2 * Copyright (c) 2015-2016 The FreeBSD Foundation
4 * This software was developed by Andrew Turner under
5 * sponsorship from the FreeBSD Foundation.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/limits.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
41 #include <machine/armreg.h>
42 #include <machine/md_var.h>
43 #include <machine/pcb.h>
44 #include <machine/vfp.h>
46 /* Sanity check we can store all the VFP registers */
47 CTASSERT(sizeof(((struct pcb *)0)->pcb_fpustate.vfp_regs) == 16 * 32);
49 static MALLOC_DEFINE(M_FPUKERN_CTX, "fpukern_ctx",
50 "Kernel contexts for VFP state");
53 struct vfpstate *prev;
54 #define FPU_KERN_CTX_DUMMY 0x01 /* avoided save for the kern thread */
55 #define FPU_KERN_CTX_INUSE 0x02
57 struct vfpstate state;
65 cpacr = READ_SPECIALREG(cpacr_el1);
66 cpacr = (cpacr & ~CPACR_FPEN_MASK) | CPACR_FPEN_TRAP_NONE;
67 WRITE_SPECIALREG(cpacr_el1, cpacr);
76 cpacr = READ_SPECIALREG(cpacr_el1);
77 cpacr = (cpacr & ~CPACR_FPEN_MASK) | CPACR_FPEN_TRAP_ALL1;
78 WRITE_SPECIALREG(cpacr_el1, cpacr);
83 * Called when the thread is dying or when discarding the kernel VFP state.
84 * If the thread was the last to use the VFP unit mark it as unused to tell
85 * the kernel the fp state is unowned. Ensure the VFP unit is off so we get
86 * an exception on the next access.
89 vfp_discard(struct thread *td)
96 if (PCPU_GET(fpcurthread) == td)
97 PCPU_SET(fpcurthread, NULL);
103 vfp_store(struct vfpstate *state)
105 __uint128_t *vfp_state;
108 vfp_state = state->vfp_regs;
112 "stp q0, q1, [%2, #16 * 0]\n"
113 "stp q2, q3, [%2, #16 * 2]\n"
114 "stp q4, q5, [%2, #16 * 4]\n"
115 "stp q6, q7, [%2, #16 * 6]\n"
116 "stp q8, q9, [%2, #16 * 8]\n"
117 "stp q10, q11, [%2, #16 * 10]\n"
118 "stp q12, q13, [%2, #16 * 12]\n"
119 "stp q14, q15, [%2, #16 * 14]\n"
120 "stp q16, q17, [%2, #16 * 16]\n"
121 "stp q18, q19, [%2, #16 * 18]\n"
122 "stp q20, q21, [%2, #16 * 20]\n"
123 "stp q22, q23, [%2, #16 * 22]\n"
124 "stp q24, q25, [%2, #16 * 24]\n"
125 "stp q26, q27, [%2, #16 * 26]\n"
126 "stp q28, q29, [%2, #16 * 28]\n"
127 "stp q30, q31, [%2, #16 * 30]\n"
128 : "=&r"(fpcr), "=&r"(fpsr) : "r"(vfp_state));
130 state->vfp_fpcr = fpcr;
131 state->vfp_fpsr = fpsr;
135 vfp_restore(struct vfpstate *state)
137 __uint128_t *vfp_state;
140 vfp_state = state->vfp_regs;
141 fpcr = state->vfp_fpcr;
142 fpsr = state->vfp_fpsr;
145 "ldp q0, q1, [%2, #16 * 0]\n"
146 "ldp q2, q3, [%2, #16 * 2]\n"
147 "ldp q4, q5, [%2, #16 * 4]\n"
148 "ldp q6, q7, [%2, #16 * 6]\n"
149 "ldp q8, q9, [%2, #16 * 8]\n"
150 "ldp q10, q11, [%2, #16 * 10]\n"
151 "ldp q12, q13, [%2, #16 * 12]\n"
152 "ldp q14, q15, [%2, #16 * 14]\n"
153 "ldp q16, q17, [%2, #16 * 16]\n"
154 "ldp q18, q19, [%2, #16 * 18]\n"
155 "ldp q20, q21, [%2, #16 * 20]\n"
156 "ldp q22, q23, [%2, #16 * 22]\n"
157 "ldp q24, q25, [%2, #16 * 24]\n"
158 "ldp q26, q27, [%2, #16 * 26]\n"
159 "ldp q28, q29, [%2, #16 * 28]\n"
160 "ldp q30, q31, [%2, #16 * 30]\n"
163 : : "r"(fpcr), "r"(fpsr), "r"(vfp_state));
167 vfp_save_state(struct thread *td, struct pcb *pcb)
171 KASSERT(pcb != NULL, ("NULL vfp pcb"));
172 KASSERT(td == NULL || td->td_pcb == pcb, ("Invalid vfp pcb"));
175 * savectx() will be called on panic with dumppcb as an argument,
176 * dumppcb doesn't have pcb_fpusaved set, so set it to save
179 if (pcb->pcb_fpusaved == NULL)
180 pcb->pcb_fpusaved = &pcb->pcb_fpustate;
187 * Only store the registers if the VFP is enabled,
188 * i.e. return if we are trapping on FP access.
190 cpacr = READ_SPECIALREG(cpacr_el1);
191 if ((cpacr & CPACR_FPEN_MASK) == CPACR_FPEN_TRAP_NONE) {
192 KASSERT(PCPU_GET(fpcurthread) == td,
193 ("Storing an invalid VFP state"));
195 vfp_store(pcb->pcb_fpusaved);
203 * Update the VFP state for a forked process or new thread. The PCB will
204 * have been copied from the old thread.
207 vfp_new_thread(struct thread *newtd, struct thread *oldtd, bool fork)
211 newpcb = newtd->td_pcb;
213 /* Kernel threads start with clean VFP */
214 if ((oldtd->td_pflags & TDP_KTHREAD) != 0) {
215 newpcb->pcb_fpflags &=
216 ~(PCB_FP_STARTED | PCB_FP_KERN | PCB_FP_NOSAVE);
218 MPASS((newpcb->pcb_fpflags & (PCB_FP_KERN|PCB_FP_NOSAVE)) == 0);
220 newpcb->pcb_fpflags &= ~PCB_FP_STARTED;
224 newpcb->pcb_fpusaved = &newpcb->pcb_fpustate;
225 newpcb->pcb_vfpcpu = UINT_MAX;
229 * Reset the FP state to avoid leaking state from the parent process across
230 * execve() (and to ensure that we get a consistent floating point environment
231 * in every new process).
234 vfp_reset_state(struct thread *td, struct pcb *pcb)
237 bzero(&pcb->pcb_fpustate.vfp_regs, sizeof(pcb->pcb_fpustate.vfp_regs));
238 KASSERT(pcb->pcb_fpusaved == &pcb->pcb_fpustate,
239 ("pcb_fpusaved should point to pcb_fpustate."));
240 pcb->pcb_fpustate.vfp_fpcr = initial_fpcr;
241 pcb->pcb_fpustate.vfp_fpsr = 0;
242 pcb->pcb_vfpcpu = UINT_MAX;
243 pcb->pcb_fpflags = 0;
249 vfp_restore_state(void)
256 cpu = PCPU_GET(cpuid);
257 curpcb = curthread->td_pcb;
258 curpcb->pcb_fpflags |= PCB_FP_STARTED;
263 * If the previous thread on this cpu to use the VFP was not the
264 * current thread, or the current thread last used it on a different
265 * cpu we need to restore the old state.
267 if (PCPU_GET(fpcurthread) != curthread || cpu != curpcb->pcb_vfpcpu) {
268 vfp_restore(curthread->td_pcb->pcb_fpusaved);
269 PCPU_SET(fpcurthread, curthread);
270 curpcb->pcb_vfpcpu = cpu;
281 /* Check if there is a vfp unit present */
282 pfr = READ_SPECIALREG(id_aa64pfr0_el1);
283 if ((pfr & ID_AA64PFR0_FP_MASK) == ID_AA64PFR0_FP_NONE)
286 /* Disable to be enabled when it's used */
289 if (PCPU_GET(cpuid) == 0)
290 thread0.td_pcb->pcb_fpusaved->vfp_fpcr = initial_fpcr;
293 SYSINIT(vfp, SI_SUB_CPU, SI_ORDER_ANY, vfp_init, NULL);
295 struct fpu_kern_ctx *
296 fpu_kern_alloc_ctx(u_int flags)
298 struct fpu_kern_ctx *res;
301 sz = sizeof(struct fpu_kern_ctx);
302 res = malloc(sz, M_FPUKERN_CTX, ((flags & FPU_KERN_NOWAIT) ?
303 M_NOWAIT : M_WAITOK) | M_ZERO);
308 fpu_kern_free_ctx(struct fpu_kern_ctx *ctx)
311 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) == 0, ("free'ing inuse ctx"));
312 /* XXXAndrew clear the memory ? */
313 free(ctx, M_FPUKERN_CTX);
317 fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx, u_int flags)
322 KASSERT((flags & FPU_KERN_NOCTX) != 0 || ctx != NULL,
323 ("ctx is required when !FPU_KERN_NOCTX"));
324 KASSERT(ctx == NULL || (ctx->flags & FPU_KERN_CTX_INUSE) == 0,
325 ("using inuse ctx"));
326 KASSERT((pcb->pcb_fpflags & PCB_FP_NOSAVE) == 0,
327 ("recursive fpu_kern_enter while in PCB_FP_NOSAVE state"));
329 if ((flags & FPU_KERN_NOCTX) != 0) {
331 if (curthread == PCPU_GET(fpcurthread)) {
332 vfp_save_state(curthread, pcb);
334 PCPU_SET(fpcurthread, NULL);
337 pcb->pcb_fpflags |= PCB_FP_KERN | PCB_FP_NOSAVE |
342 if ((flags & FPU_KERN_KTHR) != 0 && is_fpu_kern_thread(0)) {
343 ctx->flags = FPU_KERN_CTX_DUMMY | FPU_KERN_CTX_INUSE;
347 * Check either we are already using the VFP in the kernel, or
348 * the saved state points to the default user space.
350 KASSERT((pcb->pcb_fpflags & PCB_FP_KERN) != 0 ||
351 pcb->pcb_fpusaved == &pcb->pcb_fpustate,
352 ("Mangled pcb_fpusaved %x %p %p", pcb->pcb_fpflags, pcb->pcb_fpusaved, &pcb->pcb_fpustate));
353 ctx->flags = FPU_KERN_CTX_INUSE;
354 vfp_save_state(curthread, pcb);
355 ctx->prev = pcb->pcb_fpusaved;
356 pcb->pcb_fpusaved = &ctx->state;
357 pcb->pcb_fpflags |= PCB_FP_KERN;
358 pcb->pcb_fpflags &= ~PCB_FP_STARTED;
364 fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx)
370 if ((pcb->pcb_fpflags & PCB_FP_NOSAVE) != 0) {
371 KASSERT(ctx == NULL, ("non-null ctx after FPU_KERN_NOCTX"));
372 KASSERT(PCPU_GET(fpcurthread) == NULL,
373 ("non-NULL fpcurthread for PCB_FP_NOSAVE"));
377 pcb->pcb_fpflags &= ~(PCB_FP_NOSAVE | PCB_FP_STARTED);
380 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) != 0,
381 ("FPU context not inuse"));
382 ctx->flags &= ~FPU_KERN_CTX_INUSE;
384 if (is_fpu_kern_thread(0) &&
385 (ctx->flags & FPU_KERN_CTX_DUMMY) != 0)
387 KASSERT((ctx->flags & FPU_KERN_CTX_DUMMY) == 0, ("dummy ctx"));
391 pcb->pcb_fpflags &= ~PCB_FP_STARTED;
392 pcb->pcb_fpusaved = ctx->prev;
395 if (pcb->pcb_fpusaved == &pcb->pcb_fpustate) {
396 pcb->pcb_fpflags &= ~PCB_FP_KERN;
398 KASSERT((pcb->pcb_fpflags & PCB_FP_KERN) != 0,
399 ("unpaired fpu_kern_leave"));
406 fpu_kern_thread(u_int flags __unused)
408 struct pcb *pcb = curthread->td_pcb;
410 KASSERT((curthread->td_pflags & TDP_KTHREAD) != 0,
411 ("Only kthread may use fpu_kern_thread"));
412 KASSERT(pcb->pcb_fpusaved == &pcb->pcb_fpustate,
413 ("Mangled pcb_fpusaved"));
414 KASSERT((pcb->pcb_fpflags & PCB_FP_KERN) == 0,
415 ("Thread already setup for the VFP"));
416 pcb->pcb_fpflags |= PCB_FP_KERN;
421 is_fpu_kern_thread(u_int flags __unused)
425 if ((curthread->td_pflags & TDP_KTHREAD) == 0)
427 curpcb = curthread->td_pcb;
428 return ((curpcb->pcb_fpflags & PCB_FP_KERN) != 0);