2 * FPU register's regset abstraction, for ptrace, core dumps, etc.
4 #include <asm/fpu/internal.h>
5 #include <asm/fpu/signal.h>
6 #include <asm/fpu/regset.h>
9 * The xstateregs_active() routine is the same as the regset_fpregs_active() routine,
10 * as the "regset->n" for the xstate regset will be updated based on the feature
11 * capabilites supported by the xsave.
13 int regset_fpregs_active(struct task_struct *target, const struct user_regset *regset)
15 struct fpu *target_fpu = &target->thread.fpu;
17 return target_fpu->fpstate_active ? regset->n : 0;
20 int regset_xregset_fpregs_active(struct task_struct *target, const struct user_regset *regset)
22 struct fpu *target_fpu = &target->thread.fpu;
24 return (cpu_has_fxsr && target_fpu->fpstate_active) ? regset->n : 0;
27 int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
28 unsigned int pos, unsigned int count,
29 void *kbuf, void __user *ubuf)
31 struct fpu *fpu = &target->thread.fpu;
36 fpu__activate_fpstate_read(fpu);
37 fpstate_sanitize_xstate(fpu);
39 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
40 &fpu->state.fxsave, 0, -1);
43 int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
44 unsigned int pos, unsigned int count,
45 const void *kbuf, const void __user *ubuf)
47 struct fpu *fpu = &target->thread.fpu;
53 fpu__activate_fpstate_write(fpu);
54 fpstate_sanitize_xstate(fpu);
56 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
57 &fpu->state.fxsave, 0, -1);
60 * mxcsr reserved bits must be masked to zero for security reasons.
62 fpu->state.fxsave.mxcsr &= mxcsr_feature_mask;
65 * update the header bits in the xsave header, indicating the
66 * presence of FP and SSE state.
69 fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FPSSE;
74 int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
75 unsigned int pos, unsigned int count,
76 void *kbuf, void __user *ubuf)
78 struct fpu *fpu = &target->thread.fpu;
79 struct xregs_state *xsave;
85 fpu__activate_fpstate_read(fpu);
87 xsave = &fpu->state.xsave;
90 * Copy the 48bytes defined by the software first into the xstate
91 * memory layout in the thread struct, so that we can copy the entire
92 * xstateregs to the user using one user_regset_copyout().
94 memcpy(&xsave->i387.sw_reserved,
95 xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
97 * Copy the xstate memory layout.
99 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
103 int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
104 unsigned int pos, unsigned int count,
105 const void *kbuf, const void __user *ubuf)
107 struct fpu *fpu = &target->thread.fpu;
108 struct xregs_state *xsave;
114 fpu__activate_fpstate_write(fpu);
116 xsave = &fpu->state.xsave;
118 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
120 /* xcomp_bv must be 0 when using uncompacted format */
121 if (!ret && xsave->header.xcomp_bv)
125 * mxcsr reserved bits must be masked to zero for security reasons.
127 xsave->i387.mxcsr &= mxcsr_feature_mask;
128 xsave->header.xfeatures &= xfeatures_mask;
130 * These bits must be zero.
132 memset(&xsave->header.reserved, 0, 48);
135 * In case of failure, mark all states as init:
138 fpstate_init(&fpu->state);
143 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
146 * FPU tag word conversions.
149 static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
151 unsigned int tmp; /* to avoid 16 bit prefixes in the code */
153 /* Transform each pair of bits into 01 (valid) or 00 (empty) */
155 tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
156 /* and move the valid bits to the lower byte. */
157 tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
158 tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
159 tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
164 #define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16)
165 #define FP_EXP_TAG_VALID 0
166 #define FP_EXP_TAG_ZERO 1
167 #define FP_EXP_TAG_SPECIAL 2
168 #define FP_EXP_TAG_EMPTY 3
170 static inline u32 twd_fxsr_to_i387(struct fxregs_state *fxsave)
173 u32 tos = (fxsave->swd >> 11) & 7;
174 u32 twd = (unsigned long) fxsave->twd;
176 u32 ret = 0xffff0000u;
179 for (i = 0; i < 8; i++, twd >>= 1) {
181 st = FPREG_ADDR(fxsave, (i - tos) & 7);
183 switch (st->exponent & 0x7fff) {
185 tag = FP_EXP_TAG_SPECIAL;
188 if (!st->significand[0] &&
189 !st->significand[1] &&
190 !st->significand[2] &&
192 tag = FP_EXP_TAG_ZERO;
194 tag = FP_EXP_TAG_SPECIAL;
197 if (st->significand[3] & 0x8000)
198 tag = FP_EXP_TAG_VALID;
200 tag = FP_EXP_TAG_SPECIAL;
204 tag = FP_EXP_TAG_EMPTY;
206 ret |= tag << (2 * i);
212 * FXSR floating point environment conversions.
216 convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)
218 struct fxregs_state *fxsave = &tsk->thread.fpu.state.fxsave;
219 struct _fpreg *to = (struct _fpreg *) &env->st_space[0];
220 struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0];
223 env->cwd = fxsave->cwd | 0xffff0000u;
224 env->swd = fxsave->swd | 0xffff0000u;
225 env->twd = twd_fxsr_to_i387(fxsave);
228 env->fip = fxsave->rip;
229 env->foo = fxsave->rdp;
231 * should be actually ds/cs at fpu exception time, but
232 * that information is not available in 64bit mode.
234 env->fcs = task_pt_regs(tsk)->cs;
235 if (tsk == current) {
236 savesegment(ds, env->fos);
238 env->fos = tsk->thread.ds;
240 env->fos |= 0xffff0000;
242 env->fip = fxsave->fip;
243 env->fcs = (u16) fxsave->fcs | ((u32) fxsave->fop << 16);
244 env->foo = fxsave->foo;
245 env->fos = fxsave->fos;
248 for (i = 0; i < 8; ++i)
249 memcpy(&to[i], &from[i], sizeof(to[0]));
252 void convert_to_fxsr(struct task_struct *tsk,
253 const struct user_i387_ia32_struct *env)
256 struct fxregs_state *fxsave = &tsk->thread.fpu.state.fxsave;
257 struct _fpreg *from = (struct _fpreg *) &env->st_space[0];
258 struct _fpxreg *to = (struct _fpxreg *) &fxsave->st_space[0];
261 fxsave->cwd = env->cwd;
262 fxsave->swd = env->swd;
263 fxsave->twd = twd_i387_to_fxsr(env->twd);
264 fxsave->fop = (u16) ((u32) env->fcs >> 16);
266 fxsave->rip = env->fip;
267 fxsave->rdp = env->foo;
268 /* cs and ds ignored */
270 fxsave->fip = env->fip;
271 fxsave->fcs = (env->fcs & 0xffff);
272 fxsave->foo = env->foo;
273 fxsave->fos = env->fos;
276 for (i = 0; i < 8; ++i)
277 memcpy(&to[i], &from[i], sizeof(from[0]));
280 int fpregs_get(struct task_struct *target, const struct user_regset *regset,
281 unsigned int pos, unsigned int count,
282 void *kbuf, void __user *ubuf)
284 struct fpu *fpu = &target->thread.fpu;
285 struct user_i387_ia32_struct env;
287 fpu__activate_fpstate_read(fpu);
289 if (!static_cpu_has(X86_FEATURE_FPU))
290 return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
293 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
294 &fpu->state.fsave, 0,
297 fpstate_sanitize_xstate(fpu);
299 if (kbuf && pos == 0 && count == sizeof(env)) {
300 convert_from_fxsr(kbuf, target);
304 convert_from_fxsr(&env, target);
306 return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
309 int fpregs_set(struct task_struct *target, const struct user_regset *regset,
310 unsigned int pos, unsigned int count,
311 const void *kbuf, const void __user *ubuf)
313 struct fpu *fpu = &target->thread.fpu;
314 struct user_i387_ia32_struct env;
317 fpu__activate_fpstate_write(fpu);
318 fpstate_sanitize_xstate(fpu);
320 if (!static_cpu_has(X86_FEATURE_FPU))
321 return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
324 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
325 &fpu->state.fsave, 0,
328 if (pos > 0 || count < sizeof(env))
329 convert_from_fxsr(&env, target);
331 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &env, 0, -1);
333 convert_to_fxsr(target, &env);
336 * update the header bit in the xsave header, indicating the
340 fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FP;
345 * FPU state for core dumps.
346 * This is only used for a.out dumps now.
347 * It is declared generically using elf_fpregset_t (which is
348 * struct user_i387_struct) but is in fact only used for 32-bit
349 * dumps, so on 64-bit it is really struct user_i387_ia32_struct.
351 int dump_fpu(struct pt_regs *regs, struct user_i387_struct *ufpu)
353 struct task_struct *tsk = current;
354 struct fpu *fpu = &tsk->thread.fpu;
357 fpvalid = fpu->fpstate_active;
359 fpvalid = !fpregs_get(tsk, NULL,
360 0, sizeof(struct user_i387_ia32_struct),
365 EXPORT_SYMBOL(dump_fpu);
367 #endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */