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/*- * Copyright (c) 2003 Peter Wemm. * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * William Jolitz. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD: release/9.1.0/sys/amd64/amd64/cpu_switch.S 231979 2012-02-21 20:56:03Z kib $ */ #include <machine/asmacros.h> #include <machine/specialreg.h> #include "assym.s" #include "opt_sched.h" /*****************************************************************************/ /* Scheduling */ /*****************************************************************************/ .text #ifdef SMP #define LK lock ; #else #define LK #endif #if defined(SCHED_ULE) && defined(SMP) #define SETLK xchgq #else #define SETLK movq #endif /* * cpu_throw() * * This is the second half of cpu_switch(). It is used when the current * thread is either a dummy or slated to die, and we no longer care * about its state. This is only a slight optimization and is probably * not worth it anymore. Note that we need to clear the pm_active bits so * we do need the old proc if it still exists. * %rdi = oldtd * %rsi = newtd */ ENTRY(cpu_throw) movl PCPU(CPUID),%eax testq %rdi,%rdi jz 1f /* release bit from old pm_active */ movq PCPU(CURPMAP),%rdx LK btrl %eax,PM_ACTIVE(%rdx) /* clear old */ 1: movq TD_PCB(%rsi),%r8 /* newtd->td_proc */ movq PCB_CR3(%r8),%rdx movq %rdx,%cr3 /* new address space */ jmp swact END(cpu_throw) /* * cpu_switch(old, new, mtx) * * Save the current thread state, then select the next thread to run * and load its state. * %rdi = oldtd * %rsi = newtd * %rdx = mtx */ ENTRY(cpu_switch) /* Switch to new thread. First, save context. */ movq TD_PCB(%rdi),%r8 orl $PCB_FULL_IRET,PCB_FLAGS(%r8) movq (%rsp),%rax /* Hardware registers */ movq %r15,PCB_R15(%r8) movq %r14,PCB_R14(%r8) movq %r13,PCB_R13(%r8) movq %r12,PCB_R12(%r8) movq %rbp,PCB_RBP(%r8) movq %rsp,PCB_RSP(%r8) movq %rbx,PCB_RBX(%r8) movq %rax,PCB_RIP(%r8) testl $PCB_DBREGS,PCB_FLAGS(%r8) jnz store_dr /* static predict not taken */ done_store_dr: /* have we used fp, and need a save? */ cmpq %rdi,PCPU(FPCURTHREAD) jne 3f movq PCB_SAVEFPU(%r8),%r8 clts cmpl $0,use_xsave jne 1f fxsave (%r8) jmp 2f 1: movq %rdx,%rcx movl xsave_mask,%eax movl xsave_mask+4,%edx /* xsave (%r8) */ .byte 0x41,0x0f,0xae,0x20 movq %rcx,%rdx 2: smsw %ax orb $CR0_TS,%al lmsw %ax xorl %eax,%eax movq %rax,PCPU(FPCURTHREAD) 3: /* Save is done. Now fire up new thread. Leave old vmspace. */ movq TD_PCB(%rsi),%r8 /* switch address space */ movq PCB_CR3(%r8),%rcx movq %cr3,%rax cmpq %rcx,%rax /* Same address space? */ jne swinact SETLK %rdx, TD_LOCK(%rdi) /* Release the old thread */ jmp sw1 swinact: movq %rcx,%cr3 /* new address space */ movl PCPU(CPUID), %eax /* Release bit from old pmap->pm_active */ movq PCPU(CURPMAP),%rcx LK btrl %eax,PM_ACTIVE(%rcx) /* clear old */ SETLK %rdx, TD_LOCK(%rdi) /* Release the old thread */ swact: /* Set bit in new pmap->pm_active */ movq TD_PROC(%rsi),%rdx /* newproc */ movq P_VMSPACE(%rdx), %rdx addq $VM_PMAP,%rdx LK btsl %eax,PM_ACTIVE(%rdx) /* set new */ movq %rdx,PCPU(CURPMAP) sw1: #if defined(SCHED_ULE) && defined(SMP) /* Wait for the new thread to become unblocked */ movq $blocked_lock, %rdx 1: movq TD_LOCK(%rsi),%rcx cmpq %rcx, %rdx pause je 1b #endif /* * At this point, we've switched address spaces and are ready * to load up the rest of the next context. */ /* Skip loading user fsbase/gsbase for kthreads */ testl $TDP_KTHREAD,TD_PFLAGS(%rsi) jnz do_kthread /* * Load ldt register */ movq TD_PROC(%rsi),%rcx cmpq $0, P_MD+MD_LDT(%rcx) jne do_ldt xorl %eax,%eax ld_ldt: lldt %ax /* Restore fs base in GDT */ movl PCB_FSBASE(%r8),%eax movq PCPU(FS32P),%rdx movw %ax,2(%rdx) shrl $16,%eax movb %al,4(%rdx) shrl $8,%eax movb %al,7(%rdx) /* Restore gs base in GDT */ movl PCB_GSBASE(%r8),%eax movq PCPU(GS32P),%rdx movw %ax,2(%rdx) shrl $16,%eax movb %al,4(%rdx) shrl $8,%eax movb %al,7(%rdx) do_kthread: /* Do we need to reload tss ? */ movq PCPU(TSSP),%rax movq PCB_TSSP(%r8),%rdx testq %rdx,%rdx cmovzq PCPU(COMMONTSSP),%rdx cmpq %rax,%rdx jne do_tss done_tss: movq %r8,PCPU(RSP0) movq %r8,PCPU(CURPCB) /* Update the TSS_RSP0 pointer for the next interrupt */ movq %r8,COMMON_TSS_RSP0(%rdx) movq %rsi,PCPU(CURTHREAD) /* into next thread */ /* Test if debug registers should be restored. */ testl $PCB_DBREGS,PCB_FLAGS(%r8) jnz load_dr /* static predict not taken */ done_load_dr: /* Restore context. */ movq PCB_R15(%r8),%r15 movq PCB_R14(%r8),%r14 movq PCB_R13(%r8),%r13 movq PCB_R12(%r8),%r12 movq PCB_RBP(%r8),%rbp movq PCB_RSP(%r8),%rsp movq PCB_RBX(%r8),%rbx movq PCB_RIP(%r8),%rax movq %rax,(%rsp) ret /* * We order these strangely for several reasons. * 1: I wanted to use static branch prediction hints * 2: Most athlon64/opteron cpus don't have them. They define * a forward branch as 'predict not taken'. Intel cores have * the 'rep' prefix to invert this. * So, to make it work on both forms of cpu we do the detour. * We use jumps rather than call in order to avoid the stack. */ store_dr: movq %dr7,%rax /* yes, do the save */ movq %dr0,%r15 movq %dr1,%r14 movq %dr2,%r13 movq %dr3,%r12 movq %dr6,%r11 movq %r15,PCB_DR0(%r8) movq %r14,PCB_DR1(%r8) movq %r13,PCB_DR2(%r8) movq %r12,PCB_DR3(%r8) movq %r11,PCB_DR6(%r8) movq %rax,PCB_DR7(%r8) andq $0x0000fc00, %rax /* disable all watchpoints */ movq %rax,%dr7 jmp done_store_dr load_dr: movq %dr7,%rax movq PCB_DR0(%r8),%r15 movq PCB_DR1(%r8),%r14 movq PCB_DR2(%r8),%r13 movq PCB_DR3(%r8),%r12 movq PCB_DR6(%r8),%r11 movq PCB_DR7(%r8),%rcx movq %r15,%dr0 movq %r14,%dr1 /* Preserve reserved bits in %dr7 */ andq $0x0000fc00,%rax andq $~0x0000fc00,%rcx movq %r13,%dr2 movq %r12,%dr3 orq %rcx,%rax movq %r11,%dr6 movq %rax,%dr7 jmp done_load_dr do_tss: movq %rdx,PCPU(TSSP) movq %rdx,%rcx movq PCPU(TSS),%rax movw %cx,2(%rax) shrq $16,%rcx movb %cl,4(%rax) shrq $8,%rcx movb %cl,7(%rax) shrq $8,%rcx movl %ecx,8(%rax) movb $0x89,5(%rax) /* unset busy */ movl $TSSSEL,%eax ltr %ax jmp done_tss do_ldt: movq PCPU(LDT),%rax movq P_MD+MD_LDT_SD(%rcx),%rdx movq %rdx,(%rax) movq P_MD+MD_LDT_SD+8(%rcx),%rdx movq %rdx,8(%rax) movl $LDTSEL,%eax jmp ld_ldt END(cpu_switch) /* * savectx(pcb) * Update pcb, saving current processor state. */ ENTRY(savectx) /* Save caller's return address. */ movq (%rsp),%rax movq %rax,PCB_RIP(%rdi) movq %rbx,PCB_RBX(%rdi) movq %rsp,PCB_RSP(%rdi) movq %rbp,PCB_RBP(%rdi) movq %r12,PCB_R12(%rdi) movq %r13,PCB_R13(%rdi) movq %r14,PCB_R14(%rdi) movq %r15,PCB_R15(%rdi) movq %cr0,%rsi movq %rsi,PCB_CR0(%rdi) movq %cr2,%rax movq %rax,PCB_CR2(%rdi) movq %cr3,%rax movq %rax,PCB_CR3(%rdi) movq %cr4,%rax movq %rax,PCB_CR4(%rdi) movq %dr0,%rax movq %rax,PCB_DR0(%rdi) movq %dr1,%rax movq %rax,PCB_DR1(%rdi) movq %dr2,%rax movq %rax,PCB_DR2(%rdi) movq %dr3,%rax movq %rax,PCB_DR3(%rdi) movq %dr6,%rax movq %rax,PCB_DR6(%rdi) movq %dr7,%rax movq %rax,PCB_DR7(%rdi) movl $MSR_FSBASE,%ecx rdmsr movl %eax,PCB_FSBASE(%rdi) movl %edx,PCB_FSBASE+4(%rdi) movl $MSR_GSBASE,%ecx rdmsr movl %eax,PCB_GSBASE(%rdi) movl %edx,PCB_GSBASE+4(%rdi) movl $MSR_KGSBASE,%ecx rdmsr movl %eax,PCB_KGSBASE(%rdi) movl %edx,PCB_KGSBASE+4(%rdi) sgdt PCB_GDT(%rdi) sidt PCB_IDT(%rdi) sldt PCB_LDT(%rdi) str PCB_TR(%rdi) 2: movq %rsi,%cr0 /* The previous %cr0 is saved in %rsi. */ movl $1,%eax ret END(savectx) /* * Wrapper around fpusave to care about TS0_CR. */ ENTRY(ctx_fpusave) movq %cr0,%rsi clts call fpusave movq %rsi,%cr0 ret END(ctx_fpusave)