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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.
*
* $FreeBSD$
*/
#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)
movq %rsi,%r12
movq %rsi,%rdi
call pmap_activate_sw
jmp sw1
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
.globl ctx_switch_xsave
ctx_switch_xsave:
/* This is patched to xsaveopt if supported, see fpuinit_bsp1() */
xsave (%r8)
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 %rsi,%r12
movq %rdi,%r13
movq %rdx,%r15
movq %rsi,%rdi
callq pmap_activate_sw
SETLK %r15,TD_LOCK(%r13) /* Release the old thread */
sw1:
movq TD_PCB(%r12),%r8
#if defined(SCHED_ULE) && defined(SMP)
/* Wait for the new thread to become unblocked */
movq $blocked_lock, %rdx
1:
movq TD_LOCK(%r12),%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(%r12)
jnz do_kthread
/*
* Load ldt register
*/
movq TD_PROC(%r12),%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 %r12,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,%rax
movq %rax,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)
movl $MSR_EFER,%ecx
rdmsr
movl %eax,PCB_EFER(%rdi)
movl %edx,PCB_EFER+4(%rdi)
movl $MSR_STAR,%ecx
rdmsr
movl %eax,PCB_STAR(%rdi)
movl %edx,PCB_STAR+4(%rdi)
movl $MSR_LSTAR,%ecx
rdmsr
movl %eax,PCB_LSTAR(%rdi)
movl %edx,PCB_LSTAR+4(%rdi)
movl $MSR_CSTAR,%ecx
rdmsr
movl %eax,PCB_CSTAR(%rdi)
movl %edx,PCB_CSTAR+4(%rdi)
movl $MSR_SF_MASK,%ecx
rdmsr
movl %eax,PCB_SFMASK(%rdi)
movl %edx,PCB_SFMASK+4(%rdi)
sgdt PCB_GDT(%rdi)
sidt PCB_IDT(%rdi)
sldt PCB_LDT(%rdi)
str PCB_TR(%rdi)
movl $1,%eax
ret
END(savectx)
/*
* resumectx(pcb)
* Resuming processor state from pcb.
*/
ENTRY(resumectx)
/* Switch to KPML4phys. */
movq KPML4phys,%rax
movq %rax,%cr3
/* Force kernel segment registers. */
movl $KDSEL,%eax
movw %ax,%ds
movw %ax,%es
movw %ax,%ss
movl $KUF32SEL,%eax
movw %ax,%fs
movl $KUG32SEL,%eax
movw %ax,%gs
movl $MSR_FSBASE,%ecx
movl PCB_FSBASE(%rdi),%eax
movl 4 + PCB_FSBASE(%rdi),%edx
wrmsr
movl $MSR_GSBASE,%ecx
movl PCB_GSBASE(%rdi),%eax
movl 4 + PCB_GSBASE(%rdi),%edx
wrmsr
movl $MSR_KGSBASE,%ecx
movl PCB_KGSBASE(%rdi),%eax
movl 4 + PCB_KGSBASE(%rdi),%edx
wrmsr
/* Restore EFER. */
movl $MSR_EFER,%ecx
movl PCB_EFER(%rdi),%eax
wrmsr
/* Restore fast syscall stuff. */
movl $MSR_STAR,%ecx
movl PCB_STAR(%rdi),%eax
movl 4 + PCB_STAR(%rdi),%edx
wrmsr
movl $MSR_LSTAR,%ecx
movl PCB_LSTAR(%rdi),%eax
movl 4 + PCB_LSTAR(%rdi),%edx
wrmsr
movl $MSR_CSTAR,%ecx
movl PCB_CSTAR(%rdi),%eax
movl 4 + PCB_CSTAR(%rdi),%edx
wrmsr
movl $MSR_SF_MASK,%ecx
movl PCB_SFMASK(%rdi),%eax
wrmsr
/* Restore CR0, CR2, CR4 and CR3. */
movq PCB_CR0(%rdi),%rax
movq %rax,%cr0
movq PCB_CR2(%rdi),%rax
movq %rax,%cr2
movq PCB_CR4(%rdi),%rax
movq %rax,%cr4
movq PCB_CR3(%rdi),%rax
movq %rax,%cr3
/* Restore descriptor tables. */
lidt PCB_IDT(%rdi)
lldt PCB_LDT(%rdi)
#define SDT_SYSTSS 9
#define SDT_SYSBSY 11
/* Clear "task busy" bit and reload TR. */
movq PCPU(TSS),%rax
andb $(~SDT_SYSBSY | SDT_SYSTSS),5(%rax)
movw PCB_TR(%rdi),%ax
ltr %ax
#undef SDT_SYSTSS
#undef SDT_SYSBSY
/* Restore debug registers. */
movq PCB_DR0(%rdi),%rax
movq %rax,%dr0
movq PCB_DR1(%rdi),%rax
movq %rax,%dr1
movq PCB_DR2(%rdi),%rax
movq %rax,%dr2
movq PCB_DR3(%rdi),%rax
movq %rax,%dr3
movq PCB_DR6(%rdi),%rax
movq %rax,%dr6
movq PCB_DR7(%rdi),%rax
movq %rax,%dr7
/* Restore other callee saved registers. */
movq PCB_R15(%rdi),%r15
movq PCB_R14(%rdi),%r14
movq PCB_R13(%rdi),%r13
movq PCB_R12(%rdi),%r12
movq PCB_RBP(%rdi),%rbp
movq PCB_RSP(%rdi),%rsp
movq PCB_RBX(%rdi),%rbx
/* Restore return address. */
movq PCB_RIP(%rdi),%rax
movq %rax,(%rsp)
xorl %eax,%eax
ret
END(resumectx)
|