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.inc" 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 2f 132 movq PCB_SAVEFPU(%r8),%r8 133 clts 134 cmpl $0,use_xsave(%rip) 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: 147 /* Save is done. Now fire up new thread. Leave old vmspace. */ 148 movq %rsi,%r12 149 movq %rdi,%r13 150 movq %rdx,%r15 151 movq %rsi,%rdi 152 callq pmap_activate_sw 153 SETLK %r15,TD_LOCK(%r13) /* Release the old thread */ 154sw1: 155 movq TD_PCB(%r12),%r8 156#if defined(SCHED_ULE) && defined(SMP) 157 /* Wait for the new thread to become unblocked */ 158 movq $blocked_lock, %rdx 1591: 160 movq TD_LOCK(%r12),%rcx 161 cmpq %rcx, %rdx 162 pause 163 je 1b 164#endif 165 /* 166 * At this point, we've switched address spaces and are ready 167 * to load up the rest of the next context. 168 */ 169 170 /* Skip loading LDT and user fsbase/gsbase for kthreads */ 171 testl $TDP_KTHREAD,TD_PFLAGS(%r12) 172 jnz do_kthread 173 174 /* 175 * Load ldt register 176 */ 177 movq TD_PROC(%r12),%rcx 178 cmpq $0, P_MD+MD_LDT(%rcx) 179 jne do_ldt 180 xorl %eax,%eax 181ld_ldt: lldt %ax 182 183 /* Restore fs base in GDT */ 184 movl PCB_FSBASE(%r8),%eax 185 movq PCPU(FS32P),%rdx 186 movw %ax,2(%rdx) 187 shrl $16,%eax 188 movb %al,4(%rdx) 189 shrl $8,%eax 190 movb %al,7(%rdx) 191 192 /* Restore gs base in GDT */ 193 movl PCB_GSBASE(%r8),%eax 194 movq PCPU(GS32P),%rdx 195 movw %ax,2(%rdx) 196 shrl $16,%eax 197 movb %al,4(%rdx) 198 shrl $8,%eax 199 movb %al,7(%rdx) 200 201do_kthread: 202 /* Do we need to reload tss ? */ 203 movq PCPU(TSSP),%rax 204 movq PCB_TSSP(%r8),%rdx 205 testq %rdx,%rdx 206 cmovzq PCPU(COMMONTSSP),%rdx 207 cmpq %rax,%rdx 208 jne do_tss 209done_tss: 210 movq %r8,PCPU(RSP0) 211 movq %r8,PCPU(CURPCB) 212 /* Update the TSS_RSP0 pointer for the next interrupt */ 213 cmpq $~0,PCPU(UCR3) 214 je 1f 215 movq PCPU(PTI_RSP0),%rax 216 movq %rax,TSS_RSP0(%rdx) 217 jmp 2f 2181: movq %r8,TSS_RSP0(%rdx) 2192: 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 movq PCPU(CURTHREAD),%rdi 237 call fpu_activate_sw 238 ret 239 240 /* 241 * We order these strangely for several reasons. 242 * 1: I wanted to use static branch prediction hints 243 * 2: Most athlon64/opteron cpus don't have them. They define 244 * a forward branch as 'predict not taken'. Intel cores have 245 * the 'rep' prefix to invert this. 246 * So, to make it work on both forms of cpu we do the detour. 247 * We use jumps rather than call in order to avoid the stack. 248 */ 249 250store_dr: 251 movq %dr7,%rax /* yes, do the save */ 252 movq %dr0,%r15 253 movq %dr1,%r14 254 movq %dr2,%r13 255 movq %dr3,%r12 256 movq %dr6,%r11 257 movq %r15,PCB_DR0(%r8) 258 movq %r14,PCB_DR1(%r8) 259 movq %r13,PCB_DR2(%r8) 260 movq %r12,PCB_DR3(%r8) 261 movq %r11,PCB_DR6(%r8) 262 movq %rax,PCB_DR7(%r8) 263 andq $0x0000fc00, %rax /* disable all watchpoints */ 264 movq %rax,%dr7 265 jmp done_store_dr 266 267load_dr: 268 movq %dr7,%rax 269 movq PCB_DR0(%r8),%r15 270 movq PCB_DR1(%r8),%r14 271 movq PCB_DR2(%r8),%r13 272 movq PCB_DR3(%r8),%r12 273 movq PCB_DR6(%r8),%r11 274 movq PCB_DR7(%r8),%rcx 275 movq %r15,%dr0 276 movq %r14,%dr1 277 /* Preserve reserved bits in %dr7 */ 278 andq $0x0000fc00,%rax 279 andq $~0x0000fc00,%rcx 280 movq %r13,%dr2 281 movq %r12,%dr3 282 orq %rcx,%rax 283 movq %r11,%dr6 284 movq %rax,%dr7 285 jmp done_load_dr 286 287do_tss: movq %rdx,PCPU(TSSP) 288 movq %rdx,%rcx 289 movq PCPU(TSS),%rax 290 movw %cx,2(%rax) 291 shrq $16,%rcx 292 movb %cl,4(%rax) 293 shrq $8,%rcx 294 movb %cl,7(%rax) 295 shrq $8,%rcx 296 movl %ecx,8(%rax) 297 movb $0x89,5(%rax) /* unset busy */ 298 movl $TSSSEL,%eax 299 ltr %ax 300 jmp done_tss 301 302do_ldt: movq PCPU(LDT),%rax 303 movq P_MD+MD_LDT_SD(%rcx),%rdx 304 movq %rdx,(%rax) 305 movq P_MD+MD_LDT_SD+8(%rcx),%rdx 306 movq %rdx,8(%rax) 307 movl $LDTSEL,%eax 308 jmp ld_ldt 309END(cpu_switch) 310 311/* 312 * savectx(pcb) 313 * Update pcb, saving current processor state. 314 */ 315ENTRY(savectx) 316 /* Save caller's return address. */ 317 movq (%rsp),%rax 318 movq %rax,PCB_RIP(%rdi) 319 320 movq %rbx,PCB_RBX(%rdi) 321 movq %rsp,PCB_RSP(%rdi) 322 movq %rbp,PCB_RBP(%rdi) 323 movq %r12,PCB_R12(%rdi) 324 movq %r13,PCB_R13(%rdi) 325 movq %r14,PCB_R14(%rdi) 326 movq %r15,PCB_R15(%rdi) 327 328 movq %cr0,%rax 329 movq %rax,PCB_CR0(%rdi) 330 movq %cr2,%rax 331 movq %rax,PCB_CR2(%rdi) 332 movq %cr3,%rax 333 movq %rax,PCB_CR3(%rdi) 334 movq %cr4,%rax 335 movq %rax,PCB_CR4(%rdi) 336 337 movq %dr0,%rax 338 movq %rax,PCB_DR0(%rdi) 339 movq %dr1,%rax 340 movq %rax,PCB_DR1(%rdi) 341 movq %dr2,%rax 342 movq %rax,PCB_DR2(%rdi) 343 movq %dr3,%rax 344 movq %rax,PCB_DR3(%rdi) 345 movq %dr6,%rax 346 movq %rax,PCB_DR6(%rdi) 347 movq %dr7,%rax 348 movq %rax,PCB_DR7(%rdi) 349 350 movl $MSR_FSBASE,%ecx 351 rdmsr 352 movl %eax,PCB_FSBASE(%rdi) 353 movl %edx,PCB_FSBASE+4(%rdi) 354 movl $MSR_GSBASE,%ecx 355 rdmsr 356 movl %eax,PCB_GSBASE(%rdi) 357 movl %edx,PCB_GSBASE+4(%rdi) 358 movl $MSR_KGSBASE,%ecx 359 rdmsr 360 movl %eax,PCB_KGSBASE(%rdi) 361 movl %edx,PCB_KGSBASE+4(%rdi) 362 movl $MSR_EFER,%ecx 363 rdmsr 364 movl %eax,PCB_EFER(%rdi) 365 movl %edx,PCB_EFER+4(%rdi) 366 movl $MSR_STAR,%ecx 367 rdmsr 368 movl %eax,PCB_STAR(%rdi) 369 movl %edx,PCB_STAR+4(%rdi) 370 movl $MSR_LSTAR,%ecx 371 rdmsr 372 movl %eax,PCB_LSTAR(%rdi) 373 movl %edx,PCB_LSTAR+4(%rdi) 374 movl $MSR_CSTAR,%ecx 375 rdmsr 376 movl %eax,PCB_CSTAR(%rdi) 377 movl %edx,PCB_CSTAR+4(%rdi) 378 movl $MSR_SF_MASK,%ecx 379 rdmsr 380 movl %eax,PCB_SFMASK(%rdi) 381 movl %edx,PCB_SFMASK+4(%rdi) 382 383 sgdt PCB_GDT(%rdi) 384 sidt PCB_IDT(%rdi) 385 sldt PCB_LDT(%rdi) 386 str PCB_TR(%rdi) 387 388 movl $1,%eax 389 ret 390END(savectx) 391 392/* 393 * resumectx(pcb) 394 * Resuming processor state from pcb. 395 */ 396ENTRY(resumectx) 397 /* Switch to KPML4phys. */ 398 movq KPML4phys,%rax 399 movq %rax,%cr3 400 401 /* Force kernel segment registers. */ 402 movl $KDSEL,%eax 403 movw %ax,%ds 404 movw %ax,%es 405 movw %ax,%ss 406 movl $KUF32SEL,%eax 407 movw %ax,%fs 408 movl $KUG32SEL,%eax 409 movw %ax,%gs 410 411 movl $MSR_FSBASE,%ecx 412 movl PCB_FSBASE(%rdi),%eax 413 movl 4 + PCB_FSBASE(%rdi),%edx 414 wrmsr 415 movl $MSR_GSBASE,%ecx 416 movl PCB_GSBASE(%rdi),%eax 417 movl 4 + PCB_GSBASE(%rdi),%edx 418 wrmsr 419 movl $MSR_KGSBASE,%ecx 420 movl PCB_KGSBASE(%rdi),%eax 421 movl 4 + PCB_KGSBASE(%rdi),%edx 422 wrmsr 423 424 /* Restore EFER one more time. */ 425 movl $MSR_EFER,%ecx 426 movl PCB_EFER(%rdi),%eax 427 wrmsr 428 429 /* Restore fast syscall stuff. */ 430 movl $MSR_STAR,%ecx 431 movl PCB_STAR(%rdi),%eax 432 movl 4 + PCB_STAR(%rdi),%edx 433 wrmsr 434 movl $MSR_LSTAR,%ecx 435 movl PCB_LSTAR(%rdi),%eax 436 movl 4 + PCB_LSTAR(%rdi),%edx 437 wrmsr 438 movl $MSR_CSTAR,%ecx 439 movl PCB_CSTAR(%rdi),%eax 440 movl 4 + PCB_CSTAR(%rdi),%edx 441 wrmsr 442 movl $MSR_SF_MASK,%ecx 443 movl PCB_SFMASK(%rdi),%eax 444 wrmsr 445 446 /* Restore CR0, CR2, CR4 and CR3. */ 447 movq PCB_CR0(%rdi),%rax 448 movq %rax,%cr0 449 movq PCB_CR2(%rdi),%rax 450 movq %rax,%cr2 451 movq PCB_CR4(%rdi),%rax 452 movq %rax,%cr4 453 movq PCB_CR3(%rdi),%rax 454 movq %rax,%cr3 455 456 /* Restore descriptor tables. */ 457 lidt PCB_IDT(%rdi) 458 lldt PCB_LDT(%rdi) 459 460#define SDT_SYSTSS 9 461#define SDT_SYSBSY 11 462 463 /* Clear "task busy" bit and reload TR. */ 464 movq PCPU(TSS),%rax 465 andb $(~SDT_SYSBSY | SDT_SYSTSS),5(%rax) 466 movw PCB_TR(%rdi),%ax 467 ltr %ax 468 469#undef SDT_SYSTSS 470#undef SDT_SYSBSY 471 472 /* Restore debug registers. */ 473 movq PCB_DR0(%rdi),%rax 474 movq %rax,%dr0 475 movq PCB_DR1(%rdi),%rax 476 movq %rax,%dr1 477 movq PCB_DR2(%rdi),%rax 478 movq %rax,%dr2 479 movq PCB_DR3(%rdi),%rax 480 movq %rax,%dr3 481 movq PCB_DR6(%rdi),%rax 482 movq %rax,%dr6 483 movq PCB_DR7(%rdi),%rax 484 movq %rax,%dr7 485 486 /* Restore other callee saved registers. */ 487 movq PCB_R15(%rdi),%r15 488 movq PCB_R14(%rdi),%r14 489 movq PCB_R13(%rdi),%r13 490 movq PCB_R12(%rdi),%r12 491 movq PCB_RBP(%rdi),%rbp 492 movq PCB_RSP(%rdi),%rsp 493 movq PCB_RBX(%rdi),%rbx 494 495 /* Restore return address. */ 496 movq PCB_RIP(%rdi),%rax 497 movq %rax,(%rsp) 498 499 xorl %eax,%eax 500 ret 501END(resumectx) 502