1/*- 2 * Copyright (c) 2003 Peter Wemm. 3 * Copyright (c) 1990 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD$ 34 */ 35 36#include <machine/asmacros.h> 37#include <machine/specialreg.h> 38 39#include "assym.s" 40#include "opt_sched.h" 41 42/*****************************************************************************/ 43/* Scheduling */ 44/*****************************************************************************/ 45 46 .text 47 48#ifdef SMP 49#define LK lock ; 50#else 51#define LK 52#endif 53 54#if defined(SCHED_ULE) && defined(SMP) 55#define SETLK xchgq 56#else 57#define SETLK movq 58#endif 59 60/* 61 * cpu_throw() 62 * 63 * This is the second half of cpu_switch(). It is used when the current 64 * thread is either a dummy or slated to die, and we no longer care 65 * about its state. This is only a slight optimization and is probably 66 * not worth it anymore. Note that we need to clear the pm_active bits so 67 * we do need the old proc if it still exists. 68 * %rdi = oldtd 69 * %rsi = newtd 70 */ 71ENTRY(cpu_throw) 72 movq %rsi,%r12 73 movq %rsi,%rdi 74 call pmap_activate_sw 75 jmp sw1 76END(cpu_throw) 77 78/* 79 * cpu_switch(old, new, mtx) 80 * 81 * Save the current thread state, then select the next thread to run 82 * and load its state. 83 * %rdi = oldtd 84 * %rsi = newtd 85 * %rdx = mtx 86 */ 87ENTRY(cpu_switch) 88 /* Switch to new thread. First, save context. */ 89 movq TD_PCB(%rdi),%r8 90 orl $PCB_FULL_IRET,PCB_FLAGS(%r8) 91 92 movq (%rsp),%rax /* Hardware registers */ 93 movq %r15,PCB_R15(%r8) 94 movq %r14,PCB_R14(%r8) 95 movq %r13,PCB_R13(%r8) 96 movq %r12,PCB_R12(%r8) 97 movq %rbp,PCB_RBP(%r8) 98 movq %rsp,PCB_RSP(%r8) 99 movq %rbx,PCB_RBX(%r8) 100 movq %rax,PCB_RIP(%r8) 101 102 testl $PCB_DBREGS,PCB_FLAGS(%r8) 103 jnz store_dr /* static predict not taken */ 104done_store_dr: 105 106 /* have we used fp, and need a save? */ 107 cmpq %rdi,PCPU(FPCURTHREAD) 108 jne 3f 109 movq PCB_SAVEFPU(%r8),%r8 110 clts 111 cmpl $0,use_xsave 112 jne 1f 113 fxsave (%r8) 114 jmp 2f 1151: movq %rdx,%rcx 116 movl xsave_mask,%eax 117 movl xsave_mask+4,%edx 118 .globl ctx_switch_xsave 119ctx_switch_xsave: 120 /* This is patched to xsaveopt if supported, see fpuinit_bsp1() */ 121 xsave (%r8) 122 movq %rcx,%rdx 1232: smsw %ax 124 orb $CR0_TS,%al 125 lmsw %ax 126 xorl %eax,%eax 127 movq %rax,PCPU(FPCURTHREAD) 1283: 129 /* Save is done. Now fire up new thread. Leave old vmspace. */ 130 movq %rsi,%r12 131 movq %rdi,%r13 132 movq %rdx,%r15 133 movq %rsi,%rdi 134 callq pmap_activate_sw 135 SETLK %r15,TD_LOCK(%r13) /* Release the old thread */ 136sw1: 137 movq TD_PCB(%r12),%r8 138#if defined(SCHED_ULE) && defined(SMP) 139 /* Wait for the new thread to become unblocked */ 140 movq $blocked_lock, %rdx 1411: 142 movq TD_LOCK(%r12),%rcx 143 cmpq %rcx, %rdx 144 pause 145 je 1b 146#endif 147 /* 148 * At this point, we've switched address spaces and are ready 149 * to load up the rest of the next context. 150 */ 151 152 /* Skip loading user fsbase/gsbase for kthreads */ 153 testl $TDP_KTHREAD,TD_PFLAGS(%r12) 154 jnz do_kthread 155 156 /* 157 * Load ldt register 158 */ 159 movq TD_PROC(%r12),%rcx 160 cmpq $0, P_MD+MD_LDT(%rcx) 161 jne do_ldt 162 xorl %eax,%eax 163ld_ldt: lldt %ax 164 165 /* Restore fs base in GDT */ 166 movl PCB_FSBASE(%r8),%eax 167 movq PCPU(FS32P),%rdx 168 movw %ax,2(%rdx) 169 shrl $16,%eax 170 movb %al,4(%rdx) 171 shrl $8,%eax 172 movb %al,7(%rdx) 173 174 /* Restore gs base in GDT */ 175 movl PCB_GSBASE(%r8),%eax 176 movq PCPU(GS32P),%rdx 177 movw %ax,2(%rdx) 178 shrl $16,%eax 179 movb %al,4(%rdx) 180 shrl $8,%eax 181 movb %al,7(%rdx) 182 183do_kthread: 184 /* Do we need to reload tss ? */ 185 movq PCPU(TSSP),%rax 186 movq PCB_TSSP(%r8),%rdx 187 testq %rdx,%rdx 188 cmovzq PCPU(COMMONTSSP),%rdx 189 cmpq %rax,%rdx 190 jne do_tss 191done_tss: 192 movq %r8,PCPU(RSP0) 193 movq %r8,PCPU(CURPCB) 194 /* Update the TSS_RSP0 pointer for the next interrupt */ 195 movq %r8,COMMON_TSS_RSP0(%rdx) 196 movq %r12,PCPU(CURTHREAD) /* into next thread */ 197 198 /* Test if debug registers should be restored. */ 199 testl $PCB_DBREGS,PCB_FLAGS(%r8) 200 jnz load_dr /* static predict not taken */ 201done_load_dr: 202 203 /* Restore context. */ 204 movq PCB_R15(%r8),%r15 205 movq PCB_R14(%r8),%r14 206 movq PCB_R13(%r8),%r13 207 movq PCB_R12(%r8),%r12 208 movq PCB_RBP(%r8),%rbp 209 movq PCB_RSP(%r8),%rsp 210 movq PCB_RBX(%r8),%rbx 211 movq PCB_RIP(%r8),%rax 212 movq %rax,(%rsp) 213 ret 214 215 /* 216 * We order these strangely for several reasons. 217 * 1: I wanted to use static branch prediction hints 218 * 2: Most athlon64/opteron cpus don't have them. They define 219 * a forward branch as 'predict not taken'. Intel cores have 220 * the 'rep' prefix to invert this. 221 * So, to make it work on both forms of cpu we do the detour. 222 * We use jumps rather than call in order to avoid the stack. 223 */ 224 225store_dr: 226 movq %dr7,%rax /* yes, do the save */ 227 movq %dr0,%r15 228 movq %dr1,%r14 229 movq %dr2,%r13 230 movq %dr3,%r12 231 movq %dr6,%r11 232 movq %r15,PCB_DR0(%r8) 233 movq %r14,PCB_DR1(%r8) 234 movq %r13,PCB_DR2(%r8) 235 movq %r12,PCB_DR3(%r8) 236 movq %r11,PCB_DR6(%r8) 237 movq %rax,PCB_DR7(%r8) 238 andq $0x0000fc00, %rax /* disable all watchpoints */ 239 movq %rax,%dr7 240 jmp done_store_dr 241 242load_dr: 243 movq %dr7,%rax 244 movq PCB_DR0(%r8),%r15 245 movq PCB_DR1(%r8),%r14 246 movq PCB_DR2(%r8),%r13 247 movq PCB_DR3(%r8),%r12 248 movq PCB_DR6(%r8),%r11 249 movq PCB_DR7(%r8),%rcx 250 movq %r15,%dr0 251 movq %r14,%dr1 252 /* Preserve reserved bits in %dr7 */ 253 andq $0x0000fc00,%rax 254 andq $~0x0000fc00,%rcx 255 movq %r13,%dr2 256 movq %r12,%dr3 257 orq %rcx,%rax 258 movq %r11,%dr6 259 movq %rax,%dr7 260 jmp done_load_dr 261 262do_tss: movq %rdx,PCPU(TSSP) 263 movq %rdx,%rcx 264 movq PCPU(TSS),%rax 265 movw %cx,2(%rax) 266 shrq $16,%rcx 267 movb %cl,4(%rax) 268 shrq $8,%rcx 269 movb %cl,7(%rax) 270 shrq $8,%rcx 271 movl %ecx,8(%rax) 272 movb $0x89,5(%rax) /* unset busy */ 273 movl $TSSSEL,%eax 274 ltr %ax 275 jmp done_tss 276 277do_ldt: movq PCPU(LDT),%rax 278 movq P_MD+MD_LDT_SD(%rcx),%rdx 279 movq %rdx,(%rax) 280 movq P_MD+MD_LDT_SD+8(%rcx),%rdx 281 movq %rdx,8(%rax) 282 movl $LDTSEL,%eax 283 jmp ld_ldt 284END(cpu_switch) 285 286/* 287 * savectx(pcb) 288 * Update pcb, saving current processor state. 289 */ 290ENTRY(savectx) 291 /* Save caller's return address. */ 292 movq (%rsp),%rax 293 movq %rax,PCB_RIP(%rdi) 294 295 movq %rbx,PCB_RBX(%rdi) 296 movq %rsp,PCB_RSP(%rdi) 297 movq %rbp,PCB_RBP(%rdi) 298 movq %r12,PCB_R12(%rdi) 299 movq %r13,PCB_R13(%rdi) 300 movq %r14,PCB_R14(%rdi) 301 movq %r15,PCB_R15(%rdi) 302 303 movq %cr0,%rax 304 movq %rax,PCB_CR0(%rdi) 305 movq %cr2,%rax 306 movq %rax,PCB_CR2(%rdi) 307 movq %cr3,%rax 308 movq %rax,PCB_CR3(%rdi) 309 movq %cr4,%rax 310 movq %rax,PCB_CR4(%rdi) 311 312 movq %dr0,%rax 313 movq %rax,PCB_DR0(%rdi) 314 movq %dr1,%rax 315 movq %rax,PCB_DR1(%rdi) 316 movq %dr2,%rax 317 movq %rax,PCB_DR2(%rdi) 318 movq %dr3,%rax 319 movq %rax,PCB_DR3(%rdi) 320 movq %dr6,%rax 321 movq %rax,PCB_DR6(%rdi) 322 movq %dr7,%rax 323 movq %rax,PCB_DR7(%rdi) 324 325 movl $MSR_FSBASE,%ecx 326 rdmsr 327 movl %eax,PCB_FSBASE(%rdi) 328 movl %edx,PCB_FSBASE+4(%rdi) 329 movl $MSR_GSBASE,%ecx 330 rdmsr 331 movl %eax,PCB_GSBASE(%rdi) 332 movl %edx,PCB_GSBASE+4(%rdi) 333 movl $MSR_KGSBASE,%ecx 334 rdmsr 335 movl %eax,PCB_KGSBASE(%rdi) 336 movl %edx,PCB_KGSBASE+4(%rdi) 337 movl $MSR_EFER,%ecx 338 rdmsr 339 movl %eax,PCB_EFER(%rdi) 340 movl %edx,PCB_EFER+4(%rdi) 341 movl $MSR_STAR,%ecx 342 rdmsr 343 movl %eax,PCB_STAR(%rdi) 344 movl %edx,PCB_STAR+4(%rdi) 345 movl $MSR_LSTAR,%ecx 346 rdmsr 347 movl %eax,PCB_LSTAR(%rdi) 348 movl %edx,PCB_LSTAR+4(%rdi) 349 movl $MSR_CSTAR,%ecx 350 rdmsr 351 movl %eax,PCB_CSTAR(%rdi) 352 movl %edx,PCB_CSTAR+4(%rdi) 353 movl $MSR_SF_MASK,%ecx 354 rdmsr 355 movl %eax,PCB_SFMASK(%rdi) 356 movl %edx,PCB_SFMASK+4(%rdi) 357 358 sgdt PCB_GDT(%rdi) 359 sidt PCB_IDT(%rdi) 360 sldt PCB_LDT(%rdi) 361 str PCB_TR(%rdi) 362 363 movl $1,%eax 364 ret 365END(savectx) 366 367/* 368 * resumectx(pcb) 369 * Resuming processor state from pcb. 370 */ 371ENTRY(resumectx) 372 /* Switch to KPML4phys. */ 373 movq KPML4phys,%rax 374 movq %rax,%cr3 375 376 /* Force kernel segment registers. */ 377 movl $KDSEL,%eax 378 movw %ax,%ds 379 movw %ax,%es 380 movw %ax,%ss 381 movl $KUF32SEL,%eax 382 movw %ax,%fs 383 movl $KUG32SEL,%eax 384 movw %ax,%gs 385 386 movl $MSR_FSBASE,%ecx 387 movl PCB_FSBASE(%rdi),%eax 388 movl 4 + PCB_FSBASE(%rdi),%edx 389 wrmsr 390 movl $MSR_GSBASE,%ecx 391 movl PCB_GSBASE(%rdi),%eax 392 movl 4 + PCB_GSBASE(%rdi),%edx 393 wrmsr 394 movl $MSR_KGSBASE,%ecx 395 movl PCB_KGSBASE(%rdi),%eax 396 movl 4 + PCB_KGSBASE(%rdi),%edx 397 wrmsr 398 399 /* Restore EFER. */ 400 movl $MSR_EFER,%ecx 401 movl PCB_EFER(%rdi),%eax 402 wrmsr 403 404 /* Restore fast syscall stuff. */ 405 movl $MSR_STAR,%ecx 406 movl PCB_STAR(%rdi),%eax 407 movl 4 + PCB_STAR(%rdi),%edx 408 wrmsr 409 movl $MSR_LSTAR,%ecx 410 movl PCB_LSTAR(%rdi),%eax 411 movl 4 + PCB_LSTAR(%rdi),%edx 412 wrmsr 413 movl $MSR_CSTAR,%ecx 414 movl PCB_CSTAR(%rdi),%eax 415 movl 4 + PCB_CSTAR(%rdi),%edx 416 wrmsr 417 movl $MSR_SF_MASK,%ecx 418 movl PCB_SFMASK(%rdi),%eax 419 wrmsr 420 421 /* Restore CR0, CR2, CR4 and CR3. */ 422 movq PCB_CR0(%rdi),%rax 423 movq %rax,%cr0 424 movq PCB_CR2(%rdi),%rax 425 movq %rax,%cr2 426 movq PCB_CR4(%rdi),%rax 427 movq %rax,%cr4 428 movq PCB_CR3(%rdi),%rax 429 movq %rax,%cr3 430 431 /* Restore descriptor tables. */ 432 lidt PCB_IDT(%rdi) 433 lldt PCB_LDT(%rdi) 434 435#define SDT_SYSTSS 9 436#define SDT_SYSBSY 11 437 438 /* Clear "task busy" bit and reload TR. */ 439 movq PCPU(TSS),%rax 440 andb $(~SDT_SYSBSY | SDT_SYSTSS),5(%rax) 441 movw PCB_TR(%rdi),%ax 442 ltr %ax 443 444#undef SDT_SYSTSS 445#undef SDT_SYSBSY 446 447 /* Restore debug registers. */ 448 movq PCB_DR0(%rdi),%rax 449 movq %rax,%dr0 450 movq PCB_DR1(%rdi),%rax 451 movq %rax,%dr1 452 movq PCB_DR2(%rdi),%rax 453 movq %rax,%dr2 454 movq PCB_DR3(%rdi),%rax 455 movq %rax,%dr3 456 movq PCB_DR6(%rdi),%rax 457 movq %rax,%dr6 458 movq PCB_DR7(%rdi),%rax 459 movq %rax,%dr7 460 461 /* Restore other callee saved registers. */ 462 movq PCB_R15(%rdi),%r15 463 movq PCB_R14(%rdi),%r14 464 movq PCB_R13(%rdi),%r13 465 movq PCB_R12(%rdi),%r12 466 movq PCB_RBP(%rdi),%rbp 467 movq PCB_RSP(%rdi),%rsp 468 movq PCB_RBX(%rdi),%rbx 469 470 /* Restore return address. */ 471 movq PCB_RIP(%rdi),%rax 472 movq %rax,(%rsp) 473 474 xorl %eax,%eax 475 ret 476END(resumectx) 477