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 34#include <machine/asmacros.h> 35#include <machine/specialreg.h> 36 37#include "assym.inc" 38 39/*****************************************************************************/ 40/* Scheduling */ 41/*****************************************************************************/ 42 43 .text 44 45/* 46 * cpu_throw() 47 * 48 * This is the second half of cpu_switch(). It is used when the current 49 * thread is either a dummy or slated to die, and we no longer care 50 * about its state. This is only a slight optimization and is probably 51 * not worth it anymore. Note that we need to clear the pm_active bits so 52 * we do need the old proc if it still exists. 53 * %rdi = oldtd 54 * %rsi = newtd 55 */ 56ENTRY(cpu_throw) 57 movq %rsi,%r12 58 movq %rsi,%rdi 59 call pmap_activate_sw 60 jmp sw1 61END(cpu_throw) 62 63/* 64 * cpu_switch(old, new, mtx) 65 * 66 * Save the current thread state, then select the next thread to run 67 * and load its state. 68 * %rdi = oldtd 69 * %rsi = newtd 70 * %rdx = mtx 71 */ 72ENTRY(cpu_switch) 73 /* Switch to new thread. First, save context. */ 74 leaq TD_MD_PCB(%rdi),%r8 75 76 movq (%rsp),%rax /* Hardware registers */ 77 movq %r15,PCB_R15(%r8) 78 movq %r14,PCB_R14(%r8) 79 movq %r13,PCB_R13(%r8) 80 movq %r12,PCB_R12(%r8) 81 movq %rbp,PCB_RBP(%r8) 82 movq %rsp,PCB_RSP(%r8) 83 movq %rbx,PCB_RBX(%r8) 84 movq %rax,PCB_RIP(%r8) 85 86 testl $PCB_FULL_IRET,PCB_FLAGS(%r8) 87 jnz 2f 88 orl $PCB_FULL_IRET,PCB_FLAGS(%r8) 89 testl $TDP_KTHREAD,TD_PFLAGS(%rdi) 90 jnz 2f 91 testb $CPUID_STDEXT_FSGSBASE,cpu_stdext_feature(%rip) 92 jz 2f 93 rdfsbase %rax 94 movq %rax,PCB_FSBASE(%r8) 95 movq %rdx,%r12 96 movl $MSR_KGSBASE,%ecx /* Read user gs base */ 97 rdmsr 98 shlq $32,%rdx 99 orq %rdx,%rax 100 movq %rax,PCB_GSBASE(%r8) 101 movq %r12,%rdx 102 1032: 104 testl $PCB_DBREGS,PCB_FLAGS(%r8) 105 jnz store_dr /* static predict not taken */ 106done_store_dr: 107 108 /* have we used fp, and need a save? */ 109 cmpq %rdi,PCPU(FPCURTHREAD) 110 jne ctx_switch_fpusave_done 111 movq PCB_SAVEFPU(%r8),%r9 112 clts 113 cmpl $0,use_xsave(%rip) 114 jne 1f 115 fxsave (%r9) 116 jmp ctx_switch_fpusave_done 1171: movq %rdx,%rcx 118 movl xsave_mask,%eax 119 movl xsave_mask+4,%edx 120 testl $PCB_32BIT,PCB_FLAGS(%r8) 121 jne ctx_switch_xsave32 122 .globl ctx_switch_xsave 123ctx_switch_xsave: 124 /* This is patched to xsaveopt if supported, see fpuinit_bsp1() */ 125 xsave64 (%r9) 126ctx_switch_xsave_done: 127 movq %rcx,%rdx 128ctx_switch_fpusave_done: 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 movq %r15,TD_LOCK(%r13) /* Release the old thread */ 136sw1: 137 leaq TD_MD_PCB(%r12),%r8 138 movq $blocked_lock, %rdx 139 movq TD_LOCK(%r12),%rcx 140 cmpq %rcx, %rdx 141 je sw1wait 142sw1cont: 143 /* 144 * At this point, we've switched address spaces and are ready 145 * to load up the rest of the next context. 146 */ 147 148 /* Skip loading LDT and user fsbase/gsbase for kthreads */ 149 testl $TDP_KTHREAD,TD_PFLAGS(%r12) 150 jnz do_kthread 151 152 /* 153 * Load ldt register 154 */ 155 movq TD_PROC(%r12),%rcx 156 cmpq $0, P_MD+MD_LDT(%rcx) 157 jne do_ldt 158 xorl %eax,%eax 159ld_ldt: lldt %ax 160 161 /* Restore fs base in GDT */ 162 movl PCB_FSBASE(%r8),%eax 163 movq PCPU(FS32P),%rdx 164 movw %ax,2(%rdx) 165 shrl $16,%eax 166 movb %al,4(%rdx) 167 shrl $8,%eax 168 movb %al,7(%rdx) 169 170 /* Restore gs base in GDT */ 171 movl PCB_GSBASE(%r8),%eax 172 movq PCPU(GS32P),%rdx 173 movw %ax,2(%rdx) 174 shrl $16,%eax 175 movb %al,4(%rdx) 176 shrl $8,%eax 177 movb %al,7(%rdx) 178 179do_kthread: 180 /* Do we need to reload tss ? */ 181 movq PCPU(TSSP),%rax 182 movq PCB_TSSP(%r8),%rdx 183 movq PCPU(PRVSPACE),%r13 184 addq $PC_COMMONTSS,%r13 185 testq %rdx,%rdx 186 cmovzq %r13,%rdx 187 cmpq %rax,%rdx 188 jne do_tss 189done_tss: 190 movq TD_MD_STACK_BASE(%r12),%r9 191 movq %r9,PCPU(RSP0) 192 movq %r8,PCPU(CURPCB) 193 movq PCPU(PTI_RSP0),%rax 194 cmpq $~0,PCPU(UCR3) 195 cmove %r9,%rax 196 movq %rax,TSS_RSP0(%rdx) 197 movq %r12,PCPU(CURTHREAD) /* into next thread */ 198 199 /* Test if debug registers should be restored. */ 200 testl $PCB_DBREGS,PCB_FLAGS(%r8) 201 jnz load_dr /* static predict not taken */ 202done_load_dr: 203 204 /* Restore context. */ 205 movq PCB_R15(%r8),%r15 206 movq PCB_R14(%r8),%r14 207 movq PCB_R13(%r8),%r13 208 movq PCB_R12(%r8),%r12 209 movq PCB_RBP(%r8),%rbp 210 movq PCB_RSP(%r8),%rsp 211 movq PCB_RBX(%r8),%rbx 212 movq PCB_RIP(%r8),%rax 213 movq %rax,(%rsp) 214 movq PCPU(CURTHREAD),%rdi 215 call fpu_activate_sw 216 cmpb $0,cpu_flush_rsb_ctxsw(%rip) 217 jne rsb_flush 218 ret 219 220 /* 221 * We order these strangely for several reasons. 222 * 1: I wanted to use static branch prediction hints 223 * 2: Most athlon64/opteron cpus don't have them. They define 224 * a forward branch as 'predict not taken'. Intel cores have 225 * the 'rep' prefix to invert this. 226 * So, to make it work on both forms of cpu we do the detour. 227 * We use jumps rather than call in order to avoid the stack. 228 */ 229 230store_dr: 231 movq %dr7,%rax /* yes, do the save */ 232 movq %dr0,%r15 233 movq %dr1,%r14 234 movq %dr2,%r13 235 movq %dr3,%r12 236 movq %dr6,%r11 237 movq %r15,PCB_DR0(%r8) 238 movq %r14,PCB_DR1(%r8) 239 movq %r13,PCB_DR2(%r8) 240 movq %r12,PCB_DR3(%r8) 241 movq %r11,PCB_DR6(%r8) 242 movq %rax,PCB_DR7(%r8) 243 andq $0x0000fc00, %rax /* disable all watchpoints */ 244 movq %rax,%dr7 245 jmp done_store_dr 246 247load_dr: 248 movq %dr7,%rax 249 movq PCB_DR0(%r8),%r15 250 movq PCB_DR1(%r8),%r14 251 movq PCB_DR2(%r8),%r13 252 movq PCB_DR3(%r8),%r12 253 movq PCB_DR6(%r8),%r11 254 movq PCB_DR7(%r8),%rcx 255 movq %r15,%dr0 256 movq %r14,%dr1 257 /* Preserve reserved bits in %dr7 */ 258 andq $0x0000fc00,%rax 259 andq $~0x0000fc00,%rcx 260 movq %r13,%dr2 261 movq %r12,%dr3 262 orq %rcx,%rax 263 movq %r11,%dr6 264 movq %rax,%dr7 265 jmp done_load_dr 266 267do_tss: movq %rdx,PCPU(TSSP) 268 movq %rdx,%rcx 269 movq PCPU(TSS),%rax 270 movw %cx,2(%rax) 271 shrq $16,%rcx 272 movb %cl,4(%rax) 273 shrq $8,%rcx 274 movb %cl,7(%rax) 275 shrq $8,%rcx 276 movl %ecx,8(%rax) 277 movb $0x89,5(%rax) /* unset busy */ 278 movl $TSSSEL,%eax 279 ltr %ax 280 jmp done_tss 281 282do_ldt: movq PCPU(LDT),%rax 283 movq P_MD+MD_LDT_SD(%rcx),%rdx 284 movq %rdx,(%rax) 285 movq P_MD+MD_LDT_SD+8(%rcx),%rdx 286 movq %rdx,8(%rax) 287 movl $LDTSEL,%eax 288 jmp ld_ldt 289 290 .globl ctx_switch_xsave32 291ctx_switch_xsave32: 292 xsave (%r9) 293 jmp ctx_switch_xsave_done 294END(cpu_switch) 295 296/* 297 * savectx(pcb) 298 * Update pcb, saving current processor state. 299 */ 300ENTRY(savectx) 301 /* Save caller's return address. */ 302 movq (%rsp),%rax 303 movq %rax,PCB_RIP(%rdi) 304 305 movq %rbx,PCB_RBX(%rdi) 306 movq %rsp,PCB_RSP(%rdi) 307 movq %rbp,PCB_RBP(%rdi) 308 movq %r12,PCB_R12(%rdi) 309 movq %r13,PCB_R13(%rdi) 310 movq %r14,PCB_R14(%rdi) 311 movq %r15,PCB_R15(%rdi) 312 313 movq %cr0,%rax 314 movq %rax,PCB_CR0(%rdi) 315 movq %cr2,%rax 316 movq %rax,PCB_CR2(%rdi) 317 movq %cr3,%rax 318 movq %rax,PCB_CR3(%rdi) 319 movq %cr4,%rax 320 movq %rax,PCB_CR4(%rdi) 321 322 movq %dr0,%rax 323 movq %rax,PCB_DR0(%rdi) 324 movq %dr1,%rax 325 movq %rax,PCB_DR1(%rdi) 326 movq %dr2,%rax 327 movq %rax,PCB_DR2(%rdi) 328 movq %dr3,%rax 329 movq %rax,PCB_DR3(%rdi) 330 movq %dr6,%rax 331 movq %rax,PCB_DR6(%rdi) 332 movq %dr7,%rax 333 movq %rax,PCB_DR7(%rdi) 334 335 movl $MSR_FSBASE,%ecx 336 rdmsr 337 movl %eax,PCB_FSBASE(%rdi) 338 movl %edx,PCB_FSBASE+4(%rdi) 339 movl $MSR_GSBASE,%ecx 340 rdmsr 341 movl %eax,PCB_GSBASE(%rdi) 342 movl %edx,PCB_GSBASE+4(%rdi) 343 movl $MSR_KGSBASE,%ecx 344 rdmsr 345 movl %eax,PCB_KGSBASE(%rdi) 346 movl %edx,PCB_KGSBASE+4(%rdi) 347 movl $MSR_EFER,%ecx 348 rdmsr 349 movl %eax,PCB_EFER(%rdi) 350 movl %edx,PCB_EFER+4(%rdi) 351 movl $MSR_STAR,%ecx 352 rdmsr 353 movl %eax,PCB_STAR(%rdi) 354 movl %edx,PCB_STAR+4(%rdi) 355 movl $MSR_LSTAR,%ecx 356 rdmsr 357 movl %eax,PCB_LSTAR(%rdi) 358 movl %edx,PCB_LSTAR+4(%rdi) 359 movl $MSR_CSTAR,%ecx 360 rdmsr 361 movl %eax,PCB_CSTAR(%rdi) 362 movl %edx,PCB_CSTAR+4(%rdi) 363 movl $MSR_SF_MASK,%ecx 364 rdmsr 365 movl %eax,PCB_SFMASK(%rdi) 366 movl %edx,PCB_SFMASK+4(%rdi) 367 368 sgdt PCB_GDT(%rdi) 369 sidt PCB_IDT(%rdi) 370 sldt PCB_LDT(%rdi) 371 str PCB_TR(%rdi) 372 373 movl $1,%eax 374 ret 375END(savectx) 376 377/* 378 * resumectx(pcb) 379 * Resuming processor state from pcb. 380 */ 381ENTRY(resumectx) 382 /* Switch to KPML5/4phys. */ 383 movq KPML4phys,%rax 384 movq KPML5phys,%rcx 385 cmpl $0, la57 386 cmovne %rcx, %rax 387 movq %rax,%cr3 388 389 /* Force kernel segment registers. */ 390 movl $KDSEL,%eax 391 movw %ax,%ds 392 movw %ax,%es 393 movw %ax,%ss 394 movl $KUF32SEL,%eax 395 movw %ax,%fs 396 movl $KUG32SEL,%eax 397 movw %ax,%gs 398 399 movl $MSR_FSBASE,%ecx 400 movl PCB_FSBASE(%rdi),%eax 401 movl 4 + PCB_FSBASE(%rdi),%edx 402 wrmsr 403 movl $MSR_GSBASE,%ecx 404 movl PCB_GSBASE(%rdi),%eax 405 movl 4 + PCB_GSBASE(%rdi),%edx 406 wrmsr 407 movl $MSR_KGSBASE,%ecx 408 movl PCB_KGSBASE(%rdi),%eax 409 movl 4 + PCB_KGSBASE(%rdi),%edx 410 wrmsr 411 412 /* Restore EFER one more time. */ 413 movl $MSR_EFER,%ecx 414 movl PCB_EFER(%rdi),%eax 415 wrmsr 416 417 /* Restore fast syscall stuff. */ 418 movl $MSR_STAR,%ecx 419 movl PCB_STAR(%rdi),%eax 420 movl 4 + PCB_STAR(%rdi),%edx 421 wrmsr 422 movl $MSR_LSTAR,%ecx 423 movl PCB_LSTAR(%rdi),%eax 424 movl 4 + PCB_LSTAR(%rdi),%edx 425 wrmsr 426 movl $MSR_CSTAR,%ecx 427 movl PCB_CSTAR(%rdi),%eax 428 movl 4 + PCB_CSTAR(%rdi),%edx 429 wrmsr 430 movl $MSR_SF_MASK,%ecx 431 movl PCB_SFMASK(%rdi),%eax 432 wrmsr 433 434 /* Restore CR0, CR2, CR4 and CR3. */ 435 movq PCB_CR0(%rdi),%rax 436 movq %rax,%cr0 437 movq PCB_CR2(%rdi),%rax 438 movq %rax,%cr2 439 movq PCB_CR4(%rdi),%rax 440 movq %rax,%cr4 441 movq PCB_CR3(%rdi),%rax 442 movq %rax,%cr3 443 444 /* Restore descriptor tables. */ 445 lidt PCB_IDT(%rdi) 446 lldt PCB_LDT(%rdi) 447 448#define SDT_SYSTSS 9 449#define SDT_SYSBSY 11 450 451 /* Clear "task busy" bit and reload TR. */ 452 movq PCPU(TSS),%rax 453 andb $(~SDT_SYSBSY | SDT_SYSTSS),5(%rax) 454 movw PCB_TR(%rdi),%ax 455 ltr %ax 456 457#undef SDT_SYSTSS 458#undef SDT_SYSBSY 459 460 /* Restore debug registers. */ 461 movq PCB_DR0(%rdi),%rax 462 movq %rax,%dr0 463 movq PCB_DR1(%rdi),%rax 464 movq %rax,%dr1 465 movq PCB_DR2(%rdi),%rax 466 movq %rax,%dr2 467 movq PCB_DR3(%rdi),%rax 468 movq %rax,%dr3 469 movq PCB_DR6(%rdi),%rax 470 movq %rax,%dr6 471 movq PCB_DR7(%rdi),%rax 472 movq %rax,%dr7 473 474 /* Restore other callee saved registers. */ 475 movq PCB_R15(%rdi),%r15 476 movq PCB_R14(%rdi),%r14 477 movq PCB_R13(%rdi),%r13 478 movq PCB_R12(%rdi),%r12 479 movq PCB_RBP(%rdi),%rbp 480 movq PCB_RSP(%rdi),%rsp 481 movq PCB_RBX(%rdi),%rbx 482 483 /* Restore return address. */ 484 movq PCB_RIP(%rdi),%rax 485 movq %rax,(%rsp) 486 487 xorl %eax,%eax 488 ret 489END(resumectx) 490 491/* Wait for the new thread to become unblocked */ 492sw1wait: 4931: 494 pause 495 movq TD_LOCK(%r12),%rcx 496 cmpq %rcx, %rdx 497 je 1b 498 jmp sw1cont 499