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 91 movq (%rsp),%rax /* Hardware registers */ 92 movq %r15,PCB_R15(%r8) 93 movq %r14,PCB_R14(%r8) 94 movq %r13,PCB_R13(%r8) 95 movq %r12,PCB_R12(%r8) 96 movq %rbp,PCB_RBP(%r8) 97 movq %rsp,PCB_RSP(%r8) 98 movq %rbx,PCB_RBX(%r8) 99 movq %rax,PCB_RIP(%r8) 100 101 testl $PCB_FULL_IRET,PCB_FLAGS(%r8) 102 jnz 2f 103 orl $PCB_FULL_IRET,PCB_FLAGS(%r8) 104 testl $TDP_KTHREAD,TD_PFLAGS(%rdi) 105 jnz 2f 106 testb $CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip) 107 jz 2f 108 movl %fs,%eax 109 cmpl $KUF32SEL,%eax 110 jne 1f 111 rdfsbase %rax 112 movq %rax,PCB_FSBASE(%r8) 1131: movl %gs,%eax 114 cmpl $KUG32SEL,%eax 115 jne 2f 116 movq %rdx,%r12 117 movl $MSR_KGSBASE,%ecx /* Read user gs base */ 118 rdmsr 119 shlq $32,%rdx 120 orq %rdx,%rax 121 movq %rax,PCB_GSBASE(%r8) 122 movq %r12,%rdx 123 1242: 125 testl $PCB_DBREGS,PCB_FLAGS(%r8) 126 jnz store_dr /* static predict not taken */ 127done_store_dr: 128 129 /* have we used fp, and need a save? */ 130 cmpq %rdi,PCPU(FPCURTHREAD) 131 jne 3f 132 movq PCB_SAVEFPU(%r8),%r8 133 clts 134 cmpl $0,use_xsave 135 jne 1f 136 fxsave (%r8) 137 jmp 2f 1381: movq %rdx,%rcx 139 movl xsave_mask,%eax 140 movl xsave_mask+4,%edx 141 .globl ctx_switch_xsave 142ctx_switch_xsave: 143 /* This is patched to xsaveopt if supported, see fpuinit_bsp1() */ 144 xsave (%r8) 145 movq %rcx,%rdx 1462: smsw %ax 147 orb $CR0_TS,%al 148 lmsw %ax 149 xorl %eax,%eax 150 movq %rax,PCPU(FPCURTHREAD) 1513: 152 /* Save is done. Now fire up new thread. Leave old vmspace. */ 153 movq %rsi,%r12 154 movq %rdi,%r13 155 movq %rdx,%r15 156 movq %rsi,%rdi 157 callq pmap_activate_sw 158 SETLK %r15,TD_LOCK(%r13) /* Release the old thread */ 159sw1: 160 movq TD_PCB(%r12),%r8 161#if defined(SCHED_ULE) && defined(SMP) 162 /* Wait for the new thread to become unblocked */ 163 movq $blocked_lock, %rdx 1641: 165 movq TD_LOCK(%r12),%rcx 166 cmpq %rcx, %rdx 167 pause 168 je 1b 169#endif 170 /* 171 * At this point, we've switched address spaces and are ready 172 * to load up the rest of the next context. 173 */ 174 175 /* Skip loading LDT and user fsbase/gsbase for kthreads */ 176 testl $TDP_KTHREAD,TD_PFLAGS(%r12) 177 jnz do_kthread 178 179 /* 180 * Load ldt register 181 */ 182 movq TD_PROC(%r12),%rcx 183 cmpq $0, P_MD+MD_LDT(%rcx) 184 jne do_ldt 185 xorl %eax,%eax 186ld_ldt: lldt %ax 187 188 /* Restore fs base in GDT */ 189 movl PCB_FSBASE(%r8),%eax 190 movq PCPU(FS32P),%rdx 191 movw %ax,2(%rdx) 192 shrl $16,%eax 193 movb %al,4(%rdx) 194 shrl $8,%eax 195 movb %al,7(%rdx) 196 197 /* Restore gs base in GDT */ 198 movl PCB_GSBASE(%r8),%eax 199 movq PCPU(GS32P),%rdx 200 movw %ax,2(%rdx) 201 shrl $16,%eax 202 movb %al,4(%rdx) 203 shrl $8,%eax 204 movb %al,7(%rdx) 205 206do_kthread: 207 /* Do we need to reload tss ? */ 208 movq PCPU(TSSP),%rax 209 movq PCB_TSSP(%r8),%rdx 210 testq %rdx,%rdx 211 cmovzq PCPU(COMMONTSSP),%rdx 212 cmpq %rax,%rdx 213 jne do_tss 214done_tss: 215 movq %r8,PCPU(RSP0) 216 movq %r8,PCPU(CURPCB) 217 /* Update the TSS_RSP0 pointer for the next interrupt */ 218 movq %r8,COMMON_TSS_RSP0(%rdx) 219 movq %r12,PCPU(CURTHREAD) /* into next thread */ 220 221 /* Test if debug registers should be restored. */ 222 testl $PCB_DBREGS,PCB_FLAGS(%r8) 223 jnz load_dr /* static predict not taken */ 224done_load_dr: 225 226 /* Restore context. */ 227 movq PCB_R15(%r8),%r15 228 movq PCB_R14(%r8),%r14 229 movq PCB_R13(%r8),%r13 230 movq PCB_R12(%r8),%r12 231 movq PCB_RBP(%r8),%rbp 232 movq PCB_RSP(%r8),%rsp 233 movq PCB_RBX(%r8),%rbx 234 movq PCB_RIP(%r8),%rax 235 movq %rax,(%rsp) 236 ret 237 238 /* 239 * We order these strangely for several reasons. 240 * 1: I wanted to use static branch prediction hints 241 * 2: Most athlon64/opteron cpus don't have them. They define 242 * a forward branch as 'predict not taken'. Intel cores have 243 * the 'rep' prefix to invert this. 244 * So, to make it work on both forms of cpu we do the detour. 245 * We use jumps rather than call in order to avoid the stack. 246 */ 247 248store_dr: 249 movq %dr7,%rax /* yes, do the save */ 250 movq %dr0,%r15 251 movq %dr1,%r14 252 movq %dr2,%r13 253 movq %dr3,%r12 254 movq %dr6,%r11 255 movq %r15,PCB_DR0(%r8) 256 movq %r14,PCB_DR1(%r8) 257 movq %r13,PCB_DR2(%r8) 258 movq %r12,PCB_DR3(%r8) 259 movq %r11,PCB_DR6(%r8) 260 movq %rax,PCB_DR7(%r8) 261 andq $0x0000fc00, %rax /* disable all watchpoints */ 262 movq %rax,%dr7 263 jmp done_store_dr 264 265load_dr: 266 movq %dr7,%rax 267 movq PCB_DR0(%r8),%r15 268 movq PCB_DR1(%r8),%r14 269 movq PCB_DR2(%r8),%r13 270 movq PCB_DR3(%r8),%r12 271 movq PCB_DR6(%r8),%r11 272 movq PCB_DR7(%r8),%rcx 273 movq %r15,%dr0 274 movq %r14,%dr1 275 /* Preserve reserved bits in %dr7 */ 276 andq $0x0000fc00,%rax 277 andq $~0x0000fc00,%rcx 278 movq %r13,%dr2 279 movq %r12,%dr3 280 orq %rcx,%rax 281 movq %r11,%dr6 282 movq %rax,%dr7 283 jmp done_load_dr 284 285do_tss: movq %rdx,PCPU(TSSP) 286 movq %rdx,%rcx 287 movq PCPU(TSS),%rax 288 movw %cx,2(%rax) 289 shrq $16,%rcx 290 movb %cl,4(%rax) 291 shrq $8,%rcx 292 movb %cl,7(%rax) 293 shrq $8,%rcx 294 movl %ecx,8(%rax) 295 movb $0x89,5(%rax) /* unset busy */ 296 movl $TSSSEL,%eax 297 ltr %ax 298 jmp done_tss 299 300do_ldt: movq PCPU(LDT),%rax 301 movq P_MD+MD_LDT_SD(%rcx),%rdx 302 movq %rdx,(%rax) 303 movq P_MD+MD_LDT_SD+8(%rcx),%rdx 304 movq %rdx,8(%rax) 305 movl $LDTSEL,%eax 306 jmp ld_ldt 307END(cpu_switch) 308 309/* 310 * savectx(pcb) 311 * Update pcb, saving current processor state. 312 */ 313ENTRY(savectx) 314 /* Save caller's return address. */ 315 movq (%rsp),%rax 316 movq %rax,PCB_RIP(%rdi) 317 318 movq %rbx,PCB_RBX(%rdi) 319 movq %rsp,PCB_RSP(%rdi) 320 movq %rbp,PCB_RBP(%rdi) 321 movq %r12,PCB_R12(%rdi) 322 movq %r13,PCB_R13(%rdi) 323 movq %r14,PCB_R14(%rdi) 324 movq %r15,PCB_R15(%rdi) 325 326 movq %cr0,%rax 327 movq %rax,PCB_CR0(%rdi) 328 movq %cr2,%rax 329 movq %rax,PCB_CR2(%rdi) 330 movq %cr3,%rax 331 movq %rax,PCB_CR3(%rdi) 332 movq %cr4,%rax 333 movq %rax,PCB_CR4(%rdi) 334 335 movq %dr0,%rax 336 movq %rax,PCB_DR0(%rdi) 337 movq %dr1,%rax 338 movq %rax,PCB_DR1(%rdi) 339 movq %dr2,%rax 340 movq %rax,PCB_DR2(%rdi) 341 movq %dr3,%rax 342 movq %rax,PCB_DR3(%rdi) 343 movq %dr6,%rax 344 movq %rax,PCB_DR6(%rdi) 345 movq %dr7,%rax 346 movq %rax,PCB_DR7(%rdi) 347 348 movl $MSR_FSBASE,%ecx 349 rdmsr 350 movl %eax,PCB_FSBASE(%rdi) 351 movl %edx,PCB_FSBASE+4(%rdi) 352 movl $MSR_GSBASE,%ecx 353 rdmsr 354 movl %eax,PCB_GSBASE(%rdi) 355 movl %edx,PCB_GSBASE+4(%rdi) 356 movl $MSR_KGSBASE,%ecx 357 rdmsr 358 movl %eax,PCB_KGSBASE(%rdi) 359 movl %edx,PCB_KGSBASE+4(%rdi) 360 movl $MSR_EFER,%ecx 361 rdmsr 362 movl %eax,PCB_EFER(%rdi) 363 movl %edx,PCB_EFER+4(%rdi) 364 movl $MSR_STAR,%ecx 365 rdmsr 366 movl %eax,PCB_STAR(%rdi) 367 movl %edx,PCB_STAR+4(%rdi) 368 movl $MSR_LSTAR,%ecx 369 rdmsr 370 movl %eax,PCB_LSTAR(%rdi) 371 movl %edx,PCB_LSTAR+4(%rdi) 372 movl $MSR_CSTAR,%ecx 373 rdmsr 374 movl %eax,PCB_CSTAR(%rdi) 375 movl %edx,PCB_CSTAR+4(%rdi) 376 movl $MSR_SF_MASK,%ecx 377 rdmsr 378 movl %eax,PCB_SFMASK(%rdi) 379 movl %edx,PCB_SFMASK+4(%rdi) 380 381 sgdt PCB_GDT(%rdi) 382 sidt PCB_IDT(%rdi) 383 sldt PCB_LDT(%rdi) 384 str PCB_TR(%rdi) 385 386 movl $1,%eax 387 ret 388END(savectx) 389 390/* 391 * resumectx(pcb) 392 * Resuming processor state from pcb. 393 */ 394ENTRY(resumectx) 395 /* Switch to KPML4phys. */ 396 movq KPML4phys,%rax 397 movq %rax,%cr3 398 399 /* Force kernel segment registers. */ 400 movl $KDSEL,%eax 401 movw %ax,%ds 402 movw %ax,%es 403 movw %ax,%ss 404 movl $KUF32SEL,%eax 405 movw %ax,%fs 406 movl $KUG32SEL,%eax 407 movw %ax,%gs 408 409 movl $MSR_FSBASE,%ecx 410 movl PCB_FSBASE(%rdi),%eax 411 movl 4 + PCB_FSBASE(%rdi),%edx 412 wrmsr 413 movl $MSR_GSBASE,%ecx 414 movl PCB_GSBASE(%rdi),%eax 415 movl 4 + PCB_GSBASE(%rdi),%edx 416 wrmsr 417 movl $MSR_KGSBASE,%ecx 418 movl PCB_KGSBASE(%rdi),%eax 419 movl 4 + PCB_KGSBASE(%rdi),%edx 420 wrmsr 421 422 /* Restore EFER one more time. */ 423 movl $MSR_EFER,%ecx 424 movl PCB_EFER(%rdi),%eax 425 wrmsr 426 427 /* Restore fast syscall stuff. */ 428 movl $MSR_STAR,%ecx 429 movl PCB_STAR(%rdi),%eax 430 movl 4 + PCB_STAR(%rdi),%edx 431 wrmsr 432 movl $MSR_LSTAR,%ecx 433 movl PCB_LSTAR(%rdi),%eax 434 movl 4 + PCB_LSTAR(%rdi),%edx 435 wrmsr 436 movl $MSR_CSTAR,%ecx 437 movl PCB_CSTAR(%rdi),%eax 438 movl 4 + PCB_CSTAR(%rdi),%edx 439 wrmsr 440 movl $MSR_SF_MASK,%ecx 441 movl PCB_SFMASK(%rdi),%eax 442 wrmsr 443 444 /* Restore CR0, CR2, CR4 and CR3. */ 445 movq PCB_CR0(%rdi),%rax 446 movq %rax,%cr0 447 movq PCB_CR2(%rdi),%rax 448 movq %rax,%cr2 449 movq PCB_CR4(%rdi),%rax 450 movq %rax,%cr4 451 movq PCB_CR3(%rdi),%rax 452 movq %rax,%cr3 453 454 /* Restore descriptor tables. */ 455 lidt PCB_IDT(%rdi) 456 lldt PCB_LDT(%rdi) 457 458#define SDT_SYSTSS 9 459#define SDT_SYSBSY 11 460 461 /* Clear "task busy" bit and reload TR. */ 462 movq PCPU(TSS),%rax 463 andb $(~SDT_SYSBSY | SDT_SYSTSS),5(%rax) 464 movw PCB_TR(%rdi),%ax 465 ltr %ax 466 467#undef SDT_SYSTSS 468#undef SDT_SYSBSY 469 470 /* Restore debug registers. */ 471 movq PCB_DR0(%rdi),%rax 472 movq %rax,%dr0 473 movq PCB_DR1(%rdi),%rax 474 movq %rax,%dr1 475 movq PCB_DR2(%rdi),%rax 476 movq %rax,%dr2 477 movq PCB_DR3(%rdi),%rax 478 movq %rax,%dr3 479 movq PCB_DR6(%rdi),%rax 480 movq %rax,%dr6 481 movq PCB_DR7(%rdi),%rax 482 movq %rax,%dr7 483 484 /* Restore other callee saved registers. */ 485 movq PCB_R15(%rdi),%r15 486 movq PCB_R14(%rdi),%r14 487 movq PCB_R13(%rdi),%r13 488 movq PCB_R12(%rdi),%r12 489 movq PCB_RBP(%rdi),%rbp 490 movq PCB_RSP(%rdi),%rsp 491 movq PCB_RBX(%rdi),%rbx 492 493 /* Restore return address. */ 494 movq PCB_RIP(%rdi),%rax 495 movq %rax,(%rsp) 496 497 xorl %eax,%eax 498 ret 499END(resumectx) 500