1/*- 2 * Copyright (c) 2014 Ian Lepore <ian@freebsd.org> 3 * Copyright (c) 2012 Mark Tinguely 4 * 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 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. 15 * 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 26 * SUCH DAMAGE. 27 */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD: stable/11/sys/arm/arm/vfp.c 325810 2017-11-14 16:03:07Z jhb $"); 31 32#ifdef VFP 33#include <sys/param.h> 34#include <sys/systm.h> 35#include <sys/proc.h> 36#include <sys/imgact_elf.h> 37#include <sys/kernel.h> 38 39#include <machine/armreg.h> 40#include <machine/elf.h> 41#include <machine/frame.h> 42#include <machine/md_var.h> 43#include <machine/pcb.h> 44#include <machine/undefined.h> 45#include <machine/vfp.h> 46 47/* function prototypes */ 48static int vfp_bounce(u_int, u_int, struct trapframe *, int); 49static void vfp_restore(struct vfp_state *); 50 51extern int vfp_exists; 52static struct undefined_handler vfp10_uh, vfp11_uh; 53/* If true the VFP unit has 32 double registers, otherwise it has 16 */ 54static int is_d32; 55 56/* 57 * About .fpu directives in this file... 58 * 59 * We should need simply .fpu vfpv3, but clang 3.5 has a quirk where setting 60 * vfpv3 doesn't imply that vfp2 features are also available -- both have to be 61 * explicitly set to get all the features of both. This is probably a bug in 62 * clang, so it may get fixed and require changes here some day. Other changes 63 * are probably coming in clang too, because there is email and open PRs 64 * indicating they want to completely disable the ability to use .fpu and 65 * similar directives in inline asm. That would be catastrophic for us, 66 * hopefully they come to their senses. There was also some discusion of a new 67 * syntax such as .push fpu=vfpv3; ...; .pop fpu; and that would be ideal for 68 * us, better than what we have now really. 69 * 70 * For gcc, each .fpu directive completely overrides the prior directive, unlike 71 * with clang, but luckily on gcc saying v3 implies all the v2 features as well. 72 */ 73 74#define fmxr(reg, val) \ 75 __asm __volatile(" .fpu vfpv2\n .fpu vfpv3\n" \ 76 " vmsr " __STRING(reg) ", %0" :: "r"(val)); 77 78#define fmrx(reg) \ 79({ u_int val = 0;\ 80 __asm __volatile(" .fpu vfpv2\n .fpu vfpv3\n" \ 81 " vmrs %0, " __STRING(reg) : "=r"(val)); \ 82 val; \ 83}) 84 85static u_int 86get_coprocessorACR(void) 87{ 88 u_int val; 89 __asm __volatile("mrc p15, 0, %0, c1, c0, 2" : "=r" (val) : : "cc"); 90 return val; 91} 92 93static void 94set_coprocessorACR(u_int val) 95{ 96 __asm __volatile("mcr p15, 0, %0, c1, c0, 2\n\t" 97 : : "r" (val) : "cc"); 98 isb(); 99} 100 101 102 /* called for each cpu */ 103void 104vfp_init(void) 105{ 106 u_int fpsid, fpexc, tmp; 107 u_int coproc, vfp_arch; 108 109 coproc = get_coprocessorACR(); 110 coproc |= COPROC10 | COPROC11; 111 set_coprocessorACR(coproc); 112 113 fpsid = fmrx(fpsid); /* read the vfp system id */ 114 fpexc = fmrx(fpexc); /* read the vfp exception reg */ 115 116 if (!(fpsid & VFPSID_HARDSOFT_IMP)) { 117 vfp_exists = 1; 118 is_d32 = 0; 119 PCPU_SET(vfpsid, fpsid); /* save the fpsid */ 120 elf_hwcap |= HWCAP_VFP; 121 122 vfp_arch = 123 (fpsid & VFPSID_SUBVERSION2_MASK) >> VFPSID_SUBVERSION_OFF; 124 125 if (vfp_arch >= VFP_ARCH3) { 126 tmp = fmrx(mvfr0); 127 PCPU_SET(vfpmvfr0, tmp); 128 elf_hwcap |= HWCAP_VFPv3; 129 130 if ((tmp & VMVFR0_RB_MASK) == 2) { 131 elf_hwcap |= HWCAP_VFPD32; 132 is_d32 = 1; 133 } else 134 elf_hwcap |= HWCAP_VFPv3D16; 135 136 tmp = fmrx(mvfr1); 137 PCPU_SET(vfpmvfr1, tmp); 138 139 if (PCPU_GET(cpuid) == 0) { 140 if ((tmp & VMVFR1_FZ_MASK) == 0x1) { 141 /* Denormals arithmetic support */ 142 initial_fpscr &= ~VFPSCR_FZ; 143 thread0.td_pcb->pcb_vfpstate.fpscr = 144 initial_fpscr; 145 } 146 } 147 148 if ((tmp & VMVFR1_LS_MASK) >> VMVFR1_LS_OFF == 1 && 149 (tmp & VMVFR1_I_MASK) >> VMVFR1_I_OFF == 1 && 150 (tmp & VMVFR1_SP_MASK) >> VMVFR1_SP_OFF == 1) 151 elf_hwcap |= HWCAP_NEON; 152 if ((tmp & VMVFR1_FMAC_MASK) >> VMVFR1_FMAC_OFF == 1) 153 elf_hwcap |= HWCAP_VFPv4; 154 } 155 156 /* initialize the coprocess 10 and 11 calls 157 * These are called to restore the registers and enable 158 * the VFP hardware. 159 */ 160 if (vfp10_uh.uh_handler == NULL) { 161 vfp10_uh.uh_handler = vfp_bounce; 162 vfp11_uh.uh_handler = vfp_bounce; 163 install_coproc_handler_static(10, &vfp10_uh); 164 install_coproc_handler_static(11, &vfp11_uh); 165 } 166 } 167} 168 169SYSINIT(vfp, SI_SUB_CPU, SI_ORDER_ANY, vfp_init, NULL); 170 171 172/* start VFP unit, restore the vfp registers from the PCB and retry 173 * the instruction 174 */ 175static int 176vfp_bounce(u_int addr, u_int insn, struct trapframe *frame, int code) 177{ 178 u_int cpu, fpexc; 179 struct pcb *curpcb; 180 ksiginfo_t ksi; 181 182 if ((code & FAULT_USER) == 0) 183 panic("undefined floating point instruction in supervisor mode"); 184 185 critical_enter(); 186 187 /* 188 * If the VFP is already on and we got an undefined instruction, then 189 * something tried to executate a truly invalid instruction that maps to 190 * the VFP. 191 */ 192 fpexc = fmrx(fpexc); 193 if (fpexc & VFPEXC_EN) { 194 /* Clear any exceptions */ 195 fmxr(fpexc, fpexc & ~(VFPEXC_EX | VFPEXC_FP2V)); 196 197 /* kill the process - we do not handle emulation */ 198 critical_exit(); 199 200 if (fpexc & VFPEXC_EX) { 201 /* We have an exception, signal a SIGFPE */ 202 ksiginfo_init_trap(&ksi); 203 ksi.ksi_signo = SIGFPE; 204 if (fpexc & VFPEXC_UFC) 205 ksi.ksi_code = FPE_FLTUND; 206 else if (fpexc & VFPEXC_OFC) 207 ksi.ksi_code = FPE_FLTOVF; 208 else if (fpexc & VFPEXC_IOC) 209 ksi.ksi_code = FPE_FLTINV; 210 ksi.ksi_addr = (void *)addr; 211 trapsignal(curthread, &ksi); 212 return 0; 213 } 214 215 return 1; 216 } 217 218 /* 219 * If the last time this thread used the VFP it was on this core, and 220 * the last thread to use the VFP on this core was this thread, then the 221 * VFP state is valid, otherwise restore this thread's state to the VFP. 222 */ 223 fmxr(fpexc, fpexc | VFPEXC_EN); 224 curpcb = curthread->td_pcb; 225 cpu = PCPU_GET(cpuid); 226 if (curpcb->pcb_vfpcpu != cpu || curthread != PCPU_GET(fpcurthread)) { 227 vfp_restore(&curpcb->pcb_vfpstate); 228 curpcb->pcb_vfpcpu = cpu; 229 PCPU_SET(fpcurthread, curthread); 230 } 231 232 critical_exit(); 233 return (0); 234} 235 236/* 237 * Restore the given state to the VFP hardware. 238 */ 239static void 240vfp_restore(struct vfp_state *vfpsave) 241{ 242 uint32_t fpexc; 243 244 /* On vfpv3 we may need to restore FPINST and FPINST2 */ 245 fpexc = vfpsave->fpexec; 246 if (fpexc & VFPEXC_EX) { 247 fmxr(fpinst, vfpsave->fpinst); 248 if (fpexc & VFPEXC_FP2V) 249 fmxr(fpinst2, vfpsave->fpinst2); 250 } 251 fmxr(fpscr, vfpsave->fpscr); 252 253 __asm __volatile( 254 " .fpu vfpv2\n" 255 " .fpu vfpv3\n" 256 " vldmia %0!, {d0-d15}\n" /* d0-d15 */ 257 " cmp %1, #0\n" /* -D16 or -D32? */ 258 " vldmiane %0!, {d16-d31}\n" /* d16-d31 */ 259 " addeq %0, %0, #128\n" /* skip missing regs */ 260 : "+&r" (vfpsave) : "r" (is_d32) : "cc" 261 ); 262 263 fmxr(fpexc, fpexc); 264} 265 266/* 267 * If the VFP is on, save its current state and turn it off if requested to do 268 * so. If the VFP is not on, does not change the values at *vfpsave. Caller is 269 * responsible for preventing a context switch while this is running. 270 */ 271void 272vfp_store(struct vfp_state *vfpsave, boolean_t disable_vfp) 273{ 274 uint32_t fpexc; 275 276 fpexc = fmrx(fpexc); /* Is the vfp enabled? */ 277 if (fpexc & VFPEXC_EN) { 278 vfpsave->fpexec = fpexc; 279 vfpsave->fpscr = fmrx(fpscr); 280 281 /* On vfpv3 we may need to save FPINST and FPINST2 */ 282 if (fpexc & VFPEXC_EX) { 283 vfpsave->fpinst = fmrx(fpinst); 284 if (fpexc & VFPEXC_FP2V) 285 vfpsave->fpinst2 = fmrx(fpinst2); 286 fpexc &= ~VFPEXC_EX; 287 } 288 289 __asm __volatile( 290 " .fpu vfpv2\n" 291 " .fpu vfpv3\n" 292 " vstmia %0!, {d0-d15}\n" /* d0-d15 */ 293 " cmp %1, #0\n" /* -D16 or -D32? */ 294 " vstmiane r0!, {d16-d31}\n" /* d16-d31 */ 295 " addeq %0, %0, #128\n" /* skip missing regs */ 296 : "+&r" (vfpsave) : "r" (is_d32) : "cc" 297 ); 298 299 if (disable_vfp) 300 fmxr(fpexc , fpexc & ~VFPEXC_EN); 301 } 302} 303 304/* 305 * The current thread is dying. If the state currently in the hardware belongs 306 * to the current thread, set fpcurthread to NULL to indicate that the VFP 307 * hardware state does not belong to any thread. If the VFP is on, turn it off. 308 * Called only from cpu_throw(), so we don't have to worry about a context 309 * switch here. 310 */ 311void 312vfp_discard(struct thread *td) 313{ 314 u_int tmp; 315 316 if (PCPU_GET(fpcurthread) == td) 317 PCPU_SET(fpcurthread, NULL); 318 319 tmp = fmrx(fpexc); 320 if (tmp & VFPEXC_EN) 321 fmxr(fpexc, tmp & ~VFPEXC_EN); 322} 323 324#endif 325 326