vfp.c revision 266160
1/* 2 * Copyright (c) 2012 Mark Tinguely 3 * 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include <sys/cdefs.h> 29__FBSDID("$FreeBSD: stable/10/sys/arm/arm/vfp.c 266160 2014-05-15 17:30:16Z ian $"); 30 31#ifdef VFP 32#include <sys/param.h> 33#include <sys/systm.h> 34#include <sys/proc.h> 35#include <sys/kernel.h> 36 37#include <machine/frame.h> 38#include <machine/fp.h> 39#include <machine/pcb.h> 40#include <machine/undefined.h> 41#include <machine/vfp.h> 42 43/* function prototypes */ 44unsigned int get_coprocessorACR(void); 45static int vfp_bounce(u_int, u_int, struct trapframe *, int); 46static void vfp_restore(struct vfp_state *); 47void vfp_discard(void); 48void vfp_store(struct vfp_state *); 49void set_coprocessorACR(u_int); 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/* The VFMXR command using coprocessor commands */ 57#define fmxr(reg, val) \ 58 __asm __volatile("mcr p10, 7, %0, " __STRING(reg) " , c0, 0" :: "r"(val)); 59 60/* The VFMRX command using coprocessor commands */ 61#define fmrx(reg) \ 62({ u_int val = 0;\ 63 __asm __volatile("mrc p10, 7, %0, " __STRING(reg) " , c0, 0" : "=r"(val));\ 64 val; \ 65}) 66 67u_int 68get_coprocessorACR(void) 69{ 70 u_int val; 71 __asm __volatile("mrc p15, 0, %0, c1, c0, 2" : "=r" (val) : : "cc"); 72 return val; 73} 74 75void 76set_coprocessorACR(u_int val) 77{ 78 __asm __volatile("mcr p15, 0, %0, c1, c0, 2\n\t" 79 : : "r" (val) : "cc"); 80 isb(); 81} 82 83 84 /* called for each cpu */ 85void 86vfp_init(void) 87{ 88 u_int fpsid, fpexc, tmp; 89 u_int coproc, vfp_arch; 90 91 coproc = get_coprocessorACR(); 92 coproc |= COPROC10 | COPROC11; 93 set_coprocessorACR(coproc); 94 95 fpsid = fmrx(VFPSID); /* read the vfp system id */ 96 fpexc = fmrx(VFPEXC); /* read the vfp exception reg */ 97 98 if (!(fpsid & VFPSID_HARDSOFT_IMP)) { 99 vfp_exists = 1; 100 is_d32 = 0; 101 PCPU_SET(vfpsid, fpsid); /* save the VFPSID */ 102 103 vfp_arch = 104 (fpsid & VFPSID_SUBVERSION2_MASK) >> VFPSID_SUBVERSION_OFF; 105 106 if (vfp_arch >= VFP_ARCH3) { 107 tmp = fmrx(VMVFR0); 108 PCPU_SET(vfpmvfr0, tmp); 109 110 if ((tmp & VMVFR0_RB_MASK) == 2) 111 is_d32 = 1; 112 113 tmp = fmrx(VMVFR1); 114 PCPU_SET(vfpmvfr1, tmp); 115 } 116 117 /* initialize the coprocess 10 and 11 calls 118 * These are called to restore the registers and enable 119 * the VFP hardware. 120 */ 121 if (vfp10_uh.uh_handler == NULL) { 122 vfp10_uh.uh_handler = vfp_bounce; 123 vfp11_uh.uh_handler = vfp_bounce; 124 install_coproc_handler_static(10, &vfp10_uh); 125 install_coproc_handler_static(11, &vfp11_uh); 126 } 127 } 128} 129 130SYSINIT(vfp, SI_SUB_CPU, SI_ORDER_ANY, vfp_init, NULL); 131 132 133/* start VFP unit, restore the vfp registers from the PCB and retry 134 * the instruction 135 */ 136static int 137vfp_bounce(u_int addr, u_int insn, struct trapframe *frame, int code) 138{ 139 u_int fpexc; 140 struct pcb *curpcb; 141 struct thread *vfptd; 142 int i; 143 144 if (!vfp_exists) 145 return 1; /* vfp does not exist */ 146 i = disable_interrupts(I32_bit|F32_bit); 147 fpexc = fmrx(VFPEXC); /* read the vfp exception reg */ 148 if (fpexc & VFPEXC_EN) { 149 vfptd = PCPU_GET(vfpcthread); 150 /* did the kernel call the vfp or exception that expect us 151 * to emulate the command. Newer hardware does not require 152 * emulation, so we don't emulate yet. 153 */ 154#ifdef SMP 155 /* don't save if newer registers are on another processor */ 156 if (vfptd /* && (vfptd == curthread) */ && 157 (vfptd->td_pcb->pcb_vfpcpu == PCPU_GET(cpu))) 158#else 159 /* someone did not save their registers, */ 160 if (vfptd /* && (vfptd == curthread) */) 161#endif 162 vfp_store(&vfptd->td_pcb->pcb_vfpstate); 163 164 fpexc &= ~VFPEXC_EN; 165 fmxr(VFPEXC, fpexc); /* turn vfp hardware off */ 166 if (vfptd == curthread) { 167 /* kill the process - we do not handle emulation */ 168 restore_interrupts(i); 169 killproc(curthread->td_proc, "vfp emulation"); 170 return 1; 171 } 172 /* should not happen. someone did not save their context */ 173 printf("vfp_bounce: vfpcthread: %p curthread: %p\n", 174 vfptd, curthread); 175 } 176 fpexc |= VFPEXC_EN; 177 fmxr(VFPEXC, fpexc); /* enable the vfp and repeat command */ 178 curpcb = curthread->td_pcb; 179 /* If we were the last process to use the VFP, the process did not 180 * use a VFP on another processor, then the registers in the VFP 181 * will still be ours and are current. Eventually, we will make the 182 * restore smarter. 183 */ 184 vfp_restore(&curpcb->pcb_vfpstate); 185#ifdef SMP 186 curpcb->pcb_vfpcpu = PCPU_GET(cpu); 187#endif 188 PCPU_SET(vfpcthread, curthread); 189 restore_interrupts(i); 190 return 0; 191} 192 193/* vfs_store is called from from a VFP command to restore the registers and 194 * turn on the VFP hardware. 195 * Eventually we will use the information that this process was the last 196 * to use the VFP hardware and bypass the restore, just turn on the hardware. 197 */ 198static void 199vfp_restore(struct vfp_state *vfpsave) 200{ 201 u_int vfpscr = 0; 202 203 /* 204 * Work around an issue with GCC where the asm it generates is 205 * not unified syntax and fails to assemble because it expects 206 * the ldcleq instruction in the form ldc<c>l, not in the UAL 207 * form ldcl<c>, and similar for stcleq. 208 */ 209#ifdef __clang__ 210#define ldclne "ldclne" 211#define stclne "stclne" 212#else 213#define ldclne "ldcnel" 214#define stclne "stcnel" 215#endif 216 if (vfpsave) { 217 __asm __volatile("ldc p10, c0, [%1], #128\n" /* d0-d15 */ 218 "cmp %2, #0\n" /* -D16 or -D32? */ 219 ldclne" p11, c0, [%1], #128\n" /* d16-d31 */ 220 "addeq %1, %1, #128\n" /* skip missing regs */ 221 "ldr %0, [%1]\n" /* set old vfpscr */ 222 "mcr p10, 7, %0, cr1, c0, 0\n" 223 : "=&r" (vfpscr) : "r" (vfpsave), "r" (is_d32) : "cc"); 224 } 225} 226 227/* vfs_store is called from switch to save the vfp hardware registers 228 * into the pcb before switching to another process. 229 * we already know that the new process is different from this old 230 * process and that this process last used the VFP registers. 231 * Below we check to see if the VFP has been enabled since the last 232 * register save. 233 * This routine will exit with the VFP turned off. The next VFP user 234 * will trap to restore its registers and turn on the VFP hardware. 235 */ 236void 237vfp_store(struct vfp_state *vfpsave) 238{ 239 u_int tmp, vfpscr = 0; 240 241 tmp = fmrx(VFPEXC); /* Is the vfp enabled? */ 242 if (vfpsave && (tmp & VFPEXC_EN)) { 243 __asm __volatile("stc p11, c0, [%1], #128\n" /* d0-d15 */ 244 "cmp %2, #0\n" /* -D16 or -D32? */ 245 stclne" p11, c0, [%1], #128\n" /* d16-d31 */ 246 "addeq %1, %1, #128\n" /* skip missing regs */ 247 "mrc p10, 7, %0, cr1, c0, 0\n" /* fmxr(VFPSCR) */ 248 "str %0, [%1]\n" /* save vfpscr */ 249 : "=&r" (vfpscr) : "r" (vfpsave), "r" (is_d32) : "cc"); 250 } 251#undef ldcleq 252#undef stcleq 253 254#ifndef SMP 255 /* eventually we will use this information for UP also */ 256 PCPU_SET(vfpcthread, 0); 257#endif 258 tmp &= ~VFPEXC_EN; /* disable the vfp hardware */ 259 fmxr(VFPEXC , tmp); 260} 261 262/* discard the registers at cpu_thread_free() when fpcurthread == td. 263 * Turn off the VFP hardware. 264 */ 265void 266vfp_discard() 267{ 268 u_int tmp = 0; 269 270 /* 271 * No need to protect the access to vfpcthread by disabling 272 * interrupts, since it's called from cpu_throw(), who is called 273 * with interrupts disabled. 274 */ 275 276 PCPU_SET(vfpcthread, 0); /* permanent forget about reg */ 277 tmp = fmrx(VFPEXC); 278 tmp &= ~VFPEXC_EN; /* turn off VFP hardware */ 279 fmxr(VFPEXC, tmp); 280} 281 282#endif 283 284