		single precision instructions meaning that it can execute in
 31 *		either FR0 or FR1.
 32 * @soft:	The soft(-float) requirement means that the program being
 33 *		loaded needs has no FPU dependency at all (i.e. it has no
 34 *		FPU instructions).
 35 * @fr1:	The program being loaded depends on FPU being in FR=1 mode.
 36 * @frdefault:	The program being loaded depends on the default FPU mode.
 37 *		That is FR0 for O32 and FR1 for N32/N64.
 38 * @fre:	The program being loaded depends on FPU with FRE=1. This mode is
 39 *		a bridge which uses FR=1 whilst still being able to maintain
 40 *		full compatibility with pre-existing code using the O32 FP32
 41 *		ABI.
 42 *
 43 * More information about the FP ABIs can be found here:
 44 *
 45 * https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking#10.4.1._Basic_mode_set-up
 46 *
 47 */
 48
 49struct mode_req {
 50	bool single;
 51	bool soft;
 52	bool fr1;
 53	bool frdefault;
 54	bool fre;
 55};
 56
 57static const struct mode_req fpu_reqs[] = {
 58	[MIPS_ABI_FP_ANY]    = { true,  true,  true,  true,  true  },
 59	[MIPS_ABI_FP_DOUBLE] = { false, false, false, true,  true  },
 60	[MIPS_ABI_FP_SINGLE] = { true,  false, false, false, false },
 61	[MIPS_ABI_FP_SOFT]   = { false, true,  false, false, false },
 62	[MIPS_ABI_FP_OLD_64] = { false, false, false, false, false },
 63	[MIPS_ABI_FP_XX]     = { false, false, true,  true,  true  },
 64	[MIPS_ABI_FP_64]     = { false, false, true,  false, false },
 65	[MIPS_ABI_FP_64A]    = { false, false, true,  false, true  }
 66};
 67
 68/*
 69 * Mode requirements when .MIPS.abiflags is not present in the ELF.
 70 * Not present means that everything is acceptable except FR1.
 71 */
 72static struct mode_req none_req = { true, true, false, true, true };
 73
 74int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
 75		     bool is_interp, struct arch_elf_state *state)
 76{
 77	union {
 78		struct elf32_hdr e32;
 79		struct elf64_hdr e64;
 80	} *ehdr = _ehdr;
 81	struct elf32_phdr *phdr32 = _phdr;
 82	struct elf64_phdr *phdr64 = _phdr;
 83	struct mips_elf_abiflags_v0 abiflags;
 84	bool elf32;
 85	u32 flags;
 86	int ret;
 87
 88	elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
 89	flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
 90
 91	/* Lets see if this is an O32 ELF */
 92	if (elf32) {
 93		if (flags & EF_MIPS_FP64) {
 94			/*
 95			 * Set MIPS_ABI_FP_OLD_64 for EF_MIPS_FP64. We will override it
 96			 * later if needed
 97			 */
 98			if (is_interp)
 99				state->interp_fp_abi = MIPS_ABI_FP_OLD_64;
100			else
101				state->fp_abi = MIPS_ABI_FP_OLD_64;
102		}
103		if (phdr32->p_type != PT_MIPS_ABIFLAGS)
104			return 0;
105
106		if (phdr32->p_filesz < sizeof(abiflags))
107			return -EINVAL;
108
109		ret = kernel_read(elf, phdr32->p_offset,
110				  (char *)&abiflags,
111				  sizeof(abiflags));
112	} else {
113		if (phdr64->p_type != PT_MIPS_ABIFLAGS)
114			return 0;
115		if (phdr64->p_filesz < sizeof(abiflags))
116			return -EINVAL;
117
118		ret = kernel_read(elf, phdr64->p_offset,
119				  (char *)&abiflags,
120				  sizeof(abiflags));
121	}
122
123	if (ret < 0)
124		return ret;
125	if (ret != sizeof(abiflags))
126		return -EIO;
127
128	/* Record the required FP ABIs for use by mips_check_elf */
129	if (is_interp)
130		state->interp_fp_abi = abiflags.fp_abi;
131	else
132		state->fp_abi = abiflags.fp_abi;
133
134	return 0;
135}
136
137int arch_check_elf(void *_ehdr, bool has_interpreter, void *_interp_ehdr,
138		   struct arch_elf_state *state)
139{
140	union {
141		struct elf32_hdr e32;
142		struct elf64_hdr e64;
143	} *ehdr = _ehdr;
144	union {
145		struct elf32_hdr e32;
146		struct elf64_hdr e64;
147	} *iehdr = _interp_ehdr;
148	struct mode_req prog_req, interp_req;
149	int fp_abi, interp_fp_abi, abi0, abi1, max_abi;
150	bool elf32;
151	u32 flags;
152
153	elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
154	flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
155
156	/*
157	 * Determine the NaN personality, reject the binary if not allowed.
158	 * Also ensure that any interpreter matches the executable.
159	 */
160	if (flags & EF_MIPS_NAN2008) {
161		if (mips_use_nan_2008)
162			state->nan_2008 = 1;
163		else
164			return -ENOEXEC;
165	} else {
166		if (mips_use_nan_legacy)
167			state->nan_2008 = 0;
168		else
169			return -ENOEXEC;
170	}
171	if (has_interpreter) {
172		bool ielf32;
173		u32 iflags;
174
175		ielf32 = iehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
176		iflags = ielf32 ? iehdr->e32.e_flags : iehdr->e64.e_flags;
177
178		if ((flags ^ iflags) & EF_MIPS_NAN2008)
179			return -ELIBBAD;
180	}
181
182	if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT))
183		return 0;
184
185	fp_abi = state->fp_abi;
186
187	if (has_interpreter) {
188		interp_fp_abi = state->interp_fp_abi;
189
190		abi0 = min(fp_abi, interp_fp_abi);
191		abi1 = max(fp_abi, interp_fp_abi);
192	} else {
193		abi0 = abi1 = fp_abi;
194	}
195
196	if (elf32 && !(flags & EF_MIPS_ABI2)) {
197		/* Default to a mode capable of running code expecting FR=0 */
198		state->overall_fp_mode = cpu_has_mips_r6 ? FP_FRE : FP_FR0;
199
200		/* Allow all ABIs we know about */
201		max_abi = MIPS_ABI_FP_64A;
202	} else {
203		/* MIPS64 code always uses FR=1, thus the default is easy */
204		state->overall_fp_mode = FP_FR1;
205
206		/* Disallow access to the various FPXX & FP64 ABIs */
207		max_abi = MIPS_ABI_FP_SOFT;
208	}
209
210	if ((abi0 > max_abi && abi0 != MIPS_ABI_FP_UNKNOWN) ||
211	    (abi1 > max_abi && abi1 != MIPS_ABI_FP_UNKNOWN))
212		return -ELIBBAD;
213
214	/* It's time to determine the FPU mode requirements */
215	prog_req = (abi0 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi0];
216	interp_req = (abi1 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi1];
217
218	/*
219	 * Check whether the program's and interp's ABIs have a matching FPU
220	 * mode requirement.
221	 */
222	prog_req.single = interp_req.single && prog_req.single;
223	prog_req.soft = interp_req.soft && prog_req.soft;
224	prog_req.fr1 = interp_req.fr1 && prog_req.fr1;
225	prog_req.frdefault = interp_req.frdefault && prog_req.frdefault;
226	prog_req.fre = interp_req.fre && prog_req.fre;
227
228	/*
229	 * Determine the desired FPU mode
230	 *
231	 * Decision making:
232	 *
233	 * - We want FR_FRE if FRE=1 and both FR=1 and FR=0 are false. This
234	 *   means that we have a combination of program and interpreter
235	 *   that inherently require the hybrid FP mode.
236	 * - If FR1 and FRDEFAULT is true, that means we hit the any-abi or
237	 *   fpxx case. This is because, in any-ABI (or no-ABI) we have no FPU
238	 *   instructions so we don't care about the mode. We will simply use
239	 *   the one preferred by the hardware. In fpxx case, that ABI can
240	 *   handle both FR=1 and FR=0, so, again, we simply choose the one
241	 *   preferred by the hardware. Next, if we only use single-precision
242	 *   FPU instructions, and the default ABI FPU mode is not good
243	 *   (ie single + any ABI combination), we set again the FPU mode to the
244	 *   one is preferred by the hardware. Next, if we know that the code
245	 *   will only use single-precision instructions, shown by single being
246	 *   true but frdefault being false, then we again set the FPU mode to
247	 *   the one that is preferred by the hardware.
248	 * - We want FP_FR1 if that's the only matching mode and the default one
249	 *   is not good.
250	 * - Return with -ELIBADD if we can't find a matching FPU mode.
251	 */
252	if (prog_req.fre && !prog_req.frdefault && !prog_req.fr1)
253		state->overall_fp_mode = FP_FRE;
254	else if ((prog_req.fr1 && prog_req.frdefault) ||
255		 (prog_req.single && !prog_req.frdefault))
256		/* Make sure 64-bit MIPS III/IV/64R1 will not pick FR1 */
257		state->overall_fp_mode = ((current_cpu_data.fpu_id & MIPS_FPIR_F64) &&
258					  cpu_has_mips_r2_r6) ?
259					  FP_FR1 : FP_FR0;
260	else if (prog_req.fr1)
261		state->overall_fp_mode = FP_FR1;
262	else  if (!prog_req.fre && !prog_req.frdefault &&
263		  !prog_req.fr1 && !prog_req.single && !prog_req.soft)
264		return -ELIBBAD;
265
266	return 0;
267}
268
269static inline void set_thread_fp_mode(int hybrid, int regs32)
270{
271	if (hybrid)
272		set_thread_flag(TIF_HYBRID_FPREGS);
273	else
274		clear_thread_flag(TIF_HYBRID_FPREGS);
275	if (regs32)
276		set_thread_flag(TIF_32BIT_FPREGS);
277	else
278		clear_thread_flag(TIF_32BIT_FPREGS);
279}
280
281void mips_set_personality_fp(struct arch_elf_state *state)
282{
283	/*
284	 * This function is only ever called for O32 ELFs so we should
285	 * not be worried about N32/N64 binaries.
286	 */
287
288	if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT))
289		return;
290
291	switch (state->overall_fp_mode) {
292	case FP_FRE:
293		set_thread_fp_mode(1, 0);
294		break;
295	case FP_FR0:
296		set_thread_fp_mode(0, 1);
297		break;
298	case FP_FR1:
299		set_thread_fp_mode(0, 0);
300		break;
301	default:
302		BUG();
303	}
304}
305
306/*
307 * Select the IEEE 754 NaN encoding and ABS.fmt/NEG.fmt execution mode
308 * in FCSR according to the ELF NaN personality.
309 */
310void mips_set_personality_nan(struct arch_elf_state *state)
311{
312	struct cpuinfo_mips *c = &boot_cpu_data;
313	struct task_struct *t = current;
314
315	t->thread.fpu.fcr31 = c->fpu_csr31;
316	switch (state->nan_2008) {
317	case 0:
318		break;
319	case 1:
320		if (!(c->fpu_msk31 & FPU_CSR_NAN2008))
321			t->thread.fpu.fcr31 |= FPU_CSR_NAN2008;
322		if (!(c->fpu_msk31 & FPU_CSR_ABS2008))
323			t->thread.fpu.fcr31 |= FPU_CSR_ABS2008;
324		break;
325	default:
326		BUG();
327	}
328}
v4.10.11
  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
 11#include <linux/binfmts.h>
 12#include <linux/elf.h>
 13#include <linux/export.h>
 14#include <linux/sched.h>
 15
 16#include <asm/cpu-features.h>
 17#include <asm/cpu-info.h>
 18
 19/* Whether to accept legacy-NaN and 2008-NaN user binaries.  */
 20bool mips_use_nan_legacy;
 21bool mips_use_nan_2008;
 22
 23/* FPU modes */
 24enum {
 25	FP_FRE,
 26	FP_FR0,
 27	FP_FR1,
 28};
 29
 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
 52struct mode_req {
 53	bool single;
 54	bool soft;
 55	bool fr1;
 56	bool frdefault;
 57	bool fre;
 58};
 59
 60static 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 */
 75static struct mode_req none_req = { true, true, false, true, true };
 76
 77int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
 78		     bool is_interp, struct arch_elf_state *state)
 79{
 80	union {
 81		struct elf32_hdr e32;
 82		struct elf64_hdr e64;
 83	} *ehdr = _ehdr;
 84	struct elf32_phdr *phdr32 = _phdr;
 85	struct elf64_phdr *phdr64 = _phdr;
 86	struct mips_elf_abiflags_v0 abiflags;
 87	bool elf32;
 88	u32 flags;
 89	int ret;
 90
 91	elf32 = ehdr->e32.e_ident[EI_CLASS] == ELFCLASS32;
 92	flags = elf32 ? ehdr->e32.e_flags : ehdr->e64.e_flags;
 93
 94	/* Let's see if this is an O32 ELF */
 95	if (elf32) {
 96		if (flags & EF_MIPS_FP64) {
 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 {
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	}
125
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
140int arch_check_elf(void *_ehdr, bool has_interpreter, void *_interp_ehdr,
141		   struct arch_elf_state *state)
142{
143	union {
144		struct elf32_hdr e32;
145		struct elf64_hdr e64;
146	} *ehdr = _ehdr;
147	union {
148		struct elf32_hdr e32;
149		struct elf64_hdr e64;
150	} *iehdr = _interp_ehdr;
151	struct mode_req prog_req, interp_req;
152	int fp_abi, interp_fp_abi, abi0, abi1, max_abi;
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;
158
159	/*
160	 * Determine the NaN personality, reject the binary if not allowed.
161	 * Also ensure that any interpreter matches the executable.
162	 */
163	if (flags & EF_MIPS_NAN2008) {
164		if (mips_use_nan_2008)
165			state->nan_2008 = 1;
166		else
167			return -ENOEXEC;
168	} else {
169		if (mips_use_nan_legacy)
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
185	if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT))
186		return 0;
187
188	fp_abi = state->fp_abi;
189
190	if (has_interpreter) {
191		interp_fp_abi = state->interp_fp_abi;
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
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;
202
203		/* Allow all ABIs we know about */
204		max_abi = MIPS_ABI_FP_64A;
205	} else {
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;
211	}
212
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];
220
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)
267		return -ELIBBAD;
268
269	return 0;
270}
271
272static inline void set_thread_fp_mode(int hybrid, int regs32)
273{
274	if (hybrid)
275		set_thread_flag(TIF_HYBRID_FPREGS);
276	else
277		clear_thread_flag(TIF_HYBRID_FPREGS);
278	if (regs32)
279		set_thread_flag(TIF_32BIT_FPREGS);
280	else
281		clear_thread_flag(TIF_32BIT_FPREGS);
282}
283
284void 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	 */
290
291	if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT))
292		return;
293
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);
303		break;
304	default:
305		BUG();
306	}
307}
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 */
313void 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}
332
333int 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}
347EXPORT_SYMBOL(mips_elf_read_implies_exec);