2 * Copyright (c) 2015-2016 The FreeBSD Foundation
5 * This software was developed by Andrew Turner under
6 * sponsorship from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/limits.h>
37 #include <sys/kernel.h>
38 #include <sys/malloc.h>
42 #include <machine/armreg.h>
43 #include <machine/md_var.h>
44 #include <machine/pcb.h>
45 #include <machine/vfp.h>
47 /* Sanity check we can store all the VFP registers */
48 CTASSERT(sizeof(((struct pcb *)0)->pcb_fpustate.vfp_regs) == 16 * 32);
50 static MALLOC_DEFINE(M_FPUKERN_CTX, "fpukern_ctx",
51 "Kernel contexts for VFP state");
54 struct vfpstate *prev;
55 #define FPU_KERN_CTX_DUMMY 0x01 /* avoided save for the kern thread */
56 #define FPU_KERN_CTX_INUSE 0x02
58 struct vfpstate state;
66 cpacr = READ_SPECIALREG(cpacr_el1);
67 cpacr = (cpacr & ~CPACR_FPEN_MASK) | CPACR_FPEN_TRAP_NONE;
68 WRITE_SPECIALREG(cpacr_el1, cpacr);
77 cpacr = READ_SPECIALREG(cpacr_el1);
78 cpacr = (cpacr & ~CPACR_FPEN_MASK) | CPACR_FPEN_TRAP_ALL1;
79 WRITE_SPECIALREG(cpacr_el1, cpacr);
84 * Called when the thread is dying or when discarding the kernel VFP state.
85 * If the thread was the last to use the VFP unit mark it as unused to tell
86 * the kernel the fp state is unowned. Ensure the VFP unit is off so we get
87 * an exception on the next access.
90 vfp_discard(struct thread *td)
97 if (PCPU_GET(fpcurthread) == td)
98 PCPU_SET(fpcurthread, NULL);
104 vfp_store(struct vfpstate *state)
106 __uint128_t *vfp_state;
109 vfp_state = state->vfp_regs;
113 "stp q0, q1, [%2, #16 * 0]\n"
114 "stp q2, q3, [%2, #16 * 2]\n"
115 "stp q4, q5, [%2, #16 * 4]\n"
116 "stp q6, q7, [%2, #16 * 6]\n"
117 "stp q8, q9, [%2, #16 * 8]\n"
118 "stp q10, q11, [%2, #16 * 10]\n"
119 "stp q12, q13, [%2, #16 * 12]\n"
120 "stp q14, q15, [%2, #16 * 14]\n"
121 "stp q16, q17, [%2, #16 * 16]\n"
122 "stp q18, q19, [%2, #16 * 18]\n"
123 "stp q20, q21, [%2, #16 * 20]\n"
124 "stp q22, q23, [%2, #16 * 22]\n"
125 "stp q24, q25, [%2, #16 * 24]\n"
126 "stp q26, q27, [%2, #16 * 26]\n"
127 "stp q28, q29, [%2, #16 * 28]\n"
128 "stp q30, q31, [%2, #16 * 30]\n"
129 : "=&r"(fpcr), "=&r"(fpsr) : "r"(vfp_state));
131 state->vfp_fpcr = fpcr;
132 state->vfp_fpsr = fpsr;
136 vfp_restore(struct vfpstate *state)
138 __uint128_t *vfp_state;
141 vfp_state = state->vfp_regs;
142 fpcr = state->vfp_fpcr;
143 fpsr = state->vfp_fpsr;
146 "ldp q0, q1, [%2, #16 * 0]\n"
147 "ldp q2, q3, [%2, #16 * 2]\n"
148 "ldp q4, q5, [%2, #16 * 4]\n"
149 "ldp q6, q7, [%2, #16 * 6]\n"
150 "ldp q8, q9, [%2, #16 * 8]\n"
151 "ldp q10, q11, [%2, #16 * 10]\n"
152 "ldp q12, q13, [%2, #16 * 12]\n"
153 "ldp q14, q15, [%2, #16 * 14]\n"
154 "ldp q16, q17, [%2, #16 * 16]\n"
155 "ldp q18, q19, [%2, #16 * 18]\n"
156 "ldp q20, q21, [%2, #16 * 20]\n"
157 "ldp q22, q23, [%2, #16 * 22]\n"
158 "ldp q24, q25, [%2, #16 * 24]\n"
159 "ldp q26, q27, [%2, #16 * 26]\n"
160 "ldp q28, q29, [%2, #16 * 28]\n"
161 "ldp q30, q31, [%2, #16 * 30]\n"
164 : : "r"(fpcr), "r"(fpsr), "r"(vfp_state));
168 vfp_save_state(struct thread *td, struct pcb *pcb)
172 KASSERT(pcb != NULL, ("NULL vfp pcb"));
173 KASSERT(td == NULL || td->td_pcb == pcb, ("Invalid vfp pcb"));
176 * savectx() will be called on panic with dumppcb as an argument,
177 * dumppcb doesn't have pcb_fpusaved set, so set it to save
180 if (pcb->pcb_fpusaved == NULL)
181 pcb->pcb_fpusaved = &pcb->pcb_fpustate;
188 * Only store the registers if the VFP is enabled,
189 * i.e. return if we are trapping on FP access.
191 cpacr = READ_SPECIALREG(cpacr_el1);
192 if ((cpacr & CPACR_FPEN_MASK) == CPACR_FPEN_TRAP_NONE) {
193 KASSERT(PCPU_GET(fpcurthread) == td,
194 ("Storing an invalid VFP state"));
196 vfp_store(pcb->pcb_fpusaved);
204 * Reset the FP state to avoid leaking state from the parent process across
205 * execve() (and to ensure that we get a consistent floating point environment
206 * in every new process).
209 vfp_reset_state(struct thread *td, struct pcb *pcb)
212 bzero(&pcb->pcb_fpustate.vfp_regs, sizeof(pcb->pcb_fpustate.vfp_regs));
213 KASSERT(pcb->pcb_fpusaved == &pcb->pcb_fpustate,
214 ("pcb_fpusaved should point to pcb_fpustate."));
215 pcb->pcb_fpustate.vfp_fpcr = initial_fpcr;
216 pcb->pcb_fpustate.vfp_fpsr = 0;
217 pcb->pcb_vfpcpu = UINT_MAX;
218 pcb->pcb_fpflags = 0;
224 vfp_restore_state(void)
231 cpu = PCPU_GET(cpuid);
232 curpcb = curthread->td_pcb;
233 curpcb->pcb_fpflags |= PCB_FP_STARTED;
238 * If the previous thread on this cpu to use the VFP was not the
239 * current thread, or the current thread last used it on a different
240 * cpu we need to restore the old state.
242 if (PCPU_GET(fpcurthread) != curthread || cpu != curpcb->pcb_vfpcpu) {
243 vfp_restore(curthread->td_pcb->pcb_fpusaved);
244 PCPU_SET(fpcurthread, curthread);
245 curpcb->pcb_vfpcpu = cpu;
256 /* Check if there is a vfp unit present */
257 pfr = READ_SPECIALREG(id_aa64pfr0_el1);
258 if ((pfr & ID_AA64PFR0_FP_MASK) == ID_AA64PFR0_FP_NONE)
261 /* Disable to be enabled when it's used */
264 if (PCPU_GET(cpuid) == 0)
265 thread0.td_pcb->pcb_fpusaved->vfp_fpcr = initial_fpcr;
268 SYSINIT(vfp, SI_SUB_CPU, SI_ORDER_ANY, vfp_init, NULL);
270 struct fpu_kern_ctx *
271 fpu_kern_alloc_ctx(u_int flags)
273 struct fpu_kern_ctx *res;
276 sz = sizeof(struct fpu_kern_ctx);
277 res = malloc(sz, M_FPUKERN_CTX, ((flags & FPU_KERN_NOWAIT) ?
278 M_NOWAIT : M_WAITOK) | M_ZERO);
283 fpu_kern_free_ctx(struct fpu_kern_ctx *ctx)
286 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) == 0, ("free'ing inuse ctx"));
287 /* XXXAndrew clear the memory ? */
288 free(ctx, M_FPUKERN_CTX);
292 fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx, u_int flags)
297 KASSERT((flags & FPU_KERN_NOCTX) != 0 || ctx != NULL,
298 ("ctx is required when !FPU_KERN_NOCTX"));
299 KASSERT(ctx == NULL || (ctx->flags & FPU_KERN_CTX_INUSE) == 0,
300 ("using inuse ctx"));
301 KASSERT((pcb->pcb_fpflags & PCB_FP_NOSAVE) == 0,
302 ("recursive fpu_kern_enter while in PCB_FP_NOSAVE state"));
304 if ((flags & FPU_KERN_NOCTX) != 0) {
306 if (curthread == PCPU_GET(fpcurthread)) {
307 vfp_save_state(curthread, pcb);
309 PCPU_SET(fpcurthread, NULL);
312 pcb->pcb_fpflags |= PCB_FP_KERN | PCB_FP_NOSAVE |
317 if ((flags & FPU_KERN_KTHR) != 0 && is_fpu_kern_thread(0)) {
318 ctx->flags = FPU_KERN_CTX_DUMMY | FPU_KERN_CTX_INUSE;
322 * Check either we are already using the VFP in the kernel, or
323 * the the saved state points to the default user space.
325 KASSERT((pcb->pcb_fpflags & PCB_FP_KERN) != 0 ||
326 pcb->pcb_fpusaved == &pcb->pcb_fpustate,
327 ("Mangled pcb_fpusaved %x %p %p", pcb->pcb_fpflags, pcb->pcb_fpusaved, &pcb->pcb_fpustate));
328 ctx->flags = FPU_KERN_CTX_INUSE;
329 vfp_save_state(curthread, pcb);
330 ctx->prev = pcb->pcb_fpusaved;
331 pcb->pcb_fpusaved = &ctx->state;
332 pcb->pcb_fpflags |= PCB_FP_KERN;
333 pcb->pcb_fpflags &= ~PCB_FP_STARTED;
339 fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx)
345 if ((pcb->pcb_fpflags & PCB_FP_NOSAVE) != 0) {
346 KASSERT(ctx == NULL, ("non-null ctx after FPU_KERN_NOCTX"));
347 KASSERT(PCPU_GET(fpcurthread) == NULL,
348 ("non-NULL fpcurthread for PCB_FP_NOSAVE"));
352 pcb->pcb_fpflags &= ~(PCB_FP_NOSAVE | PCB_FP_STARTED);
355 KASSERT((ctx->flags & FPU_KERN_CTX_INUSE) != 0,
356 ("FPU context not inuse"));
357 ctx->flags &= ~FPU_KERN_CTX_INUSE;
359 if (is_fpu_kern_thread(0) &&
360 (ctx->flags & FPU_KERN_CTX_DUMMY) != 0)
362 KASSERT((ctx->flags & FPU_KERN_CTX_DUMMY) == 0, ("dummy ctx"));
366 pcb->pcb_fpflags &= ~PCB_FP_STARTED;
367 pcb->pcb_fpusaved = ctx->prev;
370 if (pcb->pcb_fpusaved == &pcb->pcb_fpustate) {
371 pcb->pcb_fpflags &= ~PCB_FP_KERN;
373 KASSERT((pcb->pcb_fpflags & PCB_FP_KERN) != 0,
374 ("unpaired fpu_kern_leave"));
381 fpu_kern_thread(u_int flags __unused)
383 struct pcb *pcb = curthread->td_pcb;
385 KASSERT((curthread->td_pflags & TDP_KTHREAD) != 0,
386 ("Only kthread may use fpu_kern_thread"));
387 KASSERT(pcb->pcb_fpusaved == &pcb->pcb_fpustate,
388 ("Mangled pcb_fpusaved"));
389 KASSERT((pcb->pcb_fpflags & PCB_FP_KERN) == 0,
390 ("Thread already setup for the VFP"));
391 pcb->pcb_fpflags |= PCB_FP_KERN;
396 is_fpu_kern_thread(u_int flags __unused)
400 if ((curthread->td_pflags & TDP_KTHREAD) == 0)
402 curpcb = curthread->td_pcb;
403 return ((curpcb->pcb_fpflags & PCB_FP_KERN) != 0);